Order-Fulfillment and Across-the-Dock Concepts, Design, and Operations Handbook

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Author: David E. Mulcahy | John Dieltz

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Order-Fulfillment and Across-the-Dock Concepts, Design, and Operations Handbook

SL0446_C00.fm Page 2 Wednesday, November 19, 2003 2:40 PM

Order-Fulfillment and Across-the-Dock Concepts, Design, and Operations Handbook David E. Mulcahy and John Dieltz

ST. LUCIE PRES S A CRC Press Company Boca Raton London New York Washington, D.C.


Library of Congress Cataloging-in-Publication Data Mulcahy, David E. Order fulfillment and across the dock concepts, design, and operations handbook / David E. Mulcahy, John Dieltz. p. cm. Includes index. ISBN 1-57444-044-6 1. Physical distribution of goods—Management—Handbooks, manuals, etc. 2. Warehouses—Management—Handbooks, manuals, etc. 3. Business logistics—Management—Handbooks, manuals, etc. I. Dieltz, John. II. Title. HF5415.7.M85 2003 658.7¢88—dc22

2003066730

This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage or retrieval system, without prior permission in writing from the publisher. The consent of CRC Press LLC does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Specific permission must be obtained in writing from CRC Press LLC for such copying. Direct all inquiries to CRC Press LLC, 2000 N.W. Corporate Blvd., Boca Raton, Florida 33431. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation, without intent to infringe.

Visit the CRC Press Web site at www.crcpress.com © 2004 by CRC Press LLC St. Lucie Press is an imprint of CRC Press LLC No claim to original U.S. Government works International Standard Book Number 1-57444-044-6 Library of Congress Card Number 2003066730 Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 Printed on acid-free paper


Preface The objective for writing this practitioner (practical how-to-do-it) book is to provide warehouse and distribution professionals with a handbook that contains insights and tips to make their order-fulfillment or across-the-dock operation more efficient and cost effective. The chapters focus on a specific order-fulfillment classification or across-the-dock operation. The arrangement or focus of each chapter on a particular topic provides a reader with a quick and easy reference. These chapters cover equipment applications, concepts, and practices that are considered for implementation whether your operation is a large-, medium- or small-size business. The book contains illustrations, forms, and tables that assist in developing your order-fulfillment or across-the-dock operation to (1) reduce product damage, (2) enhance product flow, (3) increase employee productivity, (4) improve customer service, (5) reduce operating costs and improve profits, (6) maintain on-schedule deliveries, and (7) assure asset protection. It is necessary to understand that the purpose of the book is to help develop the skill and knowledge of its readers to design, organize, and operate a material handling or product transportation concept. Since the profession of order-fulfillment operations and across-the-dock operations management, material handling concept design and logistics is constantly changing, the book may not include the latest changes in the state-of-the-art references to new technologies, the various equipment applications, or material handling concepts. It is also necessary to recognize that this book cannot cover all the available equipment applications, technologies, and material handling concepts in the field of warehouse distribution, order-fulfillment, and across-the-dock operations. The book does assist in the training and obtaining of practical experience which has no substitute. To assist in this objective, line art illustrations and sketches are used to visually present a piece of equipment or material handling concept. It is important for the reader to use the collection of data, concepts, and forms as a guide. Prior to the purchase and installation of your new order-fulfillment or across-the-dock concept or equipment, it is essential that you develop and project correct, accurate, and adequate facility, inventory, stock-keeping units (SKUs), transactions data, and design factors. Because these are the design bases for your proposed order-fulfillment or across-the-dock equipment application or facility, it is prudent for you to gather and review vendor literature and to visit existing facilities that utilize the order-fulfillment or across-the-dock concept or equipment application. These activities permit you to become familiar with the operational characteristics of the order-fulfillment or across-the-dock concept or equipment application that is under consideration for implementation in your facility. The concept and performance specifications, physical design, and installation characteristics are subject to


redesign, improvement, and modification. They are also required to meet vendor, local, and governmental standards and specifications. Each chapter of this book deals with key aspects and issues of planning and managing an order-fulfillment or across-the-dock operation. Some of these issues are: how your facility layout and product location affects employee productivity; when to use the 80/20 rule and where to locate your power SKUs; how to route your order pickers and organize their work for the best productivity; how to determine the best small-item, hanging garment, carton, and pallet load pick concept; how to control the batch release; how to determine what is required for an acrossthe-dock operation; how to choose the most efficient and cost effective small-item, hanging garment, carton and pallet load pick concept for business; how to the identify the pick position; how to control pick position replenishment; how to choose the best sortation concept for your business. Most logistics professionals have learned from their experience with a preplanned and organized order-fulfillment or across-the-dock operation so that they have increased accurate and on-time deliveries, reduced costs, and improved profits. By getting and maintaining an order-fulfillment or across-the-dock concept as outlined in the book, it will improve your existing order-fulfillment or across-the-dock operation and provide future strategies for your next warehouse or plant facility. The authors would like to express their thanks to all material handling, warehouse and distribution, and logistics professionals with whom they have had an association at various companies, as fellow managers, as clients, as speakers at seminars, and as publishers. David E. Mulcahy John P. Dieltz


Authors David E. Mulcahy has been with QVC Corporation since 1999. He earned a B.S. degree in business administration from Salem (Massachusetts) State College and an M.B.A. degree from the University of Dallas. He has more than 30 years of increasingly responsible experience in all aspects of order-fulfillment and across-the-dock operations and international supply chain management. A prolific author and speaker, this is his third book. John P. Dieltz is currently employed as an application engineer for the Kingway Inca Clymer Material Handling Company. He earned an undergraduate degree in engineering from South Dakota State University and a Master’s degree in industrial engineering from Iowa State University. He has more than 10 years of experience in distribution working on order-fulfillment solutions for companies shipping different types of products.


SL0446_bookTOC.fm Page 9 Wednesday, November 19, 2003 2:41 PM

Contents Chapter 1

Order-Fulfillment and Across-the-Dock Strategic Considerations......1

Introduction ......................................................................................................1 Piece and Information Flows ...........................................................................2 Economic Value................................................................................................3 Order-Fulfillment or Across-the-Dock Operation Serves Your Company ......3 Order-Fulfillment or Across-the-Dock Operation Resources..........................3 Company Order-Fulfillment or Across-the-Dock Operational Objectives......4 Important Order-Fulfillment or Across-the-Dock Trends and Issues .............4 E-Commerce and the Internet..........................................................................4 Overview ..........................................................................................................5 Chapter 2

Order-Fulfillment and Across-the-Dock Objectives and Their Impact on Your Company’s Profit and Customer Service ..................7

Introduction ......................................................................................................7 Order-Fulfillment Activities .............................................................................7 Across-the-Dock Activities ..............................................................................7 Piece-Handling Characteristics .......................................................................8 Order-Fulfillment Operation Objective............................................................9 Across-the-Dock Operation Objective.............................................................9 Order-Fulfillment and Across-the-Dock Operation Activities ........................9 Yard Control .........................................................................................10 Unloading .............................................................................................11 Verifying Piece Quality and Quantity..................................................11 Receiving ..............................................................................................11 Piece Identification ...............................................................................12 Packaging..............................................................................................12 Horizontal or Vertical Transportation...................................................13 Storage ..................................................................................................13 Deposit..................................................................................................13 Inventory Control..................................................................................13 IMS Customer-Order Download ..........................................................13 Carton or Shipping Container Makeup................................................14 Customer-Order Pick............................................................................14 Sorting...................................................................................................15 Replenishment ......................................................................................15 Packaging..............................................................................................16 Package Sealing....................................................................................16 Package Weighing and Manifest ..........................................................17


Loading and Shipping Activities..........................................................17 Customer Return, Out-of-Season, and Transfer ..................................17 Across-the-Dock Operations ................................................................18 Maintenance, Sanitation, and Security.................................................18 On-Schedule and Accurate Performance of an Order-Fulfillment or Across-the-Dock Operation and Customer Delivery Activities Means Profits and Satisfied Customers .....................................................................18 Why Is an Accurate, Efficient, and Cost-Effective Order-Fulfillment or Across-the-Dock Operation Important?...........................................19 What Is the Standard for a Good Order-Fulfillment or Across-the-Dock Operation? ................................................................19 How to Improve Your Order-fulfillment or Across-the-Dock Operation......20 Look at the Employee Numbers ..........................................................20 Develop a Standard ..............................................................................21 Use Batched Customer Orders and Dual-Cycle Activities..................21 Reduce Travel Time and Distance .......................................................22 Improve the SKU Hit Concentration and Hit Density ........................22 Use ABC or Power SKU Allocation....................................................23 Use Kit or Family Group SKUs ..........................................................24 Keep It Simple and Clear.....................................................................24 Use Sequential Order Pick Patterns .....................................................25 Cube the Order Picker Activity or Automatic Pick Requirement .......25 Smooth or Level the Work Volume......................................................26 Use Part-Time Employees....................................................................26 Apply the Golden Zone or Proper Elevation and Location of the Pick Position .........................................................................................27 Change from Paper Pick Document to Self-Adhesive Label, Paperless, or Automatic Pick Method..................................................27 Develop a Good Equipment and Facility Layout and Flow Pattern ...................................................................................................28 Maintain Clear Aisles and Practice Good Housekeeping....................28 Maintain Good Lighting in the Pick Aisle or Pick Line.....................28 Change Your Employee Work from a Human-Paced Method to a Machine-Paced Method........................................................................29 Add Material Handling or Piece Transportation Equipment to Your Employee Work ....................................................................................29 Use Automatic Identification................................................................30 Provide Sufficient Work .......................................................................30 Use the Pick and Pack Method for High Volume of a Few SingleItem or Flat Wear Apparel SKUs for Single-Customer Orders ..........30 Ensure On-Time and Accurate Pick Position Replenishment .............31 Determine Where to Start the Single-Item Order Pickers...................31 Have an Arithmetic Progression through a Pick Aisle or along the Pick Line...............................................................................................32 Pick Position Numbers That End with Even Numbers on the Right and Pick Position Numbers That End with Odd Numbers on the Left ..... 33


Increase Your Employee Pride .............................................................33 Implement a Work Incentive Program .................................................34 Controlling Your Order-Fulfillment or Across-the-Dock Operation....34 Employee Productivity Must Be Tied to Your Order-Fulfillment and Across-the-Dock Operation..................................................................35 Short-Interval Scheduling ..............................................................................35 SIS for Your Order-Fulfillment or Across-the-Dock Activities ...........36 How SIS Works ....................................................................................36 How to Project Your Order-Fulfillment or Across-the-Dock Operating Budget ............................................................................................................37 Annual Order-Fulfillment or Across-the-Dock Operating Expense Budget Methods ...................................................................................37 Why Have Capital Investments?....................................................................43 What Is the Capital Expenditure Justification? ...................................43 How Depreciation Expense Affects Your Company Income Statement and Balance Sheet ................................................................................43 How Does Your Employee Productivity Affect Your Company’s Income Statement? ......................................................................................................44 What Does Good Employee Productivity Mean to Your Company’s Income Statement? ...............................................................................44 Reasons for Economic Justification Factors..................................................44 Economic Justification Process ............................................................45 Order-Fulfillment or Across-the-Dock Method Alternatives ...............45 What Is the Useful Life?......................................................................45 What Is the Rate of Return? ................................................................46 What Are the Inflation Rate and Growth Rate? ..................................46 What Are the Economic Factors? ........................................................47 What Are the Noneconomic Factors? ..................................................47 Quantify the Economic and Noneconomic Factors.............................47 Order-Fulfillment and Across-the-Dock Method Implementation and Project Management ......................................................................................47 Order-Fulfillment or Across-the-Dock Method Project Management Activities...............................................................................................47 How to Estimate Costs, Write Functional Specifications, Review Bids, Administer Contracts, and Implement Your Order-Fulfillment or Across-the-Dock Method .....................................................................48 When and How to Select and Use a Consultant ...........................................90 Where Do You Find Assistance for Your Operation?..........................90 Providing Accurate and On-Time Operational Design Information...............................................................................90 Internal (In-House) Expert ...................................................................90 External or Outside Consultant............................................................91 Order-Fulfillment or Across-the-Dock Equipment Vendors ................91 What Are the Signals That Your Operation Requires a Consultant?...91 What Are the Activities That Require an External Consultant? .........92 What Should Your Consultant Examine?.............................................92


Who from Your Company Should Work on Your Project? ........................................................................................92 Order-Fulfillment or Across-the-Dock Project Team Organization.....92 Where Do You Find Consultants?........................................................93 Insights for Your Consultant Selection Process...................................94 Projects That Involve Consultants........................................................94 What Information Does Your Consultant Require for Your Project? .................................................................................................94 Why Is High Employee Productivity Important?..........................................95 What Is Employee Productivity? .........................................................95 What Are the Business Factors That Affect Your Productivity? .........95 Areas for Employee Productivity Improvement ..................................96 Guidelines for a Successful Employee Productivity Program ............98 Employee Hours Must Be Consistent................................................102 Seven Order-Fulfillment or Across-the-Dock Ratios...................................103 Order-Fulfillment or Across-the-Dock Employee (Labor) Ratio ......103 Direct-Employee Handling Loss Ratio ..............................................104 Piece or Customer-Order Movement or Operation Ratio .................104 Customer-Order-Fulfillment Cycle Efficiency Ratio .........................105 Space-Utilization Efficiency Ratio.....................................................105 Equipment Utilization Ratio ..............................................................106 Aisle-Space Potential Ratio................................................................106 Keep It Simple .............................................................................................107 It Must Be Cost Effective ............................................................................107 Results Must Be Timely ..............................................................................107 Various Measurement Standards..................................................................107 Agreed-Upon or Budgeted Standard..................................................108 Industry Standard................................................................................108 Your Company Standard ....................................................................108 Time-Study Standard..........................................................................108 Regression Analysis............................................................................108 Employee Productivity Is Tied to Your Annual Expense Budget...............109 Chapter 3

Order-Fulfillment Systems ...............................................................111

Introduction ..................................................................................................111 The Basics of Split-Case Order Picking .....................................................111 Put System Basics........................................................................................113 Other Product Issues ....................................................................................113 Storage or Picking Medium.........................................................................113 Static Shelving....................................................................................113 Carton Flow Racks .............................................................................114 Pallet Flow Lanes ...............................................................................117 Picking Modules.................................................................................117 General Pick-Line Layout............................................................................118 Types of Order-Fulfillment Systems............................................................118


Cart Systems.......................................................................................120 Pick-to-Paper Systems........................................................................120 Radio Frequency Scanner and Voice Systems...................................121 A-Frame Systems ...............................................................................123 Tilt-Tray or Cross-Belt Sorter Systems .............................................126 Carousel Systems................................................................................129 Carousel Put Systems .........................................................................132 Pick-to-Light and Pick-to-Display Systems.......................................132 Put-to-Display Systems ......................................................................137 Complex Picking Systems..................................................................138 Check Weighing .................................................................................139 Summary ......................................................................................................139 Chapter 4

Garment-on-Hanger Order-Fulfillment Operations .........................141

Introduction ..................................................................................................141 Hanging Garment or GOH Item..................................................................142 Base Operational Data and Pick-Area Information..................................................................................142 Peak, Average, and Most Frequent GOH or Customer-Order Volumes .....143 Peak, Average, and Most Frequent GOH Piece or Customer-Order Volumes ..............................................................................................143 Facility Design Information and Considerations.........................................144 SKU Location on the Pick Line or in the Pick Aisle .................................147 GOH SKU Allocation or Profile Methods ..................................................148 Random or Mixed Method.................................................................148 Separation by Length .........................................................................148 Separation by Season and GOH Length............................................149 Pick-Area Design .........................................................................................149 Building Considerations...............................................................................149 Building Shape ...................................................................................150 Building Height ..................................................................................151 Pick-Line or Pick-Aisle Design...................................................................151 GOH Piece and Customer-Order Flow ..............................................151 Drawings.............................................................................................153 List of Activities...........................................................................................154 Pick-Line or Pick-Aisle Design Parameters................................................154 GOH Pick-Line or Pick-Aisle Sequence of Activities ................................155 GOH Receiving and Unloading...................................................................156 GOH Unloading Methods ..................................................................157 Flat-Packed Garment to GOH Methods.............................................159 GOH Sort-and-Count Activity .....................................................................160 GOH Cart Method..............................................................................161 Nonpowered Trolley Rail Method .....................................................161 Other GOH Dock-Area Handling Considerations ......................................161 Grouping Three or Five Pieces into One Bundle ..............................162


Quality Assurance ........................................................................................162 Hanging-Garment Steaming ........................................................................162 Manual Steaming................................................................................162 Automatic Steaming ...........................................................................163 Plastic Bag Bottoms.....................................................................................163 Open Plastic Bag Bottom...................................................................164 Secure Plastic Bag Bottom.................................................................164 Hanging-Garment Bagging Activity ............................................................164 Manual Bagging .................................................................................164 Automatic Bagging.............................................................................165 GOH In-House Transportation.....................................................................165 Horizontal GOH Transportation ..................................................................165 Objectives ...........................................................................................165 Design Parameters ..............................................................................166 Nonpowered Horizontal Transportation ......................................................167 Horizontal Transportation Methods ...................................................167 Above-Floor Nonpowered Horizontal Transportation Group............168 Overhead Nonpowered Horizontal Transportation Group.................174 Powered Horizontal Transportation Group ........................................196 Trolleyless GOH Transport Concepts..........................................................217 Various Trolleyless GOH Transport Concepts...................................217 Vertical GOH Transportation .......................................................................226 Vertical Transportation Objectives .....................................................226 Vertical Transportation Design Parameters........................................227 Computer Simulation of a GOH Transportation System ..................228 Vertical Transportation Design Factors..............................................228 Various Vertical Transportation Systems ...........................................229 GOH Static-Rail Storage and Pick Methods.........................................................................................242 Various GOH Storage and Pick Design Parameters and Key Components ........................................................................................242 GOH Storage and Pick Position Design Considerations...................242 GOH Storage and Pick Rail Capacity ...............................................243 Various Static-Rail Storage and Pick Methods..................................243 Hanging Garment Storage and Order-Fulfillment Methods........................254 Employee Travels to the Pick Position ..............................................255 Stock Travels to a Pick-Position Method ..........................................266 GOH Order-Picker Routing Patterns ...........................................................277 Overhead Trolley Picking in the Pick Aisle ......................................277 Storage and Pick-Area Design Considerations ...........................................278 Types of Pick Position........................................................................278 GOH SKU Location in the Pick Aisle...............................................279 Pick-Aisle Characteristics ..................................................................281 Aisle Direction of Flow......................................................................281 Various In-House Hanging Garment Transportation Methods ...................288 GOH Cart Method..............................................................................288


Nonpowered Overhead Trolley Method.............................................288 Trolleyless Method .............................................................................288 Tote on a Nonpowered or Powered Conveyor...................................289 Completed Customer-Order Package Take-Away Method................289 Customer-Order Check Methods .......................................................293 Packing Instruction and Shipping Label Preparation ........................294 Hanging Garment Packing Considerations ........................................295 Chapter 5

Planning a Carton or Full-Case Order-Fulfillment Operation ........303

Introduction ..................................................................................................303 Carton or Handling Unit ..............................................................................303 Base Operational Data and Pick-Area Information..................................................................................303 Peak, Average, and Most Frequent Carton or Customer-Order Volumes ..............................................................................................304 Facility Design Information and Considerations.........................................306 Carton Order-Fulfillment Facility Layout Considerations ..........................307 Layout Philosophies and Principles ...................................................308 SKU Location on the Pick Line or in the Pick Aisle .................................318 Pick-Area Design .........................................................................................319 Pick-Line or Pick-Aisle Design .........................................................319 Carton and Customer-Order Flow......................................................319 Drawings.............................................................................................321 Pick-Line or Pick-Aisle Design Parameters................................................322 Purpose of a Carton Order-Fulfillment Operation ......................................323 Carton Order-Fulfillment Activities .............................................................323 Truck Yard Control Activity...............................................................324 Unloading Activity .............................................................................324 Receiving and Checking Activities ....................................................325 Identification Activity .........................................................................325 Internal Transportation Activity .........................................................326 Deposit in Storage Activity ................................................................326 Picking and Identification Activity ....................................................326 In-House Transportation Activity.......................................................326 Sorting Activity ..................................................................................326 Storage Withdrawal and Replenishment Activity ..............................326 Manifesting Activity ...........................................................................327 Loading and Shipping Activity ..........................................................327 Customer-Returns Activity .................................................................327 Order-Pick Activity.............................................................................327 Various Order-Pick Methods..............................................................330 Employee and Picked-SKU In-House Transportation Methods........340 Order-Picker Routing Patterns .....................................................................359 No Routing Pattern.............................................................................359 Sequential Routing Patterns ...............................................................359


Disadvantages and Advantages of Electric Pallet Trucks ...........................364 Order Instruction ..........................................................................................364 Keep It Simple and Clear...................................................................364 Information on the Order-Pick Instruction ........................................365 Various Order-Pick Instructions .........................................................366 Paperless Order-Picking Methods ......................................................367 Pick-Position Identification..........................................................................368 No Method..........................................................................................369 Manual Printing on the Carton ..........................................................369 Manually Printed Label on the Carton or Pick Position ...................370 Preprinted Self-Adhesive Label .........................................................370 Human- and Machine-Readable Cardboard or Paper Label in a Holder ..............................................................................................370 Placard Hung from the Ceiling or Embedded in the Floor...............370 Digital Display on the Pick Position or Structure.............................371 Digital Display on the RF Device .....................................................371 Electric Tractor or Tugger Method..............................................................371 Various Tow Tractors or Tuggers .......................................................371 Powered Forklift-Truck Method ..................................................................374 Order-Picker Trucks or HROS.....................................................................374 Rail Guidance...............................................................................................375 Aisle Entry Guides .............................................................................375 Rail Installation Parameters ...............................................................375 Electronic Guidance Group................................................................377 When to Use Rail or Wire Guidance.................................................379 End-Of-Aisle Vehicle Slowdown Devices ...................................................379 Vehicle Slowdown Methods...............................................................380 Carton High-Rise Order-Picker Trucks .......................................................381 Order-Picker Truck with a Carton Load-Carrying Surface ...............382 Counterbalanced Truck.......................................................................382 Straddle Truck ....................................................................................382 Platform Truck....................................................................................382 VNA Truck .........................................................................................382 Order-Pick Devices ......................................................................................383 High-Rise Truck Routing Methods .............................................................383 One-Way High-Rise Order-Picker Truck Routing Pattern ................384 Two-Way High-Rise Order-Picker Truck Routing Pattern................384 HROS Considerations ..................................................................................385 Methods in Which an Employee Walks to Pick Positions and Picked Cartons Are Transported Away ....................................................................385 Batched or Grouped Customer Orders ..............................................386 Batch Control Methods ......................................................................386 Batch Release Methods ......................................................................387 How to Determine the Carton Quantity per Batch............................388 Pick Faces or Positions ......................................................................389 Pallet Orientation................................................................................389


Pallet Height .......................................................................................389 Various Employee Pick-to-Powered Conveyor Methods ............................390 Standard Pallet Rack, Parallel to the Pick Conveyor ........................390 Standard Pallet Rack, Perpendicular to the Pick Conveyor ..............391 Carton Flow Rack or Decked Pallet Rack.........................................392 Pallet Flow Rack, Parallel to the Pick Conveyor ..............................393 Pallet Flow Rack, Perpendicular to the Pick Conveyor ....................395 Pick Tunnel ..................................................................................................396 Underside Deck or Netting ..........................................................................396 Determining the Carton-Conveyor Travel Path ...........................................396 How to Cross the Carton-Conveyor Travel Path .........................................397 Safety Gate .........................................................................................398 Stairs and Platform .............................................................................398 Stile .....................................................................................................398 Ships Ladder with Slats between Conveyor Rollers .........................398 Carton Travel on a Conveyor Travel Path ...................................................399 Skewed Rollers ...................................................................................399 Sleeve-Wrapped or Taped Rollers......................................................399 Angled Deflector ................................................................................399 Empty-Pallet Return.....................................................................................400 Order-Picker Removal of the Empty Pallet .......................................400 Empty-Pallet Guide Path ....................................................................400 Powered Mechanical Pallet-Flow Method .........................................401 Manually Controlled Overhead Powered Mechanical Hoist with a Set of Hooks....................................................................................401 Empty-Pallet Position ..................................................................................401 Elevated Employee Walkway.......................................................................402 Solid-Deck Walkway ..........................................................................402 Open-Deck or Grated-Deck Walkway ...............................................402 Stairs.............................................................................................................403 Order-Picker Routing Pattern ......................................................................403 Order-Picker Instruction Method.................................................................403 Sorting Method ............................................................................................403 Sorting to Temporary Storage and Shipping Area.............................404 Direct-Loading Method ......................................................................405 Shipping Cartons on Carts or Pallets.................................................405 Various Sorting Types ........................................................................405 Sorting Is the Heart of the Batched Order-Pick Method ..................406 Employee Rides to Pick Positions and Picked Cartons Are Transported Away.............................................................................................................412 Pick Car ..............................................................................................413 Decombe Truck ..................................................................................413 Stock-to-Employee Pick Methods ...............................................................414 Carton Carousel ..................................................................................414 Cart Carousel ......................................................................................415 S.I. Cartrac..........................................................................................415


Sort Link.............................................................................................416 Storage Area or ASRS Front-End ......................................................416 Mini-Load ...........................................................................................418 Automatic Order-Pick Methods...................................................................419 S.I. Ordermatic ...................................................................................419 Vertique...............................................................................................421 Nonconveyable or Very-Large-SKU Order-Pick Methods ..........................422 Various Nonconveyable Carton Pick Methods ..................................422 Nonconveyable Carton Pick Vehicles ................................................422 Nonconveyable Picked-Carton Flow..................................................425 Arrangement of the Pick Positions ....................................................426 Carton or Pallet Replenishment...................................................................427 Types of Pick Position .................................................................................427 Fixed Pick Position.............................................................................427 Floating Pick Position ........................................................................428 Put-Away and Withdrawal Transaction-Verification and Inventory-Tracking Methods........................................................................................................428 Human Memory..................................................................................428 Handwritten Paper Document ............................................................428 Manual File.........................................................................................429 Bar-Code Scanning.............................................................................429 Various Replenishment Methods .................................................................430 Random Replenishment......................................................................430 Slug Replenishment............................................................................430 Sweep Replenishment ........................................................................430 WMS Replenishment..........................................................................431 SKU Allocation to the Pick Area ................................................................431 No Method..........................................................................................431 ABC Method ......................................................................................431 Family Group......................................................................................432 Various Replenishment Quantities...............................................................432 Pallet ...................................................................................................432 Replenishment of One Layer of a Pallet ...........................................432 Replenishment of Less Than One Layer of a Pallet .........................433 Various Timing Methods for Replenishment ..............................................433 Manual Method ..................................................................................433 Computer Method...............................................................................433 Chapter 6

Pallet Order-Fulfillment Operations ................................................435

Introduction ..................................................................................................435 Base Operational Data and Area Information .............................................435 Peak, Average, and Most Frequent Pallet Volumes or Customer-Order Volumes ..............................................................................................436 Facility Design Information and Considerations.........................................438 SKU Location in the Storage/Pick Area .....................................................440


Pallet Storage-Area Design..........................................................................440 Pallet Flow ...................................................................................................441 Horizontal One-Way Flow Pattern.....................................................443 Horizontal Two-Way Flow Pattern.....................................................443 Drawings ......................................................................................................444 Block Drawing....................................................................................444 Plan-View Drawing ............................................................................444 List of Activities...........................................................................................444 Pallet Rack-Row and Vehicle-Aisle Design Parameters .............................445 Pallet-Handling Sequence Of Activities ......................................................446 Schedule and Yard Control of Vendor and Customer Delivery Trucks ......446 Receiving and Shipping Dock Locations ....................................................447 Combination Docks ............................................................................447 Separated Docks .................................................................................448 Scattered Docks ..................................................................................448 Truck Access to the Docks.................................................................449 Truck Traffic-Flow Patterns .........................................................................450 One-Way Pattern.................................................................................450 Two-Way Pattern ................................................................................450 Delivery-Truck Holding Area ......................................................................450 Block Method .....................................................................................450 45˚-Angle Method ..............................................................................451 Back-To-Back and Side-To-Side Method ..........................................451 Landing Gear Pad ........................................................................................451 Other Important Truck Features ..................................................................451 Truck-Yard Security .....................................................................................451 Truck Loading and Maneuvering Areas ......................................................452 Truck Dimensions for Docks.......................................................................453 Truck Dock Design Factors .........................................................................453 Flush-Dock Designs ...........................................................................454 Open-Dock Design .............................................................................455 Enclosed-Dock Design .......................................................................455 Side-Loading or Finger Docks...........................................................456 Drive through the Facility ..................................................................456 Staggered or Saw-Tooth Dock ...........................................................456 Pier Dock ............................................................................................457 Freestanding Dock or Dock House....................................................457 Mobile Yard Ramp .............................................................................457 Other Dock Design Features ..............................................................457 Unloading and Loading Methods ................................................................466 Manual Unloading and Loading Methods .........................................466 Mechanical Unloading and Loading Methods...................................469 Automatic Unloading and Loading Methods ....................................471 Railcar Unloading and Loading Methods ...................................................472 Various Railcar Dock Designs.....................................................................473 Flush Dock .........................................................................................473


Rail Platform Dock ............................................................................473 Inside Rail Dock.................................................................................474 Mobile or Remote Dock Ramp..........................................................474 Single Railcar Unloading.............................................................................474 Controlled or Selective Railcar Unloading ........................................475 Double Railcar Unloading..................................................................475 Various Railcar Dock Board Designs to Bridge The Gap ..........................475 Portable Dock Board ..........................................................................475 Vertically Stored Dock Board ............................................................475 Portable Railcar to Railcar Dock Board ............................................476 Bascule Bridge .............................................................................................476 Railcar Dock-Area Options .........................................................................476 Pallet Unloading Activity.............................................................................476 Floor-Stacked Method ........................................................................477 Pallet-Board Method ..........................................................................477 Slip-Sheet Method ..............................................................................477 Container Method...............................................................................478 Pallet Receiving Activity .............................................................................479 Need for Sufficient, Clear Finished-Floor Space and Aisles ......................479 How to Project the Required Number of Docks .........................................480 Manual Calculation ............................................................................480 Manual Simulation .............................................................................480 Computer Simulation .........................................................................480 How to Determine the Dock-Area Size ......................................................481 Mobile Truck Paths ............................................................................481 Pallet Staging Area .............................................................................481 Four Important Rack and Facility Dimensions ...........................................484 Clear Space between Two Building Columns ...................................484 Clear Space between the Finished-Floor Surface and the Lowest Ceiling Obstruction ............................................................................485 Pallet Load Dimensions .....................................................................485 Pallet Load Bottom Support Device ..................................................486 Other Important Clearances or Open Spaces ..............................................486 Ceiling Clearance for Fire Sprinklers..........................................................486 Clearance between Two Pallets and Rack Support Members ...........487 Clearances for a Straddle Forklift Truck ...........................................487 A Rack-Supported Building Means a Wider Rack Base Plate .........487 Flue or Open Space between Back-to-Back Racks or Walls ............488 Finished-Floor Stacked Pallet Clearance ...........................................488 With a Tall-Rack Facility, Allow for Baffle Levels and Additional Sprinkers .............................................................................................488 White Space along the Wall for a Food Facility ...............................488 Conveyors Adjacent to a Building Column Require Open Space ....488 Other Factors That Affect Employee Productivity......................................489 Physical Components of a Pallet Storage/Pick Method..............................489 Pallet Load..........................................................................................489


Pallet Load-Handling Vehicle.............................................................503 Pallet Load Storage/Pick Position Methods ......................................523 Pallet Identification.............................................................................540 In-House Transportation Methods ...............................................................549 Human-Powered Pallet Truck ............................................................549 Powered Pallet Truck..........................................................................549 Forklift Truck......................................................................................549 Powered Vehicle with a Train of Carts ..............................................549 AGV....................................................................................................550 Chapter 7

Single-Item, GOH, Carton, or Pallet Across-the-Dock Operations ........................................................................................563

Introduction ..................................................................................................563 Across-the-Dock Definition .........................................................................565 Objective of an Across-the-Dock Operation ...............................................565 What Is Required .........................................................................................566 Who from Your Company Is Involved ........................................................566 The Vendor Responsibility...........................................................................567 Piece or Customer Identification .................................................................567 Human-Readable Identification..........................................................568 Machine-Readable Identification........................................................569 Human- and Machine-Readable Identification ..................................569 Across-the-Dock Formats and Piece Flow Methods ...................................571 Manufacturing Cross-Docking Method .............................................572 Distribution Cross-Docking Method..................................................573 Terminal Cross-Docking Method.......................................................573 Various Across-the-Dock Piece Characteristics ..........................................574 Unsorted and Unlabeled Pieces .........................................................574 Unsorted and Labeled Pieces .............................................................574 Sorted and Labeled Pieces .................................................................575 Receiving and Shipping Dock Areas Are Most Important..........................575 Receiving and Shipping Dock Projections and Other Considerations .......577 Required Truck Dock Number...........................................................577 Required Number of Shipping or Customer Delivery-Truck Docks ..................................................................................................581 Receiving and Shipping Dock Staging Area or Conveyor Network ..............................................................................................581 Delivery Truck Access to the Truck Docks .......................................581 Truck-Yard Traffic-Flow Patterns.......................................................583 Delivery-Truck Temporary Holding Area ..........................................583 Landing-Gear Pad...............................................................................584 Truck-Yard Security ...........................................................................585 Delivery-Truck Canopy ......................................................................585 Delivery-Truck Unloading and Maneuvering Area ...........................585 Delivery-Truck Dimensions for the Docks........................................586


Other Important Delivery-Truck Yard Features .................................587 Delivery Truck Dock Design Factors ................................................587 Unloading Method .......................................................................................605 Manual-Unloading Methods...............................................................605 Mechanical-Unloading Methods ........................................................607 Piece Change................................................................................................627 Small-Item Across-the-Dock Operation Customer-Order and Shipping Piece ....................................................................................627 Small-Item, Flat Wear, or GOH Across-the-Dock Operation .....................628 Master-Carton Open Activity .............................................................628 SKU Ticketing ....................................................................................628 Various Small-Item, Flat Wear, and GOH Across-the-Dock Sorting Methods ..............................................................................................630 Across-the-Dock Small-Item or Flat Wear Apparel or Customer-Order Sorting.................................................................................................630 Packing Verification............................................................................638 Filling the Customer Shipping Container Voids................................639 Seal the Customer Shipping Container..............................................639 Shipping Address on the Customer Shipping Container...................639 Manifesting and Loading Customer Shipping Containers ................640 Handling GOH or Hanging Garments in an Across-the-Dock Operation ......................................................................................................641 Unloading of GOH .............................................................................642 Handling Hanging Garments in Boxes ..............................................642 Unloading Objective...........................................................................642 GOH Sorting.......................................................................................643 Master-Carton Across-the-Dock Sorting Methods ......................................647 Carton Conveyor Transportation and Sorting Is the Heart of the Batched Across-the-Dock Method .....................................................648 Across-the-Dock Carton Sorting Design Parameters and Factors..........................................................................................648 Manual Across-the-Dock Carton Sorting Methods ...........................649 Mechanized Carton Sorting................................................................651 Various Sorting Surfaces or Conveyor Travel Paths..........................654 Mechanical Divert Component ..........................................................656 Various Divert Devices or Methods ...................................................656 Carton Conveyor Customer Shipping-Lane Design ..........................670 Conveyor Considerations....................................................................670 Temporary Hold Area of Across-the-Dock Sorted Cartons Method................................................................................................673 Across-the-Dock Shipping Sorting Method.......................................674 Direct or Fluid Load of Across-the-Dock Cartons ............................674 Separating Shipping Cartons into Units ............................................674 Mimic Display and Control Panel .....................................................675 Nonconveyable Across-the-Dock Carton Sorting ..............................675 Pallet or Unit-Load Across-the-Dock Methods...........................................681


Pallet as the Across-the-Dock Unit-Load Support Device................682 Important Pallet Dimensions..............................................................682 Basic Pallet Designs ...........................................................................683 Slip-Sheet............................................................................................683 Various Pallet Across-the-Dock Transportation Methods..................685 Various Forklift Trucks.......................................................................685 Index ......................................................................................................................691



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Order-Fulfillment and Across-the-Dock Strategic Considerations INTRODUCTION

This introductory chapter will: • • • • •

Identify key order-fulfillment and across-the-dock functions Look at piece and information flows Define terms used in the distribution industry to describe order-fulfillment and across-the-dock operations Outline the objectives of distribution operations Note the trends that are shaping order-fulfillment and across-the-dock operations and facilities

Order-fulfillment operations are similar across industry groups, whether the operation handles small items, flat wear, garments on hangers (GOH), cartons, or pallets. Each order-fulfillment operation performs most or all of the basic distribution activities. These activities include receiving operations, put-away and storage, order-fulfillment, shipping, and returns. Each activity can be broken into more specific tasks. Receiving operations consist of unloading vendor or customer delivery trucks and receiving, checking, and marking inbound merchandise. Put-away entails internal horizontal and vertical transportation to the storage/pick area, work station, or outbound staging area. Storage includes deposit, withdrawal, and replenishment transactions. Order-fulfillment consists of order picking or distribution, sorting and checking, packing, and sealing. Shipping operations comprise weighing, manifesting, loading, and shipping. Returns processing involves handling of returns, out-ofseason pieces, and customer transfers. Across-the-dock operations are also similar in all industry groups. Most, whether for small items, flat wear, GOH, cartons, or pallets, include the following components: • •

Controlling vendor or customer truck movement in the yard Unloading, counting, and (as required) checking and marking the merchandise

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2

Order-Fulfillment Concepts, Design, and Operations

• • • • • •

Applying a sorting label (as required) Internal horizontal or vertical piece transportation from the inbound dock area to a work station or sorting area Sorting onto the dock staging area or directly into the customer delivery vehicle Completing the manifest Performing the various store and hold activities for the residual inventory Performing maintenance, sanitation, and loss-prevention activities

PIECE AND INFORMATION FLOWS Piece and information flow patterns in order-fulfillment are similar to water flowing through a large funnel. The funnel’s mouth is wide and accepts a very large piece quantity and a great deal of information. Over several days or weeks a broad mix of pieces in various storage quantities from numerous vendors is delivered to your distribution facility on various delivery vehicles. The customer information flow for storage pieces or customer orders occurs on a daily basis (more frequent than the piece receipt) along with the piece receipt information that is sent to the distribution operation. These storage pieces are placed into the company’s inventory files along with the customer orders. The time frame for an order-fulfillment operation to complete a customer-order and delivery cycle is generally short — less than 24 hours for most operations. The time frame of the customer-order and delivery cycle is determined by top management, based on customers, geographic location, and customer delivery address. As pieces flow through the funnel, various value-added distribution activities are performed to ensure that the items satisfy customer needs and earn a profit for the company. With an increase in customers, orders, and value-added activities, the time available to perform these activities becomes increasingly shorter; this represents the funnel’s mouth. The funnel for across-the-dock piece and information flow is more streamlined because the across-the-dock operation does not enter pieces into inventory. Instead, the pieces inventory passes through the distribution facility to the customer. If there is a residual inventory after the across-the-dock operation, it is noted in the facility’s warehouse management system (WMS) inventory files and placed in the storage area. If customers require additional pieces, the customer orders are completed from this residual inventory and conventional store and hold flows apply to the inventory and information. With an across-the-dock operation, pieces arrive at the facility and are released to customers daily. This fast piece-flow, or non-store-and-hold, style of inventory management gives the piece and information flow a smaller funnel mouth. Another characteristic of the across-the-dock piece flow funnel shape is that the size of the funnel’s middle section is similar to that of the mouth and exit opening. This similar dimension is a result of the fact that pieces are constantly flowing through the funnel. At some across-the-dock operations where the customer delivery


Order-Fulfillment and Across-the-Dock Strategic Considerations

3

vehicle is held at the shipping dock until it has a full load, the funnel exit has a wider opening than the funnel mouth. The customer information flow for across-the-dock pieces or customer orders occurs on a daily basis as pieces arrive at the facility. When a vendor piece arrives at the receiving dock, the customer-order information is released — or has already been released — to the across-the-dock operation. This action allows pieces to flow from the receiving dock through the sorting system and onto the customer delivery vehicle.

ECONOMIC VALUE An order-fulfillment or across-the-dock operation has an economic value in a company. The operation ensures that the stock-keeping unit (SKU) inventory, or the flow through the supply-chain logistics system, receives time and place value. The value is summarized in the following statement: “Your order-fulfillment or across-the-dock operation ensures that the right piece is in the right condition, at the right place (work station or customer location), at the right time, in the right quantity, and at the right cost.” Order-fulfillment or across-the-dock operations contribute to company profits by reducing operational costs and by satisfying your customers.

ORDER-FULFILLMENT OR ACROSS-THE-DOCK OPERATION SERVES YOUR COMPANY Your order-fulfillment or across-the-dock operation helps your company achieve its objectives by performing the following services. First, it consolidates customer demand for pieces to achieve economies of scale. With today’s communication systems, your order-fulfillment or across-the-dock operations and customer delivery system can handle more customers and reduce the cost per piece. Second, it provides geographic piece distribution to your customers. The service ensures that your customer is receiving the best delivery cost per piece. Third, it provides the means for your company to flow pieces through its supply-chain logistics system. These pieces are produced throughout the year to accommodate seasonal demand. This service allows your company to reduce costs by purchasing large-scale piece quantities, providing your customers with the lowest piece cost and allowing for yearround demand.

ORDER-FULFILLMENT OR ACROSS-THE-DOCK OPERATION RESOURCES You can maximize your order-fulfillment or across-the-dock operation and customer delivery by efficient use of scarce resources, which in turn help you meet strategy objectives in the company supply chain. Available resources include facility layout; order-fulfillment systems; employees; land; owned or leased buildings; your management team; computers and software; piece vendors; customers; consultants; and order-fulfillment vendors, industry groups, and associations.


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COMPANY ORDER-FULFILLMENT OR ACROSS-THEDOCK OPERATIONAL OBJECTIVES The objectives of order-fulfillment or across-the-dock operations are to improve profits and provide customer service. To achieve these objectives, an order-fulfillment or across-the-dock operation tries to: • • • • • • • • •

Maximize facility use and customer carton or delivery vehicle space utilization Maximize order-fulfillment or across-the-dock system utilization Maximize employee utilization Reduce SKU handlings Maintain SKU accessibility Maintain the designed SKU rotation, also known as “inventory turns” Minimize logistics operational expenses Ensure company asset protection Ensure customer satisfaction

IMPORTANT ORDER-FULFILLMENT OR ACROSSTHE-DOCK TRENDS AND ISSUES The important order-fulfillment or across-the-dock operational trends and issues are: • • • • • • • •

New technologies and computer controls Automatic identification Pick position just-in-time replenishment Equipment and labor flexibility Maintenance of smaller inventories with material requirements planning (MRP) and distribution requirements planning (DRP) Use of mechanized or automatic machines Contract or third-party operations (3P) Customer-order mix and size changes with the increasing use of E-commerce

These factors have had an increasing impact on today’s order-fulfillment or across-the-dock operations, and will affect new operations and facilities planned for the year 2010. These new operations and facilities are designed to provide on-time and fast-response customer-order deliveries, handle a wide piece mix and SKU quantity, handle a smaller customer-order size or SKU quantity, and meet a high requirement for accurate order-fulfillment or across-the-dock sorting with minimal errors and damage.

E-COMMERCE AND THE INTERNET E-commerce and the Internet have dramatically changed the order-fulfillment or across-the-dock customer-order profile. These new technologies have increased the


Order-Fulfillment and Across-the-Dock Strategic Considerations

5

number and frequency of customer orders, the importance of accurate order entry, and the piece mix. They have also decreased the order size (in pieces) per customer order and reduced the order/delivery cycle time.

OVERVIEW The purpose of this book is to provide the reader with equipment applications, procedures, practices, tips, and insights to consider implementing in an orderfulfillment or across-the-dock operation. The book will also provide readers with an opportunity to maximize their company’s profits by reducing logistics operating costs, and maximize customer service with on-time and accurate deliveries.



2

Order-Fulfillment and Across-the-Dock Objectives and Their Impact on Your Company’s Profit and Customer Service INTRODUCTION

This chapter defines the order-fulfillment and across-the-dock operation objectives of your company and customers. The chapter objectives are (1) to list and review order-fulfillment and across-the-dock activities, and (2) to provide techniques for design, facility construction, equipment installation, planning, and control.

ORDER-FULFILLMENT ACTIVITIES In most small-item, flat wear, garments on hangers (GOH), master carton, or pallet order-fulfillment operations, the same activities occur, regardless of the size of the distribution operation or whether the operation involves manual, mechanized, or automatic pick processes. The distribution activity groups are (1) preorder pick activities, (2) order pick activities, and (3) postorder pick activities.

ACROSS-THE-DOCK ACTIVITIES The same distribution activities occur in most small-item, flat wear, GOH, master carton, or pallet across-the-dock operations. These include vendor control, unloading, sorting, and loading. Specifically, these activities involve (1) fulfilling vendor packaging specifications, applying a customer-discrete identification to each piece exterior, and, in the retail industry, attaching a price ticket to each piece; (2) unloading, counting, labelling and receiving; (3) sorting; (4) creating the manifest; (5) transferring any residual

7


8


inventory to a store, hold, and pick area; (6) loading and shipping; and (7) fulfilling customer delivery.

PIECE-HANDLING CHARACTERISTICS As pieces flow through a company’s supply chain, there is a good possibility that there will be a change to the piece characteristics. This is particularly the case during order-fulfillment or across-the-dock operation activities with their associated piece flow patterns. Changes might include: •

• • •

A small-item order-fulfillment operation receives stock-keeping units (SKUs) on pallets or master cartons and sends individual pieces and master cartons to your company’s customers. A GOH order-fulfillment operation receives large SKU quantities and sends individual and multiple GOH pieces to your company’s customers. A carton order-fulfillment operation receives pallets or cartons and sends individual cartons or several cartons or pallets to your company’s customers. A pallet distribution order-fulfillment operation receives pallets and sends one or several pallets to your company’s customers.

A characteristic of order-fulfillment operations is that the piece flow is defined as a store and hold product flow method. With the store and hold product flow method, pieces are transferred through the piece facility storage and pick positions. With each customer order, pieces are withdrawn from the storage or pick position and sent to the customer dock staging area or are loaded directly onto a customer delivery truck. In an order-fulfillment operation, the piece flow pattern steps are (1) from the receiving area to the storage area; (2) from the storage position to a pick position; and (3) from the pick position into a customer shipping carton or into a captive container through the pack area, to the manifest area, and into a customer staging area or directly onto a customer delivery truck. With an across-the-dock operation, as a piece flows through the distribution operation, there is a slight possibility of a change in the piece handling characteristics. In most across-the-dock operations, if the piece is received as a pallet, the piece shipped to the customer is a master carton or pallet. With a small-item, flat wear, or GOH across-the-dock operation, the operation receives master cartons, flatpack GOH SKUs, or a large GOH quantity. The operation then sends individual or multiple small items, flat wear, or GOH SKUs to customers. The across-the-dock operation characteristic is that the pieces are not entered into the distribution facility inventory. All vendor pieces for an across-the-dock operation are customer-ordered SKUs. These SKUs are separated into individual customer orders from a mix of customer-ordered pieces. After the sorting activity, the individual customer pieces are quickly consolidated into a shipping container, staged in the customer-assigned location on the shipping dock, or sent directly onto the customer delivery truck. Any residual piece inventory is placed according to a store and hold method.


Order-Fulfillment and Across-the-Dock Objectives

9

ORDER-FULFILLMENT OPERATION OBJECTIVE The order-fulfillment operation objective is to ensure that SKUs meet company quality standards, which require that the correct SKU is transferred from the storage position to the correct pick position, in sufficient quantity and at the appropriate time. Standards furthermore require that SKUs are withdrawn in the right quantity, in the correct condition, and on schedule; they must have a packing list, be packaged in a protective and labeled shipping container, be properly manifested, and be delivered to a customer delivery location within the customer-order and delivery cycle time. These order-fulfillment activities, successfully completed, satisfy your customer-order requirement at the lowest possible operating cost.

ACROSS-THE-DOCK OPERATION OBJECTIVE The across-the-dock operation objective is to ensure that (1) each piece meets company standards, (2) each piece is properly packaged and labeled with a customer discrete identification, (3) each piece is unloaded at the proper time and sorted or separated by customer identification, (4) the total piece count matches the vendor manifest, and (5) the purchase order (PO) piece quantity is sent either to the customer-assigned staging area or directly to the customer delivery truck. A customer delivery truck ensures that customer-ordered pieces arrive at the customer delivery location at a specific time that satisfies your customer demand at the lowest operating cost.

ORDER-FULFILLMENT AND ACROSS-THE-DOCK OPERATION ACTIVITIES To achieve these order-fulfillment or across-the-dock operational objectives, you must design your facility and equipment layout and piece and information (or customer order) flow patterns to minimize piece handlings, ensure an efficient and cost-effective operation, ensure accurate and on-time piece and information flows through your company supply chain, and complete operational transactions that satisfy your customer’s orders. Order-fulfillment operation activities may be categorized as follows: •

Preorder pick activities • Vendor or customer delivery truck yard control • Unloading and palletizing pieces • Receiving and SKU quality and quantity check • Ensuring that a discrete identification is placed on each piece or SKU • Packaging, labeling, and placing a price ticket on each SKU for some small-item, flat wear, or GOH SKUs • Internal transport activity • Depositing in a storage position • Inventory control


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•

•

Order pick activities • Information management system (IMS) customer-order entry and download to print order pick documents and order pick labels, or, for paperless pick, download to the pick area or to an automatic pick machine microcomputer • Carton makeup, labeling, and packing list (attached or inserted into a pick container) • Manual order pick or computer impulse to release a SKU from a pick position • Piece replenishment from the reserve storage position to the SKU pick position • Trash removal Postorder pick activities • Order pick quality or quantity check, as required • Filling container voids • Sealing the container • Labeling and manifesting the customer-order shipping container • Loading • Shipping • Handling customer returns • Handling out-of-season pieces • Handling transfers • Maintenance, sanitation, and loss prevention activities

An across-the-dock operation is considered a more streamlined company distribution-logistics strategy, with activities that include vendor control, vendor and customer delivery yard control, quality control (counting and sorting), and smallitem packing and loading onto a customer delivery truck. During the across-thedock operation, other activities include: • • • • • • • • • •

Vendor piece preparation Vendor and customer delivery truck yard control IMS downloading and customer discrete label creation Unloading, receiving, and labeling SKUs Quality control (counting, sorting, or separating by customer identification) Packaging and manifesting Separating into units with other customer-order SKUs in a customerassigned staging area, or loading directly onto a customer delivery truck Storing and holding residual pieces and handling customer returns, outof-season pieces, and transfers Customer delivery Maintenance, sanitation, and loss prevention

YARD CONTROL At an order-fulfillment or across-the-dock operation, yard control activity ensures that the appropriate vendor delivery truck or oceangoing container is spotted at the



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correct receiving dock and that the customer delivery truck is spotted at the correct shipping dock. Whenever possible, the receiving dock assigned to a vendor delivery truck minimizes the internal transportation distance from the dock to the storage/pick position, or from the customer-order manifest area to the customer shipping dock door. With some store and hold operations, the yard control activity includes spotting vendor railcars on your rail spur. The railcar spot on the rail spur ensures the shortest internal transport distance from the railcar receiving dock to the piece storage location.

UNLOADING With an order-fulfillment or across-the-dock operation, the piece unloading activity involves unloading small-item master cartons, GOH on trolleys or carts, master cartons, or pallets from a vendor delivery truck, container, or railcar onto the receiving dock staging area. After a quality and quantity check, pieces are transferred according to internal transport procedure. With an across-the-dock operation, a piece is directly moved from a vendor delivery truck; through quality control, counting, and sorting; and to the customer-assigned dock staging area or directly onto a customer delivery truck. With an order-fulfillment operation, a piece is quality- and quantity-checked and transferred from a vendor delivery vehicle according to internal transport procedure. After a piece is transferred to internal transport, the piece is moved from the dock area to the assigned storage or pick position. After a customer orders a SKU, the SKU is withdrawn, prepared for shipment, manifested, and loaded onto a customer delivery truck.

VERIFYING PIECE QUALITY

AND

QUANTITY

In an order-fulfillment operation, the next preorder pick activity is to verify that vendor piece quality and quantity meet your company’s PO and piece specifications. This activity ensures that (1) the SKU quantity delivered to your order-fulfillment operation matches your company’s PO quantity, and (2) the received piece quality is per your company’s PO specifications and quality standard. In an across-the-dock operation, piece quality and quantity characteristics are considered vital to an efficient and cost-effective piece flow. Across-the-dock piece quality and quantity characteristics are key components that ensure a continuous piece flow through your supply chain. To ensure accurate SKU quantity and quality per your company’s piece standards and PO specifications, pieces are randomly checked at the vendor location or at your company’s receiving dock.

RECEIVING At order-fulfillment facilities, the next preorder pick activity is the receiving activity. A company employee physically transfers the SKU from a vendor delivery truck,


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enters the SKU quantity into the warehouse management system (WMS) inventory, and transports the SKU to the storage or pick position staging area. In an across-the-dock operation, the piece is transferred from a vendor delivery truck through transport and sorting to a customer-assigned shipping dock staging area, or directly onto a customer delivery truck. Following your company’s procedures, piece samples are taken to the quality control area for inspection. In order-fulfillment operations, the vendor pieces are transferred from the dock area to a storage area position. In the storage area position, the pieces are placed on a Quality Assurance (QA) hold status until QA approves or rejects the samples. If QA approves the piece quality, the pieces are available for the order-fulfillment activity. If QA rejects the piece quality, the pieces are held in the storage area position for vendor disposition and are not available for the orderfulfillment pick activity.

PIECE IDENTIFICATION The fifth order-fulfillment or across-the-dock operation activity is the SKU identification activity. During an order-fulfillment operation at the receiving dock, if the SKUs are not vendor-labeled, an employee places a code on each piece, master carton, GOH trolley or cart, or pallet exterior surface. In an order-fulfillment operation, the code is used in other facility functions to distinguish one SKU from another. The code has alpha characters and numeric digits, bar codes, or radio frequency (RF) tags that serve as an instruction to the employee who handles the piece. For smallitem operations, in the receiving dock area the SKU identification activity is performed after a group of SKUs are placed in a material handling or shipping container. With across-the-dock operations, the piece vendor applies the appropriate customer discrete label onto a single item, GOH, carton, pallet, or piece exterior surface. If the piece is not vendor-labeled with a customer-discrete label, an across-the-dock receiving employee applies a discrete label onto each piece’s exterior surface. Ticketing In some retail store order-fulfillment or across-the-dock operations, a sub-activity to the SKU identification activity is the individual SKU price ticketing activity. An employee or machine places a price ticket onto each individual SKU or sale piece. This price ticket activity is very common in GOH, flat wear, small-item, or master carton (ready for retail sale) distribution operations. In a price ticketing activity, a mechanical printer prints the price tickets. A price ticket is a label that is glued, clipped, stitched, or hooked onto the SKU or placed on the SKU exterior surface.

PACKAGING The next order-fulfillment activity is the SKU packaging activity. In a small-item packaging activity, an employee places an individual SKU or a SKU group into a material handling or shipping container. Containers include plastic bags, paper bags, chipboard boxes, and cardboard boxes. In a GOH operation that receives flat-pack garments, each



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piece is transferred from a vendor box to a hanger. The individual GOH piece is placed in a plastic or paper bag. In a carton and pallet load operation, the packaging activity ensures that the cartons are properly sealed and are secured on a pallet.

HORIZONTAL

OR

VERTICAL TRANSPORTATION

The next preorder pick activity in an order-fulfillment operation is internal horizontal or vertical transport from the receiving dock staging area to the storage and pick staging area. With an across-the-dock operation, the piece transport activity moves the pieces from the receiving dock area through the sorting area to a customer shipping dock staging area or directly onto a customer delivery truck. Manual or mechanized transport is used in the transport activity.

STORAGE In an order-fulfillment operation, the piece storage activity provides a distribution facility with a physical position to store a SKU. When required by a customer-order, the SKU is transferred from the storage position to the pick position. In an across-the-dock operation, any residual piece inventory is transferred to the storage or pick position.

DEPOSIT The next preorder pick activity in an order-fulfillment operation is to deposit the pieces to the assigned storage or pick position. An accurate and on-time completion of the deposit activity ensures that the right SKU is in the proper place, in the proper quantity, in the correct condition, and at the correct time. The piece deposit activity permits on-time pick position replenishment.

INVENTORY CONTROL The next order-fulfillment operation activity is the inventory control activity. The inventory control activity ensures that pieces are transferred to the correct storage or pick position in the correct quantity. Other WMS or inventory control concerns are (1) ensuring proper piece rotation, (2) using accurate SKU counts, (3) employing minimal stock outs and out of stocks at the pick position,* (4) tracking the piece flow through the supply chain or through each segment, and (5) verifying that each logistics segment transaction is completed.

IMS CUSTOMER-ORDER DOWNLOAD The next order-fulfillment or across-the-dock operation activity is the IMS department customer-order receipt, order entry processing, and transfer to a pick line * A stock out occurs when, per a customer order, a pick instruction (an employee or automated pick device) arrives at a pick location and the pick position is depleted, but the inventory file indicates an onhand SKU inventory quantity. An out of stock occurs when, per a customer-order, a pick instruction arrives at a pick position, the pick position is depleted, and the inventory file has no on-hand inventory quantity.


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printer, unloading dock printer, microcomputer, or automatic pick machine. The IMS customer-order download activity ensures that (1) the proper pick documents, self-adhesive labels for a batched customer-order, or individual customer orders are cubed, per a customer shipping carton or delivery truck; (2) the items are ready for the order pick activity; and (3) customer orders are properly sequenced and available for a paperless pick line start station or for traveling through an automatic pick machine.

CARTON

OR

SHIPPING CONTAINER MAKEUP

For a small-item, flat wear, or GOH order-fulfillment operation, the next operation activity is the customer-order carton or container makeup and entry to the pick line activity. In an order-fulfillment operation, an employee picks a customer-ordered SKU into a captive customer-order container or shipping carton. In a batched customer-order pick and sort operation, customer shipping carton makeup is performed at a pack station. Per the SKU quantity of the customer-order, SKU cube characteristics, container size, material, and weight, and per customer delivery requirements and company practices, an employee or machine transfers a formed carton or customer shipping container onto a pick line or onto a pick vehicle. A small-item, one-piece corrugated carton has sealed bottom flaps for easy handling and transport over a conveyor surface. If a two-piece carton is used on a pick line, the carton bottom piece is placed under the carton top piece. At the end of the pick line, the top is placed onto the carton opening. Other container types are considered captive containers. These containers are made of plastic, wood, or metal. Small-item pick containers have optional open tops, handles, or hand grips; meshed sides and bottoms; stacking and nesting components; and three side guards with one open side. In a GOH operation, the device is a plastic, metal, or wood hanger. To ensure efficient movement in a GOH operation, the hanger size, hook dimensions, and material are standard. When GOH pieces are prepared for a customer-order delivery, the GOH shipping container options include paper bag, plastic bag, flat box, box hang bar, delivery truck rope loop, and cart hang bar.

CUSTOMER-ORDER PICK In a small-item, flat wear, GOH, master carton, or pallet operation, the next orderfulfillment activity is the customer-order pick activity. After a customer-order pick instruction is printed or downloaded to a microcomputer, an employee or pick machine transfers the proper SKU and SKU quantity from the pick position to a transport conveyor, into a container, or onto a vehicle load carrying surface. At the pack station, customer-ordered and picked SKUs are consolidated and packaged in a shipping carton and then held in the assigned customer staging area or loaded directly onto a customer delivery truck.



15

SORTING When an order-fulfillment operation processes batched orders, or when an acrossthe-dock operation processes pieces or customer orders, the piece or customer-order sorting activity is the key to an accurate and on-time shipping activity. The sorting activity allows an order-fulfillment or across-the-dock operation to handle a high customer-order and piece volume. In an order-fulfillment operation, the sorting activity is the first postorder pick activity. When a single-item, flat wear, or master carton order pick activity is in the batched customer-order mode, the sorting activity separates each customer-ordered and discrete-labeled single item, flat wear, or master carton from a mix of customer-ordered and discrete-labeled pieces. The sorting activity verifies that the SKU was withdrawn from a pick position and was transported to a customer-order packing area or directly onto a customer delivery truck. In an across-the-dock operation, the mixed customer-ordered and discretelabeled SKUs, master cartons, or pieces are unloaded from a vendor delivery truck and sorted. Per each piece sorting or customer-discrete label, the sorting activity transfers each piece or master carton from the sorting travel path to the customer sorting holding area or direct-load conveyor lane. The SKU sorting components include: • • • •

A human, machine, or human-machine bar code label that is on each piece’s exterior surface Piece transport and sorting with a constant travel speed A communication network that involves a bar code scanner, a tracking procedure, a microcomputer, and a divert device A divert lane with queue space

The pieces or customer orders are individuated on a sorting conveyor travel path, and, with the proper gap between two pieces or customer orders, a bar code scanner reads the bar code. The bar code scanner sends the bar code data over the communication network to the microcomputer. While maintaining a constant travel speed, the microcomputer and tracking device activate a divert device at the appropriate time in order to transfer the assigned piece or customer-order from the sorting conveyor travel path to the customer temporary holding rack location, outbound staging area, or customer delivery truck. Per the SKU and operation sorting location is a bin, container, chute, or conveyor. Manual or mechanized active, passive, and active-passive SKU sorting requires manual- or automatic-discrete identification. Identification requires a manual identification code, a bar code, or an RF tag on each piece, as well as data entry and communications technology.

REPLENISHMENT In an order-fulfillment operation involving single items, flat wear, GOH, or master cartons, SKU replenishment is another postorder pick activity. SKU replenishment


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ensures that the correct SKU is removed from an assigned storage position on schedule and in the proper quantity, and is placed in the correct SKU pick position. The SKU replenishment steps are as follows: • • • • •

List the SKU pick positions that require replenishment. Prioritize SKU quantity withdrawal from the storage area. Transfer the SKU to a SKU pick position. Verify completion of the replenishment transaction. Update the storage and pick position inventory file.

In a small-item, flat wear, GOH, or master carton order-fulfillment operation, an employee transfers pieces from a random storage position to a fixed pick position. In a pallet operation, the piece or pallet deposit from the receiving dock to an assigned storage position is a replenishment activity.

PACKAGING In an order-fulfillment operation, outbound SKU packaging is the next postorder pick activity. Its objective is to ensure that the SKU is protected from damage during delivery from your facility to a customer delivery location and that the SKU is received by your customer in satisfactory condition. In the distribution business, the condition of a SKU’s exterior package is your customer’s first impression of your company’s order-fulfillment service. This fact is especially true for catalog, E-commerce, and direct mail businesses. The packaging activity functions are to verify the SKU quality and quantity order pick accuracy; with filler material, fill the voids in the customer shipping carton; seal or close the shipping container bottom and top flaps or bag; place your customer delivery address label in the appropriate location onto a shipping carton exterior surface; and transfer the package onto the transport method. Most SKU packaging activities are in a small-item or GOH operation. The SKU packaging activities for a carton or a pallet load operation are to unpack cartons onto a pallet or cart, secure the cartons to a cart or pallet, label the master carton or pallet, and transfer the carton or pallet to a shipping staging area or onto a customer delivery vehicle.

PACKAGE SEALING At a small-item or hanging garment order-fulfillment operation, the next activity is your customer package seal activity. The delivery carton seal activity ensures that your customer shipping carton does not open during transport from your operation to your customer’s delivery address, and that when the package is delivered to a customer delivery address, the SKUs are in the package. The sealing method for a package is to pack multiple SKUs loosely in one large container, or to pack an individual SKU or a few SKUs in the appropriate sized container, bag, or carton. The customer-order shipping container is sealed with a self-seal method, tape, plastic bands, or plastic wrap.



PACKAGE WEIGHING

AND

17

MANIFEST

At an order-fulfillment or across-the-dock operation, the next activities are the shipping carton weighing and manifest activities. The customer-order shipping carton weighing and manifest activities’ objectives are to ensure that each customer carton receives the proper transport fee or postage; list the customer-discrete identification number and weight; send the package by the most cost-effective transport method; have the proper documentation in the customer-order shipping carton; obtain the exact weight and manifest per the customer-discrete identification number; and verify that the customer-order was completed by your operation. The carton weighing and manifest activities are to use a scale that shows the exact weight for each carton, verify that the actual carton weight and computer projected carton weight match within a variance, and ensure that the customer discrete identification is listed on the transport document. With the computer projected weight method, the scale interface is direct to the host computer or to a microcomputer. The microcomputer has received the customer-order carton computer projected weight from the host computer.

LOADING

AND

SHIPPING ACTIVITIES

The carton loading and shipping operation functions are considered the next direct labor function. The loading and shipping function ensures that your customer-order shipping carton is transferred from the sorting travel path and onto your customer delivery truck. The loading and shipping function is a direct load activity or an activity to temporarily hold the customer-order shipping containers in the shipping staging area, or at a later time to load them onto a customer delivery truck.

CUSTOMER RETURN, OUT-OF-SEASON,

AND

TRANSFER

With an order-fulfillment or across-the-dock operation, the next distribution or transport department activity is to handle customer pieces, returns, and out-of-season pieces between two retail customer locations. The customer return activity is an activity that occurs in all industries. It is most evident (varying from 5 to 38% of the shipped volume) in the catalog, E-commerce, and direct mail industries. In the carton handling industry, the customer return estimated rate is 1 to 5% of the volume that is shipped to customers. The customer return activity ensures that your customer returned order quantity was received at your facility; that your customer received the appropriate credit; and that the returned merchandise physically flows through your facility and is returned and entered in inventory, placed in a SKU pick position, sent to an outlet store, donated to charity, disposed in the trash, or returned to the vendor. Out-of-season pieces and transfer activities occur in the retail and catalog industry. The out-of-season piece activity is a distribution activity to hold temporarily in a storage position pieces that did not sell at a retail store or to customers. With your company’s top management approval, the retail outlet places the SKUs into packages


18


and returns the out-of-season pieces to the distribution facility for temporary storage. At a later date when all the stores have returned the out-of-season pieces to the distribution facility, the company’s top management decides how to handle the outof-season pieces. Piece transfers are overstock merchandise moves from a retail store location with low sales, through the distribution or transport system, to another retail store location that has high sales for the merchandise. With your company’s top management approval, and with the proper documentation, the merchandise becomes a piece transfer that flows from one store to another store through your company’s distribution and transportation operations as an across-the-dock piece.

ACROSS-THE-DOCK OPERATIONS The across-the-dock operation activities that are similar to the order-fulfillment operation activities are using customer and vendor delivery truck yard control; receiving and unloading pieces; downloading customer orders from the host computer to the microcomputer; sorting customer orders; separating into units at a shipping staging dock area or directly loading them onto a customer delivery truck; manifesting; and storing and holding the residual inventory. An across-the-dock operation’s unique activities are IMS host computer download of the customer orders to a microcomputer and customer shipping label print time. In an across-the-dock application, the host computer downloads customer orders through a microcomputer to the print machine; this occurs prior to a vendor delivery truck space at the receiving dock. If the across-the-dock pieces are not vendor labeled, during the piece unloading process an across-the-dock employee or label machine places a customer-discrete identification onto each piece’s exterior surface.

MAINTENANCE, SANITATION,

AND

SECURITY

The remaining key order-fulfillment and across-the-dock operational functions are the maintenance, sanitation, and security activities. These activities’ objectives are to protect your company’s assets and to ensure that the inventory, building, and equipment are available to satisfy your customer orders and operate at the lowest possible cost.

ON-SCHEDULE AND ACCURATE PERFORMANCE OF AN ORDER-FULFILLMENT OR ACROSS-THE-DOCK OPERATION AND CUSTOMER DELIVERY ACTIVITIES MEANS PROFITS AND SATISFIED CUSTOMERS The effective and efficient completion of the preorder pick, order pick, and postorder pick order-fulfillment activities or across-the-dock piece activities and customer delivery activities ensure that your company’s customers are satisfied with the best service. When these activities are completed on schedule and at the lowest cost, the SKU, SKU package, and documentation makes a positive and lasting impression on



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your company’s customers. This impression ensures that your order-fulfillment or across-the-dock operation is profitable and has satisfied customers.

WHY IS AN ACCURATE, EFFICIENT, AND COST-EFFECTIVE ORDERFULFILLMENT OR ACROSS-THE-DOCK OPERATION IMPORTANT? An accurate, efficient, and cost-effective order-fulfillment or across-the-dock operation is important to your company. It is the company department plus customer delivery truck activity that performs the last customer-order or piece handling before it arrives at your customer location. Furthermore, it is the customer receiving the order on time, accurately, and without damage who determines the customer service quality. When compared to the other distribution facility operational activities and departments, the order-fulfillment, pick position replenishment, label, pick, sort, fill, check, seal, manifest, and loading and across-the-dock activities combined have the largest number of employees. The facts are that the manual order-fulfillment method has the largest employee number, the mechanized order-fulfillment method has a medium employee number, and the automatic order-fulfillment method has the smallest employee number. With this large employee number, the conclusions are that the order-fulfillment method costs as a percentage of the total order-fulfillment or across-the-dock operational costs have the highest dollar amount. As a cost percentage in relation to sales, it has the highest percentage, while as a cost per piece handled, it has the highest dollar amount. As a line item on an order-fulfillment or across-the-dock segment annual operating expense statement or budget, it has the highest dollar amount. When a company expands its piece mix, changes the product mix, increases the SKU number, or increases the customer number or customer orders, this operation has the greatest ability to efficiently and cost-effectively handle the new business volume or SKU growth, and to maintain the customer service standard.

WHAT IS THE STANDARD FOR A GOOD ORDER-FULFILLMENT ACROSS-THE-DOCK OPERATION?

OR

The standard for a good order-fulfillment or across-the-dock operation is the company’s basic performance standard. This basic performance standard is common to any size company that is in any industry whether it serves a retail, industrial, E-commerce, direct mail, catalog, or personal consumer customer group. The order-fulfillment basic performance standard is to provide the best customer service at the lowest possible cost. Stated in the broadest terms, the order-fulfillment standard is to ensure that the right SKU is in the correct pick position in sufficient quantity at the appropriate time; is withdrawn in the right quantity, in the correct condition, on schedule; is packaged in a protective and labeled shipping carton; and is properly manifested and delivered to the customer delivery location at the lowest possible operating cost. The across-the-dock performance standard is very similar to the order-fulfillment performance standard. The across-the-dock basic performance standard is to ensure


20


that the correct piece quantity is unloaded, labeled correctly, properly sorted by customer-order quantity, and staged with the other customer pieces or loaded directly onto the customer delivery truck; the delivery truck must also arrive at the correct customer delivery location at the scheduled time. These across-the-dock activities are performed at the lowest possible operating cost.

HOW TO IMPROVE YOUR ORDER-FULFILLMENT OR ACROSS-THE-DOCK OPERATION To maintain your company’s customer service standard and to operate your orderfulfillment or across-the-dock operation at the lowest possible cost, you must improve your order-fulfillment or across-the-dock operation. Whether your orderfulfillment operation has a manual, mechanized, or automated method, or the acrossthe-dock operation has a manual or mechanized method, the potential customer service or operating cost improvement areas are as follows. Look at the employee numbers for each activity. Develop a customer service standard. Consider batched customer orders and pallet handling with dual cycle activities. Reduce order picker travel time and distance. Improve the SKU hit pick concentration and hit density. Use the ABC or power SKU allocation method. Use kit or family group SKUs. Use clear and simple pick instructions, pick position identification, and sorting instructions. Use an employee or order picker routing sequence. Cube your employee or automatic pick machine work. Provide queue space. Level the work volume over the week work days. Use part-time employees. Apply the golden zone theory to the SKU pick positions. Change from a paper order pick document method to a self-adhesive label, paperless order pick, or automatic order pick method. Develop a good equipment layout, piece flow, and facility layout. Provide clean and clear aisles. Ensure well lighted aisles. Change from a human-paced to a machine-paced method. Use nonpowered or powered equipment. Use automatic identification in the order-fulfillment or across-the-dock method. For each workday, provide the employee with sufficient work. With a historically high customer-order volume for a small single SKU, or a historically high volume for several SKUs, pick and pack these SKUs off-line. Ensure on-time and accurate pick position replenishment to the pick aisle or along the pick line. Have a properly designed order picker or pick line start location. In a pick aisle or along a pick line, ensure an arithmetic progression. Place pick position numbers that end with even digits on the pick aisle’s right side and place pick position that end with odd digits on the pick aisle’s left side. For the majority of the time, keep the order picker in the pick aisle or on the pick line.

LOOK

AT THE

EMPLOYEE NUMBERS

The first guideline to improve your order-fulfillment or across-the-dock operation is to look at the employee numbers. This means that you identify the employee order-fulfillment or across-the-dock activities that have the highest employee number, labor cost plus fringe benefits, or operational cost factor.



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The other operational factors are overtime; piece, building, or equipment damage; order pick overages, shortages, or errors; off-schedule customer-order deliveries; and employee injuries. An employee productivity improvement in the orderfulfillment or across-the-dock operational activity with a high employee number has the greatest impact on your order-fulfillment or across-the-dock operation in total employee productivity, annual operating expenses, and ability to provide on-schedule and accurate customer service.

DEVELOP

A

STANDARD

The second step to improve your order-fulfillment or across-the-dock operation is to develop an operational employee productivity standard. The order-fulfillment or across-the-dock employee productivity standard is an employee productivity figure. This figure states your operation’s production as customer orders, cartons, or pieces in a measurement factor that was completed by your operation’s total employee work hours or costs. In an order-fulfillment or across-the-dock operation, employee productivity is the key factor to project the labor expense line for the annual expense budget.

USE BATCHED CUSTOMER ORDERS

AND

DUAL-CYCLE ACTIVITIES

The third operation improvement guideline is a specific guideline to improve your order-fulfillment activity. This guideline is to batch your customer orders or ordered SKUs. Batched customer orders means that your computer program groups together a specific customer-order number and prints order pick instructions for these specific customer ordered SKUs. The customer-ordered SKU requirement for printing is per SKUs that are sequenced by pick position number on self-adhesive pick labels or sequenced by pick position lines on a paper pick document or downloaded to a radio frequency (RF) pick device. This SKU pick position sequential print for picker instructions permits the order picker to pick the ordered SKU quantity for all customer orders within the batch. The batched customer-order pick activity options are first, with a paper pick document or RF device, to place the picked SKU immediately into a customer-order holding location. This approach is used for small items, flat wear, or GOH pieces. With the second option, after a label pick activity, the picked and labeled SKUs are placed into the appropriate customer sorting location. With the third option, after a label pick activity, the picked and labeled SKUs are sent as a group to a sorting area. In the sorting area, the SKUs are separated to the appropriate customer sorting/packing/staging location. This approach is used for loose small items, flat wear, cartons, or GOH pieces. The batched customer-order pick method increases order picker productivity due to a reduction in the order picker travel distance and a reduction in the repetitive employee order pick activities. The method requires a computer program, computer time, sorting method, sorting location, sorting labor, and sorting time. Most orderfulfillment professionals believe that the batched customer-order pick method provides picker productivity improvements that substantially offset the sorting activity


22


costs. This method has applications in a small-item, flat wear, GOH, or carton orderfulfillment operation. In a pallet-handling operation, a pallet dual cycle activity is most effective for a forklift truck or automated storage and retrieval system (ASRS) operation. The dual-cycle activity has the forklift truck enter a storage aisle, travel down the aisle to the assigned storage position, perform the storage deposit transaction, continue travel in the same storage aisle to another storage position, complete a withdrawal transaction, and exit the storage aisle. When a dual-cycle activity is compared to a single-cycle activity, the dual-cycle activity improves forklift truck productivity by approximately 20%. To achieve this productivity increase, storage areas have storage aisle pallet pickup and delivery (P/D) stations. A P/D station provides an opportunity to balance the in and out pallet storage transactions per aisle. The required forklift truck or ASRS storage transactions are preprinted on a document or are available online.

REDUCE TRAVEL TIME

AND

DISTANCE

The next operational improvement guideline is to reduce your order picker travel time and distance between two pick positions. Small-item, GOH, or carton orderfulfillment operations have a large SKU number that varies in size, weight, and pick volume, and the order-fulfillment area has many pick positions and aisles. As an order picker travels through a pick aisle or along a pick line between two pick positions, this represents unproductive travel time and distance. In a small-item, flat wear, GOH, or carton order-fulfillment operation, a dramatic order picker productivity increase results from decreasing the order picker unproductive travel time and distance between two pick positions.

IMPROVE

THE

SKU HIT CONCENTRATION

AND

HIT DENSITY

The next element to improve your order picker productivity is to improve the SKU hit concentration and SKU hit density. To do this, you allocate on a pick line or along a pick line your SKUs according to Pareto’s law (the 80/20 rule, named after Vilfredo Pareto [1848–1923], Italian economist), which states that 80% of your pick volume is derived from 20% of your SKUs. The SKU hit concentration means the SKU number that is ordered by your customers or lines (stops or hits) within a particular pick aisle or along a pick line, or the pick position number within one aisle that has SKUs withdrawn for a customerorder. The SKU hit density is the SKU number (quantity) that a customer-order has of a particular SKU (one pick position) or the number (hit quantity) for one SKU to complete a customer-order line. High SKU hit concentration and SKU hit density dramatically improve order picker productivity due to the reduction in travel time and distance between two picks (hits or pick positions). For best results in a single-item pick onto a conveyor, into a tote or carton, or carton pick to conveyor order-fulfillment operation, the order pickers are assigned to pick line zones or specific pick aisle numbers. Order-fulfillment professionals believe that the grouping of slow-moving (low-hit) SKUs



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improves the hit concentration and hit density for these SKUs, increasing the employee productivity for the order-fulfillment operation.

USE ABC

OR

POWER SKU ALLOCATION

When an order-fulfillment area layout is based on SKU popularity, it is based on Pareto’s law. This law states that 80% of the wealth is held by 20% of the people. In the small-item, flat wear, GOH, carton, or pallet order-fulfillment industry, this law indicates that 80% of the volume shipped to your customers is derived from 20% of your SKUs. Many studies have indicated that another 10% of the volume shipped to your customers results from another 30% of your SKUs, and that an additional 5% of your volume shipped to your customers is attributed to 55% of your SKUs. If you are in the catalog or direct mail business with 2 to 4 catalogs introduced within a year, then 90 to 95% of your business is from 5% of your SKUs. This is because each catalog has a different inventory of SKUs. In recent studies, the results show that 95% of your volume shipped to your customers is obtained from 55% of your SKUs, which is referred to as “Pareto’s law revisited.” ABC Theory When a distribution professional refers to Pareto’s law and its three zones, their reference is to the ABC theory. The ABC theory simply states that a distribution operation’s pick aisle or pick line zones are as follows. The A pick zone is allocated to the fast-moving SKUs. These SKUs are few in number and have a large inventory quantity per SKU. The B zone is allocated to the medium-moving SKUs. These SKUs are medium in number and have a medium inventory quantity per SKU. The C zone is allocated to the slow-moving SKUs. These SKUs are large in number and have a small inventory quantity per SKU. If a distribution operation layout has receiving and shipping docks that are located on the facility’s front side and a SKU’s pick location is based on the ABC theory, it locates the fast-moving SKUs at the pick line’s front. If a distribution operation’s receiving and shipping docks are located on a building’s opposite sides, the fast-moving SKUs are located by the unloading and loading ratio. The unloading and loading ratio compares the trip number that unloading and loading employees require to handle a piece delivery truck. When an employee unloading trip number equals an employee loading trip number, the SKU or pallet is located near the shipping docks or in any location in the pick aisle. When employee unloading trips are more numerous than employee loading trips, the SKU or pallet is located near the receiving docks. This feature reduces your order picker employee total travel distance and time. Power or Fast-Moving SKUs in One Pick Area The next order-fulfillment productivity improvement guideline is to have the power or fast-moving SKUs located in one pick aisle or pick zone. This method has an inventory (SKU) allocation program that locates all fast-moving SKUs into pick


24


positions that are within one pick aisle or pick zone. These pick positions are adjacent to one another. This philosophy has all your promotional, seasonal, special sale, and fast-moving SKUs in one pick aisle or pick line zone. This SKU arrangement increases your order picker hit concentration (picks per aisle number) and hit density (hits per SKU number). A high hit concentration and hit density means high order picker and replenishment employee productivity due to a short travel distance between two pick positions. The key to an accurate, efficient, and on-time small-item, flat wear, GOH, carton, or pallet order-fulfillment operation with the power SKUs in one area method is to have the storage pieces available to replenish a pick position and to have a completed customer-order or picked SKU take-away transport method.

USE KIT

OR

FAMILY GROUP SKUS

The next order-fulfillment improvement guideline concentrates on the pick area SKU allocation. In addition to the SKUs handled, SKU popularity, or Pareto’s law and mobile order pick vehicle travel distance, good pick area layout is dictated by your company’s requirement that the SKUs are sorted or sent to the customer by family group. With this guideline, by a predetermined criterion, the SKUs are assigned to specific pick positions. This location is one or multiple pick aisles or one or multiple pick zones within a pick line or pick aisle. This pick aisle or pick line layout philosophy requires that the order-fulfillment pick positions and method are designed to accommodate SKUs that have similar characteristics. These are to have similar dimensions, weight, and SKU material components; to have components for the same final product; to be located in the same aisle in a retail store; to require normal, refrigerated, or freezer conditions; to require high security; to be separated into long or short GOH; to be separated by toxic or nontoxic materials; to have one style (such as musical for shoes) or all sizes; to be separated by edible or inedible; to be separated by flammable or nonflammable; to be separated by flat wear type, such as by style and color with all sizes; and to be separated into stackable and nonstackable pieces.

KEEP IT SIMPLE

AND

CLEAR

The next employee productivity improvement guideline is the small-item, flat wear, GOH, carton, or pallet order picker instruction method. The best order picker instruction method is to keep order picker instruction as simple as possible. This allows the order picker to read the instructions, clearly understand the instructions, and complete a pick transaction. These order pick instruction methods are a paper document, a self-adhesive label, or a paperless or lighted display panel that appears on a pick light device or RF device. Each order pick instruction method presents the order pick instruction as alphabetic characters, numeric digits, or a combination of both. Each individual or alphabetic character and numeric digit group identifies a customer discrete identification, a specific pick aisle pick position, or a SKU pick position on your distribution pick line and the customer-ordered SKU quantity. At each pick position, attached to a pick position structural support member is a



25

corresponding set of alphabetic characters, numeric digits, or a combination of the two. During the order pick activity, when an order picker matches the pick instruction document or label alphabetic characters or numeric digits to a pick position identification, this match serves as a signal to an order picker that the order picker has arrived at the correct pick position. At this pick position an order picker completes a pick transaction. In a batched customer-order-fulfillment operation or in an across-the-dock operation, to complete the mixed SKU or customer-order sorting for grouped customer orders, the sorting instruction on a piece or customer-order and the identification at the customer sorting location are clearly understood and easily matched by a sorting employee. When a batched customer piece sorting instruction is compared to an order pick instruction, these instructions have similar design parameters and objectives.

USE SEQUENTIAL ORDER PICK PATTERNS In a small-item, flat wear, GOH, carton, or pallet order-fulfillment industry, the sequential order picker routing patterns are the preferred patterns to improve order picker productivity. The sequential order picker routing pattern has an arithmetic progression in the pick position numbers through a pick aisle or along a pick line. This means that the lowest SKU pick position number is 1 or 0 and is located at the entrance to the pick line or pick aisle. The highest pick position number is 99 or 100 (or greater) and is located at the exit to the pick line or pick aisle. In these sequential order picker routing patterns, the order picker starts at the first required SKU pick position in the pick line or pick aisle. As the order picker travels down a pick aisle or along the pick line to the pick aisle or pick line end, the next required pick position is as close as possible to the previous SKU pick position. In your order-fulfillment operation, any sequential order picker routing pattern provides your operation with an efficient and cost-effective order picker group. Advantages include reduced employee unproductive travel time. This feature means two or fewer trips per pick aisle or pick line. Other advantages are lowered employee fatigue, minimized employee confusion, and increased employee productivity.

CUBE

THE

ORDER PICKER ACTIVITY

OR

AUTOMATIC PICK REQUIREMENT

The next elements for a good small-item, flat wear, GOH, or carton order picker improvement are to minimize unnecessary conversation between two order pickers while they are in a pick aisle or pick line, and to ensure that an order picker is capable to handle the picked SKUs without additional trips in a pick aisle or along a pick line. If your order-fulfillment operation order pick instruction method “cubes out“ or divides each order picker activity or automatic pick machine, SKU release is based on a predetermined criterion. Per your customer-order pick method, the computer program determines the carton number for a customer-order; the order picker number


26


per pick aisle; placement on a pick line per size of the carton; and per the carton cube, the SKU number that is released from an automatic pick machine. The other factors that determine the order pick cube or SKU quantity per container are the container, human, or delivery vehicle load-carrying surface’s optimum internal dimensions and weight capacity to carry SKUs; each SKU’s dimensions and weight; the additional cube and weight added to the previous queued total cube and weight as each SKU is added to the customer carton; and the carton or load-carrying capacity utilization or fill rate. From these data, the computer optimizes the employee or vehicle trips within a pick aisle and for a carton on a pick line, or from an automatic pick machine, the SKU number that easily fits within the carton. This cube feature reduces an order picker’s unproductive travel time, reduces piece damage, and minimizes the shipping carton void filler material quantity. If an order-fulfillment operation has no match for the SKU to a human-carry or carton capacity, there is a high probability that an order picker section for a customer order exceeds the human or carton capacity. To complete a customer-order portion, this no-match situation has a high potential to have an order picker make unnecessary, unproductive, or less than optimum travel trips between a pick aisle and a customer pack station; to cause additional order picker hand movements into the carton to arrange SKUs inside the carton; or to cause an automatic pick machine to overfill a carton and create piece damage or pick errors. In an across-the-dock operation, the cube for the pieces that are loaded onto a customer delivery truck or placed in the assigned customer shipping dock staging area is a key factor to ensure good employee delivery truck loading productivity, minimal piece damage, and full customer delivery trucks. The pick activity cube is considered for a small-item, flat wear, GOH, or carton order-fulfillment operation. With a small-item, flat wear, GOH, carton, or pallet across-the-dock operation, the cube optimizes a customer delivery truck loading.

SMOOTH

OR

LEVEL

THE

WORK VOLUME

The next guideline to improve your small-item, flat wear apparel, GOH, carton, or pallet order-fulfillment or across-the-dock operation’s employee productivity is to level the week’s work volume evenly over the number of workdays. Leveling to a week causes your daily customer-order and piece handling volume to be at relatively the same quantity for each workday. This averaged daily work volume ensures that your order-fulfillment or across-the-dock employees have sufficient and productive work quantity for each work day. This means that there is no unproductive employee time to change jobs within the operation.

USE PART-TIME EMPLOYEES The next guideline to improve an order-fulfillment or across-the-dock operation’s employee productivity or cost per piece is to use part-time employees. Your smallitem, flat wear apparel, GOH, carton, or pallet order-fulfillment or across-the-dock operation experiences peak volume periods, but you hired full-time employees for the average business volume. During the peak business volume conditions, due to



27

the overtime pay for your regular full-time employees, you use part-time and lower cost employees to complete the work volume that is above-average work. This parttime employee approach features include maintaining the per-piece labor cost because part-time employees do not have the same fringe benefits as the regular or full-time employees. There is no overtime premium pay, and use of part-time employees permits your experienced full-time employees to perform the key orderfulfillment or across-the-dock activities while the part-time employees are able to perform the unproductive or less skilled order-fulfillment or across-the-dock operation activities.

APPLY THE GOLDEN ZONE PICK POSITION

OR

PROPER ELEVATION

AND

LOCATION

OF THE

The next order-fulfillment employee productivity improvement guideline is for a small-item, flat wear, GOH, or carton operation. This guideline focuses on a SKU pick position elevation and a SKU physical location on a pick shelf or rack level. Many order-fulfillment professionals refer to the best pick position elevation as the golden zone. The physical elevation in a hand-stack rack, shelf, or case-flow rack pick position method is a very important factor that contributes to order picker productivity and replenishment employee productivity. To achieve the maximum order picker or replenishment employee productivity, the SKU golden zone pick position elevation reduces an order pick or replenishment employee’s reach or bend to complete a replenishment transaction. In a hand-stack rack, shelf, or flow-rack pick method, this means that the top and bottom (pigeonhole) pick position levels are the least desirable pick positions. The golden zone pick position levels are located between the 20-inch elevation above the floor surface and the 5-foot, 6-inch elevation above the floor surface. These golden zone levels are the preferred pick positions. These elevations for the golden zone vary slightly for an order picker or replenishment employee’s average height.

CHANGE FROM PAPER PICK DOCUMENT TO SELF-ADHESIVE LABEL, PAPERLESS, OR AUTOMATIC PICK METHOD The next small-item, flat wear, GOH, carton, or pallet order-fulfillment employee productivity improvement guideline is to change your order picker instruction format. This change is from the paper pick document to a paperless order picker instruction format or an automatic pick method. When a manual or mechanized order-fulfillment method uses a paper pick document, the paper document has lines and columns. Most paper pick documents use standard style type black ink characters and digits on white paper. To obtain the pick instruction, the paper pick document method requires an order picker to read the proper line for a SKU pick position and SKU quantity. After a pick position transaction completion, the order picker places a mark adjacent to the appropriate line or location on the paper document. This mark verifies the SKU pick activity completion.


28


A self-adhesive label placed onto a SKU exterior surface, a paperless (pick to light or RF device) pick instruction, or an automatic pick method reduces several order picker unproductive activities: reading the order pick document and locating the specific line for a pick transaction, and placing a mark on a paper pick document that verifies pick transaction completion. Eliminating these activities reduces an employee’s unproductive clerk activities in an order pick activity.

DEVELOP A GOOD EQUIPMENT AND FACILITY LAYOUT AND FLOW PATTERN The next order-fulfillment and across-the-dock operation employee productivity improvement guideline is to develop a good equipment and facility layout and piece flow pattern for a pick line or pick aisle and travel paths. The order-fulfillment or across-the-dock operation order pickers, employees, and pieces flow between two facility locations, through the pick aisles to the pick positions, and through a sorting method. These activities require material handling equipment that occupies space. A good equipment and facility layout and piece flow pattern ensure minimal piece and employee travel time and distance, a continuous employee piece flow between two facility locations; good facility space utilization; accurate and on-time piece or customer-order deliveries with minimal damage; and sufficient aisle width to ensure an on-time transaction completion with minimal damage. All these factors improve employee productivity at the lowest operating cost.

MAINTAIN CLEAR AISLES

AND

PRACTICE GOOD HOUSEKEEPING

The next order-fulfillment employee productivity improvement guideline is to maintain clear aisles and practice good housekeeping. As an order picker or replenishment employee travels through a pick aisle or replenishment aisle pick positions, to ensure proper travel speed without unintentional stops, all pick and replenishment aisles must be clean and must not have obstacles. Many order-fulfillment professionals have stated that good housekeeping in a distribution operation enhances employee productivity by 5%.

MAINTAIN GOOD LIGHTING

IN THE

PICK AISLE

OR

PICK LINE

The next order-fulfillment employee productivity improvement guideline is to have good lighting in a pick aisle, pick line, or replenishment aisle. The light fixture options for your pick line or pick aisle are to have the light fixtures hung directly above a pick or replenishment aisle center or perpendicular to a pick and replenishment aisle. This arrangement has the light fixtures above the rack or shelf pick positions. With both alternative light fixture arrangements, the light fixture program requires you to specify the desired lighting (lumen) level at 30 inches above the floor surface. With the light fixtures hung directly above a pick or replenishment aisle center, the light fixtures hang from the ceiling joists, cross support members that are attached to the pick position structural members, or onto the second-level mezzanine or walkway support members. This light fixture arrangement has fixtures that illuminate a pick or replenishment aisle’s entire length and width. When required to



29

replace a light fixture, the maintenance employees have easy access to the fixtures. Your pick or replenishment employees are generally more familiar with this light fixture arrangement. When the light fixture arrangement is perpendicular to a pick or replenishment aisle and above the rack or shelf pick positions, it has light fixtures that are hung from the second-floor structural support members. In this arrangement a light fixture row begins above your first pick row, continues above the other pick rows and aisles, and ends above your last pick row. The center spacing between the light fixture rows ensures that the light (lumen) level is as specified by your written functional specifications. To replace light fixtures, your maintenance employees have a more difficult task with this arrangement because the light fixtures are above the pick positions, making them less accessible. Your warehouse employees are unlikely to have this type of light fixture arrangement in their homes or retail shops and are less familiar with it.

CHANGE YOUR EMPLOYEE WORK MACHINE-PACED METHOD

FROM A

HUMAN-PACED METHOD

TO A

A technique to dramatically improve your order-fulfillment or across-the-dock employee productivity is to change work from a human-paced method to a machinepaced method. When considering this change, you identify your order-fulfillment or across-the-dock operational functions that have a large employee number; the highest overtime; a large degree of piece, building, or equipment damage; the highest employee injuries; high off-scheduled activities; and high errors. When you are looking to improve an order-fulfillment or across-the-dock employee work activity, you match the activity with the equipment. Some considerations are to use nonpowered or powered queue conveyors or automatic guided vehicles (AGVs) or another transport method that moves multiple pieces or customer orders between two work stations; to mechanize or automate your piece or customerorder delivery to a work station; to attach a bar code or RF tag to your piece or customer-order and use bar code scanners or RF readers; to automate work activities such as labeling, picking, weighing, and sorting; and to use guided aisles for mobile vehicle travel.

ADD MATERIAL HANDLING YOUR EMPLOYEE WORK

OR

PIECE TRANSPORTATION EQUIPMENT

TO

In your order-fulfillment or across-the-dock operation, the most dramatic employee efficiency improvements are realized from equipment or methods used to handle or transport the maximum piece or customer-order number per trip between two work stations with the fewest handlings. The piece or customer-order equipment or method applications for your consideration are manual operated carts or pallet trucks; internal combustion or electric battery powered forklift trucks, pallet trucks, AGVs, or towed carts; nonpowered or electric powered conveyors; guided powered vehicles; a computer to schedule labor, equipment, and vendor deliveries; mechanized piece or customer-order transport methods; a method to identify each piece or customer order at a vendor facility and at your receiving dock; a method for separating into


30


units securing the largest piece quantity; and a means of providing sufficient piece or customer-order queuing prior to each activity.

USE AUTOMATIC IDENTIFICATION The next order-fulfillment or across-the-dock operation employee productivity improvement guideline is to use automatic identification for an activity that handles a piece or customer-order. The automatic identification method is a human- or machine-readable discrete code on a label, paper, or RF tag that is attached to a piece, master carton, pallet, small-item, flat wear, GOH, or customer-order. The labeled piece or customer-order is placed onto a transport method. This code is read by a bar code scanning or RF tag reading device that transmits the code data accurately online to a microcomputer. The microcomputer controls another machine that responds to the code information or stores the information in memory. The automatic identification method features are a high volume and a wide piece mix, having accurate information and online information flow, utilizing fewer employees, reduced data transfer errors, and minimized piece or customer-order transfer errors.

PROVIDE SUFFICIENT WORK The next order-fulfillment or across-the-dock operation guideline to improve employee productivity is to provide sufficient work for the employee workday. With the projected order-fulfillment pick and across-the-dock piece volume along with your expected employee productivity rates for a pick line and across-the-dock operation, you forecast the required employee number to complete the piece or customer-order volume transactions. If the actual employee number exceeds the projected required employee number, you allocate the extra employees to other logistics segment value-added activities. When compared to an unplanned employee reassignment to another order-fulfillment or across-the-dock activity, this preplanning for an employee to relocate to another activity minimizes the unproductive time for an employee to change activities.

USE THE PICK AND PACK METHOD FOR HIGH VOLUME OF A FEW SINGLEITEM OR FLAT WEAR APPAREL SKUS FOR SINGLE-CUSTOMER ORDERS An order-fulfillment employee productivity improvement guideline is that if your order-fulfillment operation has a high volume for a few single-item, flat wear apparel, or GOH SKUs, it means that you consider to pick and pack these SKUs and customer orders off-line. The off-line pick and pack activity is a single item activity that occurs when your order-fulfillment operation has a high single-line customer-order volume that has the same SKU or a pair (two SKUs) on your customer orders. The pick and pack activity has one or two additional steps in the normal order pick activity. When compared to the normal or individual employee pick activity, there is a slight decrease in the order pick productivity because the order picker picks, packs, seals, and labels the customer shipping container. This total pick and pack activity performed by one



31

employee or an employee group dramatically improves the total order-fulfillment operation employee productivity and piece flow because the merchandise is picked in a batch and the picked SKUs and customer orders bypass the normal packing and check station. If the SKU is picked as a batch and transferred to a specific pick and pack station, the order picker productivity is very high. With an off-line pick and pack activity, one order picker picks all SKUs, packs the customer pack slip and SKU into a customer shipping carton, seals and labels the order carton, and places the carton onto a take-away conveyor or material handling device. An off-line order-fulfillment employee productivity improvement guideline is to have multiple pick lines that handle the top 20% or high-volume SKUs. Each of the multiple offline pick lines has a transport method for completed customer-order transport to the next pick line station and a second transport method for all partially completed customer orders that require additional picks from SKUs in the slowmoving pick area.

ENSURE ON-TIME

AND

ACCURATE PICK POSITION REPLENISHMENT

The next order-fulfillment employee productivity improvement guideline is to ensure on-time and accurate pick position replenishment. On-time and accurate pick position replenishment ensures that the correct SKU is in the correct pick position in sufficient quantity to satisfy the customer-order quantity prior to the employee order picker or automatic pick device arriving at the pick position. During the orderfulfillment process a stock out occurs as an employee order picker or automatic pick device arrives at a pick position to complete a customer-order, and the pick position is depleted or has an insufficient SKU quantity to complete a customer-order. When a stock out occurs on a pick line, an employee order picker or automatic pick device has completed the travel distance and used the required travel time but has not completed a pick transaction. This means low employee productivity and a potential dissatisfied customer. On-time and accurate pick position replenishment is important to have a productive small-item, flat wear, GOH, or carton pick operation.

DETERMINE WHERE

TO

START

THE

SINGLE-ITEM ORDER PICKERS

On a single-item pick and pack line or pick and pass operation, the next order picker productivity improvement guideline is to have the order picker start at the pick line front. Single-item order pick line or pick aisle layouts have the fast-moving, heavyweight, and high-cube SKUs located in one pick area and the slow-moving, smallcube, and lightweight SKUs located in a separate pick line or pick zone. To obtain high employee productivity in a single customer-order pick and pack or batched customer-order pick and sort operation, you must determine in what section to start an order picker or locate an automatic pick machine. In the single-item order pick area design, the fast-moving SKUs represent 80% of the pick volume from 20% of the SKUs and the slow-moving SKUs represent 20% of the pick volume and 80% of the SKUs. On a single-item pick and pack order pick line, the order picker start locations are to start the order picker in the fast-moving, heavyweight, and high-cube pick


32


line section with the next pick line section to have the medium- to slow-moving, lightweight, and small-cube SKUs or automatic pick machine. Another option is to have the slow- to medium-moving, lightweight, and small-cube SKU pick line section at the automatic pick machine with the next pick line section to have the fast-moving, heavyweight, and high-cube SKUs. If an order picker starts in the fast-moving, heavyweight, and high-cube SKU pick line section, the results are improved pick position replenishment, high volume handled by the pick line, and a more continuous customer-order flow from a pick line to the check area due to faster customer completion. With slow-moving, lightweight, and small-size SKUs at the pick line end, it is easier for the order picker to place the SKUs into the customer shipping carton. There is a decrease in the customer carton handling number, and the method ensures high order picker productivity. The reason is the fast-moving SKUs with high hit density and concentration and the high-cube and heavyweight SKUs are easily read on the order picker instruction form (at the top) and are the first SKUs transferred into the customer carton. If an order picker starts in the slow-moving, lightweight, and small-cube SKU pick section or with the automatic pick machine section, a lower order picker productivity results because an order picker in the fast-moving, heavyweight, and high-cube SKU pick line area handles two cartons for a customer-order. This is due to the fact that one container is partially full with slow-moving SKUs and is topped off with fast-moving, heavyweight, and high-cube SKUs, and a second carton is required for the remaining fast-moving, heavyweight, or high-cube SKUs. With a paper pick instruction it is more difficult to read the order pick instruction document because the fast-moving SKUs are located at the order pick instruction document bottom. On a conveyor travel path, a slow-moving SKU partially full carton (due to lighter weight) is more difficult to transport on the conveyor transport method. It is difficult to keep replenishment activities coordinated with the order pick activities because the slow-moving SKU replenishment is handled prior to the fast-moving SKU replenishment. There is lower order picker productivity because for an order picker to transfer SKUs into the pick carton or to make space in a container for the fast-moving, heavyweight, or high-cube SKUs in a partially full carton, the order picker must rearrange the SKUs in the carton. This SKU rearrangement time in a pick carton is unproductive order picker time. If the single-item order-fulfillment operation handles each carton for one customer-order or multiple cartons for one customer-order and your pick line transport method has a bypass transport conveyor for full cartons or completed customer orders, the preferred start location is at the fast-moving, heavyweight, and high-cube SKUs section on the pick line.

HAVE AN ARITHMETIC PROGRESSION THE PICK LINE

THROUGH A

PICK AISLE

OR ALONG

An order-fulfillment operation employee productivity improvement guideline is to have an arithmetic pick position progression through a pick aisle or along the



33

pick line. The sequential arrangement for the pick positions on an order pick aisle or pick line is that the arithmetic progression method routes the order picker to remove single items, flat wear, GOH, and cartons from a pick position as the order picker walks or rides through the pick aisle or along the pick line. The arithmetic progression has the first pick position at the entrance to the aisle or line as the lowest pick position number, and the last pick position has the highest pick position number. In decked-rack, shelf, or flow-rack small-item and flat wear apparel pick-line applications, for the decked-rack, shelf, or flow-rack bay the preferred order picker routing pattern is the horizontal scheme rather than the vertical routing pattern. The horizontal pick routing scheme has an order picker start at the highest right- or lefthand corner bay pick position. From this pick position, the next possible pick position is on the same level and is adjacent to the first pick position. After all picks on the top level are completed, the order picker routing pattern is continued on the next lower bay pick level. This pattern is repeated for all pick levels. The advantages of the method are that it is easy to read and follow, high-volume and high-cube items occupy multiple locations in the golden zone, and it is easy to upgrade from a pick document to a paperless pick method.

PICK POSITION NUMBERS THAT END WITH EVEN NUMBERS ON THE RIGHT AND PICK POSITION NUMBERS THAT END WITH ODD NUMBERS ON THE LEFT The next manual single-item, flat wear apparel, GOH, or carton order-fulfillment operation employee productivity improvement guideline is to have the pick position numbers that end with even numbers on the pick aisle’s right side and the pick position numbers that end with odd numbers on the pick aisle’s left side. This will help to maximize order picker productivity. During the pick activity through the pick aisle, this numbering pattern reduces confusion; your employee daily activities have a similar numerical arrangement and when an order picker reads the pick instruction form, the even and odd number pick position scheme automatically directs the order picker to the proper pick aisle side.

INCREASE YOUR EMPLOYEE PRIDE Your next method to improve your order-fulfillment or across-the-dock operation employee productivity is to have your employees take pride in their company and in their work. Improvement in employee productivity is realized by participating in a customer delivery truck or forklift truck rodeo; posting a company sign at the facility entrance; recognizing accurate, high productivity, employee injury-free workdays and on-schedule work; supplying uniforms; presenting awards for punctuality and good attendance; having a family outing at your facility; promoting team participation; knowing your employees’ names, birthdays, and family histories; and providing a clean and properly lighted work area and safe equipment.


34

IMPLEMENT

Order-Fulfillment Concepts, Design, and Operations A

WORK INCENTIVE PROGRAM

You can increase order-fulfillment or across-the-dock productivity by motivating your employees with a work incentive program that gives them additional money or something of value for extra effort or achievement. In some companies, an incentive program has increased employee productivity by 10 to 15%. A good employee incentive program is well researched and outlined; it is also measurable, achievable, understandable, clear, fair, and administered equitably. If the order-fulfillment or across-the-dock employee work changes, the employee work incentive program changes.

CONTROLLING YOUR ORDER-FULFILLMENT DOCK OPERATION

OR

ACROSS-THE-

To have an efficient and cost-effective order-fulfillment or across-the-dock operation, your order-fulfillment or across-the-dock operation requirements are to have an accurate projected order-fulfillment or across-the-dock piece or customer-order volume, prepare an accurate annual operating expense budget, and use the short-interval schedule method. Design Year Piece Volume Level When you design an order-fulfillment or across-the-dock operation method for your new operation or consider new equipment in an existing operation, you design the facility’s key order-fulfillment or across-the-dock operation functional areas to handle a specific piece volume. When you project your order-fulfillment or across-thedock operational piece volume, you determine your operation’s piece or customerorder volume and associated order-fulfillment (pick) and across-the-dock transactions. Your design year piece or customer-order volume levels are average volume, volume between the average volume and peak volume, and peak or spike volume. If you design your order-fulfillment and across-the-dock operation method to handle your average piece volume and your actual piece volume exceeds the average piece volume, your operation situations include off-schedule activities or customer deliveries; employee overtime; increased building, equipment, and piece damage and employee injuries; and high customer complaints. For an average piece volume level, the features are a small-size land and building, lower capital investment, and low fixed material handling cost per piece. If your order-fulfillment or across-the-dock method is designed to handle a piece volume that is somewhere between your average and peak piece volume levels, when your order-fulfillment or across-the-dock actual volume exceeds the design volume, your operation situations include employee overtime; load-carrying surface, employee, or vehicle congestion; increased piece, equipment, and building damage; off-schedule activities and customer deliveries; and some customer complaints. This piece volume design level that is somewhere between your average and peak piece volume levels has advantages. These include a medium land site and building size and a medium capital investment and a medium fixed cost per unit.



35

If your order-fulfillment or across-the-dock method is designed to handle your peak volume, when your actual volume arrives at a peak volume, your operation does not experience late activities or customer deliveries and customer complaints. The peak design volume level features are a large-size site and building and additional investment, a high fixed cost per unit, and excellent customer service.

EMPLOYEE PRODUCTIVITY MUST BE TIED AND ACROSS-THE-DOCK OPERATION

TO

YOUR ORDER-FULFILLMENT

An order-fulfillment or across-the-dock employee productivity program’s true value is that it provides your order-fulfillment or across-the-dock operational manager with an employee productivity rate that is considered an accurate forecast tool. This forecast tool is used to project and control your order-fulfillment or across-the-dock labor expense dollars and to provide on-schedule service to your customers. The employee productivity rate is the basis to calculate your annual order-fulfillment or across-the-dock operational budget labor expense dollars; to make a budget dollar justification for a capital expenditure; and to forecast your labor hours, expense, pieces, vehicle deliveries, and equipment and labor schedules or number of employees per shift. After your employee productivity program is implemented in your operation, this employee productivity rate is tied to your order-fulfillment or across-the-dock operating labor expense budget and is related to your capital expenditure justification. If your order-fulfillment or across-the-dock employees do not achieve this projected employee pick or across-the-dock productivity rate, your operational performance is below par. This below par performance increases the overall company operational cost per piece or customer-order and lowers the company profits.

SHORT-INTERVAL SCHEDULING Short-interval scheduling (SIS) is a method that tracks your order-fulfillment or across-the-dock operational employee pick or handling productivity. The method is implemented in a single-item, flat wear, GOH, carton, or pallet order-fulfillment or across-the-dock operation. This operation is a manual, mechanized, or automated operation in a small, medium, or large company. This SIS method is used to track an order-fulfillment or across-the-dock individual employee pick or handling productivity for an entire shift or the work activities that are required to complete a customer-order. The SIS method is designed as a manual- or personnel computerbased method. The SIS method steps are as follows. There is a discrete order picker or delivery vehicle identification. Each employee at the dispatch station is issued the pick instructions or customer-order section or vendor delivery truck self-adhesive labels for a vendor delivery. If a vendor delivery truck has labeled pieces, the employee or employee group is assigned to handle the delivery vehicle pieces. Project the order picker or employee time to complete the task and identify the order picker or order pick vehicle travel path. Per the pick instruction, an order picker or order pick vehicle


36


stops at the required pick position or the across-the-dock employee opens a delivery truck’s doors. The employee completes all picks for a customer-order or across-thedock unloading transaction and returns to the dispatch station to receive another customer-order pick instruction or another customer delivery truck instruction.

SIS

FOR

YOUR ORDER-FULFILLMENT

OR

ACROSS-THE-DOCK ACTIVITIES

The SIS method is for the manual order-fulfillment or across-the-dock method activities in an operation. This method has a clerk who is located at a control desk. Customer-order portions are divided by a goal set employee productivity rate per hour. This rate is predetermined for each pick aisle. This feature does recognize the difference in travel minutes that an order picker travels from a control station to a pick aisle and all the activities to ensure that the customer-order is picked and delivered from the pick area to the assigned location. The result is the time that is projected for an order picker to travel from the control station, in a pick aisle to complete all pick transactions, and to deliver a customer-order portion to an assigned shipping staging area.

HOW SIS WORKS An employee or computer performs the SIS method. The employee SIS method has a bar chart with columns across the top of the page. These columns are divided into 15-minute or other predetermined time intervals. Horizontal rows start at the page top and go to the page bottom. These rows extend across the page under each column; each row represents an individual employee activity; and each employee has a bar chart page. An employee name is written on the first horizontal bar chart line. The next two horizontal lines are used for each customer-order-fulfillment or across-the-dock transaction. On the first horizontal row, a line is drawn from the issue time to the projected return time. After an employee returns to the control station, on the second row a second line is drawn from the issue time to the actual return time. The difference between the two horizontal lines is the difference between the projected employee productivity time and the actual employee productivity time. This difference shows the employee status which is on-schedule or off-schedule. Each subsequent employee activity is listed below on the two horizontal row sets. At the beginning of each workday and at the control station, each employee is given a customer-order section or an order to unload a vendor delivery truck. Upon the first customer-order section or vendor delivery truck completion, the employee returns to the control desk. At the control desk, the employee receives another customer-order section or a new vendor delivery truck. The actual employee return time is indicated on the employee corresponding event horizontal bar under the appropriate time column. The projected return time to the actual employee return time comparison indicates an employee’s actual productivity. This provides you with an on-time and exact review for each employee’s productivity performance. The employee’s actual performance is compared to your employee productivity standard.



37

If your employee’s actual time consistently beats the projected return time, your order-fulfillment or across-the-dock operation performance is better than your annual expense budgeted labor dollar amount. This excellent performance means that actual labor dollar expense is below the budgeted labor dollar expense. If your employee’s actual return time consistently exceeds the projected return time, your order-fulfillment or across-the-dock performance is lower than your annual expense dollar budget amount. This poor performance means that your actual labor expenses exceed the annual dollar budget expense amount.

HOW TO PROJECT YOUR ORDER-FULFILLMENT OR ACROSS-THE-DOCK OPERATING BUDGET Top management teams are requesting order-fulfillment or across-the-dock operational managers to prepare an annual order-fulfillment or across-the-dock operating budget. The reasons for the increase in the annual operating expense budget requests are to plan for labor and material handling equipment adjustments that result from business volume fluctuations, to anticipate and control the company cash flow, to review the operation’s actual labor expense and budgeted labor expense variance, and to act as bases for capital investment requests for a new order-fulfillment or across-the-dock method. With a large order-fulfillment or across-the-dock operation labor dollar expense amount, your budget is prepared in a sophisticated and realistic manner.

ANNUAL ORDER-FULFILLMENT OR ACROSS-THE-DOCK OPERATING EXPENSE BUDGET METHODS The order-fulfillment or across-the-dock operation annual expense budget preparation methods are the simple percentage increase method and the detailed line-item and man-hour SIS-based budget method. Both are calculated by an order-fulfillment or across-the-dock department staff member or by a computer. Simple Percentage Increase Annual Operating Expense Method The simple percentage increase annual order-fulfillment or across-the-dock operating expense budget has to determine the last fiscal year order-fulfillment or across-thedock operation annual operating expense dollar amount and obtain the percentage increase for the next fiscal year business volume. Then, in order to calculate the next fiscal year annual operating expense budget, you multiply the last fiscal year order-fulfillment or across-the-dock operation annual operating expense by the next fiscal year business volume percentage increase. Detailed Line-Item and Man-Hour SIS Budget Method The detailed line-item and man-hour SIS budget method is the second budget method. This budget method projects your company’s order-fulfillment or across-


38


the-dock operation annual operating expense. To be an effective management tool, the projected annual operational expense is shown for each period and fiscal year quarter. The company fiscal year is for a 52-week period. This week period agrees with the calendar or starts on a day other than January 1. The detailed line-item and man-hour SIS budget method recognizes that your order-fulfillment or across-the-dock method’s operational expenses fluctuate with your business volume and that your expenses consist of controllable and noncontrollable expenses. Controllable expenses are controlled by your management staff and are related to fluctuations in your business volume. The noncontrollable expenses are not controlled by your management staff and generally do not fluctuate with your business volume. The detailed line-item and man-hour SIS budget method requires you to project your order-fulfillment or across-the-dock method operation facility’s annual controllable and noncontrollable operating expenses. Controllable order-fulfillment or across-the-dock operation expenses are based on anticipated order-fulfillment or across-the-dock operation employee productivity rates, projected business volume, and contractual hourly wage rates. Some controllable expenses are labor; labor fringe benefits; piece, equipment, and building damage and employee injuries; supplies; and repairs. The noncontrollable order-fulfillment or across-the-dock annual operating expenses are based on financial department accounting methods and company nonlabor contracts. Noncontrollable expenses include labor wage rate and fringe benefits, depreciation, taxes, rent or lease rates, and third-party logistics contracts. How to Work with the Detailed Line-Item and Man-Hour SIS Budget Method After you establish your order-fulfillment or across-the-dock operation’s next fiscal year annual operating objectives, employee productivity rates, and business volume, you perform the calculations for the dollar expense budget. The budget expense is calculated for each period or fiscal year quarter. The budget process has each expense item on your order-fulfillment or across-the-dock operation’s next year fiscal budget compared to last fiscal year’s expense item actual dollar expense amount. If management requires a justification for next fiscal year’s budget expense item increase or decrease, the detailed line-item and man-hour budget method provides a complete analysis and permits you to make a statement that substantiates the line-item dollar increase or decrease. This expense fluctuation is related to your projected orderfulfillment or across-the-dock operation’s next fiscal year business volume or is substantiated by your justification. The detail line-item and man-hour budget separates your order-fulfillment or across-the-dock operation’s annual operating expenses into wages, salaries, and fringe benefits as a subtotal; other controllable expenses are separated as a second subtotal, while noncontrollable expenses are separated as a third subtotal. The detailed line-item and man-hour annual operating expense budget method calculations identify, qualify, and quantify for the fiscal year each operating



39

expense item as a controllable or noncontrollable expense item or income; obtain your company’s next fiscal year period, quarter, and annual operating calendar end dates; determine the dollar value for your company’s next fiscal year period, quarter, and annual noncontrollable expenses; project the period of completion for a capital expenditure and its impact on the next fiscal year annual operating expenses, such as depreciation and labor productivity improvements; determine the next fiscal year period projected employee productivity rate for each orderfulfillment or across-the-dock operation activity; obtain the next fiscal year annual business volume; obtain the projected hourly wage rate increase and period that an increase is to occur for each employee job classification, fringe benefits, and payroll tax rates; forecast all expected and unexpected activities and their impact on the annual operating expenses; determine the next fiscal year item and manhour annual operating expenses; identify, qualify, and quantify all annual income items for the fiscal year; and review each item’s projected expenses with your financial manager. The first step of the detailed line-item and man-hour budget method is to identify, qualify, and quantify each major expense item for the last fiscal year order-fulfillment or across-the-dock operating expense as a controllable or noncontrollable expense item. The most important expense classification is the controllable expenses because they fluctuate with an increase or decrease in the business volume. The expense dollar value increase or decrease is controlled by the order-fulfillment or across-thedock manager’s decisions. The operation’s controllable expenses are wages for all labor groups; fringe benefits; trash disposal; pallet purchases; product, building, and equipment damage and employee injury; operating supplies; guard service; sundry or other items; and telephone and fax expenses. During a review meeting with your financial manager, you obtain the past fiscal year dollar value for each controllable expense item. If the past fiscal year dollar expense figures do not cover 12 or 13 months, the order-fulfillment or across-thedock manager uses the required periods from the previous fiscal year to obtain or estimate a total for the present fiscal year periods. You also obtain the next fiscal year calendar or schedule for each month and quarter end dates. The schedule of these calendar end dates indicates each of the 13 period calendar end dates. Each period consists of 4 weeks. Three quarters of the calendar year consist of 3 periods or 12 weeks. One quarter has 4 periods or 16 weeks. The financial manager determines the 16-week quarter position on the fiscal calendar. Noncontrollable Expense Projection At the financial manager meeting, you receive the financial manager’s projection for the noncontrollable expenses. The noncontrollable expense items of the orderfulfillment or across-the-dock operation do not have a dollar value fluctuation with an increase or decrease in the business volume. These expense items are not within an operations manager’s control. The manager has an opportunity to review the budgeted dollar volume. The noncontrollable order-fulfillment or across-the-dock operation expenses are building and equipment rent or leases, property and other


40


taxes, insurance, utilities, equipment and building equipment depreciation, and office administration. After both managers agree with each line-item annual dollar value for the next fiscal year operating budget, the operations manager enters each annual line-item budget figure onto the individual budget expense account sheet. The individual budget expense account sheet is a sheet that shows the budget expense for each line item. On the individual account sheet, the manger enters all information that relates to the dollar budget value calculation. After all individual noncontrollable account sheets are completed by the operations manager, each line-item annual figure is transferred from the individual budget expense account sheet to the operating plan sheet appropriate line and column. When all noncontrollable individual line items are transferred to the operating sheet, the manager calculates the total. These calculations are the operating plan subtotal for the fixed expense line subtotal. Controllable Expense Projection The next step of the budget process is for the operations manager to determine the next fiscal year controllable expense dollar budget value for each line item. The financial manager and operations manager determine the weighted average wage rate for each order-fulfillment or across-the-dock labor job classification. This step requires a meeting with the sales or purchasing manager. At this meeting the manager receives the business piece volume projections for the year. After this meeting, the operations manager enters each business volume projection onto the appropriate line of the direct labor wage work sheet. On this work sheet, the operations manager enters each direct labor activity per shift. These activities are required to move the piece or customer-order volume though an operation. At a review meeting with the operations management staff, the operations manager projects the next fiscal year direct labor productivity rate for each shift. Direct-labor employees are considered employees who physically move your piece or control order-fulfillment or across-the-dock equipment that moves a piece. With next year’s employee productivity rates and business volumes, the operations manager calculates each shift’s direct labor gross available hours. The gross available hours or total hours are separated into subtotals for full-time or part-time employee straight (regular) hours and full-time or part-time employee overtime (OT) hours. With these gross available hour figures, the operations manager enters the corresponding average hourly wage rate for each type of job classification. As required, this hourly wage rate includes the nighttime premium per hour. If an employee contract requires an hourly wage increase, the operations manager indicates the hourly wage increase in the period that the hourly wage increase occurs and states this fact on the work sheet section. The hourly wage rate is the weighted average wage rate that was calculated by the financial manager and operations manager. The next required direct labor budget calculation is to determine the dollar expense values that are associated with the hourly direct labor. This requires that



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each labor group’s gross available hours are multiplied by the corresponding hourly wage rate. After all calculations are totaled for the fiscal year, the operations manager enters the figures onto the direct labor line of the quarter order-fulfillment or acrossthe-dock operations facility direct labor wage work sheet and operating plan sheet. The remaining labor budget line items include the indirect labor. The indirect labor is the labor that is required to support the operations, and these employees do not touch a piece or control order-fulfillment or across-the-dock equipment that moves a piece. The indirect labor classification includes supervision, clerical, cleaning or sanitation; general; and security and maintenance labor. Each indirect labor classification has its individual work sheet. As required the expense increase or decrease justification is explained at the bottom of the sheet. Management Salary An indirect labor budget expense is the salaries for the order-fulfillment or acrossthe-dock operations management staff. To budget this expense item, the operations manager enters each supervisor name or anticipated position on the operations facility indirect salary labor work sheet. After each manager staff name or position, an X is placed that indicates a salary expense for the fiscal year. On the total line, the operations manager enters a total management dollar value expense for the fiscal year. When management salary increases are granted to the management staff, it is indicated in the appropriate period. After the management team work sheet is completed, the operations manager transfers the bottom-line dollar expense total for each period to the appropriate line of the operating planning sheet. To determine the other hourly and indirect labor job wage expenses, the operations manager determines the indirect labor job number that requires regular pay and OT pay and average hourly wage for the fiscal year. After the dollar calculations are completed for the fiscal year, the operation manager transfers the dollar value from the operations facility indirect hourly wage sheet to the operating planning sheet. Nonworking Hour Expenses The next calculation is the nonworking hour calculation, which is the dollar expense value for nonworking and employee paid jobs. Some nonworking hours are sick days, sick leave, and jury duty. These nonworking hours are additions to the net available straight or regular employee hours. On the nonworking hours sheet, each expense is indicated and in the explanation section the operations manager makes a statement as to the type of nonworking hours and average hour wage rate. The dollar expense is calculated for each type of hour and is entered in the appropriate period. After the nonworking hour sheet is totaled, the figures for the fiscal year are transferred to the appropriate line of the operating planning sheet. On the operating planning sheet, the operations manager adds the year wage lines to obtain a wage bottom-line figure, which is the operation wage expense for a fiscal year.


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Fringe Benefits and Taxes The next major calculation for the detailed line-item and man-hour budget method is the employee fringe benefits and payroll tax line item. The operations manager refers to the employee contract and payroll tax laws. This information is obtained from the financial manager and determines the fringe benefits and payroll tax budget expense. Some fringe benefits include holidays, pensions, thrift plan, group insurance, vacations, workmen’s compensation, and other benefits (e.g., cafeteria or child care). Payroll taxes are the Federal Insurance Contributions Act (FICA) and federal and local government taxes. Each fringe benefit and payroll tax has an individual account work sheet. After each fringe benefit and payroll tax expense is calculated for each period, the operations manager transfers each period expense from the individual work sheet to the appropriate line on the fringe benefit and payroll tax summary sheet. For vacations, historical employee payroll records indicate the period that these fringe benefits were taken by an employee. If this information is not available, the operations manager projects the period for these expenses. After all fringe benefits and payroll tax budget figures are transferred to the fringe benefit and payroll tax summary sheet, the operations manager adds the line items to obtain a fringe benefit and payroll tax bottom-line figure. This dollar figure is the operation fringe benefit and payroll tax budget expense for the fiscal year. This bottomline figure is transferred to the appropriate line on the operating planning sheet. After the fringe benefit and payroll tax transfer, the operations manager totals direct labor, indirect nonworking expenses, fringe benefits, and payroll tax lines. The sum is the bottom-line figure for the operating planning sheet wage and salary controllable expense line. Other Controllable Expenses The last detailed line-item and man-hour budget expense group is the other controllable expense group that includes miscellaneous and sundry purchases, repairs, trash disposal, damage, operating supplies, guard service, and telephone. On a controllable individual budget expense account work sheet, the operations manager determines the fiscal year budget expense. Explanation statements are made on this sheet that substantiate line-item budget expense increase or decrease. These statements are contract agreements and anticipated special events. After each controllable individual expense account work sheet completion, the operations manager transfers the fiscal year budget expense amount to the appropriate line on the operating planning sheet. On the operating planning sheet, the operations manager adds the line items. The sum is the operation’s other controllable bottom-line expenses. To obtain the gross total budget expense for the operation, the operations manager adds the three major groups of the budget fiscal subtotal lines. There are several disadvantages to consider with this method. It is an involved task, requires exact past records and projected order-fulfillment or across-the-dock



43

employee pick and handling productivity rates, and requires several days for calculations. A computer program simplifies the budget process or task and reduces the time that is required to make the calculations or revisions. The advantages are that the method provides top, middle, and lower management with the ability to plan, control, and review your operation; and provides an understanding for an actual and budget dollar expense variance. This feature exists because each dollar expense is related to the next fiscal year projected business volume.

WHY HAVE CAPITAL INVESTMENTS? In the order-fulfillment or across-the-dock industry, major capital expenditures are related to an expansion that maintains the business growth, to improving a manual order-fulfillment or across-the-dock method, and to replacing a manual order-fulfillment or across-the-dock method with a mechanized or automated method. The order-fulfillment or across-the-dock method’s objectives are to increase the piece and customer-order number that is handled by your operation, to lower your operation annual expenses, and to maintain or to improve your on-schedule and accurate customer service.

WHAT IS

THE

CAPITAL EXPENDITURE JUSTIFICATION?

The majority of a financial justification for the proposed order-fulfillment or acrossthe-dock method is based on the projected business volume, the employee productivity and operating expenses for your existing order operation, and employee productivity and operating expenses for the proposed method. The cost figures determine the labor expense savings and the associated order-fulfillment or across-the-dock method savings. The other economic justification factors are facility construction costs; land costs and site preparation costs; other costs including building, piece, and equipment damage and employee injuries; and method investment and related depreciation expenses. The savings between the existing and proposed method provide the return on investment that is the payback for the capital investment. It is clearly recognized and understood that the numerous other costs and noneconomic factors are the customer service standard and business growth and SKU expansion. Whenever possible, these noneconomic factors are used to justify an operation capital expenditure.

HOW DEPRECIATION EXPENSE AFFECTS YOUR COMPANY INCOME STATEMENT AND BALANCE SHEET After your company makes a capital expenditure in a new order-fulfillment or acrossthe-dock method, the capital expenditure has a tremendous impact on your operation budget and actual operational expenses. The new method investment is an asset that appears on your company balance sheet. Good accounting practice has the new method listed as an asset and it is depreciated over a period of years. This depreciation is in the form of the annual depreciation expense. Depreciation expense is


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calculated by your accounting department and is the wearing down of an asset that occurs over time due to wear and tear. This annual depreciation expense is charged against your company’s income as an expense item.

HOW DOES YOUR EMPLOYEE PRODUCTIVITY AFFECT YOUR COMPANY’S INCOME STATEMENT? The employee productivity is the piece or customer-order number that one employee handles within a given time period, which is typically one hour. The employee productivity figure determines the employee hours or number of employees that worked in the operation, and is a component in the financial justification for your new method. Since your company pays an hourly wage to an employee, it is an expense item that appears on your company’s income statement. As an expense item, it is reduction to your company’s gross income. After all the expense items are subtracted from the gross income, the result is your company’s net income.

WHAT DOES GOOD EMPLOYEE PRODUCTIVITY MEAN TO YOUR COMPANY’S INCOME STATEMENT? We conclude that both the depreciation expense and employee wage expense have tremendous impact on your operation’s income. It is common knowledge that if an increase in one of your operations expense items is above the annual budgeted dollar expense amount, it causes a decrease in your company’s net income. A decrease in net income is not considered an operation objective. If a decrease in an order-fulfillment or across-the-dock method’s expense items is below the annual budgeted dollar expense amount, it causes an increase in your company’s net income. An increase in net income is considered an operational and company objective. When your company invests in a new method and your manager achieves or exceeds your company’s projected employee productivity rates that were used to justify the investment, there is no increase to your company’s cost. This situation means that there is no change to your company’s projected profit. If your order-fulfillment or across-the-dock method manager does not obtain your company’s projected employee productivity rates that were used to justify your capital expenditure, there is an increase to your operations expense. The additional labor expense raises your company’s cost unit or cost as a percentage of sales above your company’s projections. This situation increases your company cost and means that there is a lower company net profit.

REASONS FOR ECONOMIC JUSTIFICATION FACTORS Top management teams are requesting their order-fulfillment and across-the-dock operations managers to make comparative financial and nonfinancial justifications for their order-fulfillment or across-the-dock equipment capital expenditures. The



45

increase in these investment justification requests are because of the high dollar value for the modern order-fulfillment or across-the-dock method, high interest rates for borrowed money during certain periods, and limited company cash flow or capital expenditure funds. A capital expenditure investment is a project that has a life for more than one year or extends an asset’s life. The capital expenditure investment is allocated as a depreciation expense over your company’s future income. A low-dollar equipment replacement project is considered a company expense and is an expense against the year’s income. With the high-capital investment dollar amount that is associated with your proposed modern order-fulfillment or across-the-dock method, your financial evaluation analysis compares the alternatives in a realistic manner. Your company’s accounting manager is a member of your project team who provides the expertise to perform the economic justification calculations and ensures that your cash inflow and outflow classifications are within your company and Internal Revenue Service (IRS) or federal government tax on income policies.

ECONOMIC JUSTIFICATION PROCESS When you are assigned a project that requires an economic justification, your economic justification process steps are to determine the after-tax rate of return on the various methods and investments, the inflation rate per year, the growth rate per year, and the tax rate on taxable income; determine the life for the method; identify and qualify the capital investment items (cash outflows) and savings or income (cash inflows), the depreciation expense, and the resale value for the existing method; identify and qualify the noneconomic benefits for each method; and quantify or assign a numerical value for the economic and noneconomic benefits for each method.

ORDER-FULFILLMENT

OR

ACROSS-THE-DOCK METHOD ALTERNATIVES

Your first economic justification step is to develop a list for order-fulfillment or across-the-dock method alternatives. These alternatives are considered as a feasible solution to handle your company order-fulfillment or across-the-dock piece and customer-order business whether it is a new or remodel method. The alternative method factors are to determine the activities that are improved by the proposed method or the new method mechanization or automation. The other financial justification factors are available investment funds, SKU handling characteristics, piece or customer-order size or piece number or volume and the customerorder number, and other operational objectives.

WHAT IS

THE

USEFUL LIFE?

You determine the new order-fulfillment or across-the-dock method useful life to your company. In this phase, you estimate the years that your method expects to operate and handle your business volume.


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In this step, you define the project cost components. The cost components are the method material handling equipment, facility, land and landscape, and computer systems. This information is given to the accounting manager who confirms the anticipated useful life and determines the depreciation expense. The order-fulfillment or across-the-dock method annual depreciation expense is an expense item on your company’s income statement that reflects an annual decrease in the asset value that appears on your company’s balance sheet. The depreciation expense is used in the cash flow financial or working capital statement as an item that contributes to the payment of the investment.

WHAT IS

THE

RATE

OF

RETURN?

Your third item is to specify your company’s minimum acceptable rate of return from the capital investment. The minimum rate of return on the capital investment is the net (less expenses) annual cash inflows that are stated as a percentage of the capital investment. The cash inflows are the operational expense savings or income that is created from the project. This projected annual percentage compensates your company for the capital investment. The percentage on return allows your company’s executive management team to allocate your company’s discretionary funds to finance the project. The company project with the highest percentage on return is the project that is considered high priority for your company’s investment. You obtain from the accounting manager the available tax credits from the government and the minimum after tax rate or return on investment that your company considers financially attractive for its discretionary capital investment. A tax credit is a reduction in your company’s local or federal income tax that results from the investment. The tax credit is a percentage of the invested funds. If your company does not have a rate of return, you determine the rate of return. This figure is the present cost of money or the available interest rate.

WHAT ARE

THE INFLATION

RATE

AND

GROWTH RATE?

Your company’s annual growth rate and piece or customer-order volume growth rate are used in the financial analysis, and these rates are given by the accounting manager. If the inflation rate is not available, you use the inflation rate that is issued by the government. If the piece or customer-order volume growth rate is not available, your company’s historical growth rate is used as the future annual business growth rate. If the inflation rate is included in the business volume growth rate, the inflation rate is subtracted from the growth rate. The business volume growth rate is used to project the order-fulfillment or across-the-dock operation piece or customer volume. This piece or customer-order volume determines the operation’s required labor quantity; labor expense; manual, mechanized, or automated method; and other business expenses.



WHAT ARE

THE

47

ECONOMIC FACTORS?

Your fourth step is to determine the project’s financial or economic factors. These cash inflows and cash outflows result from the order-fulfillment or across-the-dock project. The cash inflows are funds that are operational expense reductions or income that is realized from asset sale. These assets were made available from the investment and the new order-fulfillment or across-the-dock operation start-up. The cash outflows are the capital expenditures for the building, land, site preparation, and equipment, with the required computer systems to operate the proposed operation.

WHAT ARE

THE

NONECONOMIC FACTORS?

Your fifth step is to identify the noneconomic or nonfinancial operational benefits to your company that result from a new method implementation. The factors do not have a tangible dollar value but do contribute to an efficient and effective order operation.

QUANTIFY

THE

ECONOMIC

AND

NONECONOMIC FACTORS

Your next step is to identify the economic and noneconomic project factors. This evaluation allows you to present the order-fulfillment or across-the-dock project that maximizes your company’s return on investment and satisfies your other company objectives. When ranking the economic and noneconomic factors, the cash inflow and cash outflow factors receive the highest value. When several order-fulfillment or across-the-dock methods have identical return on investment values, the ranking method that includes the financial and nonfinancial factors provides the total return on investment picture. This ranking method helps to determine a method that is preferred for your company’s investment and implementation.

ORDER-FULFILLMENT AND ACROSS-THE-DOCK METHOD IMPLEMENTATION AND PROJECT MANAGEMENT The following section reviews many aspects of order-fulfillment or the across-thedock method’s project management from financial justification to method implementation and start-up. The areas to be examined are estimating costs; writing functional specifications; reviewing vendor bids and administrating vendor contracts; reading blueprints and using metric measurements, military time, and Julian dates; and using consultants.

ORDER-FULFILLMENT OR ACROSS-THE-DOCK METHOD PROJECT MANAGEMENT ACTIVITIES When you are involved in an order-fulfillment or across-the-dock method project management design, purchase, and implementation, the activity sequence probably


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occurs in a sequence that is different from the order as presented in this chapter. It is the intent to provide insights and tips to the reader, not to present a fixed format for an order-fulfillment or across-the-dock method’s project management. To manage a project successfully and have the project come within budget and on time, you have a preplanned pattern for the events. The event order brings an order-fulfillment or across-the-dock method from a proposal phase through the vendor bid and implementation phase and to the start-up and operational phase. The project management process events are as follows: • • • • • • • •

• • • •

• •

Review order-fulfillment or across-the-dock method. Organize a project team. Collect piece and customer-order volume data and other method design information. Select and design the best method. Meet with suppliers and vendors and work with consultants to obtain method budget price quotes. Develop an economic and operational justification. Prepare and present a method proposal to your company’s top management. Prepare and write a method’s functional, technical, and general specifications; complete all method drawings; and send the request for quotes to the preferred vendors. Prepare and perform a method vendor bid review. Select the vendor and award and administer the vendor contracts. Review the building construction and vendor method drawings. During building construction and method installation, review and adjust building contractor and method vendor schedules and installation progress, make periodic payments, and award extras. Complete punch list and operational acceptance of the building and method. Assist with the method’s start-up and turn over to your company’s operations department.

HOW TO ESTIMATE COSTS, WRITE FUNCTIONAL SPECIFICATIONS, REVIEW BIDS, ADMINISTER CONTRACTS, AND IMPLEMENT YOUR ORDERFULFILLMENT OR ACROSS-THE-DOCK METHOD This section reviews a proven technique to manage an order-fulfillment or acrossthe-dock method project from the method design phase through the method installation and implementation phase to the start-up and operational phase. It includes how to cost-estimate a project, write project equipment bids and functional specifications, solicit vendor bids, and review vendor bids. It examines a method to administer financial control of your company’s building and method contract and a method for project implementation management.



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Cost Estimates In an order-fulfillment or across-the-dock method or building construction project, cost estimates allow you to establish and present to your top management a reliable estimate of building design required investment funds for a new facility or method. When this method cost estimate is compared to other company project cost estimates, it allows your top management to determine the company project that has the lowest cost and the best return on investment. Cost estimating is the process by which you develop the capital and expense requirements for the building construction, method installation, and land purchase for your proposed new method or facility. This land and facility with your orderfulfillment or across-the-dock concept is shown on the drawings and is described in your written functional specifications. There are many questions that are answered and information gathered prior to obtaining method, building design, and land cost estimates. It is important that you have accurate design information for a method, building construction, and land. The method, building construction, and land cost estimating objective is to include enough detail in a summary sheet. This approach permits your management to understand exactly what building design, method design, and land items that are included in your project will cost. The cost estimate types for a method, building construction, and land items are: •

•

•

Order of magnitude cost –– The order of magnitude cost estimate is a method cost estimate that varies by ±25%. The order of magnitude cost estimate is based on very broad design parameters and is given by a vendor in a very short time period. The order of magnitude cost estimate is used by your department to compare alternative methods. Budget cost –– The second cost estimate is the budget cost estimate. The budget cost estimate is based on more definitive method design factors. A budget cost estimate is based on past projects and varies by ±5%. You use a budget cost estimate for your method capital expenditure request. This capital expenditure request is submitted to your company financial (capital expenditure) review committee and is competitive with other company department financial requests for capital funds. Your staff and your company’s financial department calculates your method return on investment and number of years payback. Fixed cost –– The third method, building construction, and land estimate is a fixed cost estimate. The fixed cost estimate is based on your building design and method or engineered drawings and detailed written functional specifications. These building and method fixed cost estimates are prepared by your proposed building contractor, method vendors, and land owner. These method professionals require at least several weeks of preparation time to determine their fixed cost estimates. After receiving a vendor’s fixed cost estimates, the method fixed cost estimates do not vary. The fixed cost estimate that is submitted by your building contractor, land owner, and method vendor is the basis for a contract between a building


50


contractor, land owner, or method vendor and your company. The building contractors’ and method vendors’ fixed cost estimates are valid for a specific time. Preparation for an Order-Fulfillment or Across-the-Dock Method Cost Estimate For you to develop your order-fulfillment or across-the-dock method or equipment final cost estimate, the method information is required to be assembled by your method design team. This method design information relates to your existing and proposed method and includes method piece volume and piece and customer-order characteristics, method activities, and capacity and use method as shown on your drawings and outlined in your written functional specifications. After you have made a complete equipment list for your method, you select and use a company method budget pricing reference. The budget pricing reference helps you to develop a budget price estimate for the method or equipment. The information on your method’s plan view and detail view drawings and written functional specifications tells your company’s existing or proposed method story. Your company’s method drawings show many things, and your company’s written functional specifications indicate equipment type, such as conveyors, AGVs, tow lines, forklift trucks, shelves, racks, A-frames, digital displays, and automatic identification equipment; equipment size, which includes the piece length, width, height, and weight; equipment capacity, such as handling small items, flat wear apparel, GOH, cartons, or pallets and including length, width, height, and weight; piece or order flows and activities performed at the method activity stations; options and special features or tasks; piece or order travel paths (number of linear feet, turn number, piece or order travel path elevation changes, and equipment or load-carrying surface identification method); and facility internal dimensions, dimensions from the various building structural components, and equipment location such as the location of columns, doors, and stairs. In a method project that replaces an existing method, an inventory of the existing method determines its possible reuse in the new facility or at another facility. Your Final Order-Fulfillment or Across-the-Dock Method Project Budget Cost Includes a Contingency After you have received your budget costs for your method, building, and land cost estimates for your proposed project, you prepare a total project cost for management review and approval. A very important method project cost component is the contingency cost factor. It has been our experience that a 5 to 10% contingency cost factor for method, building, and land budget cost estimating is a standard contingency factor. The contingency cost factor establishes funds that are available for the project manager to cover unknown cost factors or those costs that are beyond the manager’s scope of work activities. These cost factors are unexpected purchases and extras. Most industry professionals agree that in their past building remodel projects, new



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facility construction, or method installation projects, the unknown factors have become a reality. This statement is true for remodeling a building or redoing an existing method. Methods to Control the New Facility Construction To construct a new facility, the building design and construction process project management approaches are as follows. Your company has individual contracts with an architect, engineering company, building contractor, and method vendor or consultant; or one contract with a design and build company that has its own architect and engineers. This one contract feature includes responsibility to purchase and install the method. Industry professionals refer to this type of contract as a turnkey contract. An individual contract with each building construction resource, method vendor, and architect and engineering company requires a company project manager. In this arrangement your company’s project manager is required to coordinate all the architectural, building construction, and method vendors in the building construction and method installation. This arrangement requires an increase in meetings and usually has longer building construction and method installation phases. The design build or turnkey construction method has your company contract with one or two companies to have complete responsibility for your new facility design, engineering, construction, method purchase, installation, and startup. With this arrangement, all the coordination between the architect, building construction company, and method vendors is controlled by a design build company. The design build company representative interfaces and meets with your company’s project manager. In most projects, a design build arrangement means a shorter building construction phase and an increase in costs. Order-Fulfillment or Across-the-Dock Method Budget Price Sources To obtain a method budget price cost estimate, the sources are your company’s past method prices, adjusted for inflation and location; your company’s method vendors who have worked on past projects, adjusted for inflation and location; the method or equipment supplier catalogs; your company’s current projects; within the past year, a method project where your company has received a vendor bid, adjusted for inflation and location; and the method budget pricing standards that are maintained by your company, adjusted for inflation and location. Information on Your Company’s Building Construction Drawings and Written Functional Specifications To obtain a fixed cost estimate for your building construction, land, and associated site preparation costs, you develop the necessary site utilization drawings, building drawings, and written functional specifications. This is your company’s preliminary (outline) building information. With this information, you select good price sources or potential architectural and engineering and building construction companies to send the building information. These companies provide the building construction,


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land, and site preparation fixed cost prices. These companies are independent companies or a joint venture company (single company) to control your project. The information that an architect; structural, mechanical, and electrical engineer; and building contractor need in order to provide an accurate and fast building construction cost estimate includes: •

• • • • •

•

•

•

• • •

The geographical site location for the professionals to determine the seismic (earthquake) zone, wind, rain, and snow loads and local building codes Estimated building size to include all floors as shown on your drawings Office area –– an attached building to a main building, a separate building, or in the main building on an elevated floor –– as shown on your drawings Future expansion needs and an expansion direction that accommodates 50 to 100% growth Peak vendor and customer delivery truck parking area requirements to include a blacktop area for visitor and employee automobiles Receiving and shipping docks for vendor delivery trucks, oceangoing containers, and rail cars, specified as blacktop with a concrete landing gear pad, dock height, drain, slope, and truck canopy Estimated property size, based on local code requirements that govern the building ratio to land (land utilization), building height, exterior color, signage, required berm or fence, and required setbacks Special building requirements, including special lighting, air conditioning, heating, floor levelness, additional mezzanines, special processing activities that include food processing, steam processing, or computer room with an uninterrupted power source (UPS), in-rack sprinklers or early suppression fast response (ESFR) ceiling-only sprinklers with required tank, pump size, roof slope, and interior siding material Cafeteria and special storage rooms such as depressed floor locations, drain with retention tank or perimeter barrier, and foam fire sprinkler system Estimated men and women number by work shift and by facility location Estimated electrical usage by location including peak battery charging requirement Vehicle or personnel traffic aisles

Building Construction, Land, and Site Preparation Budget Price Sources The following sources are available and provide you with a realistic budget price estimate for land, site preparation, a new building construction, or an existing building remodel project. The best source is to have architects and building construction companies in the proposed site area. Another source is to have architects or building construction companies that are located in your company’s headquarters city; these prices require an adjustment for the difference between your home city and the proposed site location. The R. S. Means and Dodge manuals in your company or



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public library business section provide estimated building construction costs, site preparation costs, and equipment installation costs. It is noted that the pricing for building construction differs between the two manuals. The total building construction costs from one manual are slightly different from the same building construction prices estimated in the other manual. The R. S. Means manual does provide cost comparison and adjustment for major U.S. cities. This cost difference is used to adjust budget prices from other price sources not located in the proposed geographic area. Real estate and utility companies provide current land costs and building costs for an existing building. Also important are your company’s land and building budget pricing standards or past projects. The land or building construction costs vary from an expensive cost per square foot in a large metropolitan city to a low price per square foot in the country. Your request for land or site prices has a definition for the site type. Some land prices are for unimproved land that has no utilities, water, sewer, or access roads. Improved land has one or all improvements such as access roads, water, sewer, and existing utilities. If you are interested in an existing building cost estimate, include the required square footage, clear ceiling height, preferred span between two building columns, floor loadings, dock parking, and air changes. Steps to Determine Your Architect and Building Contractor After you finalize your method layout and building shell to house your method, inventory storage area, processing area, and other required activities, your next project step is to obtain a building architect and building construction company. Obtain a List of Potential Architects or Building Construction Companies You obtain a potential architect and building construction company list from past company building projects, the local chamber of commerce, industry directories, the local telephone directory, industry associations, and professional acquaintances or magazines. Send an Evaluation Form and Preliminary Building Outline Criteria After you have determined the potential architectural, engineering, and building construction company list, you make a telephone call to determine their interest in your company’s project. This telephone interview practice saves you time and expense by finalizing your list with those architectural, engineering, and building construction companies that are interested in your company’s project and have the basic resources that are required for your project. Your next project step is to send your company’s evaluation form and preliminary building outline criteria to these companies. The preliminary building outline criteria includes your building drawings and written functional specifications plus your method drawings and written functional specifications. This information provides potential architects and building construction companies with an insight to your company’s basic building and method needs. From the architects and building construction companies, the returned and completed evaluation form provides you with an indication to each architect’s and


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building construction company’s capabilities; estimated cost for the building; landscape items; total project cost; and past projects list, which includes the client companies’ site location, contact name, telephone number, internet address, estimated project schedule, and total estimated cost. This information permits you to evaluate the architectural and building construction companies. Your architectural and building construction company review allows you to determine the architectural and building construction companies that are to receive your request for a quote, final building drawings (plan view and detail), and building outline criteria (written functional specifications). Prepare Your Company’s Bid Package Your method or equipment and building bid package preparation is the next project step. This step is to prepare your company’s building and method final drawings and written functional, specific, and general specifications. What Do Your Company’s Building and Order-Fulfillment or Acrossthe-Dock Method Drawings Do Your company’s method or final drawings are your means to communicate between your company and your architect, building contractor, and method vendors who are interested in making a bid (price quote) on your project. The final drawings are lined pictures that show how your facility and method will look and how the facility and method will operate. The building and method layout and detailed drawings have sufficient information to leave no misunderstanding for piece or customer-order method, travel path, flow, and other operational requirements. Your method layout and detailed drawings are precise and detailed enough to establish your written functional specifications, but general enough in design requirements to permit your method vendors to understand the piece and customer-order flows and customer-order and piece transport travel paths and functions. With this vendor insight and understanding, these vendor companies use their design capabilities to provide your company with the best (latest technology) and most economical method to perform the work. Your method layout (plan view) drawings and detailed equipment drawings reveal your company’s and project team’s character. The factors that send a message to architects, building construction companies, and method vendors are as follows. Have a legend that shows the method or equipment symbols. Include building column lines that are connected to the building column bubbles. The column bubbles have numeric and alphabetic characters for building column lines and dimension lines. Most drawings avoid the alphabetic characters I and O due to confusion with the numbers 1 (one) and 0 (zero). Use wide lines or double lines for walls, and whenever possible use a computer-aided drafting (CAD) machine to produce the drawings. If you use a CAD machine, use one letter or number style for notes and elevations and a second letter and number style to indicate method or equipment numbers. On the drawings, the method numbers are on the equipment, within a box with a line between the number and equipment, or with a leader line to the equipment.



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Complete Building and Order-Fulfillment or Across-the-Dock Method Bid Drawing Package To have a complete building and method drawing package for your company’s project, the required drawings are a site drawing, a building layout or plan view drawing, a building detail drawing, a method layout or plan view drawing, a method detail drawing, and a cover sheet. It should be noted that many facility and method configurations could require several drawings to show the complete picture. Site Drawing. The first company drawing is your site view drawing that shows the total site, access roads, buildings, landscape features, perimeter, fence or berm, elevations, and north directional arrow. The site drawing provides the architect, building construction company, and method vendors with the necessary information to complete their work on your project. This information includes the building outline (area) and building placement on the site in relation to a known reference point or direction (north). The north directional arrow points upward unless the site configuration requires another compass direction. Other site drawing features include associated dimensions, which are paved areas for roadways, rail tracks, automobiles or employee travel vehicles, and requirements for vendor and customer delivery trucks, automobile and cycle parking lots, setbacks, fences, or berms, and ponds or water-holding tanks; building column lines with alphabetic and numeric bubble designations; building bay size, including overall inside clear dimensions and internal offices, service areas, mezzanines, and emergency exits; the building elevations from the floor to the underside of the joists (ceiling steel), the clear dimension from the floor to the office ceiling, and the floor elevation to the external grade or ground; and the vendor and customer delivery truck receiving and shipping docks, including the doors and dock levelers, canopies, and landing gear pads. These are important areas because all order-fulfillment or across-the-dock methods start at the receiving dock and end at the shipping dock. The final features are the employee entrance, outside vendor and customer delivery truck driver entrance, visitor entrance, trees and green area, garage, fuel island, compactor, forklift truck ramp, and future expansion. Each site drawing has a summary section with the site total area in the local measurement standards; each building area square footage and the total for all buildings as base construction and percentage of total and land area; total facilities and buildings square foot area and percentage of total and land area; for each total general office, operational square foot area and percentage of total and land area; the grand total for all facilities’ area square footage and percentage of land area; the automobile or other employee transportation vehicle parking slots; the vendor and customer delivery truck parking slots; and green area total square footage and percentage. Building Layout Drawing. Your second drawing group is the building layout (plan-view) drawings. The building layout drawings have more detail or dimensions for truck doors, canopies, compactor, special doors, and forklift truck ramp location and size; vendor and customer delivery truck dock levelers, rail dock board sizes, and rail spur with center line dimensions; bay size, column size, column lines,


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expansion joints, and wall locations with stated wall use; all internal office and service area walls and door locations, with specified door size and personnel doors, drains, and convenience outlets; special floors and floor surfaces, floor drains, raised floor locations, floor levelness requirements, and floor loading requirements, and the floor area to have acid resistance treatment for battery charging areas and in-floor pits; mezzanine locations, lighting, and sprinkler risers; roof or wall hung equipment loads and centerline for method (piece or customer-order transport) travel paths; lighting levels in foot candles, uninterruptible power supply (UPS), dock lights, and battery charging and other power panel requirements in both number, amperage, and location; vending machines, convenience outlets, work station bus ducts with plugin receptacles, dedicated electrical lines, and power panels for special equipment; and walls, fences, special rooms for vaults, cafeteria, and computer equipment. Outline Building Criteria. Your outline summary building criteria (written functional specifications) and drawings make your building bid package more complete and effective. The items in the building outline criteria determine who is to receive the written functional specifications and who is your architect, specify the equipment pieces and avoid the use of “or equal,” and states that the architect building drawings are the building project parameters and are over your company’s building written functional specifications and drawings. Your building outline design criteria development encompasses all aspects to provide a building to house your inventory, method, and other necessary activities to conduct your company’s business. To obtain your desired building, you prepare building drawings and an outline design written functional specification package. Together this building document (written functional specification) and your building drawings show and state to your architect and building contractor your design requirements for your building and method requirements. Your building drawings are lined pictures that show all the building related items. These related items are elevations from a floor or elevated floors to the grade level; elevations from the floor to ceiling or clearances that you desire in the building between building obstacles or proposed building items and method; the horizontal clear dimensions between a building column and method equipment; and functional area locations and equipment. These building drawings are drawn to a scale or the same scale as the method plan view drawings; depict the building skeleton with details that outline the method operational intent; are supplemental drawings to the architect or building contractor drawings but are not actual building construction drawings; are produced on a compact disc (CD), diskette, vellum, paper, or sepia or Mylar™ reproducible material; have an organized content and are complete; clearly depict and state your method objective; are drawn correctly; and have concise and clear notes. If you are to build a new facility or relocate into an existing building, you prepare building and method or equipment layout drawings. These drawings show the existing building equipment locations and characteristics. Various Building Drawings. Your building drawings are building construction plan-view and detail view-drawings, method plan-view and detail-view drawings, special method drawings, electrical drawings, and plumbing and other utility drawings.



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Plan-View Building Construction Drawing. Your new building construction plan-view drawings are the first building drawings. The building drawings contain all necessary dimensional data that relate to method layout, all method loading requirements, and all special equipment or special conditions that your company requires in the facility. Detail-View Building Construction Drawings. The detail-view building construction drawings represent the second building drawing group. These building drawings include all items that are relevant to the physical building construction. These items are overall internal building size, length, width, and external and clear ceiling height; column foot plate size and column bay size spacing (length, width, and center lines) and bay pattern direction; all internal and external partition walls, fencing, and screening; proposed and future vendor and delivery truck, container, and rail dock door locations and sizes; vendor and customer delivery truck, container, and rail dock heights, dock levelers, canopies, drains, slopes, and concrete landing gear pads; emergency exits, doorways, and stairways; offices, restrooms, and cafeterias, including vending machines and other rooms; all pits and drains in the floor; computer room location and floor type; each piece or customer-order transport travel path, and the floor, wall, or ceiling loading and special floor treatments; compactor location; mezzanines or elevated floors that show clear space between the floors, structural support members, elevations, and stairways; ceiling or wall hung method or equipment locations; required electrical panel locations and power requirements; and all locations that require water, drains, or other utilities. Order-Fulfillment or Across-the-Dock Method Drawings. Your method drawings are the third drawing set that shows the method and piece or customer-order travel paths. The piece or customer-order travel paths are considered high traffic areas and the method equipment has imposed loads. The loads are static (stationary) and dynamic (moving) loads that are imposed upon the building floor, wall, or ceiling. Your method equipment load drawings show how the load is imposed onto the building floor, wall, or ceiling, which includes length, width, and weight and type; load type and size, which includes dead load, live load, or personnel load; state in which the load is concentrated or uniformly distributed on the piece or customer-order travel path; method of attachment for the load; conveyor motors, drives, and personnel or maintenance platforms; when a forklift truck is used, the type and wheel size and the maximum weight on one wheel to complete the storage transaction; cross-sectional views and elevations views; and construction type for the snow, wind, rain, and seismic conditions. Special Order-Fulfillment or Across-the-Dock Method or Equipment Drawings. Special method equipment or structural drawings is the fourth drawing group. This drawing group shows the additional items that include mechanical dock levelers and dock area slope; overhead dock doors, to include size and window and the door direction to open; vendor and customer delivery truck dock seals or shelters and bumpers; overhead canopy height and extension; toilet rooms and janitor fixture layouts; vision panels in wall partitions; wall and floor openings, pits, conveyor, AGV, tow line, mobile vehicle travel paths, and expansion joints; special floor


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requirements; special plumbing and drain requirements; special sprinkler requirements with fire wall and floor penetrations; special concrete landing gear pad requirements; battery charging area; and the expansion wall. Existing Building Information. If your building strategy is to relocate into an existing building, the physical building modifications or additions are probably necessary for an existing building to meet your particular method operational requirements. In advance, you try to obtain all preliminary information on the building structure, floor load capacity, available electrical power, and other utility capacities to ascertain whether its capabilities match your requirements. This building information is available from the original builder, architect drawings, or written specifications. The special building conditions are shown on the existing building drawings: all existing information about the building such as column size, bay size, activity areas, floor thickness, door locations and dimensions, power panel locations and available power, water and other utilities, and the other building facts that were previously mentioned for a new building; modifications to the building that are noted on the drawing and referenced back to a description of the modification that is contained within the written functional specifications; all new additions to the building, designated and referenced to the written functional specifications; method equipment loadings, identified on the drawing; and all major building alterations, checked carefully with your architect, builder, or order-fulfillment or across-the-dock method or equipment vendor. You should visit and survey the building to verify the building’s existing features. During this visit, it is a good practice to take building pictures or a videotape. These building pictures include the building interior and exterior and include the vendor and customer delivery truck yard area, landscape, roof, walls, floor surfaces, doors, electrical panels, all existing equipment, columns, and special rooms. Electrical Drawings. Your next drawing group is the building electrical drawings. These drawings contain all pertinent items and information about your electrical requirements inside and outside of the building. The electrical information includes light fixture types, motion detectors location, lighting patterns, and specified lighting levels above the floor surface at specific elevations. These lighting levels are stated for each method functional area. This includes a description of the work area and aisle widths. Also included are duplex convenience outlets and bus ducts for processing areas and outlets for items such as time clocks and vending machines, electric water coolers, delivery truck dock lights, and required electrical feeders for method equipment control panels. These panels are stated by amps, voltage, phase, cycle, and desired location. Specify the disconnect type and locations for all feeders. Define the stub-up type, amount or length of desired cable, and work assignment for tie-in to the method equipment panel; special requirements for future method or equipment expansion; mobile vehicle equipment battery charging areas; requirement for computers or special equipment such as a dedicated line; emergency power system (UPS) and low-voltage and spike (electrical surge) filters; emergency lighting system; and internal communication system.



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When you consider relocating into an existing building, in addition to the above electrical information, your electrical drawings indicate all existing electrical data that are obtained from a building survey. The additional electrical information includes modifications and additions to the lighting system within the building, noted and referenced to the specifications; the main electrical service amount and feed panel locations; existing equipment panel locations, with available power stated and identified; and existing battery charging locations. Plumbing and Other Utility Drawings. Your last group of building drawings consists of the plumbing and other utility drawings. These drawings show all important items, locations, and information that is related to the building plumbing and other utility requirements inside and outside of the facility. The information on these drawings includes the location of yard drains and building drains; the location and size of water tanks and holding tanks, risers, shutoff valves, and associated pumps; the locations of all outlets and piping; the location and size of all equipment such as backup generators; the location of all hose drops and fire sprinklers; and gas pipe size and location. Develop Summary Building Outline Design Criteria Your summary building outline design criteria and written building specifications are instructions to your architect and building contractor. This document is a supplement and is an explanation of your drawings. Your building outline design criteria’s six categories are general information, design criteria general, design criteria mechanical, design criteria plumbing and other utilities, design criteria electrical, and design criteria building and modifications. General Information. Your first written building functional specification section is the general information section. This general information section outlines to your architect and building construction company the items that are key to providing your company with a complete and finished building. These items include interior building and exterior grounds or landscaping. These building items satisfy your method functional requirements and comply with all local and federal government requirements and codes. General Design Criteria. Your second written building specification section is the general design criteria. The general design criteria give your architect and building construction company your requirements for property data; site improvements, grading, paving and sidewalks, landscaping, fencing, berm, entrance, roadways and parking areas, signage, sprinkler pond (tank), holding tank, cafeteria, and other activity areas; building size; bay size and column size; minimum clear height from the finished floor to ceiling steel; drawing list; concrete work, general, foundation, and floor required F rating or levelness, thickness, sealer, and rebar depth and location; structural framing, general, special loading, painting; and dock equipment and canopy and drains. Mechanical Design Criteria. Your third outline of the building design criteria section indicates the building mechanical components. This section includes heating,


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office and work area air conditioning, facility air changes, duct work, facility heating, and maintenance and battery charging area. Plumbing and Other Utility Design Criteria. Your next outline criteria section is for the building’s plumbing and other utilities. This section includes general plumbing; sewers and drainages; fixtures, restrooms, fountains, water tanks, sewer holding tanks, hazardous product holding tanks, and water closets; sprinkler or foam systems and fire hoses (drops); outlets; and gas pipe lines and usage locations. Electrical Design Criteria. Your electrical design criteria is the next building design criteria section. The section includes a general outline that includes electrical power and lighting distribution; motors and wiring; lighting in general, to include foot candle levels at a stated elevation above the floor surface for each method activity area; convenience outlets; lighting panels; raceways under or across the ceiling or floor ducts; telephone raceways; alarm system; public address and sound system; bus duct requirements; time and regular clocks; battery chargers; data processing requirements; method equipment panels; UPS size and location; and fixture type and the ability to interface with a timing device or motion detector. Existing Building Modifications. Your last building design criteria section is the existing building modifications that are required on an existing structure. Order-Fulfillment or Across-the-Dock Method and Equipment Layout Drawings Your third drawing type is the order-fulfillment or across-the-dock method or equipment layout (plan view) drawings. After your method layout has been completed on a plan view drawing, it shows all dimensions and notes that are necessary to show a completed method. This method layout includes piece or customer-order travel paths. This plan view drawing leaves no questions for your method vendors. The drawing items on the method drawings are necessary building details such as building columns and base plate size, walls, and in-floor pits; identification method work stations and functional locations with symbols and numbers, and method equipment component identification numbers or symbols; and elevations for method equipment and other items such as all doors types and mezzanines. When mezzanines are shown, the elevation is stated from the ground-level floor surface to the elevated level floor surface. Also included are stairways or elevations; clear aisle dimensions or piece or customer-order travel paths; and symbols that represent electrical panels, air compressors, and doors. Cover Sheet Your next drawing component is the drawing cover sheet. The cover sheet indicates your company’s name, proposed facility, and site location. Building, Order-Fulfillment or Across-the-Dock Method, and Equipment Detail Drawings Your next drawing package has the detail building and method drawings. The method and building detail drawing package group gives your architect, building contractor, and method vendors the direction and information for specific items. These items are



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compactor or baler location; in-floor pits; a raised floor for method equipment; mobile vehicle aisles and high traffic piece or customer-order travel paths; equipment supported mezzanines; ceiling-, wall-, or floor-supported piece or customer-order transport travel paths; wire or rail guided vehicle travel paths, elevated-piece or customer-order travel paths, floor surfaces, and wall penetrations; and proposed safety protection. Each drawing shows the clearance between method equipment and building equipment, the clear elevations from a floor surface to the bottom of the above ceiling steel, and the exact dimensions for various fixed equipment, mezzanines, or method. Order-Fulfillment or Across-the-Dock Method and Drawing List After your method and building drawing package is completed and checked for accuracy, you prepare a drawing list that indicates drawing number, drawing titles and when you issued the drawings, each drawing’s revision numbers and date, facility location, and company name. When you send a method and building drawing package or selected drawings to your architect, builder, method vendor, or other organization such as governmental agency, the drawing list is a method to verify that you sent the drawings that were requested by the requesting company. The drawing list serves as an introductory letter and to tell the receiving company the drawings that are contained in the package. Order-Fulfillment or Across-the-Dock Method Bid Process When you are required to obtain order-fulfillment or across-the-dock method or equipment bids, then there are two approaches to obtain your request for a quote. These two bid approaches are a single-source bid and a competitive bid. Single-Source Order-Fulfillment or Across-the-Dock Method Bid The single-source method bid has you send your company’s request for quote (RFQ) to one vendor. When your method has specific conditions, the single-source bid process is a good approach. The bid conditions are that you have had an excellent past relationship with the vendor, the project dollar value is within your limits, there is an emergency operational situation, or there is only one manufacturer. Competitive Order-Fulfillment or Across-the-Dock Method Bid The competitive method bid process has you send your company’s RFQ to at least three vendors. To obtain three good bids, you send the company RFQ to five vendors. The competitive bid process conditions are that the project has a high project dollar value, it requires standard method equipment, and a competitive market is present. Your Bid Package or Request for Quote Preparation Your RFQ contains your company’s detailed written functional specifications and drawings. The written functional specification and drawing package allows your method vendor to understand your method purpose. Your method RFQ or bid package preparation is based on your company’s past bid packages and follows your company’s bid quote procedure.


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The standard method bid package components are a cover sheet that states your company’s name, address, project number, date of issue, due date, and method equipment type; a table of contents; instructions to the vendors that outline the bid package intent; and a quotation intent form that requires the vendor to indicate its intention to participate in your company’s bid process. If the vendor decides to participate as a bidder on your project, the vendor returns the completed form to your company. If a vendor decides to decline to bid on the project and returns the form to your company, this procedure gives you the time to substitute another vendor. After a predetermined number of days from the bid issue date, you telephone each vendor to verify bid package receipt and the vendor’s interest in your company’s project. A vendor schedule indicates the critical project dates such as contract issue date, start installation date, test and debug date, and start-up date. Another item included is the vendor payment schedule and the contract dollar amount that is retained by your company. The drawings required section states the required vendor method plan view and detail drawings that are submitted to your company. Working conditions include a workmanship section that states what is expected from the vendors on the job site, on-site or general working conditions, and delivery road conditions at the site. It includes who is responsible to obtain all required government permits and approvals for the vendor work. In your method and building written functional specifications, you clearly state that the method vendors, architect, and builder are responsible to obtain all work (governmental) permits that are required for their work on the project. If the contractor or vendor is not responsible, they are required to notify you in writing that your company is responsible for the job or work governmental permits. Also included are insurance policies, dollar coverage, the additional insured (your company) and site location. Operational and maintenance publications, spare parts list, operator and maintenance training days and location, and the vendor training personnel are also noted. This section identifies the maintenance and operational manual number, training days, who will conduct the training sessions, and a recommended spare parts list and prices. A testing and acceptance section outlines the criteria to determine that the method is installed as specified by your company and notes the date that starts the manufacturer warranty period. A support section defines the criteria for all ceiling hung, wall, or elevated method equipment, and identifies the geographic location to allow the vendor to determine the seismic location. Air supply states the requirement for an air compressor and the need to place the air compressor inside the building in a shroud (enclosed box) with a drain or place it outside. The painting section outlines the color and coating finish for the order-fulfillment or across-the-dock method or equipment. The mechanical section details the method equipment requirements, elevations, length and width, and national standards referred to as design criteria. The electrical specification section states the type and electrical power quantity, electrical panel locations, and method control panels; size; national standards that are referred to as a design criteria; and the fixture type and its interface to a timing device or motion detector. The pieces or customer orders to be handled and flow rates sections provide the method vendor with your company’s piece or customer-



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order size; direction of travel length, width, and height; weight; peak and average volumes; physical characteristics; and hours of operation. The drawings furnished section lists all company drawings that are included in the bid package. The scope of work section provides the method vendor with the project and your business objectives. The daily operations description is a written statement that traces the piece or customer-order flow across or over the method equipment and identifies the task that is performed at each work station. The method transport equipment list is a document that assigns each piece of equipment a number; load-carrying surface description; approximate length and width; side guards; floor or other support method; load-carrying surface travel speed per minute; approximate elevations above a floor; and special comments such as tapered rollers, end stops, powered nose-over and tail, and emergency stops (E-stops). The control list is a document that gives a vendor the minimum required photoeyes; control panels; motor control system characteristics; mimic panels; minimum required E-stop buttons or pull cords; start/stop buttons or cords; and flow control sensors including scales, label applicators, counters, and bar code scanners (readers). The equipment specification summary form is a document where a vendor states the equipment quantity and type that is supplied for the project. The exceptions section permits the vendor to explain all alternative designs for your method. The pricing form is the document that requires the method vendor to list the price for each major piece of equipment, freight, unloading labor and mechanical installation labor, electrical installation labor, and additions or deductions. The pricing form’s second section is for the vendor’s macro project schedule, which states the number of days or weeks to complete the major project items, such as engineered drawings that are approved by your company; equipment manufacturing time; equipment transportation time from manufacture location to your site; method mechanical and electrical installation time; debug, startup, and acceptance time; bonds; insurance limits; warranty; taxes and permits; and local service dealer address and telephone number. Vendor Payment Schedules In your company’s bid package, you state your company’s vendor payment schedule. This section states the proposed payments for partial and final vendor work completion at your job site. These payments are made for vendor engineering work, equipment delivered to the job site, installation labor used on your project, or other expenses. A payment schedule section has your stated retention amount. The retention amount is the dollar amount that your company holds back or retains to ensure completion of your work per your company’s drawings and written functional specifications. The vendor payment schedules include lump sum; the lump sum payment has your company make one payment for the contract sum to a building contractor or method vendor. This payment is made for the work completion as outlined in your contract. The second schedule is percentage of payment. The percentage payment method requires your company to make periodic payments to a building contractor


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or method vendor. These payments are based on an agreed-upon percentage of the total contract amount. The third schedule is progress payment. The progress payment arrangement has your company make progress payments to a building contractor or method vendor. These payments are based on an agreed dollar amount for items such as engineering work, method equipment deliveries to the site, and installation labor that was used on the site. Steps to Ensure Three Accurate Bids Your method vendor relationship with your company is a very important factor that is key to obtaining an accurate bid for your request for quotes. To ensure that you have at least three bids for your method, there are several guidelines to follow. First, establish a list with five reputable method vendors. To determine that these method vendors are interested in your project, telephone each potential method vendor to determine the vendor’s interest in your project. Release your bid request promptly and send the bid to the potential method vendors by a delivery company that obtains a delivery receipt. Maintain a professional relationship with all potential method vendors. Answer all vendor questions quickly and precisely. Require on-time, accurate, and complete bids. Have alternative potential method vendors. To the method vendor, exceptions are accepted as an option to the base quote that is your company’s design. Bid Return Procedure You have the method vendors return their bids to your office. Your first bid return option is an unsealed bid. The unsealed bid return procedure is the first method vendor bid return procedure. With the unsealed bid return procedure, the method vendor returns the bid to your office. The vendor returns the bid by mail, delivery service, or by a vendor company representative. The unsealed bid procedure has a vendor bid presented to you in an open envelope. At this time you can review any or all bid sections. The second option is a sealed bid. The sealed bid procedure has your company include a bid return envelope in each vendor bid package. On the envelope exterior, your company writes the bid description, or the envelope contains a sealed bid for your method component. The vendor uses the envelope to return the sealed bid to your office. Prior to or on the bid return date, the bid return is made by a delivery service or vendor. After this bid return date and time you open and review all bids. All bids that are received after the date and time are not accepted but are held in your project file. Bid Review or Bid Evaluation Process After your method vendor bids are returned, on the bid return date you review each vendor bid. This bid review process requires you to make an economic and functional (operational) review for each vendor bid. The bid review process determines the best method vendor price and the vendor adherence to your method drawings and written functional specifications. This includes your vendor adherence to your company’s mechanical and electrical specifications.



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The method vendor bid review process steps are to establish an evaluation form for the method bid and review with a consistent format that is based on economic and critical operational information. This information includes price for the method equipment, freight, total weight, mechanical and electrical installation, total alternative pricing, and recommended price; time schedule for drawings, manufacture, transportation, installation, debug, start-up, and acceptance; payment terms for completion and penalties for delays or bonus for early start-up; warranty conditions; taxes and permits and who is responsible for drawing approval by the local authorities; prices that are valid for a number of days; compliance to local building codes and whether work permits are included in the bid; insurance limits for workmen’s compensation, automobile liability, and excess liability; name, address, and telephone number of nearest full-service dealer; mechanical specification by each component; and electrical specification by each component. After these competitive method vendor price quotes and component lists are presented on a spreadsheet, it is easy to compare each vendor price and equipment. Reviewing the prices, you have a good tool to negotiate for a better price or to improve the method design and determine the best bid. From this bid evaluation, you establish the recommend method vendor for the total project or for an equipment piece. The recommend method vendor and the price is totaled and presented to your management for its final review and approval. If you and your staff are not satisfied with the accepted bids or you desire to have other (late) bids accepted for the project, your options are to accept the other potential method vendor (late) bids, bid the method again, or request a second bid from the vendors who submitted their bids on time. After you obtain top management approval for the project and the recommended method vendor, there are several steps to maintain your company’s project schedule. First, issue a letter of intent or company purchase order to the method vendor. At a later date your company issues a job contract to the method vendor. The second step is to maintain a good professional relationship with the unsuccessful method vendors; you issue letters that explain to these vendors why they did not receive your company’s contract; and thirdly, as soon as possible, you develop a master project time schedule. This master project schedule indicates method vendor start, intermediate or milestone, and completion dates for method plan view and detail drawing completion and drawing approval; equipment manufacture and transportation; mechanical installation; electrical installation; method debug and acceptance; and method turnover or effective use. Your Company’s Purchase Order Preparation Your next step of your company’s new facility construction or order-fulfillment or across-the-dock method or equipment installation is to issue the proper PO documentation. This document includes your company’s written functional specifications and plan view and detail drawings; letters of intent; and building, master project, and method vendor schedules. These documents in your company’s PO coordinate the building contractor activities with the method vendor installation activities, and method vendor installation activities with other vendor activities.


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Your Purchase Order Contents Your PO to the method vendor has your company’s (recorded) numbered PO. The PO reference data include your method written functional specifications; engineered plan view and detail drawings; vendor proposal; letters of clarification; and attendees, letters of intent, and other important correspondence. Your complete method PO contains vendor name and address, date, ship-via address, ship-to address, bill-to address, page numbers, department number, special shipment instructions or notification, invoice acknowledgment and dollar amount separation requirements, and method description. Your PO text includes your written functional specifications for the method. These specifications include cover page, title, and reference to all the pages; your plan view and detail drawings; the method vendor proposal number and date, addenda, revisions, and letters of clarification; a statement of vendor responsibility and schedules for engineering, manufacturing, transportation, and installation; new or used equipment components; tax payment; government permits and costs; freight charges that state shipment point and destination and prepaid or collect at the delivery location; total price; earliest and latest equipment delivery date and method start installation date; and payment terms and warranty issue. Letter of Intent If you are unable to issue a formal PO and your company has to make a commitment to the method vendor, a letter of intent allows your method vendor to maintain the project schedule. The letter of intent is basically an advance purchase order from your company to the method vendor. After receiving a letter of intent and with standard method equipment, most method equipment vendors proceed with the method drawings and engineering work only, or method drawings and engineering work with limited method equipment manufacture. Your method vendor continues until the vendor receives your formal written PO or contract. Good contract administration practice specifies that you sign and approve all letters of intent sent to your method vendor. Your letter of intent includes all of the above items and it states a reasonable time limit for you and your vendor to reach a formal agreement. It is important that your correspondence, letter of intent, and PO copies are legible and sent to the appropriate vendor. A copy is placed in your files. Other Important Project Factors After your PO is released to the method vendors, you and the method vendor arrange lead (schedule) times for engineering, manufacturing, freight, mechanical installation, electrical installation, test and debug activities, and start-up times. Any method vendor revisions or updates are made to the method vendor project schedule and to your master project schedule. The revised vendor and master project schedule copies are issued to your architect, building contractor, method vendor, and your files.



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The next step is to establish the method vendor and builder project manager who is assigned to your project; start and completion drawing dates; and fabrication start and completion dates, which include the vendor plant that will manufacture your method equipment. This permits you to visit the plant and record the method equipment manufacture. You also establish the date when your method equipment manufacturer can alter its manufacturing schedule without incurring an added expense to your company. This date is very important in the case of method vendor installation changes that result from building construction date adjustments due to weather or construction progress delays. You indicate to the building contractor and method vendor the dollar amount or extra charge for a delayed method start-up due to late building construction or method installation. Order-Fulfillment or Across-the-Dock Method or Equipment Supplier Drawing Review Process To maintain the project schedule as the method vendor plan view and detail view drawings are presented to you, you expeditiously review and approve, approve as noted, or do not approve your method vendor drawings. To make corrections, revisions, or adjustments to the drawings, you write notes on the appropriate drawing. These notes indicate your method review that is shown on the drawing. Each drawing review correspondence between your company and your method vendor is made in a transmittal form or letter document. A transmittal or letter copy is sent with the drawings to the method vendor and is placed in your project files, and a set of review drawings is placed in your drawing rack. The method vendor drawings that involve ceiling load hangers, affixing sway braces to a building wall, attachment to a building structure, pit in the floor, or anchor and support from the floor are forwarded to your architect or structural engineer for review and approval. Their approval documents are sent to you and your method vendor. A copy is placed in your project file. An important part of the method vendor drawing review process is the clearance (open space) that the method equipment (product travel path) requires to fit into the facility. To ensure that there is sufficient open space, you perform a drawing review. The drawing review process requires you to look at the method travel paths with piece or customer-order on the load-carrying surface; the sprinkler line and riser elevations, shut-off valves, and locations; the ceiling-, roof-, mezzanine-, and floorsupported work or equipment platforms; stairways; water lines and heaters; chillier lines; wall penetrations and floor openings with the associated protection; lighting panels and electrical panels; and the necessary electrical power and air conditioning. Document All Changes During your facility construction and method installation phase, changes occur to a building or method drawing for many reasons. When a discrepancy occurs in your building or method drawings, you and your architect, building contractor, and method vendor adjust the drawing or change the items that are shown on the drawing. After


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the changes are made on a drawing, you note and approve the required drawing changes with a new drawing. Proper documentation or a letter or transmittal form accompanies the drawings in the change process. This notification is sent to your method vendor, architect, and building contractor, and a letter copy and a drawing set is placed in your files. Master Project Schedule With a completed master project schedule, you coordinate the method vendor schedule with the building construction and the other vendor schedules. If date adjustments are required to any other vendor and building construction company schedules, you revise and update the appropriate individual method vendor schedule and your master project schedule. This master project schedule revision reflects the required adjustments and is clearly understood by your method vendor, architect, and building contractor. To notify your method vendor, architect, or building contractor that an adjustment has been made to the master project schedule or to the building or method installation schedule, practice good communication methods. Write to each method vendor on your company’s stationery, or hold a meeting on site or at your company’s office that is attended by your method vendor, architect, and building contractor. A revised master project schedule, building schedule, and method vendor project schedule are sent or given at the meeting to your method vendor, architect, and builder. The revised schedules state the revision date and revision reason. Master Project Schedule Changes by Letter The first master project schedule revision method is to send a letter to your method vendor, architect, or builder. This letter explains the reason for a master or individual schedule change to your method vendor, architect, or builder. It is the responsibility for your method vendor, architect, or builder to make the appropriate changes to their schedules. Master Project Schedule Changes at a Meeting A second master project schedule change method is to call a meeting at your office or at the site. At this meeting, your architect, builder, and method vendor verify the master project schedule changes and notate the changes on their master project schedule copies and individual project schedules. As an enclosure to the master project schedule, copies of your revised master project schedule are given to each attendee. Each revision to the master project schedule or method vendor, builder, or architect schedule is identified with the revision date and change reason. Bar Chart Master Project Schedule The bar chart is a form for a master project schedule. The bar chart has columns. The first column states the method vendor activity. After the first column, each column indicates a time period (months, weeks, or days). The chart also has lines. Each line indicates a method vendor activity in the sequence that is required to



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complete the project. The intersection of a column and line indicates the anticipated method vendor activity start date and completion date. Drawing Review During the Master Schedule Development During the method vendor plan view and detailed view drawing development project phase, to maintain the project schedule and to ensure that your company receives the facility or method as designed by your project team, you promptly review and approve all building and method drawings. This building and method drawing review process has your attention focused on piece or customer-order flow, safety standards, and method layout per your company’s plan view and detailed drawings and written functional specifications. Contract Administration Your next important project management responsibility is to establish a mechanism to track the building construction and method installation costs. With contract administration, you track the total project cost, which includes method vendor, architect, and builder. These contract costs are tracked by your company’s invoice payment to the architect, builder, or method vendor. The first step in your company’s contract administration is reference in your written functional specifications and job contract. In these documents, you state the agreed-upon vendor payment requirements and procedures. During your first vendor meeting, you restate to the method vendor, architect, and builder that you require specific information in a specific format on each invoice. On each invoice, you require your company’s project number with description and an invoice payment amount separated into specific classifications: method equipment, mechanical labor, electrical installation labor, freight, and taxes. After your establishment of the vendor invoice procedures, you set up your individual method vendor, builder, and architect payment tracking system. An invoice payment tracking system establishes a multiple-column and multiple-line document. This document sections are a heading that includes contract date, contract number, vendor name, address, telephone, fax, and Internet address, and your company’s project number and total dollar value less your company’s retention dollar amounts. There is one column for each vendor cost classification: method equipment, mechanical labor, electrical labor, freight, taxes, and retention. Each line has the description and date for each contract or project transaction. A project transaction is your company’s payment to a vendor, job extra or change of scope to the contract that adds or subtracts from a vendor contract, a deduction that results from vendor purchase of existing method equipment, and other vendor activity that adds or subtracts dollars on a vendor contract. With multiple lines under each column, you list each method vendor project (contract) transaction that affects the contract dollar amount. The first entry is your company’s contract dollar amount and the contract issue date. Each subsequent entry is dated and the invoice dollar amount is entered under the appropriate column. During the contract life, if you make a dollar adjustment to the contract, the issue date and dollar amount are added or subtracted from


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the total contract dollar amount. The change is a change to the scope of work, or you issue extras to the job contract. This contract administration method provides you with an accurate and updated project cost status for the total project and the architect, building contractor, and method vendor. The contract administration method tracks your project costs on a paper form or an office computer and presents them on a spreadsheet. Schedule Building Construction and Order-Fulfillment or Across-theDock Method Vendor Installation Meetings During the building construction phase, a building construction review meeting is attended by you and your architect, building contractor, and method vendor. The building construction and method vendor installation job meeting copies are sent to all attendees. Approved copies are placed in your project file and sent to your architect, building contractor, and method vendors. When your method vendor is required to interface with another vendor or builder equipment, for building company and method vendor installation compatibility purposes it is vital to have a meeting. At this meeting, the method vendor reviews the equipment plan view (layout) and detail drawings with the building company and the other vendor to ensure compatibility. This coordination drawing review activity between the building company and the method vendor is described in the building and method written specifications; it does require your reiteration and your follow-up during the method vendor drawing preparation and drawing approval phases. As the building company and method vendor installation progresses, you ensure that there is a coordination between the building construction company and method vendor. This project management activity is to effect and monitor communications between the architect, building contractor, and method vendor. To ensure this coordination among these groups, the project management activities are to conduct a preliminary scheduling meeting and a meeting before the start of installation. Preliminary Schedule Meeting The preliminary project schedule meeting is held after your PO release to the building construction company and method vendor. The meeting involves your building construction company and method vendor project managers, the architect, and you. During this preliminary schedule meeting, you review the building construction schedule; interface with your method vendor and other equipment vendors; and discuss general site issues such as temporary electrical power location and quantity, heat, light, water, toilets, floor, roof, and walls for critical areas. This feature allows on-schedule method equipment installation with long lead times and ensures protection from the weather for the method equipment. If the building construction company has a construction problem or building materials (roof and wall) are in short supply, this approach allows the building construction to start in the area above the building area that protects your longest lead time for the method equipment installation. This building construction approach compensates for those building construction shortfalls (problems) and allows you to maintain the scheduled



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method start-up date. Also under review are building construction and method installation worker automobile and truck parking; access to the unloading location dock and the access road and truck yard area condition; hard-hat and hard-shoe requirements; toilet, telephone, and office usage; temporary method equipment storage area; eating, drinking, and smoking locations; and vehicle driving onto the facility floor. Meeting minutes are sent to all attendees and parties who are involved with the building construction and method installation project, and a copy is placed in your project file. Meeting before the Start of Installation This meeting is held at the new facility or remodel site 1 to 2 days prior to the start date for your method installation. The attendees at this meeting include the architect, building contractor, method vendor, and you. This meeting gives your method vendor an opportunity to visit the construction site. During this visit, the method equipment vendor reviews the building construction progress and the building readiness and utility availability for installation work. During this meeting, the method vendor reaffirms the installation schedule or postpones the installation start due to building construction status to compensate for a construction problem or a manufacturing problem. This method vendor installation delay requires your building contractor or method vendor to unload and store the method equipment and installation equipment on site in a weather protected area until the actual installation area is available. The meeting minutes are sent to your architect, building contractor, and method vendor, and a copy is placed in your project file. Meeting Attendance Is a Must During the entire building construction and method vendor installation process, your attendance at a building construction and method vendor installation job-site meeting is vital to ensure that you have project control. Attendees at these job-site coordination meetings include you and your building contractor, your building contractor’s important subcontractors, your architect, and your method vendor. At these meetings, the attendance of the project team members enables you to anticipate your method vendor or building construction schedule conflicts, provide a forum to present scheduled method equipment installation start dates, hear method vendor complaints or review other issues, understand circumstances that affect your method vendor installation progress, and schedule the next meeting. The meeting minutes are kept and copies are sent to the architect, building contractor, and method vendor, and a copy is placed in your project file. On-Site Meetings After the method vendor starts the equipment installation, on-site meetings with job superintendents on an informal weekly schedule are necessary. Most on-site meetings are held on a Friday or Monday, which permits you and your method vendor and building construction company to review the past week’s


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installation progress compared to the schedule, and to make adjustments to the next week’s planned work activities. These meetings are held at least once per week and enable the method vendor and building construction company to state method equipment manufacture problems, shipment problems, labor problems, equipment installation problems, and other job-site problems that are associated with the building construction or method vendor. Your Installation Office During the building construction and method vendor installation phase, it is a necessity, especially on a large and complex project or a long-term project, that you have an office on site. The most suitable office location is in the building. If this building location is not possible due to the building construction, you rent an office trailer. The office trailer is located in the building vicinity or adjacent to the building. The job-site office is equipped with telephone, fax machine, and portable computer with modem; file cabinet; drawing rack; desk; large flat surface table to spread drawings on its surface; heater and water heater; and light fixture and chairs. To coordinate and control the building construction and method installation activity, your office is equipped with the necessary project reference material and office supplies: a full up-to-date approved building and method drawing set; complete building and method written functional specification copies; building construction company and method vendor proposals, POs, letters of intent, correspondence letters, and transmittals; your company’s letterhead stationery, transmittal forms, and fax forms; and other miscellaneous items such as measuring tape, drawing instruments, drafting paper, required drawing scales, and office items. What to Check and Inspect During the building construction, you make inspections and checks to ensure that the actual building construction matches the architect’s drawings. You check the building structure for the tightness to tolerances to the plan view and elevation detailed drawings’ dimensions. There are many items to check. These items are the overall building length and width actual dimensions and clear dimensions from the finished floor surfaces to the ceiling steel or mezzanine finished-floor surfaces; the centerline column spacing in all directions and column base size (length and width); the location and size of the vendor and customer delivery truck docks, overhead doors, and emergency exits; the location and size of the vents within the facility walls and ceiling; the mezzanine elevations to include the clear height under the mezzanine to the level- or finished-floor surface; and the locations and size (height and width) of openings or passageways in the finished floors and walls. This includes the employee safety and fire protection of these passageways. You also check the locations and size of power panels, outlets, and lights; the locations of pits, including length, width, and depth; sprinkler rise locations and locations of the main sprinkler pipes, branches, drops, and shut-off valves; locations of light fixtures and clear vertical clearance to the finished-floor surface under the light fixtures; and stairways, platforms, and tunnels.



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During the building construction process for a special area, some companies utilize a consultant to monitor the construction progress and quality of the material and work quality. Some special areas are structural steel erection and floor flatness, cement quality, and rebar depth. In many building construction projects sprinkler drops and light fixtures are not completed prior to your method installation start date. If this situation occurs, your building inspection and check continues along with the method installation. Whenever possible all ceiling sprinklers and light fixtures are installed prior to your method installation activity. This practice reduces building construction activity and method installation activity conflicts between the building contractor (sprinkler or light fixture subcontractor) and the method installation crew, and provides lighting for the method installation work. After you check the building construction work, your activity and time involves the continuous monitoring and checking of the method vendor manufactured equipment deliveries and installation work. You monitor proper method equipment installation, maintain and review the building construction and method equipment installation schedules, oversee the desired coordination between the method vendor installation crews and building contractor crews, and ensure adherence to the agreed-upon building construction and method equipment vendor installation procedures and practices. Check Your Order-Fulfillment or Across-the-Dock Equipment Deliveries According to Murphy’s Law, if anything can go wrong, it will. This invariably applies to your method vendor equipment deliveries and installation work. No matter how well your master product schedule and method vendor installation schedules are developed by your team and how well your method vendor manufacturing and shipping departments perform, something can always go wrong. Examples include late method equipment deliveries, early deliveries, damaged equipment component receipt, or missing critical equipment sections or components to the method. By continuously checking method vendor equipment deliveries to your job site and maintaining good communications with the method vendor project manager and on-site job meetings, you minimize a method equipment delivery problem. This problem affects your method on-time start-up and you minimize other job-site problems. During the method equipment installation, you make continuous method equipment inspections and checks. These inspection and check activities make sure that the method installation does conform to your company and vendor agreed-upon method plan-view and detail-view drawings and written functional specifications. You ensure that the method installation is per your vendor plan-view and detailview drawings and written quotation specifications. A general list includes checking the method or equipment components against your written functional specifications; checking the method layout and elevation dimensions for racks, shelves, conveyors, towlines, AGVs, trolley conveyors, mezzanines, or floors, and piece or customerorder transport equipment against those that are shown on your plan-view and detail-


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view drawings; checking the powered method equipment locations for the powered equipment components such as drives, take-ups, and support hangers, and their locations in relation to vehicle, piece, or customer-order and personnel travel paths and aisles, other equipment, and employee work stations; checking piece or customer-order travel paths (aisles) for width, height, and run-out lengths and clearances; and checking control panel proper locations, push buttons, pull cords, annunciator panels, photo eyes, limit switches, and other method or piece or customerorder flow control components. As the method electrical equipment is being installed, you verify that the electrical installation is per your agreed-upon drawings and written functional specifications. Your initial method vendor electrical drawings contain schematic wiring diagrams only. For most installations, the method vendor detail conduit or wire way layout drawings are never prepared by the electrical equipment supplier, a subcontractor to the method vendor. Many electrical components such as stop/start controls, E-stop pull cords, stop/start or E-stop push buttons, photo eyes, and limit switches are shown only schematically but with no locations or height dimensions specified on their drawings. Prior to the method vendor electrical component installation, you approve each device quantity, location, and function with respect to safety, accessibility, appropriate application, and functionality. On your vendor method plan-view and detail-view drawings, the drives and takeups on conveyor travel paths are not located many times. If they are shown on drawings, the method vendor installation crew does not adhere to the location that is shown on the drawings. While locating these items as outlined in your written functional specifications, you vendor gives consideration to your operational requirements: piece or customer-order travel paths or aisles, personnel work areas and aisles, and proximity to other method or building equipment; accessibility for operators and maintenance staff; and employee safety. In general your initial method or equipment vendor air piping and air compressor layout drawings at best give a schematic layout. Per your written functional specifications your method vendor has to identify the air compressor location and air pipe path. The air pipe path follows the same path as the electrical wire path. An air piping and air compressor consideration is the air compressor location. If the air compressor is large and creates a higher noise level that is not allowed by code, to reduce the noise level the options are to have the air compressor remain inside the building and place a shroud (enclosure) around the air compressor, or to build an enclosure outside the building wall to house the air compressor. The preferred location is based on the air compressor noise level, air compressor size, accessibility to the air compressor, and drain. Check Your Building Construction and Order-Fulfillment or Acrossthe-Dock Method Equipment Vendor’s Labor Force Your next building construction and method vendor check is to make sure that your building contractor and method vendor have the right qualified labor amount. This qualified labor quantity is stated in the vendor proposal and is sufficient to complete the installation work on schedule. You have no direct supervision responsibilities to



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method vendor labor activity, but you can certainly check on the labor quality and quantity that is employed on your job. If the building construction and method vendor are understaffed and behind schedule, send a letter warning the building contractor or method vendor. If there are any method start-up shortcomings as compared to the job contract, you have taken the necessary steps to correct the situation and protect your company’s method start-up date. How to Control Job Extras During your building construction and method vendor installation, your project manager more than likely has field changes, changes of scope, and job extras. Prior to a change-of-scope or job-extra release to your building contractor or method, you obtain a price quote for the required work to the building construction and method equipment. Since the majority of your project change of scope or job extra affects a building construction item or method equipment component change, to obtain the best solution that minimizes a project schedule adjustment or project cost, you follow this guideline. For the required work, you obtain a material and labor cost and time quote from your building contractor and method vendor. After you review these two price quotes, issue a written change of scope or job-extra document to the builder or method vendor who has the preferred price quote. The change-of-scope or job-extra document is signed by you and your building construction company or method vendor. Copies are sent to the building contractor or method vendor and placed in your project file. You make adjustments to the appropriate master project, building contractor, or method vendor schedules and to the necessary builder or method vendor contract administration (cost tracking) form. The additional costs for the building construction or method vendor material and labor costs are over and above the original purchase order (job contract) dollar amount. The additional costs are required to correct poor written functional specifications or plan-view and detail-view drawings, such failing to identify who is to unload or uncrate the method equipment on site or to specify the guardrail on the wrong conveyor side. There may be extras due to poor coordination between the architect drawings, building drawings, and method vendor drawings. The extras are avoided in the bidding phase and in the final design phase by furnishing the method vendor with the architect’s up-to-date drawings and making your method vendor responsible for coordinating piece or customer-order travel paths in reference to the building obstacles and other vendor equipment. Some potential piece or customerorder travel path problems that occur result from column size and column base plate size; ceiling or wall structure steel; sprinkler heads, risers, and other piping; and ventilation ducting, piping, and other raceways. Extras may be due to interference between the method equipment and piece or customer-order travel paths. Situations like these are avoided by furnishing the method vendor or other equipment vendor who is involved in a building area with method vendor or other equipment vendor drawings, and making the method vendor responsible for checking the vendor equipment drawings for adherence to the written functional specifications and drawings, which helps to prevent interference.


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Legitimate extras are due to changes in the building construction or method layout, additional building or method equipment, and delays that are caused by the building contractor or other equipment installers on site. Contract Payment A very important project manager responsibility is to ensure that the architect, building contractor, and method vendor and their subcontractors are paid for their material and labor work. To protect your company from potential future legal problems, the architect, building contractor, and method vendor invoice submittal process requires that each progress or percentage invoice is accompanied with a partial waiver of lien and release of rights, which includes labor, material, freight, and taxes. The final invoice is accompanied with a final waiver of lien, release of rights, and completed warranty. All invoices are sent to you for approval, and the building construction company, architect, and method vendor have separated the dollar amount on the invoice as you specified in the PO or job contract. Project Progress Report The other project management responsibilities for your project manager are issuing building construction and method installation progress reports and maintaining daily building construction and method vendor record keeping. A complete project progress report is sent to your top management, architect, building construction company, method vendor, and project files. To keep your management on-the-job site status, prepare and distribute a weekly building construction and method vendor installation progress report to your management team, architect, builder, and method vendor. To be an effective tool, your report is simple, precise, and to the point. Your weekly project progress report measures the building construction and method vendor performance against the building construction and method vendor schedules and your master project schedule. During an on-site project meeting with the architect, building contractor, and method vendor, the report permits you to review the building construction and method vendor equipment installation progress and identify, evaluate, and approve solutions to improve an off-schedule project. It shows the building construction and method vendor installation problems. Since these problems are known and are associated with the building construction or method vendor installation, the report shows that you have reviewed and resolved these problems with solutions developed at your on-site project meetings. It also shows you that you are in control of the project and handling the problem. Finally, the report shows your top management that you are in control of the building construction and method vendor installation project. Various Project Progress Reports The three formats for your building construction and method installation project progress report forms are a preprinted form, a letter, and a combined building design and method layout plan view drawing.



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Preprinted Form Project Progress Report The preprinted form is the first project progress report type. The preprinted form is a specially prepared form for your building construction and method installation project. With the preprinted form, you are required to fill in the date and, for the building construction and method vendor, the percentage completed figures. This preprinted form is easily understood by your management, architect, building contractor, and method vendor. When you are required to go back and trace the weekly project progress, it is easily obtained from your files. If the project is on schedule with no problems, the preprinted form is a good project progress report. Letter Project Progress Report The letter project progress report is the second project progress report form. The letter project progress report form is preferred when you desire to make more building construction or method vendor installation qualitative statements, rather than quantitative statements. The letter project progress report form can be attached to the preprinted project progress report form or layout copy project progress report form. If the project is off schedule with numerous delays or has changes of scope or job extras, the letter form is the preferred report because you provide an explanation for these situations. Copy of the Building and Order-Fulfillment or Across-the-Dock Method or Equipment Layout Progress Report A reduced building and method layout drawing copy is the third project progress report form. To your interested parties, the building and method layout drawing copy is an excellent means of communicating the building construction and method vendor installation progress. As the building construction and method installation is completed on the site, it is identified on the plan view layout drawing copy. When your top management or key vendor management personnel visit the site, this project progress report format is quickly and easily understood. The plan view layout drawing report is understood because it is a building and method picture. There is sufficient space to write required explanatory notes; it shows most building design and method key areas, and also highlights the flow to the building construction or method installation from the receiving area through the receiving, storage, order pick, sorting, and shipping areas. A layout project progress form copy is attached to the preprinted project progress report form or letter project progress report form. This feature allows the layout progress report form to be used for an on-schedule or off-schedule project. Keep Good Records In addition to the weekly building construction and method installation project progress report, it is extremely important to keep good, legible records or files of all telephone conversations, meetings, and any daily observations and measurements. To your architect, building contractor, and method vendor, all telephone conversations and meeting minutes are confirmed by letters, no matter how insignificant. Copies are placed in your project file.


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Your easiest method for record keeping is to record daily events in the chronological order by time of day. This daily report file is easy to reference and to confirm telephone conversations, meetings, observations, and other issues. Order-Fulfillment or Across-the-Dock Method or Equipment and Building Orientation Meetings When your building construction and method installation is near completion, to familiarize your company’s operational and maintenance staff with the new building and method, you schedule a building and method orientation program or meeting. The more sophisticated, automated, or highly mechanized methods require a more extensive or specific method orientation. With a less mechanized or manual orderfulfillment method, a more general method orientation meeting is required. To ensure proper method orientation, this meeting is required for your company’s key operational and maintenance people. Your method orientation meeting format is as follows. Organize the attendees by function and schedule dates and times; organize supplies, cartons, pallets, pieces, or customer orders; explain general method and equipment features, what to do and what not to do, safety aspects, and general capabilities; obtain audiovisual aids from the vendors; simulate the method operation for all in attendance and repeat it; have color-coded drawings and reduced building and method layout drawings; have the method’s functional area supervisors repeat the orientation; and invite participation and comments from the attendees. Your normal orientation meeting begins at the receiving function; for an acrossthe-dock method it follows the piece or customer-order flow from the receiving docks through the facility, over the method, and to the shipping docks. For an orderfulfillment method it follows the piece flow from the receiving docks through the facility storage/pick and pack area and ends at the shipping dock. Whenever possible the method vendor contributes to the orientation meeting and training sessions. Training commences on an unaccepted method provided that the method vendor has granted approval. This training does not represent that your company has accepted the method. Normal operation of the method with vendor-delivered pieces or customer orders constitutes acceptance of the method. Order-Fulfillment or Across-the-Dock Equipment or Method Operational Test After proper method vendor and building construction company notification that the method and building are ready for operational testing, your method vendor and building contractor are ready to provide the operational test assistance as outlined in your company’s written functional specifications and job contract. Operational testing refers to the testing of your building equipment (systems) and method equipment that move or handle your pieces or customer orders. The method complexity and sophistication determine the time length for you and your staff to conduct the operational tests. The operational test factors are as follows. Since operational testing involves your piece or customer-order movement, the



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operational test waits until all basic mechanical, electrical, pneumatic, and hydraulic components are properly adjusted and the vendor has simulated a method checkout without pieces or customer orders. If this is not done, piece, customer-order, and method equipment damage can result, resulting in lost time to the start-up schedule due to fixing the damaged equipment. The primary responsibility to conduct the operational test lies with the method vendor. However, placing and removing the pieces or customer orders on the method at the end of the test belongs to your company. Operational testing is a continuous process and continues for several days or even weeks. It begins very slowly as far as the piece or customer-order volume is handled on the method. For the first time, one or two pieces or customer orders are routed over the method. If you encounter method problems, these problems are noted and fixed by the method vendor. Next, 12 or more pieces or customer orders are routed on the method, the flaws in the method are recorded, and the vendor makes the proper method equipment adjustments. This test action continues until the method equipment components are properly adjusted for a smooth flow for your pieces and customer orders. While conducting the operational test, care is taken by you and the method vendor to simulate all different possible conditions that could arise in a future normal operational situation. This approach helps to make your method and building as foolproof and operationally safe as possible. As part of your operational test and training program and to improve your future employee training, you videotape the training session and operational test. For new employees, this videotape shows the proper use of the method equipment. Order-Fulfillment or Across-the-Dock Equipment Acceptance Test When the operational test is successfully completed by your vendor, the vendor notifies you that the equipment is ready to perform the acceptance test. The acceptance test is defined in your written functional specifications and job contract. Prior to the method acceptance test, you review the specifications and job contract, and general observations are made to ensure that you are aware of the required functionality. Your equipment acceptance test is exactly what the words suggest. It is a test that you conduct with the result that the system is accepted for your company’s operational department use, unless something goes wrong and further operational testing is required by the vendor. After the operational test period and with your approval, your vendor starts the acceptance test. This acceptance test is conducted with the maintenance manger, key operational people, and vendor personnel. If the acceptance test result is found acceptable to your company’s operational managers, the system is conditionally accepted by your company. A punch list is developed as a result of this test. This punch list identifies items that do not meet your written functional specifications, do not affect the piece or customer-order flow, and are included in your company’s conditional system acceptance.


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Order-Fulfillment or Across-the-Dock Equipment and Building Punch List Your next step in the method installation project is to develop a punch list for the system installation and building construction. This punch list is an itemized list of things that need corrective action by the system vendor or building contractor. A punch list is divided into operational items that are mechanical or electrical items or nonoperational items. Your method operational items are those punch list items that require corrective action for the method or building equipment proper function and operational reliability. Nonoperational method items are those punch list items that are minor maintenance problems and aesthetics problems. These items are purely subjective in nature due to certain things that are desired by your operational or maintenance personnel and these items are avoided on the punch list. You avoid these items because they are usually turned down by a method vendor and building contractor. For all moving method components, such as powered conveyor travel paths or tilt tray powered chains, use a tachometer to measure the correct piece or customerorder load-carrying surface travel speed. This procedure is used to verify that the piece or customer-order load-carrying surface travel speeds are as specified in your written functional specifications or job contract. When you check the nut and bolt connection tightness, you use a wrench or torque wrench. The other important method equipment and installation punch list test equipment includes a measuring tape, a level, a plumb line, and a laser light. Each tool permits you to verify that the method equipment installation or building construction is per your company’s plan-view and detail-view drawings, written functional specifications, and your job contract. As you become aware of building construction or method equipment items that are not per your written functional specifications and job contract, these items are identified to the building contractor or method vendor. These punch list items are identified with a number on your plan-view or detail-view drawings and are listed with a number on a document. In addition to the drawings and list, you use the redtag (tape) approach. The red-tag approach has a number placed onto the drawing and list, and the same number is written onto a red tag or tape piece. The red tag (tape) is attached to the method or building equipment. When the method vendor and building contractor are working on the punch list, the red-tag punch list items are easily identified. Include Your Operational and Maintenance Staff as Part of the Punch List Team It is recommended that your operational and maintenance staff contributes to the building construction and method equipment punch list. Your staff consists of people who operate and maintain the method and building equipment; it is very important that they are members on the punch list team.



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After the building construction and method punch list preparation, at a meeting with the method vendor and building contractor fix a completion date for accomplishing the corrective work. The punch list and mutually agreed upon completion dates are distributed to the concerned parties, and a copy is placed in your project file. Your method vendor and building contractor initial punch list acceptance allows you to add more punch list items to the original punch list. During the next several days or operational run times with your operations staff and handling actual pieces or customer orders with a wide mix, these additional punch list items are noticed by you or your staff. The punch list is kept current by continually adding these new punch list items or deleting corrected times. Operational and Maintenance Training Sessions After the operational method and building equipment acceptance, you have your company’s operational and maintenance personnel training sessions. In the implementation phase, the building and method training sessions are the most important aspects for a method or building equipment turnover. As everybody knows, the method or building equipment cannot obtain the required results if it is not properly operated and maintained by your company’s operational and maintenance staff. You insist upon the building contractor and method equipment vendor to train your operational and maintenance personnel in the proper procedures and practices to operate and maintain the equipment. Initially, your operational and maintenance personnel are included in the same training sessions. These combined meetings are primarily involved to get you and your operational managers and maintenance personnel familiar with the building and method layout. A description of operations and a tour through the facility allow the personnel to get familiar with the location and mechanical and electrical controls. During this phase, emphasis is placed on getting the operational personnel familiar with the method equipment. The important method areas are piece, customer-order, vehicle, or load-carrying surface travel paths; piece and customer-order flows; pieces or customer orders that are handled by different methods; equipment limitations; and proper piece or customer-order orientation onto the equipment or load-carrying surface (important to reduce jams and piece or customer-order damage). Everyone is made thoroughly familiar with the start/stop controls, E-stops, and other building and method controls and panels locations. After completing the method and building equipment operational training, some method vendor and building contractor training time is devoted to make the maintenance personnel totally familiar with many equipment aspects. These building and method equipment aspects are familiarity with the method and building equipment and its components, adjustments and repairs, regular and preventive maintenance requirements and procedures, troubleshooting procedures, and importance for maintaining up to date spare parts inventory and using the correct lubricant or oil. Per your written functional specifications and job contract, the maintenance manuals furnished by the order-fulfillment or across-the-dock method or equipment (method) and building equipment suppliers are used during this time.


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Some Dos and Don’ts To summarize your building construction and method installation project management duties, here are some dos and don’ts. Do keep a daily record for telephone conversations, meetings, and other observations. Do confirm all telephone conservations and meeting results in writing. Do prepare periodical progress reports, videotapes, and take pictures with the date. Do keep up-to-the-minute records for the building construction status and order method equipment deliveries and installation status. Do check periodically and if possible on a daily basis the labor quality and quantity that is employed by the building contractor and method vendor and their subcontractors. Do bid and complete change of scope and job extras to the contract with a formal written document. Do get involved in the control panel, emergency push button and pull cord station, power panel, and key method activity stations locations. Do maintain an up-to-date building construction and order method cost projection and installation schedule. For the building and order method equipment, do get warranties or guarantees, and with the building construction and method vendor, do obtain partial and final waiver of liens and release rights documents. Do not deal directly with the building and method vendor subcontractors or their personnel. Do not give solutions to any problems that are included on the punch list. Do not use the building contractor or method vendor approval stamp to approve drawings. Do not give verbal approval to changes of scope or job extras. Your Order-Fulfillment or Across-the-Dock Method or Building Method Drawing (Blueprint) Is a Person’s View In the distribution industry, the terms blueprint and drawing are used interchangeably by industry professionals. The drawing or blueprint is made from paper or a reproducible material. When a drawing is used in the building construction or method design and installation project, the object that is being described is a person’s or team’s lined presentation or impression for a building or method layout. A building or method drawing’s purposes are to show how the building and method will look and operate. Drawings are required from your design team, architect, and method vendor. These drawings provide your company’s design team, architect, building construction company, method vendor, and various other groups with an understanding and interrelationship of your existing or proposed building and method equipment. CAD personal computer programs create building design and method layouts, and a diskette is used to transfer a building design or method drawing between two offices. Two- or Three-Dimensional View Drawings A building or method drawing is presented on a two- or three-dimensional drawing. In a building design and method industry, the two-dimensional drawing is the most widely used drawing type. The two-dimensional drawing presents two of the three following dimensions: length, width, and height.



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The three-dimensional drawing is a drawing that presents a building design or method and three dimensions: length, width, and height. The building construction and method drawings used in the distribution industry are drawn by a technical or engineering person. Complicated facilities or high capital methods are designed with standard methods or equipment. These building designs and methods drawings are produced on a CAD machine. Various Types of Drawing The drawing types that are used to show a facility or method are plan-view, elevation view, detail-view, isometric, sketch, layout board and standard templates, autopositive, reduced drawing, model, overlay, and CAD. Plan View Drawing The plan view drawing is the first drawing, a two-dimensional view drawing. The plan view drawing shows a facility or method length and width. This drawing is to scale and is illustrated on paper. A facility or method plan view drawing allows you to trace the piece or customerorder flow and piece or customer-order travel paths through a facility or over a method; it permits you to identify key method activity work stations and determine the size of the total facility and each method department or work station area. It helps you identify method activity interaction locations and look for the offices and other key method administrative and support areas. Elevation View Drawing An elevation view drawing is a two-dimensional drawing. This type of drawing shows to scale one of the following two-dimensional views: height and width or height and length. The drawing view details a facility or method and provides you with a view to the clear distance (space) from the floor surface to the building equipment, and to the building ceiling (steel) or mezzanine support members. When a forklift truck with an overhead guard or elevated piece or customer-order transport method travel paths are required in the distribution or facility, the elevation view drawing provides you with a view to the clear operating distances between equipment pieces or building obstacles. An elevation view drawing determines the relationship between forklift truck overhead guard or method travel path with a piece or customerorder on a load-carrying surface to a building obstacle or ceiling (steel). Some other key clearance areas are forklift truck mast, overhead guard, or backrest elevation; piece or customer-order height on overhead load-carrying surface; and piece, customer-order, or vehicle travel path clearance through passageways. Detail-View Drawing The detail-view drawing is a to-scale drawing that shows one view: length and width, length and height, or width and height. The detail-view drawing is used to illustrate a specific location on equipment with a building area method cross section. This drawing uses a large to-scale view to show the exact and detailed dimensions (space) between different equipment, equipment to a building wall, clearance from the floor surface to the ceiling (steel), or from a building column to equipment.


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Isometric Drawing An isometric drawing is a three-dimensional view that is not to scale. This drawing provides you with a deeper view to the relationship between the total facility and method and includes the building fixed equipment and offices. These drawings are considered an artist’s one color or multicolored rendering for a method or building. These isometric drawings are seen on an office wall or in a distribution magazine. Sketch A sketch is a drawing or illustration that is a to-scale or not-to-scale drawing. The sketch is a two- or three-dimensional view for equipment, work station, or method. Sketches are used in at business meeting presentation, report, or a training session. Auto-Positive An auto-positive drawing is a drawing or layout board reproduction. The autopositive is reproduced onto photographic paper and allows additional copies to be reproduced at a lower expense. To read the notes or legend on an auto-positive, the reproduction is turned on the reverse or back side. Standard Template and Layout Board A standard template and layout board is a method that presents an initial layout for a building or method. The layout board is sometimes referred to as a planning board with standard templates that is a two-dimensional view approximately to scale. Standard templates are black and white or colored line representations of a particular order-fulfillment or across-the-dock method or equipment. The layout board surface allows a person to arrange these templates to show a method within a facility’s four walls. To complete a layout board, your method design person moves (juggles) the templates on the planning board to show various methods. These various methods are created in a short period of time with very little drafting expense. On some occasions, due to the standard template flexibility, top management actively participates in the development of alternative methods. If mezzanines or additional floors are used in the building or method design, a separate planning board or clear plastic sheet set on stands represents this elevated building floor or method. Overlay An overlay is a method for clear reproduction of an additional floor to a facility or method piece or customer-order transport path. When the overlay plastic sheet is placed on top of another drawing, it provides you with a two-dimensional view of both floor areas. This view allows you to trace the pieces or customer-order travel paths and pieces or customer-order flow between floors. Most photocopy machines distort an original drawing’s dimensions; the overlay drawing approach provides you with an approximate to-scale view. CAD Drawings A CAD drawing is drawn as a one-, two-, or three-dimensional facility or method view. The computer provides you with drawings that are to any scale. These drawings are plan views, elevation views, detailed views, and a view of a facility or method



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bottom. These drawings are drawn with colored lines for specific method piece or customer-order travel paths. A floppy diskette provides you with a very flexible and simple method to transport a facility or method layout drawing between two offices. To-Scale and Not-to-Scale Drawings All drawings are to-scale or not-to-scale line representations for a building or method. A drawing that is not to scale means that the lines for a facility walls, columns, and method are not scaled to a specific measurement. A drawing that is to scale means that each line portion on a drawing is equal to a standard U.S. or metric measurement. The measurement is noted in the drawing title block. Small-Scale or Large-Scale Drawing If a small scale is used on a building or method drawing, the drawing provides a large building or method view. This large view allows you to see the entire method and to obtain a comprehensive understanding for the piece or customer-order flow and piece or customer-order transport paths. Most plan view drawings are smallscale drawings. If a large scale is used on a drawing, it shows a detail or specific section, a cross section, or an area on a building or method equipment. The large view provides you with an understanding for clearances and dimensions that are required for a method equipment or workstation to function. Most detailed view and elevation view drawings are large-scale drawings. Types of Scale Tools The scale tools that are used on a building or method drawing include the triangle scale. The triangle scale has three sides and each side represents two scales, which means that a triangle scale has six different scales. The other type is the flat scale. The flat scale has one or two sides, which means that a one-sided flat scale two scales and a two-sided scale has four scales. The architect scale is used on method plan view drawings. The scales are 10 = 1 foot, 20 = 1 foot, 30 = 1 foot, 40 = 1 foot, 50 = 1 foot, and 60 = 1 foot. The second type is the engineer’s scale. Building drawings are drawn with an engineer’s scale. The scales are 1/8 inch = 1 foot, 1/4 inch = 1 foot, 1/2 inch = 1 foot, 1/32 inch = 1 foot, 3/16 inch = 1 foot, 1/16 inch = 1 foot, 3/8 inch = 1 foot, 3/4 inch = 1 foot, 1 1/2 inches = 1 foot, and 3 inches = 1 foot. How to Use a Scale Tool on a Drawing On a drawing, you use a scale tool to verify that the dimension between two building columns or between two lines is as written on the drawing surface; the method equipment length, width, and height and the facility layout are as described on the drawing layout; and the all the equipment fits within the building physical area. This physical area is shown on the drawing. To use a scale tool on a drawing, the steps are to read the scale tool that is listed in the drawing title block, obtain the appropriate scale, and place the scale tool in your desired position on the drawing surface. This position has the scale zero located on drawing point A and has a scale line intersect (cross) the desired line or point B on a drawing. The next step is to count the scale line number between these two


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intersection points. The scale lines represent the number of feet between these two specific lines on the drawing. Portions of a foot are represented on the scale between the scale zero and the solid line on the scale. Other drawing guidelines are that a drawing with a metric measurement is scaled with a metric scale and that a drawing with a standard U.S. measurement is scaled with a U.S. scale. Various Drawing Materials Your facility and method layout and detail drawing surfaces are paper, Mylar, or paper sepia. These drawings are used to show a facility or method layout or detail view. The method and facility layout drawings are key components in a project design review process and in verifying the building construction and method installation. Paper Drawing Material. The most common drawing material is paper. When a blueprint machine copies a drawing, the paper is an off-white color and all lines are blue. When a CAD computer and colored printer produces a drawing, it is drawn on standard white paper, and the building and method travel paths are available in different colors. The paper drawing has the lowest reproduction cost. The standard paper drawing has a printer or employee color lines to identify specific areas, piece or customerorder travel paths, work stations, or equipment. With a paper drawing, an office copying machine makes copies, but it is noted that a copy machine does distort the scale and line straightness on a photocopy. Sepia Drawing Material. The second type of drawing material is an original drawing or drawing reproduction. The paper sepia allows you to make sepia reproductions that permit one to mark or write notes on the surface. After you complete the checking process, these notes are automatically a part of the drawing, and marked paper notes are a reproduced paper drawing part. Mylar Drawing Material. The third drawing type is the Mylar material that allows a drawing to be reproduced from the Mylar drawing. The Mylar cost is more expensive than the paper sepia cost. The advantages of Mylar are that it allows an employee to make notes or marks onto its surface, that all notes or marks automatically appear on all reproductions, that the method permits the greater number of reproduced drawings, and that it maintains its quality for a longer period of time. Various Drawing Components A facility or method layout or detail-view drawing components are the title block, north directional arrow, note section, match line, symbol legend, and revision section. Title Block. The first drawing component is the title block that is located on the drawing lower right-hand corner or along the right-hand side. The information that is contained in the title block includes your company’s name and address; the architect, engineer, or method vendor that produced the drawing; the date that the



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drawing was produced; the artist or CAD operator who produced the drawing; the drawing scale; and the drawing number or drawing revision number. When making a drawing list or transmittal, these drawing numbers or drawing revision numbers appear on the list or transmittal. Also included is a brief drawing method description. This description appears on the drawing list or transmittal. Lastly, there is a revision list that briefly describes each revision that was made to the drawing and the revision date. North Directional Arrow. Another drawing item is the north directional arrow, which is basically a large arrow with a capital N at its base. The arrow indicates the site compass north direction and orients the building on the site. The north direction is important in locating your receiving and shipping docks. Note Section. The third important drawing item is the note section, a written fact list that relates to the facility or your method. Match Line. The fourth drawing item is the match line. When a facility or method layout view uses several drawing sheets, the match line sequences these drawings. If you cut along each drawing match line and tape two drawings’ corresponding match lines together, the one large or newly taped drawing has one facility or method complete view. Symbol Legend. The fifth important drawing item is the symbol legend. The symbol legend is a section on the drawing that includes all symbols and each symbol definition that is used on the drawing surface. These symbols allow the design person to develop a comprehensive drawing with as little writing as possible in the drawing body. During a drawing review process you refer to the symbols to obtain a clear understanding for drawing method or building equipment. Revision Section. The sixth important drawing item is the drawing revision section. After a drawing review meeting or after any change is made to a drawing lines, notes, or items, the revision section tells the revision story. The drawing revision section describes the change and the change date and identifies who made the change. These drawing revision notes become a drawing part and serve as a quick reference. This ensures you that you are referring to the latest or most recent building or method drawing. How to Review a Drawing When you are designing a new facility or method, an important drawing and project activity is the building construction and method drawing review process. During the drawing review process, you use a red pen or pencil to mark the dimensions or notes that you want shown on the drawing or to make corrections. During a drawing review process on a plan view drawing, you look for the facility and method width and length. On a detail- or elevation-view drawing, you look for the equipment width, length, and height; clearances for piece and customer-order flows and travel paths; passageways and emergency exits; employee travel paths to work stations; and work station size and locations.


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Metric Measurements Increasingly more U.S. order-fulfillment or across-the-dock managers are presented method drawings that are in metric measurements, or purchase method equipment with metric parts. This requires you to understand metric measurements. To have a metric measurement and U.S. measurement understanding, the conversion between the two most frequent used measurements are as follows: 1 inch = 2.5 centimeters, 1 foot = 30 centimeters, 1 millimeter = 0.04 inch, 1 centimeter = 0.4 inch, 1 meter = 3.3 feet, and 1 kilogram = 2.2 pounds. Military Time Military time is a relatively simple time system that has each day start at 0000 and end at 2400. For military time before noon the military time corresponds to the regular clock time. To calculate military time after noon, you add 1200 to the clock time (e.g., 1:00 is 1300 and 4:00 is 1600). The advantages to using military time are that there is no confusion as to the hour of day or evening, such as 11:30 in the morning or 11:30 in the evening, because 11:30 in the evening is 2330 hours; and the method requires four digits (2200) instead of a six number and alphabetic character combination (10:00 p.m.). Julian Dates Julian dates are derived from the Julian calendar, which is based on an arithmetic progression from a year’s first day being with the number 1 to a year’s last day being with the number 365. The advantages to using Julian dates are that when discrete numbers are required for a date, the Julian date requires five to six digits (e.g., 365/97) instead of the standard six to eight digits (e.g., 12/31/97); and the date is understood by a manager from a foreign country. The military time and Julian date disadvantage is that your operations employees do not use these notations in their daily lives. This feature requires employee training and some difficulty to make the conversion. Charts Are Important Tools for Building Construction and OrderFulfillment or Across-the-Dock Method Installation Schedules A complex project involves controlling building construction, using order-fulfillment or across-the-dock equipment or method installation, and managing a dynamic piece or customer-order operation. The chart’s objectives are to improve your worker productivity, properly schedule labor and equipment, and control the building construction or method installation activities. To understand, schedule, and track a building construction, method installation, or piece or customer-order operation, you use a chart. The charts are bar or Gannt chart, flowchart, and program evaluation and review technique (PERT) chart.



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Bar Chart or Gannt Chart The bar or Gannt chart is the basic tool to project and track (schedule) the activities and activity dates that are required to complete work or a project. The bar chart is used to show a building construction project, method installation project, or piece or customer-order activity. The bar chart has columns and lines on a sheet or paper. At the top of the bar chart is the project name and other important project information. To use a bar chart, you write the project’s initial task in the first column and each progressive task is listed in the appropriate space in the task column. Across the chart’s top is a list for the time factor (hours, days, or weeks) that are required to complete the entire project. For each activity under the task column, a line is drawn from each task start time to its completion time. These lines are drawn for each task, resulting in bars (lines) that show the interrelationships between the various tasks. The time factor on the chart top shows each task duration and the duration for the entire project. The disadvantage of the bar chart is that it does not show the dynamic interrelationship between two project tasks. The advantages are that it is easy to understand and develop. Flow Chart The flowchart is a pictorial display that traces piece or customer-order or information flows through your facility or operation. On the flowchart each event (activity) flow path has a written description on the chart. The flowchart starts as the piece or customer order or information enters the facility; each progressive workstation (event or activity) is noted and described until the piece or customer-order or information flow exits the facility. Lines and arrows between the various activities and events show the piece or customer-order or information flow direction. The flowchart’s features are that it is difficult to identify the exact start and completion dates, there are written statements for each event, and that it shows all required activities in proper sequence to complete the project. PERT Chart The PERT chart is a planning and control technique that utilizes a network for scheduling a project’s events (activities) in the proper sequence or in a logical order to accomplish a predetermined project. The PERT chart shows the interrelationship between two project events from which a critical path is developed for the project. The critical path is the path between the first activity date and the last activity date to complete the project. The PERT chart allows your project manager to make a decision on minor events and to show how these minor modifications affect the next event or the overall project. The disadvantages of the PERT chart are that the chart is difficult to understand and requires several pages. The advantages are that it shows the interrelationship between minor and major project events, shows the start and completion dates for the project, and identifies the critical path to complete the project.


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WHEN AND HOW TO SELECT AND USE A CONSULTANT It is a fact that your order-fulfillment or across-the-dock business cycle will experience peak and low-volume periods. These periods have different volume characteristics and are beyond your management team control. During these periods, your method manager and staff are expected to satisfy your company’s operational objectives, which are to achieve the lowest operating cost and satisfy your work station or customer demands with on-time, accurate, and undamaged deliveries. To satisfy your method objectives, you arrange and organize your company’s scarce method resources, which are building and land; method equipment; labor, which includes your employees and management staff; your company’s policies and procedures; and internal and external consultants.

WHERE DO YOU FIND ASSISTANCE

FOR

YOUR OPERATION?

To assist you with your company’s operational projects, many managers obtain advice and direction from internal experts, external consultants, or vendors.

PROVIDING ACCURATE DESIGN INFORMATION

AND

ON-TIME OPERATIONAL

When you are involved in an operational project, you provide accurate and on-time operational design information. The value to provide your operational consultant with accurate, on-time, and completed questionnaires (information) means that your consultant has the correct information to complete your operational project. This means that your project is completed on schedule and on budget. Due to inaccurate client-supplied operational information or piece or customerorder movement data, it has been the authors’ experience to see wasted days of consulting services (fees and hours) on a project. At the rate of approximately $1,000 per day, these services represent an expense to your company with no return. When this situation occurs in the life of a project, it involves an extra charge to the client company from the external consultant. The extra charge is required by the external consultant to complete the project on schedule.

INTERNAL (IN-HOUSE) EXPERT The internal expert or internal (in-house) operational consultant is your company employee who is the design, planning, and implementation resource for a new or remodeled method. This expert has years of company experience and direct access to past operational projects and studies. His or her knowledge of your company’s operational support activities and functional details and familiarity with your company’s managers’ and employees’ personalities and characters are important contributions to a successful project. This information includes how your company’s personnel have handled the past implementation of a new method, procedures, changes to the piece or customer-order flows, or a new facility layout.



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These insights and knowledge reduce new or remodel method implementation and start-up problems. The internal expert benefits are lower annual operating costs and availability for other company projects. The company internal expert remains with the company and method long after the external expert and method vendor leave the project.

EXTERNAL

OR

OUTSIDE CONSULTANT

Your second order-fulfillment or across-the-dock project design, planning, and implementation professional resource is the external or outside consultant. Your external consultant is a professional individual or group under contract with your company to assist your existing management team in an operational project. For your operational dock project, this group is the design, planning, implementation, and start-up resource for your company’s operational manager. The external consultant group brings into the project an understanding for the equipment types, methods and systems, procedures, piece or customer-order flow patterns, and method vendors. These external experts can be used in a new or remodel method project. Their knowledge of the methods and method vendor’s capabilities along with their past project experience are vital contributions of objectivity to your method project. There are several reasons to use an external expert: your existing staff does not have knowledge of the latest technology or the skills; your present staff is qualified to handle the project but your staff work load is too heavy; your company’s top management desires an outside and unbiased opinion; your operation is experiencing a rapid increase in costs; you desire a concentrated effort within the scope and definition; your company is experiencing an unexpected decline in sales, an unexpected sales increase, or sales that exceed the planned growth; there is a lengthy decision making time requirement due to cumbersome committee organization; and headquarters of a large company desires to control the project.

ORDER-FULFILLMENT

OR

ACROSS-THE-DOCK EQUIPMENT VENDORS

Your third order-fulfillment or across-the-dock method design, planning, and implementation professional resource group is method vendors. By soliciting their participation in your company’s project, you gain an understanding of their equipment and knowledge of their companies’ latest technologies.

WHAT ARE THE SIGNALS THAT YOUR OPERATION REQUIRES A CONSULTANT? One key question that confronts you and your company is this: When does your order-fulfillment or across-the-dock operation require the services of an external order operations consultant? Stated another way, what are the operational signs that signal you that your operation requires an operations consultant? These signals are rapid increase in operational overtime or wages, increase in errors and off-schedule deliveries, increase in employee injuries, increase in building and operational equipment damage, increase in product damage expense, increase or decrease in business


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or volume beyond the company expectations, increase in crowded aisles with product, and poor housekeeping and poor sanitation ratings.

WHAT ARE THE ACTIVITIES THAT REQUIRE EXTERNAL CONSULTANT?

AN

After you have determined that your operation or a specific operational activity requires an external consultant, your next step is to determine the consultant’s scope of work. In the scope of work for your consultant’s operational project, you state the expected results. The scope of work identifies and states the depth for the operational activities that are involved in your company’s consultant project. These operational activities are using information and piece or customer-order flows and downloads to the pick area microcomputer; preparing and using for the piece or customer-order identification; piece or customer-order loading and unloading between a conveyor or truck and work station; storage position, pick position, vehicle or load-carrying surface identification; order picker routing, conveyor or vehicle travel path; profiling the pick line or pick aisle, dispatching the order picker or vehicle; using a manual, mechanized, or automated operation activity; and performing maintenance, sanitation, and security.

WHAT SHOULD YOUR CONSULTANT EXAMINE? Your company’s expected results are general guidelines that state how the operation is designed for your company’s anticipated business growth. When your company has an operations consultant look at your operation, he or she looks at each activity in a macro- or micro-perspective. During the company project, for each method activity your consultant looks to eliminate the activity, combine the activity with another activity, simplify the activity, and change the activity sequence or piece or customer-order flows.

WHO FROM YOUR COMPANY SHOULD WORK YOUR PROJECT?

ON

When you have an external consultant remodel an old or design a new method, your company forms a project team to control the project. Your company’s project team consists of members from distribution operations; traffic operations; engineering; maintenance; purchasing; piece or customer-order storage, pick, and transportation departments; delivery vehicle or trucking; personnel; and data processing.

ORDER-FULFILLMENT OR ACROSS-THE-DOCK PROJECT TEAM ORGANIZATION After the executive management group creates a project management team, the project team is assigned the responsibility to complete the project. With an approved capital expenditure for the project, your method project team is given the power to purchase and implement the project; execute contracts; and make payments to the architect, construction company, and the method vendors and consultants.



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The order-fulfillment or across-the-dock project management team levels are executive project team, venture manager, project manager, specialists, external consultant, and method vendors. Executive Management Team The first project management level is the executive management team level that has the senior executives from your company’s key departments that are affected by the method. This management level is the top project organization level and consists of the project sponsors who define the scope of work for the project. Venture Manager The second project management level is the venture manager who is a senior manager. This position has the project responsibilities to report to the executive management team, complete the project on budget and on schedule, provide the project visibility, determine responsibilities, establish priorities, and oversee the project. Project Manager The next management level is the project manager. This person has the definitive responsibilities of reporting to the venture manager; designing the method; developing method written functional specifications and reviewing the plan-view and detail-view drawings; selecting the method vendor and scheduling the method installation; carrying out the method implementation and integration; overseeing the method start-up; reviewing the method performance; and ensuring payments are made to the architect, building construction company, and method vendor. Project Specialists The specialists on a project team are managers and employees from your company’s departments that are involved or affected by the method project. These managers and employees are specialists who know the department activities, piece or customerorder flow, and piece or customer-order information flow, along with past method installation project experience. Order-Fulfillment or Across-the-Dock Consultants and Vendors The method consultants and equipment vendors are the noncompany representatives on the project team who contribute equipment knowledge, project installation, and start-up experience.

WHERE DO YOU FIND CONSULTANTS? When you have sufficient justification to use an external method consultant, where do you obtain sources that provide your manager with a consultant list? These sources are past projects from your company files, magazines and directories, logistics organizations, and other industry professionals.


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INSIGHTS

Order-Fulfillment Concepts, Design, and Operations FOR

YOUR CONSULTANT SELECTION PROCESS

From your operational consultant list, you perform an external consultant selection process. There are steps and insights to ensure the best selection of an external consultant for your method. First, define clearly, in writing, the project scope, objectives, and schedule that includes start and completion date, on-site data collection visits, data and statistical review meetings, method review meetings, drawing review meetings, preliminary report review meeting, and final report presentation. Next, define and limit the project scope to ensure a concentration of work by the consultant so that his or her activities accomplish the objectives. This project definition reduces the possibilities for insignificant objectives involved in the project. Next, ensure that the prospective consulting firms have a clear project scope understanding and objective along with a detailed plan to accomplish the objective. Next, require the prospective consulting firms to submit a written proposal that outlines their steps to complete the objective, schedule, and fee structure; this includes fixed fee, not-to-exceed, minimum or maximum range, man-hour and material fee, and various activities. Next, contact the prospective consultant reference client list with a concentration in the same industry or that have a similar project objective. Next, require a résumé for the consultant personnel assigned to your project. This includes the names, education, experience with the consultant, other companies, published articles, speaker participation in seminars and conferences, and membership in order logistics associations. The consultant identifies the person who is the project manager in control for the project and the project manager who is your project contact person. Next, complete a prospective consultant firm evaluation to determine the consultant’s project understanding and requirements. Lastly, with the short list for prospective consultant firms, visit their offices and meet their team members.

PROJECTS THAT INVOLVE CONSULTANTS Many companies have used external consultants for method modeling and simulation; selection of a manual, mechanized, or automated operation method, method layout, and design; materials requirement planning (MRP); method drawings and written functional specifications; performance measurement reports; method planning and scheduling systems; space forecast studies; distribution requirements planning (DRP); labor and management training; order picker routing and scheduling; CAD; piece, customer-order, and vehicle automatic identification; and safety, security, and maintenance.

WHAT INFORMATION DOES YOUR CONSULTANT REQUIRE YOUR PROJECT?

FOR

When an external consultant is involved in a project, the company’s operational and financial information is piece or customer-order characteristics. These characteristics include length, width, height, weight, and bottom surface; average and peak sales in pieces or customer orders handled; average and peak delivery in pieces or customer orders handled; average pieces per customer-order; number of work days per year and hours per work day; and all method plan-, detail-, and elevation-view drawings,



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equipment manuals, piece or customer-order and information flow charts, and past reports. The response to the consultant’s questions allows the consultant to evaluate your current operation to develop conclusions and to make recommendations. The recommendations are the basis for the future method.

WHY IS HIGH EMPLOYEE PRODUCTIVITY IMPORTANT? Employee productivity is a major order-fulfillment or across-the-dock management staff concern, and is a factor that improves any single item, flat wear, GOH, carton, or pallet operation’s efficiency. Employee productivity is the employees’ ability with an operational method to move pieces or customer orders between two locations at your budgeted operating cost and improve your on-schedule and accurate customer service. If your operational management staff is to have an efficient and productive operation, the management staff is required to have proper material handling equipment; proper operational piece or customer-order travel path layout; simple and clear operational instructions; motivated employees; scheduled activities that include vendor deliveries, labor, and equipment; smoothing of the peaks and valleys of the daily piece and customer-order volume and the piece or customer-order flow through the facility; and a realistic operational budget and objectives. You must realize that employee productivity improvement is one means to offset other operational cost increases in salaries, wages, and operational controllable and non-controllable expenses. An improvement in operational employee productivity is a very complex problem due to the nature of the business. The order-fulfillment or across-the-dock business has a fixed activity schedule for customer or workstation piece or customerorder deliveries that requires the correct piece or customer-order delivery quantity, a wide piece or customer-order mix and characteristics, and a varying piece and customer-order volume. These facts are true whether your business is a small, medium, or large company that handles single items, flat wear, GOH, cartons, or pallets. They also hold true whether your operation provides service to E-commerce, direct marketing, or catalog customers; industrial customers; manufacturing workstations; or to a pick line or storage area.

WHAT IS EMPLOYEE PRODUCTIVITY? Employee productivity is defined as the output (tons, piece quantity) that is handled or moved by your operational employees’ total number of work hours or cost. To obtain your operation employees’ productivity, your total pieces or customer orders divided by the total work hours or cost.

WHAT ARE

THE

BUSINESS FACTORS THAT AFFECT YOUR PRODUCTIVITY?

The order-fulfillment or across-the-dock business factors that affect your employee productivity are piece or customer-order mix and volume, pick positions or delivery


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locations that are located over a large area, piece or customer-order size variations, required time to complete a customer-order or workstation order and delivery cycle; and travel over a fixed travel path to complete the piece or customer-order delivery.

AREAS

FOR

EMPLOYEE PRODUCTIVITY IMPROVEMENT

To improve your order-fulfillment or across-the-dock employee productivity, the opportunities for employee productivity improvements are changing work methods or employee work arrangements, improving ways to perform the work, moving your piece or customer-order quantity with the fewest handlings and handling the largest volume per trip, scheduling and utilizing the equipment and labor at the maximum rate, improving physical surroundings and piece or customer-order travel paths, giving employee and management incentives, encouraging pride in work, and changing from a human-paced method to a mechanized or automated method. Change Your Employee Work Method You improve your order-fulfillment or across-the-dock employee productivity by improving your employee work methods or their work arrangement. In conjunction with this approach, you look to implement a new sequence for the piece or customerorder travel path and load pickups and deliveries to reduce empty load-carrying surfaces or vehicles or employee dispatch frequency; prior to work stations, you provide sufficient queue area such as queue conveyor or P/D stations; you apply the ABC theory of SKU movement to storage area positions and pick positions; you use kit or family group SKU allocation to storage and pick area; and you complete the customer-order and delivery cycle with the fewest piece or customer-order handlings. Change Your Employee Procedures Your second area for employee productivity improvement is your employee work procedures or how employees perform their work. Options are to cube the pick activity; prior to each workstation on the pick line or in a storage aisle, to provide sufficient piece or customer-order queue area or P/D stations; use sequenced piece or customer-order pickups and deliveries; use human- and machine-readable SKUdiscrete identification piece, customer-order, and vehicle identification; have the fewest piece or customer-order handlings; use clear and simple employee instructions; and increase dual cycles between two workstations. Add Equipment to Your Employee Work In your order-fulfillment or across-the-dock operation, the most dramatic employee efficiency improvements are realized from equipment or a mechanized method to handle the maximum piece or customer-order quantity per trip with the fewest handlings. Many order-fulfillment or across-the-dock method applications are manually operated pick carts or pallet trucks; internal combustion or electric battery powered forklift trucks, pallet trucks, or AGVs; gravity or electric-powered conveyors; guided powered order pick vehicles; a computer to schedule labor, equipment, and piece or customer-order deliveries; mechanized or automated piece or customer-



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order pick or transportation methods; bar code scanners and human- and machinereadable codes; separating and identifying the pieces at the vendor facility or at your receiving dock; separating or pallet-loading the largest pieces and securing the pieces; and providing sufficient piece or customer-order queuing prior to each storage area or pick line activity. Enhance the Use of Your Employees and Equipment Another method for you to improve order-fulfillment or across-the-dock employee productivity is to enhance your employees’ available work hours or equipment scheduling and vehicle utilization. Some techniques do not require investment and others require an investment. Examples include using part-time employees; purchasing or leasing in a way that is flexible, is used in several other operational areas, or is able to perform a specific task with an attachment; smoothing out the workweek peaks and valleys to improve equipment and labor utilization; ensuring controllable piece or customer-order queues prior to each work station; and ensuring that there is sufficient direct or indirect work for your full-time employee workday. Improve Your Work Area The next opportunity for you to improve your employee productivity is to improve the design, appearance, and physical surroundings of your employee work area. These opportunities are keeping the facility aisles and piece or customer-order travel paths clear; improving your housekeeping by sealing floors, painting the equipment, and painting the facility interior walls; painting the facility ceiling and walls with a light color; providing adequate lighting in the pick aisles or on the pick lines; eliminating damaged or salvaged pieces and obsolete equipment from the facility; providing adequate storage and pick aisle widths and recommended equipment clearances; painting lines in the queue areas, mobile equipment travel paths, and personnel travel paths on the floor surface; providing good order pick or vehicle routing and sufficient aisles; eliminating bottlenecks and jams; providing good and clear piece or customer-order and vehicle dispatch and order pick instructions; and eliminating work steps from the piece or customer-order flow or travel path. Implement a Work Incentive Program You increase productivity by initiating a work incentive program that offers your employees additional money or something of value for extra effort or achievement. In some companies, an incentive program has increased employee productivity by 10 to 15%. A good employee incentive program is well researched and outlined, and is measurable, achievable, understandable, clear, fair, and administered equitably. If an employee’s work changes, the work for an employee incentive program changes. Improve the Results of Your Employee Productivity To ensure that your budgeted employee productivity is achieved from new equipment implementation or from an enhancement to an existing method, it is your responsi-


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bility to ensure that your employees are using the specified and proper activity methods to perform their work. You must also make sure that you have adequate management staff and employee training, you have written rules and procedures, you provide signs and pictures in the work area, and you review your employee work activity. Increase Your Employee Pride Your next method to improve productivity is to encourage employees to take pride in their work and in their workplace. Some companies have improved employee productivity by participating in a delivery truck or forklift truck rodeo; having a company sign at the entrance to the facility; recognizing accurate, high productivity, and on-schedule work; providing uniforms; giving awards for puncutality and attendance; offering family outings; encouraging team participation; knowing your employee’s name, birthday, and family history; and providing a clean and properly lighted work area and a clean and safe equipment. Change Your Employee Work from a Human-Paced to a Machine-Paced System Your final technique to obtain an improvement in your employees’ productivity is to change their work from a human-paced system to a machine-paced system. Again, you need to identify activities that have the largest employee number; the highest overtime; largest piece, customer-order, building, or equipment damage; highest employee injuries; highest off-scheduled activities; and highest errors. To improve your employee activities, you can use a gravity or powered queue conveyor or AGVs to move pieces or customer orders between two work stations; mechanize or automate your piece or customer-order delivery or pickup; attach a bar code or RF tag to your piece, customer-order, or vehicle and use bar code scanners or RF tag readers; automate picking, labeling, weighing, and sorting activities; and add guided aisles for storage, transport, and pick vehicle travel.

GUIDELINES

FOR A

SUCCESSFUL EMPLOYEE PRODUCTIVITY PROGRAM

To implement an employee productivity program to improve your employee productivity, the guidelines are to categorize all the employee jobs or tasks in your operation; identify the activities, functions, or jobs that have incurred the highest overtime, the greatest piece, customer-order, or equipment and building damage, and highest errors and off-schedule deliveries or the highest employee injuries; total employee wage and benefit costs that are associated with each activity; and select a measure unit for each employee activity. This figure is the productivity measurement for present and proposed activities. After a new method’s implementation, compare your actual employee productivity figures to your budgeted employee productivity figures. If you use an industry average or another company’s employee productivity figures, understand the other company’s operational policies, procedures, operations,



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business, piece or customer-order characteristics, and employee productivity figure calculations. Identify Your Labor Activity That Has the Highest Numbers You identify an employee operational activity that has the highest employee number or the highest associated operating expense. An improvement in your employee productivity for one of these activities has the greatest impact on your company’s operational expenses and service to your customers. Measure Your Employee Productivity A good operational employee productivity program’s characteristics are that it is based on a unit of measure, understandable, cost effective, and timely. Unit of Measure A good order-fulfillment or across-the-dock employee productivity program characteristic is that the program is based on a measure unit. The best unit of measure in the order-fulfillment or across-the-dock operation is the piece or customer-order that is handled by your order-fulfillment or across-the-dock method. The unit of measure is a single item, flat wear, GOH, carton, pallet, or customer-order. If your operation handles pieces or customer orders, the measurement approaches are as follows. For an order-fulfillment or across-the-dock operation that has no piece or customer-order mix change, the measurement is to use the piece or customer-order that is handled by the activity. For a wide piece or customer-order mix, this measurement uses an average conversion factor that it is easy to relate to the various pieces or customer orders. The piece and customer-order unit of measure that is used in an order-fulfillment or across-the-dock operation includes tons or weight; accident-free days; expenses as a percentage of sales; overages, shortages, and damaged pieces; errors; returns; off-schedule customer-order deliveries; sanitation ratings; and machine downtime (number of vehicles or machines in maintenance). When tons or expenses as a percentage of sales are used as the unit of measure, your daily employee productivity varies due to the piece weight or dollar value. The piece or customer-order volume variation occurs by the workday, month, or season of the year and market conditions. Alternative Techniques to Measure Your Operation Order-fulfillment or across-the-dock activities move your pieces or customer orders from your receiving dock area, through your storage areas, through your value-added or pick operation, and to your shipping dock. Within each work area, your piece or customer-order is transformed or picked from large piece quantities (pallets or master cartons) as individual pallets, master cartons, or loose single items per your customerorder and assembled for shipment to satisfy your customer orders. To receive pieces and ship customer orders, an order-fulfillment or across-thedock method’s resources are labor, mechanical equipment, and building area, which is the piece, customer-order, employee, or vehicle travel path. All these


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resources have a cost associated with their use in the piece and customer-order movement. It is this total cost for the piece and customer-order movement and a detailed look at these components that economically justifies your improvements to your existing or your proposed order-fulfillment or across-the-dock method. This cost justification approach offers you an opportunity for your present or proposed method to reduce operating costs by improving labor productivity; adding mechanical equipment to handle a greater piece number or a larger customerorder volume; reducing the piece, customer-order, or vehicle travel path length or width, which is building space; reducing piece or customer-order, equipment, or building damage and reducing personnel injuries; and ensuring on-time and accurate piece or customer-order deliveries. To implement a change to improve your operation, your manager is aware of how well your operation measures up to your company’s expectations. If you realize that there is an opportunity to improve your company’s operation, how do you project the future employee productivity? Order-Fulfillment or Across-the-Dock Operation Measurements An order-fulfillment or across-the-dock method has cost components that move your pieces and customer orders. To measure your order-fulfillment or across-the-dock method performance, it is based on costs for piece or customer-order volumes. Some distribution professionals have the opinion that cost for the pieces or customer orders handled do not provide the total picture for an order-fulfillment or across-the-dock operation. They feel that seven ratios provide a more practical approach to measure your order-fulfillment or across-the-dock operation. The seven ratios provide deeper insights and understanding to an operation’s component costs because these ratios are an online review of the operation. The order-fulfillment or across-the-dock measurement techniques are dollar cost, operational expenses as a percentage of sales, weight handled per employee hour, pieces or customer orders handled per employee hour, labor ratio, direct labor handling loss ratio, piece or customer-order movement and operation ratio, customerorder cycle efficiency ratio, space utilization efficiency, equipment utilization and ratio, and aisle space potential ratio. Dollar Cost Measurement. The dollar cost measurement is the first method management measurement technique. This cost measurement technique is used because the cost factors are common to all order-fulfillment or across-the-dock methods, cost factors have an impact on your company’s financial statements and ratios; operating costs have a relationship to the management bonus program in most companies, cost is a key economic justification factor for a new method; and these costs are directly related to the operation’s annual budget in most companies. To calculate the dollar cost or operating expense measurement for your operation, your financial department provides the actual expenses or budget dollars. The disadvantages of this technique are that accounting dollar figures show the method’s past performance, there is inconsistency between two accounting periods and what is considered a cost factor, and some costs are considered noncontrollable operational factors.



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The advantages are that the method is easy to calculate, is tied to many important management activities, is used in many companies, and is tracked and compared to the historical company data. Cost per Piece or Customer-Order Handled Measurement. The cost per piece or customer-order handled measurement is the second order-fulfillment or acrossthe-dock method measurement. The cost per piece or customer-order measurement formula components are the total method costs and the total pieces and customer orders that were moved by your method. To calculate the cost piece or customer-order measurement, the total method costs are divided by the total pieces or customer orders that were handled by your operation. The disadvantages and advantages are similar to the dollar measurement technique, except that the cost per piece or customer-order handled measurement varies by your piece or customer-order volume. Costs (Expenses) as a Percentage of Sales Measurement. The next operation measurement is the cost (expenses) as a percentage of sales productivity figure. The cost as a percentage of sales measurement uses the total method costs and your total pieces or customer orders that were moved by your method. To calculate the cost as a percentage of sales measurement, the total method operational costs are divided by your company’s total sales. The disadvantages of this technique are that it fluctuates by the cost per piece or customer-order, and is affected by cost factors that are noncontrollable for the method manager. The noncontrollable costs are the operational costs that are not directly controlled by your method manager. Weight for the Pieces or Customer-Orders Handled Measurement. The weight for the pieces or customer-orders handled measurement is the next orderfulfillment or across-the-dock cost measurement. The weight for the pieces or customer-orders handled measurement components are total weight for the total pieces or customer orders that were handled by your operation, and the total employee hour number that was required to move the pieces or to complete the customer orders. To calculate the weight for this measurement, the steps are to multiply the pieces or customer orders by the associated weight for the pieces or customer orders, which results in the total piece or customer-order handled weight, and to divide this weight by the total operation employee hours. The weight for pieces or customer-orders handled measurement results are that the method measures the total weight for the pieces or customer orders that were handled by your operation, and that it shows your employee operational hours that were required to move the pieces or to complete the customer orders. With these characteristics, the weight for the pieces or customer-orders handled measurement has a direct relationship to your operation. When your operation’s piece or customer-order mix has a consistent shape and weight, the advantages are that many formula difficulties are substantially reduced and that one period measurement is compared to another period measurement. If your operation’s piece or customer-order mix has a wide shape and weight variety, you obtain a total for all


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the pieces or customer orders that were handled by your operation. The total weight calculation methods are achieved by using an average weight for the pieces or customer orders or by summing the individual pieces or customer-orders weights. Pieces or Customer-Orders Handled Measurement. The pieces or customerorders handled measurement is the next measurement. The pieces or customer-orders completed measurement is similar to the weight for the pieces or customer-orders completed measurement. The similarity is that both measurement methods are based on the piece or customer-order number completed by your operation and the total employee hour number. To calculate this measurement, the total piece or customer-order number that was completed by your operation is divided by the total employee hour number. If your method handles a wide piece or customer-order mix with a wide weight variation, the pieces or customer-orders completed measurement allows you to compare on a consistent basis several periods for your operation’s productivity.

EMPLOYEE HOURS MUST BE CONSISTENT It is your top management’s discretion to determine the total employee hours that are associated with your order-fulfillment or across-the-dock method. The value to your method productivity measurement in being consistent is that it allows you to make comparisons between two or more time periods and permits tracking your operation; to use it as an annual operational expense budget tool; and to use it to schedule employees, equipment, and vendor delivery trucks. For your order-fulfillment or across-the-dock method measurement to have these features, your employee hour number is consistent for each period. If you compare your company’s hours and ratios to another company’s figures, your manager’s concern is that the employee activities (hours) that are considered operational activities at one company are possibly different from another company’s activities. Most industry professionals agree that employees who have a direct contact with your piece or customer-order or employees who control equipment that touches or moves pieces or customer orders are considered operational employee activities. The disagreement among industry professionals and managers is about the employee activities (hours) that are associated with the indirect or support employee activities or hours. These indirect or support employee activities are supervisor, clerk, maintenance, and sanitation hours. These employee activities or employeecontrolled equipment do not directly touch or move a piece or customer-order. The agreement is that without their support activity your operation has a difficult task to maintain your budgeted operational costs, projected employee productivity, and on-schedule customer service. With this position some industry professionals consider some or all of these employee support activity hours as operational hours. It is the authors’ position that your order-fulfillment or across-the-dock productivity measurement method components are one subtotal for direct employee hours, a second subtotal for indirect employee hours, and a total for the sum for all direct and indirect employee hours. It is noted that these are major employee classifications and that within the direct and indirect labor classifications there are subclasses.



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This order-fulfillment or across-the-dock measurement method for separate labor hour classification provides you with a complete analysis for your orderfulfillment or across-the-dock operation and a tool for your employee work scheduling and annual expense budget preparation. This employee hour separation shows how employee hours, piece or customer-order volume variance (increase or decrease) has an effect on the operation employee classifications and hours, operation productivity, and costs. When required to justify an actual dollar cost to budget dollar cost variance, this employee hour classification provides you with the data to explain the variance.

SEVEN ORDER-FULFILLMENT OR ACROSS-THE-DOCK RATIOS The next group of material-handling or order-fulfillment or across-the-dock operation measurements consists of seven material-handling or order-fulfillment or acrossthe-dock ratios. These seven ratios appeared in “Bases of Material Handling.” This was a publication that was prepared by the Material Handling Institute. As stated in this publication, each of these seven ratios represents a way of establishing some material-handling or order-fulfillment or across-the-dock quantitative figures. The seven ratios’ advantages are that they allow you to determine your order-fulfillment or across-the-dock operation’s effectiveness; they permit you to use past or historical operational data; with the past, present, and projected quantitative figures, these ratios show your order-fulfillment or across-the-dock operation’s improvement; and the quantitative figures can affect your company’s short- and long-term order-fulfillment or across-the-dock investment strategies. The order-fulfillment or across-the-dock ratios are the order-fulfillment or across-the-dock employee (labor) ratio, the direct-employee (labor) handling loss ratio, the piece or customer-order movement or operation ratio, the customer-order cycle efficiency ratio, the space utilization efficiency ratio; the equipment utilization ratio, and the aisle space potential ratio.

ORDER-FULFILLMENT

OR

ACROSS-THE-DOCK EMPLOYEE (LABOR) RATIO

The order-fulfillment or across-the-dock employee (labor) ratio is the first orderfulfillment or across-the-dock quantitative ratio. The employee ratio indicates your employee hour number that was assigned to operational activities as a percentage of your company’s total operational employee number. The ratio is calculated by the employee number that was assigned to the operation and is a direct expense. This means that an employee moved or controlled equipment that moved a piece or completed a customer-order. In the formula to calculate the employee ratio, this figure is considered the numerator. Your employees who are assigned to your operation but do not perform a function as previously described are considered part of the total company employees. In the formula to calculate the employee ratio, this figure is part of the numerator. Some of these employees that are added to the total count are from the clerk, supervisors,


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sanitation, and maintenance employees. To ensure ratio consistency, a portion of this indirect employee time is considered part of the operation employee time. The advantages of the employee ratio are that it is easy to calculate; that it indicates employee or labor hours’ relationship to your company’s total employees; that if a change is made to your method work, it shows the improvement by showing the labor savings; and that when you plot an employee ratio on a graph, the historical ratio data shows a trend.

DIRECT-EMPLOYEE HANDLING LOSS RATIO The direct employee handling loss ratio is the second operation quantitative ratio. This ratio measures the direct operational employee time for your employees who are allocated to nonorder operational activities but performed an operational activity. These employees complete or in the course of their work performed an operational activity. This operational activity is additional time that is allocated to your operational activity time and reduces the direct-employee operational activity time. The ratio is calculated by the nonoperational total direct-employee time divided into the operational time lost by nonoperational direct-employee time. The advantages for this ratio are that it is easy to calculate, and when you consider a new method or a change to an existing method, it identifies all method activities that are directly affected by your method. Also, this lost employee time can be used as part of the economic justification of a new method because the employees’ hours are converted into a cost reduction. The disadvantage is that you verify that the nonoperational direct employee loss time is accurate. Steps to verify the accuracy of the nonoperational direct employee loss time include having an outside consultant evaluate the operation or perform a time study for the specific operational activity.

PIECE

OR

CUSTOMER-ORDER MOVEMENT

OR

OPERATION RATIO

The third quantitative ratio is the piece or customer-order movement or operation ratio. The piece or customer-order movement or operation ratio is the number of times that your method is required to move pieces or customer orders that are delivered to workstations or on a pick line to complete a customer’s order. The piece or customer-order movement or operation ratio is expressed as a piece or customer-order movement activity station or pick line operation ratio. In an orderfulfillment operation, the ratio is calculated by dividing the number of pick-line stations into the number of customer-order moves, which include receiving, storage replenishment, picking, packing, manifesting, and loading. For an across-the-dock operation, the ratio is calculated by dividing activity stations (receiving, scanning, manifesting, and loading) into the number of piece moves. The advantages are that it determines the efficiency of your method layout and identifies the number of items in an order-fulfillment operation that are candidates for off-line picking and packing. In addition, on a pick-line operation, it identifies slow-moving SKUs that are grouped together and reduces the number of pick position replenishment trips.



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CUSTOMER-ORDER-FULFILLMENT CYCLE EFFICIENCY RATIO The customer-cycle efficiency ratio is the next quantitative ratio. The ratio is termed the customer-order-fulfillment cycle efficiency. This ratio shows the actual operational time that is spent to pick and pack and ship a customer-order out the shipping door. This ratio indicates the time that is required for a piece or customer-order to move through your order-fulfillment or across-the-dock operation. Another ratio explanation is the time for a piece or customer-order to move from the receiving door to the shipping door. The customer-order-fulfillment cycle efficiency is calculated by dividing the total time that is required to complete (pick, pack, and ship) a customer-order into the total operational time. This ratio calculation indicates the total time or the time that is required to move pieces or customer orders from the receiving area to your storage area, from the storage area to the pick line and to your shipping door; it also indicates the total time that is required to move your pieces or customer orders from the first pick position, to the pack and manifest position, and through the shipping door. With this door-to-door analysis, this ratio shows the length of time that your piece or customerorder is in the storage area and that the customer-order is in your order-fulfillment area, or the customer-order time to travel over your across-the-dock transportation and sorting method. The value of this ratio is that shows the value of a just-in-time replenishment to the pick position or across-the-dock program for your company’s supply chain logistics strategy.

SPACE-UTILIZATION EFFICIENCY RATIO The space-utilization efficiency ratio is the fifth quantitative ratio. The space-utilization efficiency ratio measures the use of the space for your method such as racks, pick positions, or pieces, or the customer-order transport travel path in relationship to the total space for the method. Examples of the total space for the method include occupied storage positions compared to the total number of storage positions in the storage area; occupied pick positions compared to the total number of pick positions in the pick aisle, on the pick line, or in an automatic pick machine; receiving and shipping dock staging area compared to the total area; and the space for a backup vehicle or personnel aisles along a powered-vehicle travel path compared to the combined total space for all aisles in the facility. This ratio determines the occupied storage positions compared to the total number of storage positions in the storage area method. To calculate the space utilization ratio, you determine the occupied total storage positions or cubic feet and divide by your total number of storage positions or cubic feet in the storage area method. When the cubic feet or quarter-, half-, or three-quarter-full pallet analysis is made, the space utilization indicates a more exact picture. For example, in a master carton or pallet storage area, the space utilization occupied is based on storage positions with cartons or pallets, divided by the total number of storage positions in the storage area.


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The ratio’s benefit is that it identifies a company functional space that is not effectively used by an occupied storage position to the total number of storage positions in the storage area operation. This space is available space for expansion, additional pallet storage positions, or adjustments to the rack position height.

EQUIPMENT UTILIZATION RATIO The sixth quantitative ratio is the equipment utilization ratio. The occupied storage positions to the total number of storage positions utilization ratio shows the effective use of your occupied storage positions compared to the total number of storage positions. The equipment utilization ratio components are the total storage position number and your actual occupied storage position number. To determine the storage equipment utilization ratio, the total storage position number is divided into the actual occupied storage positions. To determine the pick equipment utilization ratio, the occupied pick positions in the pick aisle, along the pick line, or in automatic pick equipment are divided into the actual occupied pick positions in the pick aisle, along the pick line, or in the automatic pick equipment. The advantages of this ratio are that it shows the available equipment capacity, and if completed on a day or week basis, it indicates the slowest time period that is available for maintenance, equipment modification, or new equipment installation; and that, when the ratio is calculated for each workstation on a value-added process line, in a pick aisle, along a pick line, or in an automatic pick machine, it shows potential low pick productivity or piece or customer-order queue areas.

AISLE-SPACE POTENTIAL RATIO The aisle space potential ratio is the seventh quantitative ratio. The aisle-space potential ratio shows the effective aisle area use. This ratio is very similar to the space utilization efficiency ratio. The ratio’s components are the recommended replenishment and pick aisle space and the actual replenishment and pick aisle space. The recommended aisle space is the equipment manufacturer’s stated minimum aisle width. In the storage area, the minimum storage vehicle aisle width is the clear distance between two storage racks (product), and it is the dimension that is required for the vehicle to make a right-angle (stacking) turn. The right-angle turn allows the storage vehicle to complete a storage transaction. In other facility travel aisles, the minimum aisle widths are the aisle width that allows a vehicle to travel from one aisle to an adjacent aisle, and the aisle width that allows two-way vehicle traffic through an aisle. In a conveyor operation, the minimum travel path is the space (width and height); components are the actual space that permits pieces or customer orders to move on the conveying surface and the actual space that is required for the structure to support the conveying surface and piece or customer-order clearances.



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The actual aisle space is the actual distance between two storage racks, pieces, or two pieces of equipment, or from a piece of equipment to a building wall or obstacle. The recommended aisle floor space is calculated by your equipment manufacturer’s recommended aisle width multiplied by the aisle length. The actual aisle floor space is calculated by your actual aisle width and your actual aisle length. The benefits are that it identifies the available space that is occupied by a traffic aisle or personnel or mobile equipment travel path and when you consider a remodel or a new method that requires a narrower aisle, this floor space helps the economic justification of the alternative method.

KEEP IT SIMPLE The second consideration for a good order-fulfillment or across-the-dock employee productivity program is to keep it simple, make it complete, and make sure it is clearly understood by your employees and management supervisors.

IT MUST BE COST EFFECTIVE The third order-fulfillment or across-the-dock employee productivity program feature is that it is a cost-effective system. The method that you use to obtain your employee work activity information does not require the employees, supervisors, or clerks to spend a large amount of time. If your record-keeping process requires a large amount of time, your employee time spent to record work activity offsets your employee productivity improvements.

RESULTS MUST BE TIMELY The last employee productivity improvement program characteristic is that the actual employee activity data are gathered, reported, and analyzed in a timely manner. Timely information permits your management team to review an individual employee’s or shift’s productivity performance. This information with the projected order-fulfillment or across-the-dock method piece or customer-order volume permits your management staff to project the next day’s labor, delivery vehicle, and equipment schedules.

VARIOUS MEASUREMENT STANDARDS For a useful order-fulfillment or across-the-dock method employee productivity program, your employee productivity is tracked and compared against your company’s standard or budgeted employee productivity measurement. The order-fulfillment or across-the-dock method employee measurement standards are the agreedupon standard, the industry standard, your own company standard, the time-study standard, and the regression analysis.


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AGREED-UPON

Order-Fulfillment Concepts, Design, and Operations OR

BUDGETED STANDARD

The first order-fulfillment or across-the-dock method employee productivity measurement standard is the agreed-upon or budgeted employee productivity standard. The first step in this measurement standard is to predetermine the number of times that your employee performs the activity. This activity frequency is agreed upon by your management staff and employee group. The performance standard becomes the employee productivity rate to perform the activity. This employee productivity rate is the hourly rate that is used to project the annual labor expense for your annual operational budget or to justify your method expenditure.

INDUSTRY STANDARD The second order-fulfillment or across-the-dock employee productivity standard is an industry standard measurement or another company’s employee productivity measurement. When you use another company’s employee productivity measurement as your company’s employee productivity measurement standard, the potential problems are different piece or customer-order mix and characteristics, due to the nature of the business and size; confidence in the other company’s employee productivity figure, meaning how the productivity figure was calculated and what factors the other company used in the productivity figure; employee productivity figure components; and accounting uniformity for the employee productivity.

YOUR COMPANY STANDARD The third order-fulfillment or across-the-dock method employee productivity standard is your company’s historical or goal-set employee productivity figures as a measurement. These employee productivity figures are obtained from your company’s past order-fulfillment or across-the-dock method records.

TIME-STUDY STANDARD The time-study order-fulfillment or across-the-dock method employee productivity measurement is the next employee productivity standard. A time-study method has an industrial engineer or management staff member who is required to take several time observations of the employees who perform the activity. These observed times are averaged and are the basis for the employee productivity standard for future employees who perform the activity.

REGRESSION ANALYSIS The fifth employee productivity measurement is the regression analysis method. The regression analysis method is a mathematical calculation that involves multiple variables relating to the projected employee productivity.



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EMPLOYEE PRODUCTIVITY IS TIED TO YOUR ANNUAL EXPENSE BUDGET An order-fulfillment or across-the-dock method’s employee productivity program’s true value is that it provides your method manager with an employee productivity rate that is considered an accurate forecast tool. This forecast tool is used to project and control your company’s method labor expense dollars and to provide on-schedule service to your customers. The employee productivity rate is the basis to calculate your annual method budget labor dollar expense; calculate the budget dollar justification for a capital expenditure; and forecast your company’s labor hours, expense, vehicle deliveries, and equipment and labor schedules. After your employee productivity program is implemented in your daily method, this employee productivity is tied to the annual operating labor expense budget and is related to your capital expenditure justification. If your method employees exceed or achieve this projected employee productivity rate, top management considers that the method operation performance is above par. This above-par performance lowers the method cost per unit and increases the company profit. If your method employees do not achieve this projected employee productivity rate, top management considers that the method operation performance is below par. This below-par performance increases the method cost per unit and lowers the company profit.



3

Order-Fulfillment Systems INTRODUCTION

A variety of order-fulfillment systems are in use today. Each has a specific operating methodology, with strong points and weak points. Some are better suited to a specific order profile, while others are better suited to different types of products or different product profiles. Others are more flexible in their product suitability than others. Before considering any of the order-fulfillment systems below, a company should have data on its order profile, the velocity of all stock-keeping units (SKUs), and its customer profile. All of these data should be thoroughly analyzed to determine which type of system to implement or which system fits with the specific product type. It is not unusual for one facility to have multiple order-fulfillment methodologies, each one matching a specific product type and picking profile. Order-fulfillment systems can be divided into two types: picking systems and put systems.

THE BASICS OF SPLIT-CASE ORDER PICKING One basic guideline for all order-selection systems — manual or automated — is the product profile, or slotting on the pick line. The product profile is based on the relative velocity and physical characteristics of the individual SKUs. Higher-velocity SKUs are typically placed in what is referred to in ergonomic terms as the “golden zone.” The golden zone is the area between the knees and shoulders where a picker can be the most productive with the least amount of bending and reaching. The reader can consult an ergonomic handbook for the precise 95th percentile anthropomorphic data. Profile analysis will also dictate a storage medium, and will indicate how much product should be “on the shelf” in order to satisfy the basic criterion of the replenishment interval. As a minimum, there should be a sufficient quantity of each SKU in the primary picking location to satisfy the average need for a single picking shift. The business plan of a company may dictate up to a five-day supply in the primary picking location. The replenishment interval balances picking efficiency, space, and replenishment efficiency and effort. The profile or slotting analysis is based on the velocity of the product through the distribution center. Additional factors include the length, width, height, and

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weight of the master cartons or totes where the product is picked. Beside the individual SKU characteristics above, the SKU may belong to a product family; in other words, an order for SKU A usually includes SKU B as part of the order. These SKUs will then be placed close to each other to minimize travel between picks. SKUs with very similar size, shape, and color may present another concern. These products should not be placed next to each other on the shelf. This can eliminate two possible sources of error. The first potential error is a replenishment error. This occurs when a stocker or replenishment person puts the product in the wrong picking location. Too many similar products in close proximity increase the likelihood of a replenishment error. The second type of error is a picking error. This occurs when an order picker is working rapidly and not paying close attention. Numerous similar-looking SKUs in close proximity can lead to the picker’s selecting the wrong SKU for the order. This is more problematic for some picking methods than for others. Regardless of the cause, the customer will get the wrong item in his or her shipment and will be unaware of whether this is due to a picking error or a slotting error. To the customer, an error is an error. Careful slotting analysis will prevent both potential errors. Slotting analysis will also help to determine the correct product-storage medium. The basic types of product storage for picking are (1) static shelving, (2) carton flow racking, and (3) pallets-on-pallet flow lanes. Each of these will be addressed later in the chapter. There are several commercial slotting software packages available today. Some are available as option packages on a warehouse management system (WMS) and others are stand-alone packages. This works by analyzing the sales data to show the velocity of the products and the master product file for the carton dimensions and weight. In the past, profiling a picking operation was done infrequently, if at all. Profiling was typically done only when a new picking operation was set up. Slotting changes consisted merely of replacing an old SKU with a new SKU. Often this was based on the product dimensions. In other words, the new SKU was assigned a slot in the picking operation based solely on the physical dimensions of the available location. In some cases, slotting was based on a SKU identification number. SKUs were located consecutively by number, regardless of sales data. Changing the slotting of a picking operation is neglected for two reasons. First, the analysis is difficult to perform manually or with a spreadsheet. Second, physical movement of the product is time-consuming and must be done when picking is not in operation. While the latter still presents a problem, slotting software can make the analysis easier. Rather than changing the profile of the entire picking operation, slotting software can dynamically track all the SKUs and order the slotting moves by rank. The operations department can change the profile incrementally by attacking the highestpriority SKUs first. The department can select the 10 most beneficial moves and make those moves at the end of a shift. Over several days, the overall efficiency of the picking operation can be improved dramatically, one step at a time.


Order-Fulfillment Systems

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PUT SYSTEM BASICS Although a put system has some picking characteristics, put and pick systems are fundamentally different. Picking involves transporting the order container (carton or tote) past individual SKUs and selecting items for the order. In a put system, the order cartons are in a fixed location and the SKU container moves past the order cartons or totes. As the SKU passes by the orders, the operator selects items from the SKU container and places them in the order carton or tote. Prior to the above putting operation, some order analysis and management is required to determine which master SKU cartons are needed for the day’s orders. These cartons must be pulled or picked from storage locations so that they can pass by the order containers. Some put systems are manual; others are based on radio frequency (RF) scan, voice, light display, or carousel.

OTHER PRODUCT ISSUES If an individual SKU velocity is very large, it may be necessary to have multiple locations for picking that SKU and others of similar velocity. Some systems will allow multiple slotting or multiple locations, so that there will be sufficient quantity on the shelf to get through an entire shift without replenishing. Some systems will actually require multiple slotting because they do not readily lend themselves to replenishment while picking operations are underway. If there is a large number of very high-velocity SKUs, it may make sense to have multiple parallel picking operations. This is actually quite common in some facilities with very high-velocity SKUs. During the slack period, only one line may be in operation, while in a peak season several duplicate lines may be required to meet demand. Another variation is for a company to have several regional distribution centers with the same SKUs and the same picking equipment.

STORAGE OR PICKING MEDIUM STATIC SHELVING Static shelving is also known as bin shelving (Figure 3.1). Shelving units are usually 3 to 4 feet wide and 5 to 6 feet tall. Shelf depth can be up to 2 feet. There may be any number of shelves, depending on the physical dimensions of the product stored on them. Typically, static shelving is used for slower-velocity SKUs, because there is limited space for each SKU and replenishing while picking is very difficult. Static shelving units can be arranged in a number of different ways. They can be in long or short aisles. There can be a perpendicular conveyor at the end of the aisle (Figure 3.2), or the conveyor can run down the aisle itself. The units can be arranged in U-shaped picking cells so that the order picker can access more SKUs with less walking. The chief advantage of static shelving is low cost; static shelves can store a lot of SKUs for the money. The chief disadvantage is that the quantity of each SKU that is available for picking is rather low; bin shelving is not well suited to high-


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FIGURE 3.1 Bin shelving. (From Kingway Materials Handling, Acworth, GA. With permission.) Carton Flow

Conveyor

Static Bin Shelving FIGURE 3.2 Static shelving with conveyor perpendicular to the aisle at the end of the aisle.

velocity products. The only opening on these shelves is from the front, so replenishment and picking must take place in the same aisle space.

CARTON FLOW RACKS Carton flow racking is arranged in bays, with a varying number of shelves and SKUs per shelf (Figure 3.3). The shelves can be anywhere from 2 to 20 feet deep. Each shelf is installed with a roll track, which supports the cartons or totes of product, and dividers to separate the lanes of product. These shelves have a slight decline from back to front so that the product rolls to the front of the shelf. The angle of decline, or pitch, of the shelves is adjustable to aid the flow of the products being picked. For



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FIGURE 3.3 Carton flow rack. (From Kingway Materials Handling, Acworth, GA. With permission.)

example, hard plastic totes roll much more easily than corrugated cartons and require less shelf pitch. The width of the shelves can vary depending on the specific requirements of the installation. However, standard widths are 60 and 96 inches. Carton flow racking can be placed in stand-alone frames, mounted in pallet rack frames, or installed in multilevel pick modules. Stand-alone carton flow frames come in two styles. The first type has straight vertical frame members. The second type has a layback frame. These vertical frame members lay back a few degrees from the vertical. The purpose of this frame type is to allow the shelves to have a staggered or tiered arrangement from bottom to top. This presents the product to the picker so that it is easy to grasp and extract from the master carton. Carton flow racking has two basic types of shelves (Figure 3.4). The most common is a straight shelf. As the name implies, the shelf is completely straight, with a roll track from the front edge to the back edge. The second type of shelf is a tilt-tray shelf. The shelf has a tray on the front that tilts down a few degrees to present the product to the picker. This angle makes it easier to select an item from the carton and increases picker productivity, while decreasing the potential risk of an ergonomics-related injury. A tilt-tray shelf coupled with a layback frame presents the product to the picker so that the entire top of the product carton or tote is exposed for easy access during the picking process. This is in contrast to the straight shelf in a straight frame, where the order picker must reach in to grasp the items being picked. Carton flow can present a large number of SKUs to the picker in a relatively small space. In addition, the depth of the shelves permits stockers to put sufficient quantity on them for an entire shift. It also makes simultaneous picking and replen-


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FIGURE 3.4 Carton flow frames and shelves. (From Kingway Materials Handling, Acworth, GA. With permission.)

ishment a possibility. The picker works on the front side of the shelf, while the stockers replenish product on the back side. Carton flow is used with higher-velocity SKUs. It increases the efficiency of the picking operation compared to static shelving. It is flexible and allows replenishment during picking operations. There is another relatively new product on the market that goes by a number of different trade names. It is a roller track that looks like a small conveyor (Figure 3.5). As opposed to the narrow track with a small plastic wheel that is found on most carton flow applications, this track has the appearance of a small lightweight gravity conveyor. Each track is a few inches wide, and the tracks come in varying lengths. Coupled with some hanger brackets, the roller track is fitted into regular pallet racking. The crossbeams on the pallet rack can be staggered in height to put a pitch on the track that will make product cartons roll more easily. This track product is typically used with very heavy master cartons. New additions to this product include a tilt shelf that hangs over the pallet beam to present the product in a position that facilitates picking. This track product is used most often in retrofits of an existing distribution center, where there will be picking primarily on the ground level and pallet storage above.

FIGURE 3.5 Roller track for pallet rack. (From Span-Track® by UNEX, Jackson, NJ. With permission.)



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FIGURE 3.6 Pallet flow lane. (From Kingway Materials Handling, Acworth, GA. With permission.)

PALLET FLOW LANES Pallet flow lanes (Figure 3.6) are common for extremely high-velocity or bulky splitcase SKUs. Such items are presented for picking in this manner because they would take up too many carton flow lanes for a single shift’s picking activity, or would require continual replenishment during the shift. Like carton flow racks, pallet flow lanes can be replenished on the back side while the picker is fulfilling orders on the front side. Pallet flow lanes can be as deep as required and can hold multiple pallets. It is not unusual to have some pallet flow lanes mixed with carton flow racks to accommodate the different velocities of various SKUs in the picking operation.

PICKING MODULES A picking module is a multilevel, engineered system of picking operations, storage, and mezzanines (Figure 3.7). They have two, three, or four levels and can incorporate all of the aforementioned storage and picking media. There is usually an aisle down the center on each level for picking operations and conveyors. The entire picking module may be devoted to a single storage and picking medium, or may be divided by level into carton flow, pallet flow, and static shelving, or any other combination. The conveyor layout in a picking module configured for split-case picking most often has both gravity and powered conveyors. The powered takeaway conveyor is down the center, with a gravity line down each side. There is often a trash conveyor to dispose of empty cartons and packing materials from the master cartons. (Fullcase picking modules usually have a powered takeaway conveyor down the center, without a trash conveyor.)


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FIGURE 3.7 Multilevel picking mezzanine module. (From Kingway Materials Handling, Acworth, GA. With permission.)

If the picking is done into plastic totes, there may also be an empty tote line somewhere in the pick module to supply totes to the pickers.

GENERAL PICK-LINE LAYOUT Except as noted for some specific picking methods below, picking is done from a pick line of some sort. Static shelving, carton flow racks, and pallet flow lanes can be laid out in separate picking areas or combined. They can be arranged in a long line on one side of a conveyor or in a large U-shaped picking area. They can be arranged with a carton flow rack on one side of a conveyor and with static shelving on the other side, wherein one person picks both fast and slow items for the same area. Some very high-production pick lines have carton flow racks on both sides of a conveyor line in a cross-aisle picking arrangement. Other high-production lines use a small U-shaped picking cell with carton flow racks in front of the picker and on both sides. This greatly reduces unproductive walking by the order pickers.

TYPES OF ORDER-FULFILLMENT SYSTEMS Each of the specific order-fulfillment systems discussed below can be used in piece picking and split-case or broken-case order picking. Some can also be adapted to full-case operations. The types of split-case-order-fulfillment systems (sometimes referred to as piecepicking or each-picking systems) are pick-to-paper, RF scanner, voice, A-frame, tilttray sorter, carousel, put, and pick-to-light. Each has its strengths and weaknesses (Table 3.1). Each will perform the required task for some products. Some will work with a wider range of products and a greater variety of orders.

Paper RF scan Voice A-frame Tilt-tray Carousel pick Carousel put PTL/display pick PTL/display put

System

X

X

X

SKU Based

X X

Picker Based

X

X

X

Store Based

X X X X X

X X X

Flexible

+ + +++ + + + ++ +

Productivity

+++ ++ +++ +++ +++ +++ +++ +++

Accuracy

++ ++ + +

++++ +++ +++

Training

Order Selection Comparison

TABLE 3.1 Comparison of Order-Selection System Characteristics

$ $$$ $$$ $$$$$ $$$$$ $$$ $$$ $$$ $$$

Relative Cost

$ $

Cost to Add Picker

$

$$

$$$

Cost to Add SKUs

$

$$$ $$$ $$

Cost to Add Stores


Order-Fulfillment Systems 119


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There are some variations within each of the above systems. With each system, the order can be picked or put into a reusable tote or directly into the shipping carton. The tote may only go as far as a packing station, or it may go all the way to the retail store. Totes are expensive, but if the distribution center uses its own trucks to ship to the same retail stores, totes can be very cost-effective.

CART SYSTEMS Paper, RF scanner, voice, and pick-to-light systems can also use carts to batch-pick orders. The method is to push a cart with a batch of orders through a pick aisle once per batch, and to stop at a pick face only once per batch. If, for example, the cart has space for eight orders, the picker goes down an aisle once instead of eight times to complete the orders. The product profile for batch picking to carts is low velocity with a high number of SKUs. There is also an assumption that the order-management system will batch orders with like SKUs within a wave.

PICK-TO-PAPER SYSTEMS The pick-to-paper system is a basic manual picking method using a paper pick slip. The SKUs are usually positioned on static shelving bins, carton flow racks, or pallets in pallet flow lanes. The pick slip has the SKUs printed in the order of the physical location of the product, so the picker can go down the slip from top to bottom in sequence while walking down the pick line. In addition to the customer identification and order numbers, each pick on the pick slip has a single line entry. The line also contains, in some order designed by the operations group, the SKU number, SKU description, pick location, and quantity to pick. In a pick-to-paper scenario, one picker usually picks the entire order and then gets another pick slip for the next order. Location Identification Pick locations are identified through a master location scheme, which identifies a picking area, bay or bin, shelf, and slot. The location identification, SKU number, and description are written both on the pick location and on the picking slip. Location identification should have a logical sequence so the worker can readily identify where the next pick will be. Likewise, the picking slip should have the items sorted by location identification to facilitate efficient picking. Advantages and Disadvantages The pick-to-paper system is a low-cost and flexible picking method. There are, however, some drawbacks to paper-based picking. One issue is training. It may take several weeks for a new picker to learn all the SKUs and their locations and become a productive employee. This can be a major issue if the picking operation has a seasonal spike in orders that requires bringing in temporary labor. This method generally has a high error rate, and productivity rates are low. Error rates are high because the method relies on the picker’s finding the pick location and identifying the product. Productivity rates are also lower than more automated



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methods because the picker spends time looking for the pick location and walking the entire pick route for the order. Paper-based systems entail additional processing of orders before and after picking. After they are printed, the orders must be separated, sorted, and distributed to the picking areas in the distribution center. The method also requires postpicking reconciliation of the orders to account for shorted SKUs. This can cause delays in trucks leaving the shipping dock, because the trucks must wait for shipping manifests to be generated from the manual postpicking process. The extra man-hours required for pre- and postpicking processes causes another decrease in overall productivity. Manual picking systems do not feature real-time feedback to the host WMS or ordermanagement system for inventory control purposes.

RADIO FREQUENCY SCANNER

AND

VOICE SYSTEMS

System Characteristics The authors have put these two types of systems together because of the similar product profiles and order characteristics that work best with these methods. Recent product development efforts on both types of systems are pushing them toward greater similarity. Voice systems are adding bar-code scanners for data acquisition, and RF scanning systems are adding voice recognition. Both systems use a broad-spectrum RF backbone to support their operations. The chief differences involve the specific manner of delivering instructions to the operator and the operator response. Traditional RF scanning systems have handheld scanners with varying degrees of intelligence. The device has a liquid crystal display (LCD) display to relay instructions to the operator and a keypad for the operator to input responses. The operator uses the bar-code scanner to confirm the SKU, location, or order number. The unit relays commands and data input via the RF network back to the system controller. The controller has an interface with a host system that is either an ordermanagement system or a WMS. There is an adapted version of the handheld scanner wherein the user wears the equipment. In this case, the scanner is worn like a ring, while the LCD display and keypad are strapped to the operator’s arm. A battery pack may be worn on a belt around the operator’s waist. This frees the operator’s hand and helps to improve productivity. A voice system provides audio instructions to the operator. The operator acts on the instructions, and confirms the action with a voice response. The instructions come over the RF backbone from the system controller, and the responses go over the same RF backbone back to the system controller. Voice systems use a limited instruction set and recognize specific words in specific response sequences. They are trained to recognize the voice characteristics of each operator. The data acquisition limitations of voice systems have caused manufacturers to move toward adding bar-code scanning to their systems. Both voice and RF systems can perform a variety of functions in addition to order picking. RF systems can be mounted on fork trucks and used in directed putaway and replenishment operations. Both can also be used in receiving, and, with order picker man-up fork trucks, to pick items from pallet storage areas.


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Order Profiles Voice and RF bar-code systems work well in a high-volume SKU environment with medium to slow SKU velocity. In this setting, they are relatively inexpensive and their cost is based on the number of operators and not the number of SKUs. It is relatively easy to add SKUs. Voice systems have a small advantage over RF scanners in that the picker’s hands are free to lift larger SKUs or to grab several small SKUs. RF bar-code systems have an advantage when significant data acquisition is required while picking. Both systems can be used to batch multiple orders together on a cart to make pickers more productive. System Operation The system controller receives order information from the WMS or order-management system. Pickers receive order information based either on their assigned work area or sequentially, first-in, first-out (FIFO). In the RF scanner system the order and pick information is displayed on the scanner’s LCD display. In the voice system the picker hears a pick location. In each system the picker verifies the pick location, either by scanning or by verbal command; picks the quantity; and confirms the pick by pressing a button on the scanner or by giving a voice command. The system then responds with the next pick instruction. The picker repeats the sequence until all picks are completed. Using Scanning and Voice Systems with a Cart The operator puts several order cartons or totes on a cart (Figure 3.8). Either by scanning the order labels or by giving a voice command, the operator tells the system what specific orders he or she will be filling. The operator then gets a command to proceed to the first pick location. When the operator confirms that he or she has reached the location, he or she will be directed to pick the correct number of units for each order. The operator may pick 10 units, but put one unit in one order, three in another, four in another, and two in another. When the operator confirms the pick, the system will direct him or her to the next SKU location and repeat the sequence until the orders are completed. Advantages and Disadvantages Both systems are accurate methods of picking split-case orders. The order accuracy of the triple-scan picking method is nearly 100%. In the triple-scan method, the picker scans the location of the SKU, the SKU bar code, and the order carton to confirm each pick. While this increases picking accuracy, it comes with a penalty to productivity. Both systems eliminate pre- and postorder processing. All order transactions are in real time, and both systems can provide data to an automated manifesting system or another down-line system that sends advanced shipping notices to the customer. Like paper picking operations, the picker must search for the next pick location. In the scanner-based system, the picker reads the pick information on an LCD screen, rather than a piece of paper. With each system the picker must still do a search for



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FIGURE 3.8 A pick cart. (From S.I. Handling, Easton, PA. With permission.)

the next location and SKU. The systems present only one pick at a time. Training is not as lengthy as for a paper-based system, but pickers must still learn the locationnaming scheme used in the distribution center to find the SKUs. In addition, a voice system must be trained to recognize the voice characteristics of the individual pickers. Since both systems are picker-based vs. SKU-based, adding more pickers requires adding more scanner units or voice units.

A-FRAME SYSTEMS System Characteristics The A-frame is a highly automated picking machine that works well with a select group of SKUs (Figure 3.9). The products picked by an A-frame must have the right size, shape, packaging, and weight in order to work properly with the system. An A-frame consists of a series of vertical channels above a conveyor. The vertical channels hold the product, and there is a device at the bottom of each channel that “injects” or dispenses the SKU onto the conveyor. An A-frame is a SKU-based system, so more SKUs require a longer conveyor and more channels and dispensers. A typical A-frame setup consists of an A-frame flanked on each side by a row of carton flow or pallet flow racks. The carton flow or pallet flow racks contain the product used to replenish the A-frame.


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FIGURE 3.9 A-frame. (From S.I. Handling, Easton, PA. With permission.)

System Operation The system controller receives the order file from a host WMS or order-management system. The controller designates a length of conveyor for the order. As the designated section moves along the A-frame path, the controller fires the dispensers to pick the SKUs for the order. The conveyor takes the SKUs to a tote or shipping carton. The order items either “waterfall” into the box or go into a hopper device that dumps the product into the carton. The A-frame method is a very fast and accurate picking method for the right set of SKUs. It can dispense a lot of product in a short time. Order output rates can approach 1000 orders per hour. Because it is so fast, however, it does require considerable replenishment effort. While the picking itself is entirely automated, the A-frame may require several stockers to replenish the dispensing channels. It is not unusual to have an A-frame operate in short bursts and then have some downtime for replenishment (Figure 3.10). SKU Characteristics The A-frame method works very well with a limited set of SKUs. The SKUs must have packaging that is compatible with the dispenser’s method of getting the order on the conveyor. The SKU must also have the right weight for the dispensing system. SKUs that are too heavy or do not have the right packaging will bind with each other and cause missed picks or jam the system. Different SKUs may have different replenishment levels based on their weights. In addition to weight, packaging size and shape are important. The exterior packaging cannot bind with either the dispensing mechanism or the other packages in the SKU channel. If the surfaces of the SKU packaging material bind with the equipment or with another SKU package, the system may jam or “short pick” the order.



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FIGURE 3.10 Replenishing an A-frame. (From S.I. Handling, Easton, PA. With permission.)

The SKUs picked by an A-frame should have relatively robust packaging and should not be easily damaged. There are two times during the picking process when the product may be subject to damage. The first is during the dispensing of the SKU onto the belt. The second is when the order goes into the tote or shipping container (Figure 3.11). Since there is no human handling in the picking or packing operation, the SKUs should not be fragile and should not be of the type where the end user expects absolute perfection in the appearance of the outside package.

FIGURE 3.11 A-frame product waterfalling into totes. (From S.I. Handling, Easton, PA. With permission.)


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A-frame systems are often used for the distribution of retail drugs, music compact discs (CDs) and cassette tapes, and software CDs. These products are lightweight and have uniform shape and surface characteristics that make them compatible with the mechanism of the system. Advantages and Disadvantages The A-frame is a highly productive picking system for the right SKU set. Getting the right SKU mix or SKU packaging may be a matter of some trial and error. The A-frame is among the most expensive picking systems on a per-SKU basis. Fragile SKUs or SKUs that require some packing are not good A-frame candidates. Replenishment is a major issue in keeping the system working. Most applications include carton flow racks for the replenishment of the A-frame channels. An A-frame requires several people to perform the replenishment throughout the picking shift. While many distribution centers use an A-frame, most of them have other order-fulfillment operations for the products that cannot use the A-frame.

TILT-TRAY

OR

CROSS-BELT SORTER SYSTEMS

System Characteristics Tilt-tray (Figure 3.12) and cross-belt (Figure 3.13) sorters accomplish the same goal. They are both generally used in a catalog distribution environment where there is a large number of very diverse SKUs with low velocities. The fundamental difference between this and other order selection methods is that the SKUs are brought to the order carton or tote, as opposed to the order carton’s being brought to or passing by the SKU. The operation has three distinct stages — pick, sort, and pack — in contrast to a pick-pack-in-one operation. DID NOT READ

TILT TRAY SORT LOCATIONS

INDUCTION STATIONS TILT TRAY TRAVEL PATH RE-LATCH TRAY

TILT TRAY SORT LOCATIONS

CLEAN-OUT CHUTE

FIGURE 3.12 Tilt-tray sorter. (From Kosan Crisplant, Aarhus N, Demark. With permission.)



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FIGURE 3.13 Cross-belt sorter. (Photos courtesy of Siemans Dematic [www.siemensdematic.us].)

Orders are batched into waves based on a common characteristic, such as delivery method or route. The order selection system or WMS totals the number of each SKU for the entire wave. For example, a wave could be a batch of 300 orders. The total number of picks for a given SKU may be only five. The order pickers traverse the picking area once per wave, picking the entire amount of each SKU for the wave. During the pick, the pickers put a bar-coded label on each SKU. The label has a reference number that will route it to the correct preassigned order packing station or bin during the subsequent sort.


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FIGURE 3.14 Tilt-tray packing chute detail. (From Litton Industrial Automation. With permission.)

System Operation All of the picked items go into totes that are routed to a sorter induction point. Here, an operator removes the items from the tote and places them on an induction belt with the bar code in the correct orientation. The SKU is inducted onto a station on the sorter. The sorter can be either a large oval, shaped much like a racetrack (tilttray and some cross-belt sorters), or a straight line (small cross-belt sorters). When the SKU reaches the correct bin or packing station, the tilt-tray will tilt and dump the SKU into the chute (Figure 3.14). The cross-belt sorter accomplishes the same thing, but instead of tilting to put the SKU in the proper location, a motor rotates the belt to put the item into the right location. Both systems are used to assemble an order consisting of several items from among the thousands in a distribution center. These items may come from widely different areas of the distribution center, but are easily brought together using the sorter. One of the key variables in determining the size of the tilt-tray or cross-belt sorter is the number of orders to process in a given time period. This will dictate the number of packing stations. Typically, packers work several packing stations so they can pack orders from one wave while the items for the next wave are being inducted and sorted. There is generally a no-read return or dump station for items that get turned so that the bar code is not readable. There are also size and weight limitations on the SKUs that can use these systems. Fragile items may also be ineligible due to the possibility of damage while going down the chutes. Consult the manufacturer’s specifications on the specific systems under consideration to find their limitations. Like other sophisticated order-fulfillment systems, sorters also require an interface with a host system that is either an order management system or a WMS. Management and sorting of specific orders into waves takes place on the host system,



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and only the order data are sent to the sorter controller by waves. Reports of order completion can be sent from the sorter controller back to the host for manifesting and inventory control purposes. Advantages and Disadvantages Like A-frame systems, sorter systems are quite expensive and require detailed analysis to determine the return on investment for a capital project. If there is enough order activity to justify the expenditure, these types of systems will be highly productive. If there is not enough activity to justify the expenditure, there are other systems that can be used for this type of product and order profile.

CAROUSEL SYSTEMS Overview Carousels are among the most widely used (and abused) order-fulfillment systems on the market today. Carousels come in two basic types, horizontal (Figure 3.15) and vertical. Within these two basic types there are several variations, mostly related to the control systems. System Characteristics The fundamental principle of the carousel is to have the product come to the picker instead of the picker going to the product. This goes back to the fundamental pickerproductivity mantra: a walking picker is a picker not picking. Carousels work well for a specific type of product and a specific order profile. Orders are generally batch processed in groups of 6 to 12 at a time.

FIGURE 3.15 Horizontal carousel-pick face detail. (From Remstar International, Portland, ME. With permission.)


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The most widely used carousel system is the horizontal carousel. Most vertical carousels are used in small repair parts or record storage. The horizontal carousel consists of a series of bins on a vertical plane (Figure 3.16). A number of these vertical planes are linked together, and they all rotate horizontally on a vertical axle. A series of controls, lights, and displays indicates to the picker what number of items to pick from which bins. There is also a set of displays to indicate how many of each item should be put into each order container in the batch. A picker typically works a pod of three or more carousels at a time. The number of carousels in a pod depends on the size of the carousel and the time it takes for each carousel to rotate to the next pick item. SKU Types The types of SKUs picked from a carousel are usually small, with enough pieces in a bin to get through an entire picking shift. If one bin cannot hold enough product to get through an entire shift, then there should be a second or third bin of the same product in the pod. It is necessary to have sufficient quantity of a SKU in the pod to get through a shift because it is not possible to pick and replenish at the same time. Carousel picking operations have separate replenishment shifts and picking shifts. Pod Configuration A pod consists of a group of two or more carousels arranged side by side, with a common area for the batched order containers to sit during picking. The carousels can be tall or short. If they are too tall for a picker to reach the top tier of bins, the pod may include a lift. Pods can also be in two levels. There can be three carousel units on a lower level and three on an upper level. The picker reaches the upper level from a lift station. The reason for grouping carousels in a pod is productivity. If the order filler only works one carousel, he or she will be idle while the carousel rotates (or indexes) from one picking bin to the next. With multiple carousels in a pod, the order filler can pick and place product from one carousel, while the others are indexing to the next pick or picks. Carousels vary in size. The bigger the individual carousel unit, the longer it may take to index to the next pick. The longer it takes to index to the next pick, the more carousels should be in the pod to prevent the order filler from standing idle while waiting for the next pick. System Operation The picker assembles a batch of orders to pick. The batch can be static or dynamic. Under a static batch scenario, all the items for every order in the batch are picked before the containers are released and another batch is brought in. If the batch is dynamic, as each order is completed, that container is pushed off on a take-away conveyor and is replaced by another carton. The order filler scans a label on each carton or tote to let the system controller know that the order is available for picking. The controller rotates (or indexes) to the front of the pod the carousel with the next



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FIGURE 3.16 Carousel pod configuration. (From Remstar International, Portland, ME. With permission.)


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SKU to be picked. A light comes on to designate the proper bin to pick and a display shows the quantity to pick. The picker selects the quantity and presses a response button to indicate the pick has been made. The picker turns around to the shipping container array, where another display in front or above the carton indicates what quantity of the SKU to put into each order. When all the items are put into the order containers, the picker pushes a button to indicate to the controller that the pick is completed. While the picker is placing the picked items into the cartons, the carousel with the next pick indexes into position, so that the pick is in position when the picker is ready. Advantages and Disadvantages Carousels work very well for smaller, relatively low-velocity SKUs. The chief limitation of the carousel is the inability to pick and replenish simultaneously. This drives the distribution center to employ two shifts, one for picking and one for replenishment.

CAROUSEL PUT SYSTEMS While early carousel systems were primarily picking systems, there are now several carousel systems that are used entirely as put systems. The same carousel equipment used in reverse can become an order-accumulation or put system. In the put scenario, the bins on the carousel each represent a store or customerorder. SKUs come to the carousel operator, and the operator scans the bar code to indicate the particular SKU that is present. The carousel controller then indexes the carousel so that each customer or store carton with a requirement for that SKU comes into position and the SKU can be placed in the carton. The indicator lights and displays show the operator the quantity for each order and which order containers get the SKU. The system software is different from that of a put system but works with the same hardware. The system gets all the order input data from a host order system or WMS.

PICK-TO-LIGHT

AND

PICK-TO-DISPLAY SYSTEMS

System Characteristics Pick-to-light and pick-to-display systems are typically attached to a carton flow rack, but can be put on static shelving, pallet flow lanes, or pallet racks. Pick-to-light systems are usually pick-and-pass, where each picker works in a zone, picks only a portion of the order, and passes the order tote or carton to the picker in the next zone. A zone consists of one or more bays of carton flow racks or bin shelving units. A pick line can have one or more zones. The number of bays per zone can vary on the same pick line, based on the order profile for the shift. The number of bays per zone should roughly balance the number of picks in each zone. Therefore, one zone could have a single bay, while the next zone could have four bays.



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A carton flow rack can be laid out in a straight line, in U-shaped cells, or in a cross-aisle arrangement. The product profile and order type dictate the type of arrangement. Some systems are laid out with a fixed number of bays per zone, while others have a variable number of bays per zone depending on the order profiles and the number of available pickers for the shift. Most pick lines have conveyors for the order cartons or totes. These can run down a center aisle between two pick lines or can be attached by brackets to the carton flow rack itself. Center aisle conveyor systems typically have a three-conveyor arrangement. The center conveyor is a powered take-away conveyor, while the conveyors on either side are gravity conveyors. The pickers pull the carton or tote along the gravity conveyor while picking the order and push the order off onto the powered center conveyor when the order is complete. Some center-aisle conveyor systems route order containers to a specific zone or pick line. These systems divert the containers onto the gravity conveyor for the zone. When the order filler has competed the picks in the zone, he or she pushes the container back onto the powered conveyor line which, in turn, routes the container to the next zone with the picks for the order. This type of system has a warehouse control system that monitors the location of each active order container. The monitoring and routing are done using a bar-coded label on the container or a permanenttote identification number. Some of these systems have intricate interfaces between the conveyor control system and the picking system controller to track accurately the location and remaining picks for an order. Equipment Early pick-to-light systems had only a small light bulb in front of each SKU. The pick quantity was shown on a bay display. These systems could only display one pick at a time. This limited picker productivity. Most pick-to-light manufacturers have supplanted this type of system with one that has a light and a digital display of the pick quantity in front of each SKU. Such systems are known as pick-to-display systems. Some display all the picks in the zone simultaneously, making the pickers much more productive. While the cost per SKU is somewhat higher than in pick-to-light systems, increased productivity makes up the difference. Each SKU has a display unit at the front of the SKU lane (Figure 3.17). These displays are connected to a system controller. The system controller is connected to a host order system or WMS. In addition to the SKU display unit, there is typically a bay display unit and a bay lamp (Figure 3.18). The system may have bar-code scanners and other specialty function buttons or controls, depending on the specifications of the system and its function. Other equipment can be added to a pick-to-display system for specific functionality as required by the application. Scanners can be used to capture the serial numbers of high-value items for tracking. Traffic lights can be added so that a supervisor can see how the orders are flowing through the system and add a floater to a zone that is temporarily bottlenecking the pick line.


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FIGURE 3.17 A pick module. (From Kingway Materials Handling, Acworth, GA. With permission.)

FIGURE 3.18 A bay display and bay lamp. (From Kingway Materials Handling, Acworth, GA. With permission.)

The pick-to-display system (Figure 3.19) can interface with other distribution center systems, either directly or through the WMS. With the widespread use of local area networks, interface with other systems by means of file transfer protocols is very straightforward. Feedback to the host system is in real time. Pickers can short SKUs at the pick face and generate replenishment actions via the WMS. Depending on the capabilities of the WMS, a pick-to-display system can send signals or data to other devices, such as conveyor diverts, conveyor drive motors, check weighing systems, or package manifesting systems. The system can track order-picker productivity and compare the rates of pickers to a predetermined standard. The system will report lines and items picked and compute an hourly rate for each zone where the picker worked. These reports leave little room for doubt as to the work performed and the productivity of the workforce. System software can also cube the order to determine the number of cartons required, if the WMS does not have this capability. It can also direct the printing of carton shipping labels. System Operations Orders for the pick-to-display system come from an order-processing computer or a WMS. They can be processed in batches or waves, depending on delivery schedules or truck routes. When the processing is complete, orders are transmitted to the pickto-display controller. The WMS can assign orders a priority or a status. The priority can be high, medium, or low. Status determines whether the orders are put into the



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FIGURE 3.19 A pick-to-display pick line. (From Kingway Materials Handling, Acworth, GA. With permission.)

order queue for immediate picking or on hold status for release at a later time, as determined by operational requirements. Orders can be picked in a FIFO sequence as determined by the order download. If the order cartons arrive at the pick-to-display system in a sequence other than FIFO, the orders will be picked in a random sequence. This type of order release requires a bar-code label on the order container and a scanner to tell the controller that the order is available for picking. Once the order is scan-inducted onto the pick line, it remains in the scan order sequence. When an order is presented for picking, a beacon lights up and a digital display indicates the quantity in front of each SKU for the order, within the assigned work area or pick zone (Figure 3.16). A bay display gives the picker other information such as the order number, the batch or route code, and an instruction. A bay beacon or light above each bay helps lead the picker to the bays with the picks. With all the picks displayed in the zone, the picker can choose how to pick them for optimum efficiency. The picker confirms each pick by pressing the response button on the pick-display unit when the pick is completed. When all picks within the zone are complete for the respective order, the system tells the picker that the order is complete or that it should be passed to the next zone for more picks. There are different ways for the completed order to exit the pick line. If the pick line has only a single gravity conveyor, all the orders will stay in the pick-order sequence and will not exit until the end of the line. If there is a gravity conveyor for picking and a powered take-away conveyor, the completed order can be pushed off onto the powered conveyor when it is completed. This is called early exit. The above discussion assumes that the pick line is a continuous line. Other pick-to-display systems work in tandem with a warehouse control system that routes


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orders only to the zones required for the picks in the order. These systems treat each zone as a logical or virtual pick line. The order containers circulate on a conveyor and are routed only to the zones for the picks. The conveyor system dynamically balances the orders on the pick lines by letting the orders circulate if the divert zone is full of order containers. The picker scans the bar code on the container to pick the order. When the order is completed, the conveyor routes the order to the shipping dock. Other Light-Picking Options Some manufacturers offer optional equipment for picking SKUs with lower picking velocities, such as single display units with multicharacter displays that show both the location and the quantity to pick. Alternative pick-method lights can be used in varying densities, depending on the velocity of the product being picked. For a very slow set of SKUs, one multicharacter display can be used for several bin-shelving sections. A six-character display can designate the bin unit, the shelf, the location on the shelf, and the quantity to pick. Systems with several hundred SKUs and one display per bin shelving aisle can put all picks on a single system for a few dollars per SKU. Other displays can also be used at a level that tailors the velocity and cost per display to a lower value. Slow- to medium-velocity SKUs may have a single display per bin shelving unit or carton flow bay. A single four-digit display can accommodate several pick locations with an alphanumeric location scheme. For example, a number and letter combination such as 3D would indicate a location on the third shelf (3) in the fourth location on that shelf (D). The same display can be used for moderate-velocity SKUs, which still would not meet the criterion for a one-to-one ratio of SKU to light. In this instance, there might be one display per shelf, and the display would only indicate the specific lane on that shelf to pick, or the displays might all be on the same shelf and might indicate the column of the pick. This method may be preferred because all the displays could be put at eye level, so pickers would be less likely to miss a pick. Each of these methods should be thoroughly studied and analyzed with specific data for the situation to determine the best display-to-SKU ratio. Integrated Displays or Composite Systems All of these display methods could be and have been used in combination to produce cost-effective, highly productive systems. Typically, product velocities follow the Pareto’s law. That is, 80% of the velocity comes from 20% of the SKUs, which SKUs should be on a one-to-one ratio of pick display to SKU. The next velocity tier of SKUs can follow the ratio of one display per shelf or one display per shelving bay. The final velocity tier can be on a one-display-per-aisle basis. The layouts of these combination light systems are as varied as the distribution operations that use them. Each is highly tailored to the specific circumstances of the product type and the distribution scenario. Figure 3.2 shows a layout of such a composite pick line.



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PUT-TO-DISPLAY SYSTEMS System Characteristics Pick-to-display hardware can be run with different software to turn the system into a put system, much as a carousel pick system can become a carousel put system. The put system is used when the product profile and customer profile are the inverse of the pick system. The product profile is similar to the tilt-tray sorter product profile. The number of SKUs is very large, with low activity levels for each SKU. Rather than putting a display in front of each one of several thousand SKUs, the put system has a display for each shipping destination or customer processed in a wave. For example, the distribution center could have 15,000 SKUs. Each of the SKUs has only a few picks per day. The number of put locations is based on the number of stores or customers being processed per wave or batch. There could be a few hundred displays, one in front of each shipping location in a wave. In the above example, there could be 1000 stores or ship points processed in four waves of 250 stores each. Individual SKUs are brought to the shipping location boxes or totes. Operators scan the SKU master carton or tote to identify the SKU to the put system. The put system lights up a beacon and a quantity display for each shipping carton that needs some of that SKU for an order. When all the items for the order have been placed in the shipping carton, the order is complete and the system will indicate that it is time to push the carton onto the take-away conveyor. There are different methods for handling orders that require more than one shipping carton or tote. One is a single slot on the put system for each store or customer. This slot can be fixed or dynamically assigned. Before the wave or batch starts, the operator goes through a slot-to-order-assignment procedure that typically involves scanning the slot and carton bar code in a specific sequence. This tells the put system controller which order is in which location. The order file download from the WMS or order processing system to the put system controller tells the system what SKUs go in each carton. Just as a picker has a specific zone to pick, the individual operators of a put system have zones to work. The zones will have a set number of stores or customers that have been deemed to have a sufficient amount of work to warrant an assigned operator. The put locations may be a continuous single line of order cartons or totes, or there could be multiple levels. The exact layout will be dictated by the number of customers or stores per wave and the size of the shipping cartons. The overall objective is to have a zone with enough work for a single operator, which minimizes the amount of walking between put operations. The put system can tell the operator when a shipping carton is full or complete, or the operator can tell the system controller that the carton is full. In the former case, the system will have a flashing light or text message sent to the operator to inform him or her that it is time to push the carton off onto the take-away conveyor. In the latter case, the operator initiates a “close carton or box full” procedure to tell the system that the carton is full. If there are more items needed to complete the order, the system will have the operator erect another carton for the customer, attach a bar-coded label, and scan the label and slot bar code to assign the label to the


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order slot. If the order for that store or customer is complete, and the system is based on dynamic customer assignments, the operator may get another customer box and label to assign to the slot. In a batch or wave system, the slot typically will remain empty until all the orders in the batch are completed and a new wave is started. System Operations A put system is like the tilt-tray or cross-belt sorter operation. Rather than a singlepick process, where a SKU is picked directly to a shipping container, the put operation is a two-step process. The first step is picking which full-case containers will enter the put system. The second step is removing the SKUs from the container and putting them into the correct shipping container.

COMPLEX PICKING SYSTEMS Some distribution operations have a varied product mix and use a combination of the above systems. In this type of operation, the WMS or host order management system must be able to work with different picking methods, and must sort orders or SKUs for the same order by picking method. In this scenario, the distribution center must have a method for consolidating SKUs from various picking methods into a single shipping carton or tote. Some distribution centers handle multiple picking methods by having a pickpack operation. Here, the SKUs in each picking method area are picked into a tote that is conveyed to a packing station. Each tote has a license plate or label that links the tote to a specific customer or order. The warehouse control system tracks the totes and sends them all to the same packing station. A packer then packs the contents from several totes into a single shipping carton that goes to the customer. The alternative is to pick directly into the shipping carton. While this eliminates the cost of a separate packing operation, it may greatly increase the complexity of the conveyor system and the controls needed to route the shipping carton to the picking locations. There are many variables to consider when choosing which operation is best. Overall cost of each alternative is one of the chief considerations. Space requirements for each picking operation, and the flexibility of various picking methods are two other important considerations. Other considerations include special handling requirements, high-value item tracking and confirmation, security requirements, and order-accuracy requirements. Some operations prefer the pick-pack method simply because it results in higher order accuracy. Rather than only one picker touching the item, the packer, who also touches it, may catch a picker error and prevent the error from reaching the customer. Other operations use the pick-pack method to scan high-value items at the packing station in order to track serial numbers and to verify that an item went into the shipping carton. Other distribution centers have opted for the more efficient method of picking to the shipping carton. These centers may also have high-value tracking requirements and order-accuracy levels that need to be met. They use scanners on the pick line



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to capture serial numbers and verify pick completion. They may also use check weighing as a final order-accuracy check before the carton leaves the building.

CHECK WEIGHING Check weighing is used by many distribution operations for order-accuracy verification. The WMS product database contains a standard weight for each SKU. From individual weights, the system calculates the total weight of the order, including the shipping carton. An in-line scale captures the weight of the completed order and carton as it passes down the conveyor and before the order leaves the picking area. The actual weight is compared to the predicted weight, and if the completed order falls outside a set tolerance, the conveyor diverts the order to a conveyor spur for further checking.

SUMMARY There are many automated or semiautomated picking methods available. Each has its strengths and weaknesses. Each is better suited to some types of SKUs and fits some operations better than others. Before settling on one type, review the characteristics of each and compare their strengths with the operation at hand. Split-case order-fulfillment can be one of the most labor-intensive operations in a distribution center. It is also subject to picking errors. Simply automating an operation may not be the answer. Product variability, size, shape, or weight may eliminate one or more of the above picking methods from consideration. There are many tales of highlyautomated picking operations being installed and then taken out of service soon after installation because the entire operation was not properly analyzed. Part of the selection criteria should be an economic analysis that compares the payback and return on investment of each competing solution. While volumes have been written on how to perform this analysis, it should be noted that it is not the system’s price that makes the difference; it is how much the system will pay back the operation in the long run. It is possible that the highest-priced system may result in the lowest costs, and will therefore be the best economic decision for the longterm financial health of the company. Likewise, the cheapest solution in terms of initial price may turn out to be the most costly. Good data on order, customer, and SKU profiles are an essential part of the economic analysis. These should be analyzed along with the current productivity and order-accuracy rates. If order accuracy is an issue, try to determine the cost of an error. What does the company do when a customer reports an error in a shipment? There are often people in a customer service department who handle complaints. Is the distribution center’s order accuracy so poor that a picking error is automatically assumed? What about the cost of shipping the replacement item to the customer? Is the replacement item shipped overnight? What about returning an incorrect item? It is the authors’ experience that many companies do not have a good handle on the true direct cost of a picking error. Before undergoing some picking method


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improvement, many companies have not contested customer complaints regarding order accuracy. After implementing a picking technology, these same companies have verified their order accuracy with random audits or other means. Their documented order accuracy now exceeds 99.9%. In terms of customer satisfaction to your company, what is that kind of accuracy worth? Tie these order-accuracy improvements to productivity gains of 30 to 45%, and an order-fulfillment operation can become a competitive advantage for gaining market share and improving profitability.


4

Garment-on-Hanger Order-Fulfillment Operations INTRODUCTION

In a customer-order-fulfillment industry that includes small items, garments on hangers (GOH), cartons, and pallets, the second most complex order-fulfillment operation is the GOH operation. In the customer-order-fulfillment industry, the other terms used to designate GOH include hanging garments and rags. Unique GOH characteristics include the following: •

• • • • • • •

Dimensions: 27 inches wide, up to 5 or 6 feet long for longer GOH pieces, 1 inch deep on a load bar or rail for winter GOH pieces, and 1/4 inch deep for summer GOH pieces Requires space for a travel path or storage location Fragile, easily wrinkled, or crushable Many stock-keeping units (SKUs) for one garment style Seasonal rotation Large single SKU quantities are received and sent as single items to complete the customer-order When compared to other products, the GOH group has a higher customerorder return rate In the catalog, e-mail, and direct mail industries, customer orders are combined with products from another order-fulfillment section

With increasing customer-delivery cost and market growth in this competitive industry, the ability to combine a GOH customer-order with other items is increasing. These factors increase the requirement for a dynamically designed GOH orderfulfillment operation and facility. The main objective of this chapter is to identify and evaluate the various GOH order-fulfillment design parameters, operational characteristics, and considerations. Awareness and understanding of design considerations, characteristics, and parameters are the key factors in making your GOH operation more cost effective and more efficient. The design should also satisfy the proposed minimum service standard for present and future customers. Operational characteristics apply to the

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remodeling of an existing GOH operation or a new manual, mechanized, or automated GOH operation design. This chapter will also review the various manual and mechanized storage and order pick methods and design parameters, the many manual order-picker routing patterns, facility and pick-area equipment and layouts, and the activities required to ensure an efficient and on-time GOH piece and customer-order flow through a GOH order-fulfillment facility. The chapter sections are (1) pick-area design and operational factors and facility design parameters, and (2) GOH pieces or customer-order flow design. The second section looks at manual or mechanized pick-area activities and includes a review of several order-fulfillment pick-area layouts and functional specifications and drawings.

HANGING GARMENT OR GOH ITEM A hanging garment or GOH item is an individual piece of clothing that is supported by a wood, metal, or plastic hanger. The hanger has an open hook or face and two arms. The open hook is attached to the load bar or device on the GOH transportation path. The characteristics and size of GOH pieces range from thick and heavy long winter coats to thin, lightweight summer shorts and shirts.

BASE OPERATIONAL DATA AND PICK-AREA INFORMATION The first steps to designing a new GOH operation or facility, or remodeling an existing one, are to collect, review, evaluate, project, and approve the present and proposed GOH piece and customer-order volumes, the SKU quantity and characteristics, and all other operational parameters for each order-fulfillment activity. Other operational design parameters are related to customer-order profiles. This includes the average, median, and maximum values for the following: (1) the number of orders per day, (2) the number of pieces per order, (3) the number of shipping containers per order, (4) the number of pieces per container, and (5) the container size. Another important order characteristic is the order mix that includes types of SKUs which is length, width, height and weight, family group or pairs, value and velocity for one year. What is the hit density, or SKUs per line on a customer-order? What is the average hit concentration, or lines per customer-order? Also, take into consideration your present in-house transport conveyor or vehicle travel speeds. What are the present order-shipping methods and container sizes? Determine the Information Management System (IMS) customer-order processing and IMS download times. Customer-order priority, customer service time, and customer-order and delivery cycle time are important. The SKU profile or slotting of the pick line, the proposed pick-line conveyor layout, and all required activities should be determined. Look at the proposed pick-area block; plan-view; and detail-view drawings, which should include all order-fulfillment activities; and, finally, at the average height of your order-fulfillment employees.


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The completion of this data collection and analysis step ensures that the proposed GOH pick-area layout is designed to handle the projected customer-order volume, GOH pieces per customer-order and total daily volume, and customer-order shipping container volume. These features ensure a cost-effective and efficient GOH orderfulfillment operation that provides the lowest operational cost and accurate, on-time customer service.

PEAK, AVERAGE, AND MOST FREQUENT GOH OR CUSTOMER-ORDER VOLUMES When we review the monthly figures that are used to project a company’s GOH order-fulfillment operations, the three important volumes are the GOH volumes, lines per order, and SKUs per line; these represent the potential GOH pieces in your customer orders. An employee picks the GOH pieces. Your order-picker productivity determines the number of employees in a pick area or pack area, and the customerorder number represents the potential number of customer-shipping cartons that will flow over your pack area. A GOH order-fulfillment operation that has an increase in the number of GOH pieces handled by the pick activity (i.e., the number of pieces per customer-order), with no increase in the number of customer orders, has the potential to result in greater employee productivity. A GOH operation where the number of GOH pieces handled by the pick activity remains constant, but the number of customer orders increases (i.e., there is a decrease in the number of GOH pieces per customer-order), has the potential to result in lower employee productivity. The peak, average, and median monthly volumes of GOH pieces and customer orders are used to project your GOH operation’s future piece and customer-order volumes. Future GOH piece and customer-order volumes are based on the GOH pieces and customer orders that were handled by your company’s GOH orderfulfillment operations for a specific time period. This time period can be a day, a week, a month, or a year. Future GOH piece and customer-order volumes are based, as previously mentioned, on past GOH piece and customer-order volumes, and on your company’s anticipated growth rate in GOH orders. Future GOH piece and customer-order volumes determine your future GOH operation design and the resulting operational factors. These factors include projecting or scheduling the labor quantity and equipment that are required to handle a projected GOH order volume; the annual and other operational expenses for the operating budget of your company’s GOH operation; and the potential labor quantity, labor costs, labor savings, and other associated operational expenses that are the economic justification for a capital request.

PEAK, AVERAGE, AND MOST FREQUENT GOH PIECE OR CUSTOMER-ORDER VOLUMES The first set of a GOH operation’s piece and customer-order volumes are the peak volumes. The peak GOH piece and customer-order volumes are the highest volumes that are handled by an operation in a specific time period.


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FIGURE 4.1 GOH garment processing area. (From Railex Corporation, Queens, NY. With permission.)

The second set of volumes to consider are the average GOH piece and customerorder volumes. Average volumes are calculated by dividing the total orders or the piece count by the total time period. This customer-order volume can be for a day, a week, a month, or a year. The third set of volumes to consider are the most frequently occurring or mode volumes. The modal value of GOH piece or customer volumes for a given time period is that which occurs or repeats most frequently.

FACILITY DESIGN INFORMATION AND CONSIDERATIONS The second step is to complete the various facility design information and operations department assessments as illustrated by Figure 4.1 to Figure 4.3. The factors involved in planning a new building include the following: • •

•

Size and shape of the site location and characteristics of the access road Required square footage, derived from the projected storage inventory, pick line design, required number of pick positions, and other required pick-line function space requirements Soil condition and ability to support the imposed dynamic and static building loads, the greatest of which are the storage and pick-line area loads



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FIGURE 4.2 GOH merge. (From Railex Corporation, Queens, NY. With permission.)

FIGURE 4.3 Examples of GOH induction and discharge stations. (From Railex Corporation, Queens, NY. With permission.)

• • • •

Local building codes and restrictions, as well as seismic, wind, rain, and snow loads Available funds The number of female and male employees per shift, along with employee, vendor, and customer delivery truck parking requirements Average and peak delivery vendor and customer delivery truck dock requirements


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• •

Required electrical and other utility requirements Fire protection and emergency exit requirements

Several other facility design and operational considerations are also important. These include the building shape and its expansion capability. Included in the building height and floor area are the slope of the vertical travel path and the length run-outs for GOH pieces. The in-house transport method may require a pit in the finished floor, along with personnel protection along the pit perimeter and a fire wall, an elevated wall, or floor penetration. Safety features include fire protection, employee emergency exits, and the required walkways for each exit. Lighting fixtures must be at 30 inches above the floor; lighting fixtures should be turned on and off by activity sensors; and the various lighting levels for each activity workstation on a manual, mechanized, or automatic pick line must be determined. When pits are installed in the floor, and are not being used in connection with in-house transport, the pits are covered with hardened metal structural members and plates to support employee or vehicle traffic. Also important are rubber mats on the floor at each employee activity station and on the pick line, and ceiling fans or floor-level fans to circulate the air. This is a consideration for each level of a multiple-floor facility. In high-humidity areas, good air circulation improves employee comfort and minimizes moisture buildup on the floor. An uninterruptible power supply (UPS) provides sufficient electric power to prevent a computer crash during a power outage, and permits the facility to operate pick-line electrical equipment for a short period of time. This time period is dependent on the UPS specifications. A UPS can also help avoid damage to equipment caused by power spikes during electrical storms. Other UPS considerations include the types of systems that are connected to specific electrical equipment, the period of time to operate on battery power, and the availability and capacity of a standby generator. Most UPS systems are designed to protect computer and other sensitive electronic components. They automatically pick up the load when the primary electrical source is interrupted. Factors relating to communication include the communication method, the choice of radio frequency (RF) or hard wire, capacity, and distance. With RF, the frequency band is approved by the local and federal governments, and a site survey should be done to determine whether there is interference in the building and what number of repeater stations are needed for full coverage. With a hard-wire communication over a long distance, the system may require shielded cable or short-haul modems to ensure good communication. Hard-wire communication between two computers may also require isolated electrical power, electric spike protection, low-voltage protection, an electrical power filter to reduce undesired noise on the power line, and a dedicated communication line between the computers. Most new facilities today have a local area network that can connect a variety of computer systems together and greatly facilitate communications. The number and types of computer transactions can also dictate the types of transmission protocols used. The specific communication demands of the system should be reviewed with a computer professional.



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The objectives of facility and system design are to minimize the travel distance and time between two locations, and to require the fewest handlings for GOH pieces and customer orders. Good facility and system design will also minimize potential equipment damage and personnel injury, and ensure that the maximum product or order-quantity output is delivered accurately and on schedule.

SKU LOCATION ON THE PICK LINE OR IN THE PICK AISLE The next GOH pick-line design issue is the SKU’s physical location on the pick line. This is also known as product profiling or slotting. The SKU location along the pick-line or pick-position sequence is decided by means of certain guidelines, whether the GOH pick activity is manual or mechanized. Pick-position guidelines are based on SKU physical characteristics: length, width, and depth; seasonality; SKU velocity; value; special storage requirements; and family groupings. In most GOH pick applications, seasonal SKUs are located at the start of the pick line. In most pick-line applications, the fast-moving SKUs are located at the start of the pick line, medium-moving SKUs are located in the middle of the pick line, and slowmoving SKUs are located at the end or on the elevated rails of the pick line. In most pick areas, the longer SKUs are located in one area and the shorter SKUs are located in another area. In most GOH pick operations, high-value SKUs are allocated to a pick position that has controlled access to the pick area, or to a pick position that has a security camera. Other SKUs may require specific environmental storage conditions, such as leather goods and furs, which require a low-humidity area. Some pick-line applications have SKUs allocated to the pick line by family group. This philosophy has SKUs with similar characteristics located in sequential pick positions on the pick line. For example, SKU A is nearly always ordered along with SKUs B and C. Sometimes this pick-line arrangement is referred to as the kit philosophy. Some examples of family groups include those where the relevant SKUs are located in the same retail aisle, such as dresses and shirts that have one color with various sizes; SKUs picked for a specific customer group, as with a centralized order-fulfillment facility servicing several countries with different languages; pants that match a jacket; and SKUs that require a controlled environment. Historical SKU movement data can be used to determine candidates for bulk pick and transport to special pack stations. These SKUs can be stored separately or in a different way than the same SKUs when shipped in an “each” quantity. Most pick-line professionals consider the “golden zone” to be the preferred manual pick-position location for both short and long SKUs. The golden zone has an elevation range from a low elevation of 34 inches high above the floor for short garments to a high elevation of 70 inches for long garments. In most countries, given the average pick employee height, the golden zone is one to two short GOH pick levels or one long GOH pick level high. To reach a height of two or three GOH pick levels, there are two options. First, the GOH floor pick area can have cavities in specific areas. The cavities permit lower-level GOH items to hang below the floor. As required by code, these cavities have a wire-mesh or solid bottom and four sides


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with structural-support members. Second, the order pickers can use a ladder, a highrise order pick vehicle, or a pole with a hook to complete a storage and pick transaction at an elevated level. Prior to the final design of a pick line, golden-zone pick positions are finalized as design parameters. The next SKU-allocation consideration is the pick-line profile. The pick-line profile is used to allocate each SKU to a position on the pick line, according to one of the previously mentioned methods. The final considerations are the pick-position type and pick-position identification. These factors affect employee productivity and accuracy. The various pick-position types and pick-position identification methods are reviewed later in the chapter.

GOH SKU ALLOCATION OR PROFILE METHODS The GOH product allocation or profile determines each SKU’s position in the storage and pick area, zone, or aisle. The selected GOH profile method’s objective is to improve storage density, rail utilization, and employee productivity. The allocation options for a manual storage and pick operation are: random or mixed method, separation by length, and separation by season and by the length of the GOH.

RANDOM

OR

MIXED METHOD

The first GOH allocation method is the random- or mixed-SKU method. Any short, long, or seasonal GOH piece is placed onto any static storage and pick rail or dynamic pick position. For example, picking GOH fall season SKUs and walking past GOH summer season SKUs without picking any garments creates low employee productivity due to increased travel distance and time required to complete a transaction. Random allocation requires various top-of-rail heights in one storage and pick aisle, and has the potential for low rail utilization.

SEPARATION

BY

LENGTH

The second GOH allocation method is to separate pieces by length. This method allocates pieces to a storage and pick-rail or dynamic-moving pick position according to whether they are short or long. The method requires that specific GOH storage and pick zones have a top-of-rail height sufficient to handle long GOH pieces. A second series of GOH storage and pick zones must have a top-of-rail height sufficient to handle short GOH pieces. If there is an inventory overage of short GOH pieces and a shortage of long GOH pieces, the short GOH pieces can occupy a long GOH rail position. For a particular GOH length put-away or pick transaction, there is good employee productivity using this method due to a decrease in travel distance and fewer employee trips past positions that have no put-away or pick transactions. A long GOH piece is directed to a long GOH piece storage position and a short GOH piece is directed to a short GOH piece storage position. (If necessary, short GOH pieces can be placed in long-piece positions.) This requires that the tops of rails have two



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dimensions to match the projected inventory requirement. The method provides for high GOH rail utilization.

SEPARATION

BY

SEASON

AND

GOH LENGTH

The third GOH allocation method is a hybrid. The manual storage and pick static rail is separated into four zones. Each zone handles the projected GOH inventory for summer, fall, winter, or spring. Within each inventory area, the static storage and pick-rail or dynamic pick position is subdivided into short and long sections. The features of this method are the same as for the short and long GOH piece method except that, due to variations in the seasonal demand for GOH pieces, there is improved employee productivity.

PICK-AREA DESIGN The next major step in designing a GOH order-fulfillment facility is the development of the pick line. Pick area development requires the design team to fit the pick line or pick aisle, GOH piece, and customer-order flow patterns into an existing facility. It can also require the team to design a facility’s four walls; building columns; column spans; and roof around the pick line or pick aisle, GOH piece, and customerorder flow patterns. When we compare the two design approaches, it becomes clear that fitting a pick line into an existing facility is a more difficult task because the design constraints of the building’s columns, column spans, walls, and roof. The various steps required to complete pick-line development are to project the design year SKU number by short- or long-length GOH, inventory quantity, customer-order volume, and GOH piece and customer-order flow patterns. Next, review the various GOH pick methods and select a method. Identify the building column clear span, column size, and clear ceiling height; locate the passageways through walls and finished floors; and identify the various utility locations and the light fixture pattern. Use block drawings to refine the pick-line layout, the GOH piece and customer-order flow patterns, and other building items. Then, develop and finalize the building and pick-line drawings. Another important step is to complete a simulation that is based on GOH piece and customer-order flow patterns and volumes. The final building layout and pick-line layout drawings must also comply with local codes and company policies. The project is now ready for the bid process. Select the preferred vendor or vendors and develop building construction, remodeling, or pick-line installation plans and schedules. Vendors should install, test, and debug all building and pickline equipment, and complete a building and pick-line punch list for turning the building and pick line over to operations.

BUILDING CONSIDERATIONS Building shape and finished floor-to-clear-ceiling height are factors to be considered in the design of a GOH order-fulfillment facility. They influence the layout.


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BUILDING SHAPE The shape of the facility has an impact on equipment arrangement, GOH flow, and future expansion capabilities. Square Buildings Square buildings provide the best balance between the wall area and the finished floor area. Square buildings have a low wall area to finished floor space ratio. They create an efficient structure for internal GOH transport from the receiving area to the storage and pick and pack area. Square buildings require a good balance between the SKU number and the GOH storage and pick-position number. This is considered a good facility shape for GOH storage. It is normal, as an order-fulfillment operation expands, to expand from a square building to a rectangular building. L-Shaped Buildings In an L-shaped order-fulfillment facility, the receiving and shipping docks are located at the base, with the order-fulfillment activities in the stem. This building shape necessitates an increase in the cost of transporting GOH SKUs between the dock areas and the other order-fulfillment activity locations. The L-shaped building is best for a processing facility with an attached order-fulfillment facility. Rectangular Buildings Rectangular buildings provide an increase in the wall square footage to floor square footage ratio. The rectangle shape provides additional wall space for an increased number of dock doors. This large wall area permits efficient internal transport of GOH SKUs from the dock area to all storage pick and pack areas within the facility. The shape allows the facility to handle an inventory storage requirement that includes any SKU mix or SKU number. It is an excellent shape for an order-fulfillment facility that provides service to catalog, direct mail, E-commerce, and retail store customers. As business increases, facility expansion occurs at the short walls. U-Shaped Buildings In a U-shaped order-fulfillment facility, the shipping functions are located in one leg of the U and the receiving activities are located in the other. Storage, orderfulfillment, and other activities are located in the remaining area at the base of the U. A U-shaped building increases GOH transport activity. Rectangular Buildings (Oversized) An oversized rectangular building has the maximum proportion of wall square footage to finished floor square footage. This provides the most direct transport path from the receiving docks to the other order-fulfillment activity locations. The oversized rectangular building allows an operation to handle an across-the-dock GOH piece flow pattern.



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Triangular Buildings In a triangular facility, receiving and shipping activities are located on the triangle base, and other key order-fulfillment and support activities are on the legs. With the two legs connected at the tip, the triangle shape does not provide the maximum space utilization for square or rectangular GOH pieces and GOH shipping units.

BUILDING HEIGHT The next consideration is building height. Building height is the open space from the floor to the bottom of the structural-support member on the ceiling. In many buildings, height is sufficient to permit the constructing of additional floor elevations. Building height factors include economics; available land; shadow laws; local and occupancy codes; land conditions; and seismic, wind, rain, and snow loads. Today, most buildings are classified as high bay, medium bay, or low bay. A high-bay building has a roof at least 40 feet above ground level. Some automated storage and retrieval system (AS/RS) facilities are 60 to 80 feet high. These buildings may be rack supported or conventionally supported, and may have several floor levels and one or two equipment-supported or freestanding mezzanines. A medium-bay building is 30 to 40 feet high. With minimal fire sprinklers and fire-protected columns, a mezzanine is allowed. A low-bay building is no more than 30 feet high, with sufficient height for an equipment-supported or freestanding mezzanine.

PICK-LINE OR PICK-AISLE DESIGN The next major step in designing a GOH order-fulfillment facility is pick-line development. The pick line and the GOH piece and customer-order flow patterns may be adapted to an existing facility, or a facility may be designed around the pick line and the GOH piece and customer-order flow patterns. To fit a pick line into an existing facility is more difficult, due to the existing building’s columns, column spans, and walls, which act as design constraints.

GOH PIECE

AND

CUSTOMER-ORDER FLOW

The next set of design parameters focuses on flow patterns through the facility, various required pick activities, and pick-line design considerations. The first consideration is the GOH piece flow pattern. The GOH piece flow pattern runs from the receiving dock and quality assurance (QA) through valueadded activities and the storage and pick/pack area to the shipping area. As GOH pieces flow through the pick area, per the customer-order an order picker withdraws the required mixed pieces. These customer orders are collected onto an overhead trolley or GOH cart load bar. All completed customer orders on these transport devices are transferred to a take-away travel path. The GOH piece flow pattern corresponds to the store and hold method. The various GOH pieces flow patterns are (1) horizontal one-way or straight flow; (2) horizontal two-way, with a U- or W-shaped flow; and (3) vertical up-and-down flow.


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Horizontal One-Way Flow Pattern The horizontal one-way or straight flow pattern is referred to as “in one side and out the other.” In the horizontal one-way flow pattern, GOH pieces enter the facility from one side and exit the facility as customer orders on the opposite side. On one side, the GOH operation receives SKUs and, with mobile or fixed in-house transport equipment, the GOH pieces are moved through the various valued-added activities and pick lines to the building’s other side. On the building’s other side, the customer orders are either packed in cartons or hung on a cart, box, or rope loop for delivery to the customer. This flow pattern requires that the GOH pieces travel the entire length of the facility from the receiving docks to the shipping docks. This is a conventional facility design with a vendor delivery truck yard on one side of the building and a customer delivery truck yard on the other side. This additional truck yard does not optimize site utilization, but to utilize the air space a facility may be designed with elevated floors. One-way GOH piece and customer-order flow patterns are best for a GOH operation that handles across-the-dock GOH pieces or customer orders. Horizontal Two-Way Flow Pattern In a horizontal two-way flow pattern, the GOH pieces enter a facility from one side and exit as customer orders on the same side. A horizontal two-way flow pattern provides a good flow for a GOH order-fulfillment operation. With the receiving and shipping docks on one building side, this pattern requires only one roadway and one truck yard, which improves site utilization. The horizontal two-way flow pattern requires less truck yard and roadway surface than a one-way pattern. This feature means that less land is required; a facility can be designed with or without elevated floors; facility investment costs are lower; and there is an increased potential for dual cycles, which means a lower per-unit labor cost. The two horizontal two-way flow patterns are the U-shaped flow pattern and the W-shaped flow pattern. U-Shaped Flow Pattern The first horizontal two-way flow pattern is the U-shaped flow pattern. In this pattern, vendor GOH pieces are received on the facility’s right side and transported to various value-added activities and to the storage area and pick area, which are located in the facility’s middle. A customer-order is shipped on the facility’s left side. If you trace the flow through the facility, it makes a U pattern. W-Shaped Flow Pattern The second horizontal two-way flow pattern is the W-shaped flow pattern (literally a “double U”). In this pattern, vendor GOH pieces are received in the building’s middle and transported to the value-added activities and the storage and pick area along one of the building’s sides. On the same side, customer orders are shipped onto a delivery vehicle. The GOH piece and customer-order flow creates a W pattern.



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Vertical Up-and-Down Flow Pattern The next flow pattern is the vertical up-and-down pattern. In this pattern, the GOH pieces are received on the facility’s lower-level floor and transported over a vertical travel path to the facility’s elevated floor. On the elevated floor or level, the valueadded activities and pick-line activities are sequenced to ensure an efficient and costeffective flow across the elevated floor to the decline travel path leading to the lower floor. On the lower floor, the customer orders are placed in the staging area or loaded directly onto a customer delivery vehicle. With the vertical up-and-down flow pattern, the GOH pieces or customer orders are located either on one side or on opposite sides of the facility. The characteristics of this pattern are, first, that it has multiple finished floors in the building and a vendor or customer delivery truck yard on one side of the facility. These features mean that the facility occupies a small site, which in turn means lower land costs. Second, this pattern requires elevated floors, which means additional investment in material handling equipment and transactions. Third, the additional finished floors mean a slightly higher facility investment for additional light fixtures, stairways, and fire sprinklers. If your order-fulfillment operation handles small items, flat wear, and GOH pieces, all receiving and shipping activities are on the ground-floor level; small-item and flat wear storage and pick/pack activities are on the first elevated floor; and GOH storage and pick/pack activities are on the highest elevated floor.

DRAWINGS GOH order-fulfillment design professionals develop block and plan-view drawings and list the various value-added activities that are proposed for the facility Block Drawing A block drawing shows the GOH piece or customer-order flow pattern. The drawing shows each order-fulfillment activity. The activities are arranged in the required sequence. Lines connect two or more operational activities together. These lines permit the designer to trace the GOH piece and customer-order flows. In addition, a block drawing shows the square footage that is required for each GOH orderfulfillment activity and for the total facility, and the various functional areas with the required fire walls on each floor. The drawing should be easy to understand. Plan-View Drawing To understand in detail the GOH piece or customer-order flow through a facility, a designer develops a plan-view drawing. This detailed drawing is done to scale, and shows each order-fulfillment activity area. This drawing includes the equipment and all building items. Using a plan-view drawing can help you can understand the relationship between the various order-fulfillment activities and the space they occupy.


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LIST OF ACTIVITIES Next, list and define the various GOH order-fulfillment activities that are performed by the order-fulfillment operation in order to complete a customer-order. The activity list ensures that the design team and the operations manager have included all the order-fulfillment activities required to provide the best customer service at the lowest possible operational cost. The various GOH order-fulfillment activities are: •

• • • • •

• • •

• • •

Yard control for vendor delivery trucks or oceangoing containers, assignment of delivery trucks to a receiving dock, and customer delivery truck spotting at a shipping dock Receiving, unloading, quantity and quality control, individual GOH packing, GOH piece identification, price ticketing, and other value-added activities Internal horizontal and vertical transport between the various GOH orderfulfillment activities Warehouse management system (WMS) storage deposit transactions and inventory control IMS customer-order processing, cubing, and downloading to the pick area microcomputer Transfer of SKUs from the pick position onto a trolley or cart load bar or a dynamic rail; as required by the pick activity, SKU identification with a discrete customer code Sending of batched customer orders that include a mix of SKUs through the sorting area to the pack station Manual or automatic discrete identification manifesting The pack activity, wherein GOH pieces are packed into a carton, hung to a box or a four-wheel cart’s load bar, or loaded directly onto a customer delivery truck Trash removal from the pick line and from the facility Handling of customer returns, out-of-season or damaged items, or obsolete SKUs (including processing, transport, and storage) Security, risk management, sanitation, and maintenance to ensure adequate performance and the protection of assets and inventory from damage

PICK-LINE OR PICK-AISLE DESIGN PARAMETERS When designing a manual employee-to-stock or mechanized stock-to-employee pick line, the design considerations are: • •

•

Employee ability to complete a transaction Trolley, cart, or dynamic-rail path to move GOH pieces over the travel path; available electric or air power to move the powered chain and trolley; and the required travel path window GOH piece pick volume, customer-order volume, and shipping and delivery vehicle volumes



• •

155

SKU physical characteristics, velocity, and value How the SKU is picked from the pick position

The final considerations are to determine the GOH piece pick volume, customerorder volume, SKU type, and shipping carton volumes. The GOH piece pick volumes, customer-order volumes, and shipping carton volumes are classified as average, most frequent, and peak. The SKU type includes the basic shipping and delivery carton cube: length, width, height, and weight. Length and width are measured with the piece folded or draped in a shipping carton. The physical characteristics of a SKU include (1) physical dimensions, measured as the SKU is placed into a shipping carton, (2) product classification, and (3) SKU exterior packaging. The first characteristic, physical dimensions, includes the length, width, and height of short and long GOH pieces (for storage), and the length, width, height, and weight of short and long GOH pieces (for packing). The second SKU characteristic is the SKU product classification. Classifications include the following: value, crushable, season, packed with an insert, packed with a hanger, leather or fur, and packed as a pair. The third GOH characteristic is the exterior packaging. With a GOH piece, the cube characteristic is the SKU’s physical characteristic as it is packed into a customer delivery carton or shipped loose. The SKU exterior shipping carton categories are (1) loose on a cart load bar, (2) loose on a rope loop, (3) draped or folded in a box, and (4) hung on a box load bar. The next SKU package characteristic is the pack carton structural support strength. Structural support protects the SKU and vertically supports other cartons. The final SKU characteristic is how the SKU is picked from the pick position to the pack station: as an individual GOH piece onto a Promech or trolleyless sortation system; in bulk on a cart or overhead trolley load bar; batch-picked and separated on a trolley or cart load bar; or hand-carried by an employee. These factors determine a SKU’s ability to move through an employee, trolley, dynamic rail, or cart travel path.

GOH PICK-LINE OR PICK-AISLE SEQUENCE OF ACTIVITIES To maintain efficient and cost-effective GOH order-fulfillment, the pick activities on a pick line must be placed in sequential order. The completion of aisle activities ensures the accurate and on-time completion of a customer-order. The various pick line stations are dedicated to the following tasks: • •

Receiving customer-order pick instructions and introducing orders to the pick line Placing the discrete customer identification code on the exterior hang bar, or releasing onto the Promech travel path for sorting


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• • • • • • • • • • •

Inserting the packing list into the shipping carton SKU positioning on a pick line (manual, mechanized, or Promech method) Transporting completed customer orders by trolley or cart from the pick line to the next pick area station SKU storage and pick position activity Order pick quantity or quality checking Single customer-order packing Batched customer-order sorting and packing Customer-order container void filling Customer-order container sealing Customer-order container manifesting, loading, and shipping Trash removal from the pick line

The order-fulfillment activities are determined by your GOH pick method: (1) single customer-order pick onto a GOH cart or trolley load bar, (2) bulk pick onto a GOH cart or trolley load bar, (3) batch pick and separate customer orders onto a GOH cart or trolley load bar that has a series of fixed pegs or moveable separators, or (4) pick using a trolleyless method.

GOH RECEIVING AND UNLOADING The first GOH order-fulfillment function is to unload the GOH pieces from the vendor delivery vehicle. GOH pieces are unloaded and received as flat-packed garments in boxes or garments on hangers. When an order-fulfillment operation receives GOH pieces, the receiving activities are to unload the GOH pieces from the delivery vehicle; complete a QA inspection; identify, sort, and count the delivery quantity; steam wrinkles from the GOH pieces; and bag the GOH pieces. In the GOH distribution industry, some operations receive GOH pieces in boxes or on hangers. In most GOH order-fulfillment operations, the differences between receiving pieces on hangers and in boxes occur at the receiving dock and in the storage area. The difference in receiving is that flat-packed garments are unloaded from the delivery vehicle in a manner that is similar to unloading small-item or flat-wear master cartons from a delivery vehicle. With flat-packed garments, at the receiving dock or as soon as possible afterward, the flat-packed pieces in boxes are delivered to an opening station. As required by the marketing department, at the opening station an employee opens each box and hangs each GOH piece on a hanger. The GOH pieces on hangers are transferred to a trolley, GOH cart load bar, or dynamic rail. From the opening station, the flat-packed pieces are handled as garments on hangers. Any residual flat-packed box is handled as a master carton. After the flat-packed boxes are delivered to the opening station, the opening activity transfers the GOH flat-packed item to a hanger. Prior to the transfer, the order-fulfillment and marketing manager determines the number of flat-packed pieces that will become GOH pieces.



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GOH UNLOADING METHODS The various unloading methods are (1) hand carry, (2) rolling rack or GOH cart, (3) trolley on a rail cart, and (4) extendible trolley boom. Hand-Carry Method An employee hand-carries GOH pieces between the delivery vehicle and the receiving dock. The hand-carry method is used for an order-fulfillment operation that has a very small GOH volume. Rolling-Rack or GOH Cart Method The second GOH unloading method employs a GOH cart with a load bar. Some industry professionals refer to the GOH cart as a rolling rack. The GOH cart has two swivel casters and two rigid casters. Each pair of casters is attached to the cart by a bracket at the bottom of a structural-support member. The height of the casters determines the load bar elevation; sufficient height permits the casters and the bottom structural-support member to travel over a dock leveler and to enter and exit a delivery vehicle. A cart also has two upright posts. The base of each post is attached to the structural-support member, and the top of each post is attached to the end of the load bar. The width of the cart’s structural-support member gives a cart stability. Each load bar is connected to the top of an upright post. The diameter of the load bar must be sufficient for an employee to hang a hanger hook onto it. The load bar must have the strength necessary to carry the maximum weight of GOH pieces. The load bar span provides cart stability. To minimize damage to GOH pieces, all metal members of a cart are coated with paint, zinc, or another material. All members are welded together with sufficient strength to perform load-carrying and transport functions. An employee pushes or pulls an empty GOH cart into a delivery vehicle and transfers the GOH pieces onto the cart’s load bar. A full cart is pushed or pulled from a delivery vehicle onto the receiving dock staging area. GOH carts are used in operations with a small-to-medium GOH volume. They require only a small investment and do not require an overhead trolley system. There is the possibility of caster damage as the cart travels over a dock leveler. A fullyloaded delivery truck can be unloaded in 6 to 8 hours. Carts can be used in other GOH activities. For additional GOH cart information, the reader is referred to the GOH in-house transport section in this chapter. Trolley Cart Method The next GOH unloading method employs the GOH trolley cart (Figure 4.4). The GOH trolley cart is a four-wheeled cart that has a specially designed load bar with two adjustable end stops. GOH trolley carts have two swivel casters and two rigid casters (Figure 4.5). Each caster is attached by a bracket to the bottom of a base member. Sufficient caster height permits the cart to travel over a dock leveler and to enter and exit a delivery vehicle. Lockable wheels are optional; they ensure that


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FIGURE 4.4 GOH cart. (From Railex Corporation, Queens, NY. With permission.)

FIGURE 4.5

Casters. (From Railex Corporation, Queens, NY. With permission.)

the trolley cart is stationary when a fully-loaded trolley is transferred from the cart rail to the in-house trolley travel path. The base of each upright post is attached to a base member, and the top of each upright post is connected with a two J-hooks to the load bar. The base member has two sections that give the cart stability: two short members, each of which is connected to two sets of wheels, and a long member that is connected to the two short base members. The trolley rail has two adjustable end stops. An activated end stop prevents a trolley from moving onto or off of the trolley rail. When not activated, a trolley can move onto or off of the trolley rail. The diameter of the trolley rail should be sufficient to permit transfer between the cart trolley rail and an overhead trolley rail travel path. The cart trolley rail should have the structural support necessary to carry one or two fully-loaded trolleys. As in the rolling-rack method, to minimize GOH piece damage, all trolley cart members are coated with paint, zinc, or another material. All members are welded together with the strength necessary to perform the transport function. An employee places an empty trolley onto the cart trolley rail, sets the adjustable end stop to the “activated“ position, pushes or pulls the empty trolley into the delivery vehicle, and transfers the GOH pieces onto the load bar. With a full trolley or trolleys on the cart trolley rail, an employee pushes or pulls the trolley cart from



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the delivery vehicle onto the receiving dock staging area. On the receiving dock area, the trolley cart’s end is aligned with the overhead trolley rail’s in-feed section. At this location, the employee disengages the trolley cart’s end stop, and the fullyloaded trolley is pushed or pulled from the cart trolley rail onto the overhead trolley rail’s in-feed section. The GOH trolley cart method is suited to a small-to-medium GOH volume and requires an overhead trolley system. The required investment is low. There is some possibility of damage to the casters as the cart travels over a dock leveler. A fullyloaded delivery truck can be unloaded in 6 to 8 hours. GOH trolley carts can be used to a limited degree in other GOH activities. For additional GOH trolley cart information, we refer the reader to the GOH inhouse transport section in this chapter. Extendible Trolley Boom Method The next GOH unloading method is the extendible trolley boom method. The extendible trolley boom is a specialized, manually-operated means of unloading a trolley. The extendible boom method is used at a GOH facility that handles a medium-tohigh volume of GOH pieces on trolleys. The boom has a series of extendible channels with headers and support devices, and a trolley rail with two adjustable stops. The first stop is on the boom trolley travel path, and the second stop is located where the extendible trolley and main in-house trolley travel paths merge. If a vendor delivery truck with rope-hung GOH pieces arrives at the receiving dock, the extendible trolley boom is extended into the delivery truck. The boom is suspended from the delivery truck’s roof or from frame structures that are set on the delivery truck’s floor. In the first unloading activity, an employee sets the adjustable stop to prevent the extendible boom trolley from traveling onto the main in-house transport rail. An employee with an empty trolley cart enters the delivery truck. In the truck, the employee places the empty trolley onto the extendible trolley boom rail and sets the first adjustable stop. This adjustable stop prevents accidental travel from the transfer location. The employee transfers GOH pieces from the delivery truck rope loops onto the trolley load bar. With a full trolley load, the employee adjusts the stop and pushes the trolley forward from the delivery vehicle onto the extendible boom travel path. Full trolleys accumulate on the travel path against the end stop. After an accumulation of full trolleys, an employee adjusts the stop and the full trolleys are released from the receiving dock queue area onto the overhead trolley system. With an extendible trolley boom, a delivery truck can be unloaded in 3 to 4 hours. An extendible trolley boom requires a capital investment. A boom services one receiving dock position and unloads a delivery truck in the shortest time. It requires some setup time and must be accompanied by an overhead trolley rail system. When not in use, the boom does not take up floor space. A boom requires less maintenance and can be used on the receiving dock.

FLAT-PACKED GARMENT

TO

GOH METHODS

The GOH in-house transportation method determines whether GOH pieces are transferred to a GOH cart or trolley load bar or to a trolleyless travel path.


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Transfer to a Cart Load Bar With the cart load bar method, flat-packed GOH boxes are stacked from the pallet onto an opening table or gravity conveyor section that feeds the boxes to an opening employee. The opening employee opens the box, removes a piece from the box, and places the piece on a hanger. The opening employee transfers the piece onto a fourwheeled cart’s load bar. Pieces are placed on the cart load bar with the left arm of the garment hanging toward the lead end or left side of the cart. (In the sort, count, and storage activities, this practice ensures good employee productivity.) After a GOH cart is full, it is moved to the sort and count station. Trash is placed in the trash container or on the trash belt conveyor. GOH carts are generally preferred for a low-volume GOH operation. Transfer to a Trolley Load Bar This method is the most productive. In this method, flat-packed cartons are placed onto a gravity conveyor, which provides flat-packed carton queue at the opening station. Adjacent to the opening station is an empty trolley cart. Above the gravity conveyor is a slightly sloped trolley rail with an adjustable stop. The top-of-rail (TOR) measurement is 6 feet, 4 inches above the finished floor. An adjustable stop holds the trolley at the opening station. A short trolley travel path that provides a one- to three-trolley queue against a second adjustable end stop at the rail discharge end. The trolley rail travel path is slightly pitched toward the main trolley travel path. An adjustable switch device permits trolleys to flow onto the main travel path. As required, an employee transfers an empty trolley onto the trolley rail and adjusts the adjustable stop. The stop holds the trolley on the overhead rail at the opening station. Next, an employee transfers a piece from the flat-packed carton onto a hanger and transfers the GOH piece onto the trolley load bar. When GOH pieces are transferred onto the trolley load bar, their left-hand sleeves should be facing the trolley’s lead end. When the trolley load bar is full, an employee adjusts the first stop, which permits trolleys to travel and queue against the second adjustable stop. After a quantity of full trolleys have queued against the second stop, an employee releases the stop and the trolleys travel onto the main path. The main path transports the trolleys from the opening area to the sort and count station. Trash is placed in the trash container or on the trash belt conveyor. Transfer to a trolley load bar is preferred for an order-fulfillment operation that has a high volume and an overhead trolley system.

GOH SORT-AND-COUNT ACTIVITY The next receiving activity is the sort-and-count activity. The activity separates the vendor delivery by specific features. The sort process ensures an accurate and quick GOH detail count. GOH operations separate deliveries by (1) purchase order, (2) purchase order by style by SKU, (3) style by color, and (4) style and color by size. The detail count activity ensures that the vendor-delivered GOH quantity for



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a specific SKU that matches your purchase order quantity. GOH sort and count methods are based on GOH transport methods, and include the GOH cart method and the nonpowered trolley rail method.

GOH CART METHOD The first sort-and-count method is the GOH cart method. The GOH cart method places empty carts in two rows. Each cart is assigned to a SKU, or else the cart load bar has separators for multiple SKUs. SKU assignment depends on the sorting requirements that were reviewed earlier. An aisle is maintained between the two cart rows. An employee pushes an inbound GOH cart between the two empty cart rows and, per the GOH identification label, transfers an individual GOH piece from the inbound cart to the appropriate outside cart. After all the inbound GOH pieces are sorted to the appropriate outside cart, the employee counts the SKUs on each cart. The employee matches the quantity delivered by the vendor to the quantity on the purchase order (PO). Adjustments are made to the inventory files. Employee productivity is low with this method. It requires significant setup time and handles only a low volume. The method requires a small capital investment and a large amount of floor space. Employees must be able to read.

NONPOWERED TROLLEY RAIL METHOD The second GOH sort-and-count method is the overhead nonpowered trolley rail method. The trolley sort and count method employs three nonpowered trolley rails. The middle rail is the travel path for the inbound GOH trolleys. The rail’s discharge end has an adjustable end stop or spring-loaded switch. The two exterior trolley rails contain empty trolleys — one trolley per SKU or separators on the load bar for multiple SKUs. Each trolley’s travel path has an adjustable end stop or spring-loaded switch. As an employee pushes a full inbound trolley with mixed SKUs on the middle trolley path, per the GOH identification label and at the appropriate location, the employee stops the trolley and sorts the required individual GOH pieces onto the appropriate exterior trolley. After all the inbound GOH pieces are sorted onto the appropriate trolley, the sort activity is completed. The employee compares the delivered quantity to the PO quantity. Adjustments are made to the inventory files. The advantages are good employee productivity, no setup time, the ability to handle high volume, and a medium capital investment. In addition, overhead trolley rails do not occupy floor space.

OTHER GOH DOCK-AREA HANDLING CONSIDERATIONS During the unloading and opening process, GOH hangers are transferred onto a trolley or GOH cart load bar. All hangers face in the same direction. The options are to transfer each GOH piece onto the load bar individually, or to group three or five GOH pieces into one bundle with a rubber band and transfer the bundle onto the load bar.


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GROUPING THREE

Order-Fulfillment Concepts, Design, and Operations OR

FIVE PIECES

INTO

ONE BUNDLE

In many GOH order-fulfillment operations, GOH pieces are moved by means of nonpowered trolleys, powered trolleys, dynamic trolleyless travel paths, or fourwheel carts between two facility locations. At the assigned location, GOH pieces are transferred from the in-house transport device load bar or dynamic trolleyless travel path onto a static storage and pick rail, trolley load bar, carousel hook, or powered sorting ring. Employee productivity can be improved by moving more than one GOH piece per transaction. One method is to group three or five SKU pieces with a rubber band. With GOH bundles, there is a productivity increase for the storage employee and, during bulk pick, for an order picker. The three-to-five piece GOH bundle is completed by your vendor or by a receiving employee during the sort and count detail receiving activity. When compared to one piece per hanger, the use of bundles increases the storage area transfer quantity, minimizing the number of transfer transactions. When used along with bulk picking of single SKUs, bundles reduce the number of order-picker transfer transactions. Bundles permit an easier inventory count and minimize the possibility of hangers interlocking on a static rail or load bar. During the receiving activity, there is a slight decrease in productivity due to the extra step of placing rubber bands around bundles.

QUALITY ASSURANCE As required, the appropriate GOH sample quantity for each vendor delivery and for the relevant size and color is sent from receiving dock area to the QA department. The QA department verifies that the GOH quality matches your company standards and PO specifications. The QA department ensures that the GOH sample quantity is placed in a transfer station for transfer to a storage and pick position, and updates the WMS or inventory file.

HANGING-GARMENT STEAMING The next GOH piece activity is steaming. Steaming removes the folds and wrinkles from each GOH piece. If your flat-packed pieces are received with wrinkles, they should be removed. Each GOH piece is removed from its protective plastic or paper bag. Steaming can be manual or automatic.

MANUAL STEAMING Manual steaming uses an electric-powered portable steaming machine to steam a GOH piece. To accomplish this, a GOH piece is removed from an overhead trolley or cart load bar, the protective cover is removed, and the GOH piece is steamed. The protective cover and GOH identification label are then replaced, and the GOH piece is returned to the in-house transport device load bar. During the steaming



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activity, the steaming employee ensures that the proper identification label is returned to the proper GOH piece. If, for some reason, the identification label is damaged or lost, the steaming employee creates another label. In most operations that receive flat-packed GOH pieces, the pieces have wrinkles. If the order-fulfillment operation has a customer-order return/rework area, wrinkled pieces are sent there for steaming. An employee steams one GOH piece per transaction, which minimizes the possibility of misplacing an identification label. Manual steaming is a low-volume, low-productivity method. It can be performed, however, at any location with minimal training and a low investment.

AUTOMATIC STEAMING The second steaming method is automatic steaming. An employee transfers an unbagged GOH piece onto the steaming device’s in-feed conveyor. The conveyor has a section with a slide rail and a powered-screw conveyor that transports the GOH piece through the steam machine and onto a discharge slide rail. After GOH pieces queue against the end stop of the steam tunnel discharge slide rail, an employee transfers the steamed GOH pieces to the cover-and-label station and onto the load bar of the in-house transport device. Steaming machines require an electric or gas boiler, a water supply, and a drain. A steam tunnel can handle both long and short GOH pieces. To ensure proper transport over the powered-screw conveyor and slide-rail travel paths, the GOH hanger material and shape must be standard and must match the screw conveyor requirements. An automatic steam tunnel that provides a constant first-in, first-out (FIFO) piece flow requires proper handling to ensure that the protective bag with the GOH piece identification matches the steamed GOH piece. To assist the steam tunnel employee in verifying labels, empty hangers with clips are permanently fixed to a closed-loop slick-rail travel path with end stops at the charge end and discharge end. As an employee prepares to steam a GOH piece, the employee places its removed protective bag and label on a clip and pushes the clip forward on the slick-rail travel path. This activity is repeated for each GOH piece that is transferred into the steam tunnel. As the slick-rail clip with the protective bag and label arrive at the discharge end, the FIFO clip flow matches the GOH piece flow, ensuring that the label and protective bag match the GOH piece that is discharged from the steam tunnel. The advantages of automatic steaming are high volume and good employee productivity. Automatic steaming requires a fixed finished-floor location, good employee training, a larger financial investment, and a method for tracking GOH identification labels.

PLASTIC BAG BOTTOMS If your GOH operation stores pieces in plastic bags, your options are not to secure the bottom of the plastic bag, or to heat-seal or tie the bottom of the bag.


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OPEN PLASTIC BAG BOTTOM When your GOH storage activity does not include securing the bottom of the plastic bag, the bottom of the bag will be open as the GOH piece is moved from the receiving area to the storage area. In the lower-level GOH storage position adjacent to an aisle, the plastic bag’s bottom will be a few inches above the finished floor. In this location, as an employee or mobile vehicle moves through a dusty aisle, there is a good possibility that dust will become airborne. With airborne dust near the open bottom of a plastic bag, there is a good chance that dust will get into the bag and collect on the GOH piece.

SECURE PLASTIC BAG BOTTOM Whether the plastic bag’s bottom is secured by the vendor or in your receiving area, an employee at a workstation seals or ties the bottom of the bag. A heat-seal machine secures the bottom of the bag, or an employee ties the bag shut. Another plastic bag seal or tie location might be in the sort-and-count area or the storage area. Airborne dust cannot get into a sealed plastic bag and collect on the GOH piece. This method requires some labor or equipment (if done in-house), but maintains GOH quality.

HANGING-GARMENT BAGGING ACTIVITY The next activity is bagging. An employee or a machine places a full-length protective plastic or paper cover over the GOH piece. The protective cover prevents dust and dirt from accumulating on the GOH piece. Most GOH order-fulfillment operations use a plastic cover and either a manual bagging or an automatic bagging operation.

MANUAL BAGGING With manual bagging, an employee places the GOH piece onto a bagging device. The bagging device consists of a hook that holds the GOH hanger, and structuralsupport members and a stand that are connected to the hook and to the base. The base provides stability to the device; there is also a removable rod for a roll of plastic bags. After the hanger is placed onto the bagging hook, the employee ensures that the bag is squarely over the GOH piece and that the garment is within the bag, and then detaches the bag at the precut location. The GOH piece is then removed from the hook. The operator ensures that the accurate GOH identification is on the GOH piece, and then seals or ties the bag’s bottom and transfers the GOH piece to a trolley or cart load bar. To ensure proper bag utilization and good employee productivity and to prevent waste, most GOH operations have several manual bagging devices. Each bagging device has a roll of bag material that is precut for short and long GOH pieces. Most GOH order-fulfillment operations that receive flat-packed GOH items or that have a GOH piece return and rework activity also have a GOH piece bagging activity.



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The features of a manual bagging operation are low-volume and low-employee productivity. Manual bagging can be performed at any location with minimal training and a low investment.

AUTOMATIC BAGGING Automatic GOH piece bagging is done with a bagging machine that rotates a GOH piece through four stations. The automatic bagging machine requires an operator or a machine to place GOH pieces by their hangers onto an in-feed conveyor hook. After the GOH piece is placed on a hook, the bagging machine rotates the piece to the bagging station. At the bagging station, a plastic bag is mechanically pulled down over the GOH piece. After the automatic bagging device is returned to the upright position and separates the plastic bag along the precut line, the machine rotates the GOH piece to the out-feed station. During the bagging activity, one option is to have the machine seal the plastic bag’s bottom. At the out-feed station, an operator ensures that the GOH piece has its identification and transfers the bagged GOH piece from the bagging machine onto a slick rail or a trolley or cart load bar. As required by the length of the GOH piece, the bagging device must be supplied with short or long precut plastic material. To ensure proper transport of the GOH piece over the slide rail, the hanger material and shape are standard. As noted above, most GOH order-fulfillment operations that receive flat-packed GOH items have a bagging operation. Automatic bagging features high volume and good productivity. It requires a fixed finished floor location for the equipment, employee training, and a greater financial investment.

GOH IN-HOUSE TRANSPORTATION GOH horizontal and vertical transport systems move GOH pieces between two locations or activity stations. Many GOH facilities have multiple floor levels. The use of multiple floors within a GOH order-fulfillment operation takes advantage of the cube space above or below the ground level, and lowers a company’s total investment. To ensure maximum space utilization and employee productivity, a modern GOH order-fulfillment facility is designed with horizontal and vertical GOH transport systems (Figure 4.6).

HORIZONTAL GOH TRANSPORTATION A horizontal GOH transport system’s travel path between two facility locations remains on one elevation, either above the floor or across the floor. Horizontal transport may involve individual pieces or groups of pieces. The options are humancarried, GOH cart, trolley load bar, and trolleyless rail.

OBJECTIVES The objectives of a horizontal GOH transport system are to move GOH pieces across the floor of the facility and over a fixed or variable travel path, to ensure that the


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FIGURE 4.6 GOH between floors. (From Railex Corporation, Queens, NY. With permission.)

maximum GOH piece quantities are moved at the lowest possible cost, and to ensure that the correct GOH pieces arrive at the assigned location. GOH horizontal transport systems are all similar in that they move GOH pieces between two locations, but differ as to power source, carrier capacity, travel path space or window, and GOH volume per trip.

DESIGN PARAMETERS A very important design imperative for a GOH horizontal transport system is to ensure that the proposed GOH carrier and GOH travel path satisfy company transport objectives and order-fulfillment design requirements. To ensure that the GOH horizontal transport system meets these requirements, GOH transport plan-view and detail-view drawings must be completed, along with written functional specifications. The plan-view and detail-view drawings show the executive management team, equipment vendors, and local building authorities how the GOH transport system will look and operate. The written functional specifications that accompany the drawings tell the story of your proposed GOH transport method. Most GOH transport plan-view drawings are done on a small scale in order to show the GOH horizontal travel path through the entire facility from the dispatch station through each activity station to the final delivery station. The plan-view drawing shows the clearance or width between order-fulfillment equipment and building obstacles, as well as the number of turns along the travel path. It also shows loading and unloading stations and the total travel path length and width, including the loading and unloading spurs and the maintenance spur. A detail-view drawing is done on a larger scale than a plan-view drawing. This large-scale drawing shows a plan view or elevation view for a specific location on



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the GOH travel path, or a particular workstation. During your GOH transport design and review process, the detail-view drawing ensures that there will be no interference between order-fulfillment equipment and transport system components, building obstacles, and other specific equipment or workstations. Prior to purchasing and implementing a new transport system, you must clearly define the design parameters. These design parameters are stated in your written functional specifications, which complement your plan-view and detail-view drawings. These design parameters include the minimum, average, and maximum dimensions (length, width, height, and weight). They should also include receiving volume, picking volume, order volume, and number of trips and should show average and peak activity levels. Specify the GOH destination identification method; the total travel path distance, including the main travel path and branch travel paths; the number and types of curves; the loading and unloading length; maintenance spurs; merges; branch travel paths; and required run-outs. Note whether the travel path is fixed or variable, and whether equipment is manual or microcomputer controlled. GOH loading and unloading methods and the type of workstation pickup and delivery schedule (on-demand or predetermined) are part of the specifications. Be sure to note clearly any required clearance from order-fulfillment equipment, transport components, or building obstacles. Building parameters are also part of the specifications, including floor conditions; fire wall and elevated floor opening penetrations and protection; and electrical power source and other utilities, such as compressed air location, type, and quantity. Special considerations include structural-support members, seismic location, and finished floor or ceiling support structure. Safety concerns include employee travel path and emergency exits.

NONPOWERED HORIZONTAL TRANSPORTATION When your order-fulfillment operation needs to move GOH pieces, and your operation has several constraints that do not permit a powered GOH transport system, consider a nonpowered transport arrangement. The constraints that make nonpowered horizontal transport an efficient, costeffective, and economical system are: fewer transport trips per hour, low labor rates, a large labor pool, shorter GOH travel distance, limited capital funds, and low maintenance capability. In addition, the facility or equipment layout may not permit powered transport, or your GOH receiving, picking, and shipping volumes may be handled by a human or gravity force.

HORIZONTAL TRANSPORTATION METHODS The horizontal transportation systems that might be considered for implementation in a new or remodeled order-fulfillment operation are: above-floor nonpowered horizontal, overhead nonpowered horizontal, and overhead powered horizontal.


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ABOVE-FLOOR NONPOWERED HORIZONTAL TRANSPORTATION GROUP Above-floor nonpowered horizontal GOH transportation moves your GOH pieces across one floor level between facility locations. When you move GOH pieces between locations, the power source used to propel the pieces over the travel path is manual power or gravity. In an above-floor nonpowered horizontal transport system, the travel path between two facility locations can be variable or fixed. If the power source is manual, the operator determines the travel path. When a manual or gravity-powered transport system moves GOH pieces over a travel path, the floor of the travel path must be free and clear of all obstructions. This method does not permit other order-fulfillment activities to be performed in the travel path. If other activities are performed in or enter into the travel path, the potential for employee injury increases, the chance of damage to GOH pieces is greater, and delayed delivery to the assigned station or location may occur. The above-floor nonpowered horizontal transportation methods include humancarried, GOH cart with a load bar, and slick or slide rail. Human-Carried Method The first option is the human-carried method. Human-carrying is a variable travel path method wherein an employee picks up the GOH pieces. After receiving dispatch instructions, an employee carries GOH pieces from one location to another. The horizontal transport distance between the two locations is short. In many small-volume order-fulfillment operations, the human-carried transport method is used to move GOH pieces between two locations. In developing countries where abundant labor is available at a low cost, human-carried GOH transport is the predominant method. As the name of the method implies, the power source for moving GOH pieces between two locations is human power. This is considered a basic GOH transport method. Its features are low volume, restricted cube or weight capacity, a narrow variable travel path, and easy startup. This method may cause queues and has the potential for employee injury and GOH product damage from an employee’s dirty hands. This method requires no structural-support members or specific finished-floor conditions. The human-carried GOH transport method should not be considered for implementation in a dynamic order-fulfillment operation. GOH Carts The second above-floor nonpowered method is the manual (pushed or pulled) GOH cart with a load bar. The GOH cart is a nontilt cart. A nontilt cart design means that all wheels are in contact with the floor. The GOH cart transport is considered a variable path transport method. The advantages are larger GOH volume and capacity, the capability to travel over a longer distance, and less employee fatigue. With a loaded or empty cart, after receiving dispatch instructions an employee pushes or pulls the cart over the floor to the assigned facility location.



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Design factors include one GOH carrying load bar, employee push handles that are at one or both ends of the cart, four wheels or casters, and one long and two short bottom structural-support members. Cart Structural-Support Members The GOH cart structural-support members include two upright posts and two short and two long cross members, which are connected to each upright post. The first long cross member (or load bar) is a metal member that is connected to the top short member, while the second long cross member is connected at the bottom short member. Both the top and bottom short cross members are attached to both upright posts. As a cart is pushed or pulled across the floor, the connection between the two cross members and the upright posts ensures cart rigidity and stability. The cross members and upright posts may be welded, hinged, or secured with a nut and bolt. To reduce GOH piece damage, all upright posts and cross members are metal and have a coating applied to the exterior surface. GOH piece damage occurs when an employee handles an uncoated metal surface, which dirties the employee’s hands. When an employee handles a GOH piece with dirty hands, the dirt or rust is transferred to the GOH piece. GOH Cart Design The GOH cart is considered a specially-designed cart due to its load or hang bar. Hang Bar Characteristics Most GOH carts are designed with both hang bar ends attached to the middle of each top short cross member. The height of the hang bar above the bottom frame and the diameter of the hang bar must be sufficient to permit the operator to transfer an open-faced hanger onto the load bar. On the load bar, GOH pieces hang freely within the cart’s bottom-frame structure. As the cart travels across the floor, this hanging feature reduces GOH piece damage, such as the accidental ripping of GOH pieces by equipment or by another cart. A GOH cart’s load bar is designed to support a specific number of GOH pieces per linear footineari. Specifying the carrying capacity of a load bar is a matter of listing the maximum number of summer or winter pieces per linear foot, and noting the thickness of the hanger. All metal members of a load bar have a coated exterior surface. The diameter of the load bar should match your GOH hanger open-face hook. Cart Bottom-Frame Characteristics GOH cart bottom designs include (1) the inverted-T bottom frame; (2) the rectangular, or regular-shaped, bottom frame; and (3) the Z-shaped bottom frame. Inverted-T Bottom Frame. The first GOH cart design is the inverted, T-shaped bottom frame. A cart with this frame is considered a push or pull cart. The cart has a top load bar that is attached to the top short cross member. The short cross member is attached to each upright post’s top, and a long horizontal base frame is attached to the middle of each cart’s short bottom support member. The bottom long cross member and the short support members form an inverted T at the base of the cart.


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A wheel and caster combination is attached under the short bottom frame of each four-wheeled cart. As an employee pushes or pulls a cart across the floor, this Tframe design ensures a rigid and stable cart. To reduce GOH piece damage, a coating is applied to all cart structure members. The inverted-T shape permits the GOH cart to handle a large piece quantity. When inverted-T carts are not being used in GOH transport, the open space at the base of the cart permits an operator to nest another cart inside it. Cart nesting reduces the floor space needed to store unused carts. Rectangular, or Regular-Shaped, Bottom Frame. The second type of GOH cart has a standard rectangular bottom. The cart is designed with two upright posts, two long bottom cross members, and two short bottom cross members. Each upright post is connected at the hang bar’s top ends. Each upright post’s bottom end is connected to the middle of each short bottom member. Each long bottom cross member is connected to the ends of each of the two short bottom members. The bottom frame makes the shape of a rectangle with solid sides. A wheel or caster is attached under each short corner horizontal and each upright post member. As an employee pushes or pulls a loaded cart across the floor, the connection between the upright post member and the base frame provides stability and rigidity. A rectangular frame can handle a heavy load and gives the best rigidity and stability. When not in use, however, the cart requires the greatest amount of floor area. As an employee pushes or pulls an inverted-T cart or a rectangular cart over the cart transport travel path, the structural members and the location of the four wheels give the best rigidity and stability and allow the operator to steer the cart. An option with inverted-T or rectangular frames is a shelf at the top of the upright post. Each shelf has a lip on all four sides. As an employee places SKUs on the shelf, the lip keeps them from slipping off. The shelf is used to carry flat and lightweight loose SKUs or cartons. If you are considering a cart with a top shelf, keep in mind that this feature does prevent unused carts from being nested together. This means that carts require a large floor area. Z-Shaped Bottom Frame. The third design is the Z-shaped bottom frame. In this design, welded and coated metal members form the shape of a Z. The Z-shaped frame configuration includes a short front-bottom member and a short rear-bottom member. These two members are connected together diagonally by a long bottom member. Each short member’s middle section provides an attachment location for one of the two upright posts, and the end of each short member has a caster. As an employee moves a cart over the finished floor, the location of the casters on each short member adds to the cart’s stability. With a Z-frame cart, a swivel-caster design is preferred, because swivel casters permit easy cart movement and steering control. During cart transport, the swivel casters and the Z-shaped bottom frame are very important, since these features allow the operator to couple two carts together and pull two carts across the floor between two locations. Coupled carts mean increased employee productivity. The Z-shaped frame features an open space along the cart’s bottom legs for maximum used cart storage in a small area, and cart rigidity and stability as it is pulled across the floor.



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With a Z-frame cart, you can couple two cart legs together. A two-cart connection is considered to be safe and stable when pulled across a smooth finished floor. When two carts are coupled together, worker productivity is improved. Another Z-frame cart feature is the upright post attachment, located in the center of each base member. Locating the upright post in the middle of the base makes the cart easier to steer as it is moved over the floor. Cart Specifications The basic functional specifications for a GOH cart are: • • • •

Galvanized, zinc, or chrome-plated metal members An overall load-bar pipe diameter that matches your open-neck GOH hanger diameter A base leg cross member design that allows for a connection to the two upright posts Underside caster attachments

A base leg cross member can range from 20 to 27 inches wide. Height ranges from 64 to 78 inches from the floor to the top of the hand bar. Carts can handle GOH pieces that range from 30 to 72 inches in length. The load bar should be high enough to allow for an add-on load bar that can accommodate a 31-inch long GOH piece. The carts should have four industrial-strength swivel casters with ball bearings, each caster having a 3- to 4-inch wheel diameter. Two swivel- and two rigid-caster types and the location of the casters on the cart are considered options for cushion covers that minimize noise from the wheels. After you identify the number and type of GOH pieces per linear foot and the GOH hanger dimensions, the cart manufacturer determines the metal gauge and the diameter of the upright posts and the load bar. Your cart’s written functional specifications will state the desired structural-member connection. Securing GOH Pieces on a Load Bar During the transport of fully-loaded GOH carts, GOH pieces can fall from the load bar to the floor and become damaged with dirt, dust, or other debris. The methods used to secure GOH pieces to a load bar are: • •

A cardboard sleeve attached with adhesive tape over all the hangers and the bottom of the load bar Adhesive tape applied directly over the hangers and the top and bottom of the load bar

Cardboard Sleeve The first method for securing GOH pieces to a load bar is the cardboard-sleeve method. This method employs a preformed cardboard piece that fits full-length over the diameter of the load bar and the GOH pieces. An employee wraps both the sleeve


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and the load bar with strands of adhesive tape. The tape secures the cardboard sleeve to the load bar. As a cart travels across the finished floor, this taped cardboard sleeve reduces the movement of GOH pieces on the load bar. Since the tape is on the cardboard sleeve, there is minimal glue residue remaining on the load bar when the tape is removed from the cart, and no tape or glue residue on the GOH piece hanger. On the load bar, both sides of the cardboard sleeve extend downward 1 to 2 inches below the load bar. The advantages of this method are that it uses less tape, requires less time to load and unload a cart, and minimizes tape residue on the load bar and hangers. Adhesive Tape The other option for securing GOH pieces to a cart’s load bar is to use adhesive tape only. When the load bar is full, strands of adhesive tape are wrapped around the bottom of the bar and the GOH hangers. Wrapping the tape on the load bar minimizes GOH movement, but some tape adhesive remains on the hangers. Push Handle or Push Bar For any GOH cart (except the Z-frame cart) to be pushed or pulled across a floor, the cart requires bars, grips, or handles. Push handles must be located on the cart’s upright posts to minimize employee injury and to permit an employee to push, pull, or steer the cart. The push handles are located on the cart’s upright posts. Push handles are attached either to one or both ends of the cart. A rubber or plastic bumper may be attached to the handle ends. When several carts are queued in a line, the bumper’s diameter or outward extension should permit easy access to the push handle. Caster and Wheel Location and Design Considerations Wheels are also an important consideration. Some of the variables to determine are the axle, axle bearing, axle bracket, wheel mounting location, and type of wheel. Wheels can be casters or fixed. Casters can be swivel, rigid, lockable, or unlockable. The size of the wheel is dictated by both the load of the cart and the floor. Wheels can be exposed or covered. The wheel and caster design parameters directly affect the ability to move, steer, and load and unload GOH pieces between the cart and the SKU storage and pick position and pack station. Cart caster and wheel factors include how the casters are attached to the cart’s bottom-frame members, the wheel size and tread, whether casters are lockable or unlockable, and wheel location. The cart’s load rating or capacity will impact the choice of axles, axle bearings, and axle brackets. Caster Attachment Methods Casters typically attach to the leg or to the underside of the frame. Caster attachment options include stem, screw pipe, welded, riveted, and nut and bolt. The caster mounting method is determined by floor conditions, combined cart and GOH load weight, cost, and desired durability.



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The screw-pipe method is used on lightweight carts that travel across smooth and debris-free floors. The welded, riveted, and nut-and-bolt methods are used for carts that handle a heavy load and travel across a floor that is in poor condition, with some debris on its surface. Caster Type The second caster variable is the caster type. Casters can be rigid or swivel. Rigid casters serve to hold the wheel in a fixed direction and permit a cart to turn at the end of an aisle or at corners. A swivel caster permits the wheel to rotate in all directions. This makes the cart easy to maneuver and to align at a workstation. With most manual GOH push carts, swivel casters are located in the front and rigid casters in the rear. A Z-frame cart has swivel casters on all four wheels. Caster type is determined by the cart’s operational movement requirements, cart and GOH load weight, cart load bar and frame member lengths, floor and amount of debris, and cost. Caster Locations The mounting location refers to the location, according to the cart’s direction of travel, of the swivel casters and rigid casters. For a GOH cart, there are three basic caster configurations: two swivel casters in the front and two rigid casters in the rear, two swivel casters in the rear and two rigid casters in the front, and swivel casters in both the front and rear. Two Swivel Casters in the Front and Two Rigid Casters in the Rear. This caster arrangement permits easy turning at the ends of aisles. When turning a cart at the end of an aisle with this arrangement, the cart travels continuously from the start of the turn to the end. This configuration is best for lightweight loads and provides easy steering through turns and a wider aisle space for aligning a cart at a workstation. Two Swivel Casters in the Rear and Two Rigid Casters in the Front. This caster configuration requires increased effort and time to make a turn at the end of an aisle. This configuration can handle heavier cart loads and provides better travel on long straight paths. Two Swivel Casters in the Rear and Two Swivel Casters in the Front. A cart with four swivel casters permits easy movement in any direction with minimal difficulty in turning. This configuration handles lightweight loads well and provides easy alignment of the cart at a workstation. The disadvantage is that such carts are difficult to steer in a straight travel path. Wheel Diameter and Wheel Cover (Tread) The wheel diameter and wheel cover or tread are the next cart design factors. The wheel diameter is basically the height of a cart wheel. Wheel diameter selection depends on the floor, the amount and type of debris on the floor, the required load bar height, the GOH and cart load weight, and cost.


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The typical wheel diameter of a manual push or pull GOH cart ranges from 3 to 8 inches. The wheel diameter affects the elevation of the load bar above the floor. The load bar elevation affects the ergonomics of a GOH piece transaction. A small-diameter wheel gives a lower load-bar height and a lighter load capacity. A lower load-bar height improves ergonomics by decreasing the lift height, and improves cart stability by giving the cart a lower center of gravity. These factors result in a more stable and safer full cart during transit. A large-diameter wheel gives a high load-bar height. The cart moves more easily over a floor with cracks and joints and handles a heavier GOH and cart load weight. The second wheel component is the wheel cover or tread. The tread is the portion of the wheel that comes in contact with the floor. The wheel tread is a key factor in permitting an employee to move a GOH cart across the floor easily. Cart wheel treads may be cushioned rubber, hard rubber, or plastic. Lockable Casters or Wheels The lockable caster or wheel is a manually-activated device. When activated, the device locks the caster or wheel. In the locked position, the device restricts accidental cart movement away from the workstation. Wheel Location The next factor is the location of the wheels on the cart’s undercarriage. Casters or wheels may be mounted to the cart leg, the upright post, or the bottom support frame. The two front and rear casters or wheels should be set in a straight line between the cart’s two ends. With this arrangement, the cart is more stable as an employee moves it across the floor. The cart wheels have the same height, which makes it a nontilt cart. This is the most common feature on GOH carts in the orderfulfillment industry. Slick or Slide Rail The next above-floor nonpowered GOH transport system is the slick or slide rail method. Through an elevation change between the slick rail charge and discharge ends, a slick rail transports a single GOH piece from one location to another location. Slick rail GOH transport is a decline transport method. For additional information, we refer the reader to the nonpowered GOH transportation section that follows.

OVERHEAD NONPOWERED HORIZONTAL TRANSPORTATION GROUP The next GOH horizontal transportation group is overhead nonpowered horizontal transport. This group moves GOH pieces across an overhead nonpowered trolley. The trolley’s travel path is above the building’s floor and between two locations on one floor. With these GOH in-house transport systems, GOH pieces are moved between two locations by manual power or gravity. An overhead system can be supported in one of two ways: suspended from the ceiling (Figure 4.7) or with floor supports (Figure 4.8). An architect should verify that the facility’s ceiling or floor can handle a transport system’s total weight if an overhead GOH trolley is installed. Even if the floor is satisfactory, it may still require



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FIGURE 4.7 Examples of overhead-supported GOH. (From Railex Corporation, Queens, NY. With permission.)


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FIGURE 4.8 Floor-supported GOH. (From Railex Corporation, Queens, NY. With permission.)

a wider and thicker base plate. A ceiling-supported trolley system will require additional structural-support members (headers) in order to transfer the additional weight across several ceiling trusses. The overhead nonpowered horizontal trolley systems are (1) slick or slide rail and (2) nonpowered trolley. Slick or Slide Rail Method The first overhead nonpowered horizontal transport system is the slick or slide rail. This system moves individual GOH pieces on a hanger between two facility locations. When you use a slick rail, there is a slight elevation change between the slick rail charge and discharge locations. For more detail on this GOH transport method, we refer the reader to the decline section in this chapter. Nonpowered Overhead Trolley The second overhead nonpowered horizontal transport system is a nonpowered overhead trolley. These trolleys may employ any of the following travel paths: a tubular rail on J-hook support members; an inverted-V or bar-stock path; a strutchannel path; and an enclosed C-channel path. All of these methods are supported by a superstructure suspended from the ceiling or built up from the floor. Most nonpowered overhead trolley systems have the TOR set at an elevation of 6 feet, 4 inches above the floor. At this elevation, sufficient clear space exists between the trolley load bar and the floor for one long GOH piece. Also, at this elevation an employee standing on the floor can perform the activities that ensure proper trolley transfer to the overhead path and travel on the overhead path. These activities include transferring GOH pieces between a storage rail and a workstation or trolley load bar; using a second short-garment add-on load bar; pushing or



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pulling a single trolley or, with a pull rod, a trolley train; properly setting travel path switches for trolley traffic flow; properly setting rail stops that stop trolley travel; and adding or removing an empty trolley between the travel path and workstation. A nonpowered trolley on a tubular, strut, C-channel, or inverted-bar stock system involves the placing of GOH pieces on a trolley load bar. To move GOH pieces across an overhead nonpowered horizontal trolley between two locations requires several steps. After the pieces are placed onto a nonpowered trolley load bar, the operator pushes or pulls the trolley on the overhead trolley travel path. With a pull bar, an operator can move up to four or five loaded trolleys across the travel path at once. The GOH trolley method is used in an order-fulfillment operation that handles a medium volume, with a short-to-medium travel distance between two locations on the same floor level. Nonpowered Overhead Trolley on a Tubular Rail Supported by J-Hooks The first nonpowered overhead trolley transport system uses manual power or gravity to move trolleys over the tubular-rail travel path. The tubular-rail trolley is supported by J-hooks. Some transport professionals refer to an overhead nonpowered trolley on a tubular rail as a continuous speed trolley. The components of the tubular-rail system are the GOH trolley; the tubular rail with J-hook support devices, switches, and stops; structural-support members; and accessories, guard rails, and other devices. Nonpowered Trolley. The first component of an overhead non-powered trolley transport system is the trolley. In GOH movement, the trolley and rail are the two operational components that permit an employee to move GOH pieces over a nonpowered travel path between two facility locations. The basic parts of a J-hook trolley are two spool sets with bearings, two heads, two necks, a hang bar, and accessories. Trolley Spools. The spools with bearings are the trolley components that come in contact with and travel over the tubular rail. A trolley has four spool pairs. Two spools are located on the trolley’s front head, and two spools are located on trolley’s rear head. To ensure excellent trolley balance on the tubular rail travel path, each spool set is placed on the side of a trolley head and on the side of the rail. The spool’s concave shape matches the tubular rail’s diameter. Most trolley manufacturers’ standard spool diameters are 1 inch, 1 5/16 inch, 1 3/8 inch, and 1 5/16 inch. The spool’s diameter matches the rail diameter, permitting the spools to roll on the tubular rail. This allows an operator to move a trolley from the dispatch station over the trolley travel path to the desired location. When there is a match in diameters, the nonpowered trolley flows easily and smoothly across the tubular trolley rail. When the spool diameters are stated by the trolley manufacturer, they will match the overall tubular rail diameter. If the width between two spools is larger than the tubular rail diameter, the trolley spools will be set low on the tubular rail as an operator moves a fully-loaded trolley over it. When a trolley’s spools are set low on the travel path, it means that


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they do not turn easily on the tubular rail. This increases the coefficient of friction, thereby impeding movement; it also causes a wider distance between two spools, increases spool wear, and creates trolley travel path problems at switch locations. If the distance between two spools is narrower than the tubular rail diameter, the spools will be set high on the tubular rail as an operator moves a trolley over it. With the spools set high on the travel path, the problems are uneven wheel and rail wear and greater probability of a trolley falling or jumping from the tubular rail. For a new trolley design, a match between the trolley spool diameter and the tubular rail diameter is a functional requirement. This fact is noted on the detail drawings and in the written functional specifications. Most nonpowered trolley spools have eight bearings, or two bearings per spool. As an operator pushes or pulls the trolley over the tubular rail travel path, these bearings ensure that the trolley spool is turning on the tubular rail. Proper spool turning ensures that the trolley moves easily and smoothly over the tubular rail travel path. The two types of bearings are designed as the shielded, no-drip type, and the type that is prelubricated with nonstaining lubricant. Spool materials include hardened metal and hardened plastic or nylon. The hardened metal trolley spool is the most common type in the overhead trolley transport industry. The reasons for its popularity are that the metal spool is a much older spool technology, and metal rolls more easily. The nylon or hardened plastic spool is considered the new type of spool. The advantages of nylon or plastic are: lower cost, reduced trolley weight, less noise, lower spool maintenance, and longer rail life. If you consider purchasing used trolleys for an existing overhead nonpowered trolley transport system, the vendor should review your existing trolley drawings and written functional specifications. These specifications should state the tubular rail diameter and trolley spool diameter. Get several sample trolleys and test them on the entire existing travel path. Trolleys should travel through all switches during testing. The used trolley heads should match the existing trolley heads. This permits an operator to push or pull a trolley train over the travel pat, and ensures proper trolley queuing. In addition, check the trolley’s overall length and the GOH load bar length to ensure consistent GOH quantity and proper trolley queuing. Trolley Heads. The second trolley part is the trolley head. Each trolley has two heads. The heads are located at the trolley’s ends. A trolley head has hardened metal members that contain two spool sets; a flat, smooth exterior plate; and a section that connects the neck to the trolley load bar. The trolley heads permit an operator to set the trolley on the tubular rail travel path. The length of a trolley head is approximately 2 to 3 inches. When the neck is connected to the trolley head in a manner that allows the head and neck to turn, the trolley head has maximum flexibility. This permits an operator to easily place a trolley onto the tubular rail travel path. A trolley head has a metal case, both ends of which are flat and square. This hardened metal head case contains the two spool sets and is the location for the spool bearings and the neck connection. A trolley head with a flat, square end gives the trolley’s front head sufficient surface space on the overhead tubular rail to have a good connection with the trolley’s rear head. When a trolley train is being pulled



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over the travel path, this trolley-head match allows the operator to pull on the rear trolley. This pulling action causes the rear trolley to push the front trolleys over the travel path. To minimize GOH piece damage from the transfer of metal dirt by the operator, most trolley head exteriors are coated. When two trolleys are queued on a tubular rail travel path, the rear head of the front trolley is in contact with the lead head of the rear trolley. When two trolleys are queued on the tubular rail travel path, the open distance between the two trolley necks is approximately 2 to 3 inches. The open space permits the operator to move one trolley forward. The overall trolley dimension is the distance from the exterior of the lead trolley’s head to the exterior of the rear trolley’s rear head. The overall trolley dimension determines the trolley length on the travel path queue sections. Trolley Neck or Arm. The trolley neck or arm is the next overhead trolley component. Each trolley has two necks. The trolley neck is the part that is connected to the trolley head and attached to each end of the load bar. The neck connection method permits the trolley head to swivel. The flexibility of the trolley head allows the operator to attach the trolley to the travel path easily. The trolley neck is in a C shape, with a long mouth. The neck extends outward from the side of one trolley head. At a predetermined distance from the trolley head, the preformed neck turns downward toward the load bar. At this end of the neck, the trolley load bar is attached. In this location, the neck is located directly under the tubular rail travel path and the trolley spools. This neck location puts a full trolley load weight directly under the center of the tubular rail travel path. The location of the load weight minimizes the possibility that a trolley will fall or jump from the tubular rail travel path; the center of the GOH pieces is under the center of the trolley travel path. This location minimizes GOH piece damage and requires only a narrow travel path. To minimize GOH item damage from the transfer of metal dirt by an employee, metal trolley necks are coated. The neck covering or coating material is the same as for the trolley head. Another neck feature is the distance between the center lines of the trolley’s two necks. The length between two necks for a standard overhead nonpowered trolley is 24, 30, 36, 42, or 48 inches. These dimensions have the following piece-carrying capacities: a 24-inch-long trolley carries 12 heavyweight winter or coat GOH pieces, or 24 lightweight summer or dress GOH pieces. A trolley that is 30 inches long carries 15 heavyweight winter or coat GOH pieces, or 30 lightweight summer or dress GOH pieces. A 36-inch long trolley carries 18 heavyweight winter or coat GOH pieces, or 36 lightweight summer or dress GOH pieces. A 42-inch long trolley carries 21 heavyweight winter or coat GOH pieces, or 42 lightweight summer or dress GOH pieces. A 48-inch long trolley carries 24 heavyweight winter or coat GOH pieces, or 48 lightweight summer or dress GOH pieces. A trolley’s load bar length matches the longest trolley that travels across the tubular rail’s curves and other sections. When considering the number of GOH pieces per overhead trolley, remember that a trolley’s GOH piece-carrying capacity cannot exceed the manufacturer’s stated


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capacity. If the weight of GOH pieces exceeds the load weight, there is a possibility of damage to the tubular rail support members, and of increased wear on the overhead trolley spools. Most trolley manufacturers design their tubular rails and trolleys to handle a GOH weight of 50 pounds per linear foot. Most empty trolleys are light enough to permit an operator easily to move an empty trolley between the overhead tubular rail and the workstation. Standard trolley weights are 4 pounds for a 24-inch long trolley, 4.3 pounds for a 30-inch long trolley, 4.6 pounds for a 36-inch long trolley, 5 pounds for a 42-inch long trolley, and 5.5 pounds for a 48inch long trolley. The second trolley length dimension is the open space between the two arms. This open distance is the carrying surface of the trolley load bar, and determines the maximum GOH weight for the structural-support members of the tubular rail travel path. The third important trolley dimension is the open space between the top of the trolley load bar and the tubular rail. Most manufacturers design this open space to have a 4-inch standard clearance. As required by your GOH transport operation, this open space can be adjusted to 5 1/4 or 5 1/2 inches. This open space allows an operator to transfer GOH pieces between the trolley load bar and the workstation, and provides a location to hook a hand or pull rod onto a trolley. Another trolley arm characteristic is that each arm serves to prevent GOH pieces from sliding over the trolley load bar. This feature is important when a fully-loaded trolley moving across the tubular rail travel path makes an elevation change. Load Bar or GOH Load-Carrying Surface. The final nonpowered overhead trolley component is the trolley load bar’s carrying surface. The load bar has the same weight capacity as the tubular rail travel path (50 pounds per linear foot). Each load bar end is connected to a neck. The trolley load bar is located directly under the center of the overhead tubular rail. The trolley load bar is a hardened metal tube with a coating of chrome, zinc, galvanized metal, or another coating material. The coated metal surface minimizes the risk of GOH damage from metal dirt. The diameter of the trolley load bar matches the open-faced GOH hanger hook. The load bar and hanger hook diameters should match, so that during travel over the tubular rail travel path, the hanger is retained on the trolley load bar, and an operator can easily transfer GOH pieces between the trolley load bar and the workstation. Trolley Accessories and Options. The next nonpowered overhead trolley components are the trolley accessories and options that improve productivity and minimize GOH damage. Accessories and options include antislide pins or pegs, hanger locking bars or caps, empty trolley carts, short GOH extensions or add-on load bars, and trolley train pull bars. Antislide Pins Or Pegs. The first accessories are antislide pins or pegs. These antislide pins are inserted, secured, and evenly spaced by your trolley manufacturer on the top surface of the trolley load bar. Each antislide pin is coated with zinc, chrome, galvanized metal, or another coating material. Each pin extends approximately 1 inch above the load bar’s top surface.



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The number of pins per load bar is determined by the load bar length, transport and workstation requirements, and the manufacturer’s standard. Most trolley manufacturers and GOH transport professionals consider the standard antislide pin number per trolley load bar to be three to five pins. The open space between two pins or between a pin and the neck reduces incidences of GOH hangers becoming intertwined with other hangers or creating GOH piece-line pressure on the neck of the trolley load bar. At the workstation, when an operator transfers GOH pieces from the trolley load bar to a storage rail or to a workstation, the antislide pins ensure good transfer productivity and keep GOH pieces from falling to the floor. Load-Locking Cap. The second nonpowered overhead trolley option is the loadlocking bar or cap. The load-locking cap is attached to the top of the trolley load bar. The cap consists of a hardened metal bar with two holes, placed onto two long pins that extend upward from the trolley load bar. The trolley manufacturer secures the two long pins to the trolley load bar’s top surface. Each long pin is designed with a curve at the top, and each pin’s end is wider than the locking cap hole. When the metal locking cap is not sitting on top of a GOH piece hanger, the curved end of the cap allows the metal bar to elevate above the load bar. In this elevated position, the operator transfers GOH pieces between the trolley load bar and the storage and pick rail. The width of the end of the long pin keeps the locking cap on the trolley load bar. The long pins serve as antislide pins on the surface of the trolley load bar. The metal locking cap is a crown-shaped device with an overall width that is slightly greater than the diameter of the load bar. The cap has two holes that allow it to slide upward and downward on the two pins. During trolley travel across the overhead tubular rail travel path, and especially on a curve, a trolley with a metal locking cap in the down position on the GOH piece hangers keeps the GOH pieces on the trolley load bar. This reduces the possibility of GOH pieces falling from a trolley load bar and getting damaged. At a workstation or in the storage area, a metal locking cap in the up position creates an open space that permits GOH piece transfer. Empty-Trolley Transporter or Cart. The empty-trolley transporter or cart is the next trolley accessory. The empty-trolley transporter is a specially-designed fourwheel manual push or pull cart that has many standard GOH cart components. The difference, however, is that the load-carrying surface is designed in an A shape. The top of the A has two top trolley-carrying, full width cross members. These cross members form the top part of the A. The two middle cross members are a full cart’s width apart, from the cross member to the letter A. The middle cross members are the trolley load bar support members. After an empty trolley spool is hung on a top load-carrying cross member, the trolley hangs downward and rests against the middle cross member. The empty trolley becomes one side of the letter A. The empty trolley cart has four swivel casters. Each caster has a cushion-tread wheel cover. These features ensure easy cart maneuvering at the workstation. The empty-trolley carrying bars are 48 inches wide and are set at least 48 inches above the floor. At the middle-support cross member elevation and location, an empty trolley is hooked on the top cross member and rests on the middle cross member.


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With this arrangement, an empty trolley hangs outward and toward the floor. As the operator transfers an empty trolley to the empty-trolley cart cross member, and as the empty trolleys accumulate on the top cross member, the trolley’s bottom head does not come in contact with the floor. A fully-loaded empty-trolley cart is manually pushed or pulled across the floor to the required workstation. The empty-trolley cart increases empty-trolley transport productivity. Short GOH Add-On Load Bar or Carrier Extension. The next nonpowered overhead trolley accessory is the short GOH piece add-on load bar or carrier extension. The short GOH piece add-on load bar is a metal device with a load bar and two metal rods. One end of each metal rod is attached to a load bar, and the other end has a hook shape. The hook has the same diameter as a trolley load bar. This feature permits an employee to hook an add-on load bar onto a trolley load bar. The short GOH piece add-on load bar carries additional short GOH pieces. The short GOH piece add-on bar location is approximately in the center of the area under the trolley load bar, and in the open space between the two trolley necks. The vertical space between the trolley load bar and the floor is sufficient for GOH pieces on the trolley load bar to come in contact with the add-on bar, and for the add-on bar with a short GOH piece to hang downward and not have the bottom of the piece come in contact with the floor. This means that the trolley has the potential to carry a GOH quantity that is almost double that of a standard single load-bar trolley. The short GOH piece add-on load bar components have the same coating as the trolley components. If your GOH transport operation handles a high volume of short GOH pieces, consider using the short GOH piece add-on load bar to increase in-house transport productivity. The short GOH piece add-on bar is designed to hook over a trolley load bar. The hook length is designed to ensure that the GOH piece add-on load bar remains on the trolley load bar. In this position, the short GOH piece add-on load bar is directly under a trolley load bar, ensuring a stable load and permitting a narrow trolley travel path. The standard add-on load bar lengths that fit a standard trolley load bar are 24, 30, 36, 42, and 48 inches. For the add-on load bar to fit within the trolley’s two necks, the add-on bar must be slightly shorter than the trolley load bar. This is because the carrier extension’s two metal rods and hooks must fit within the trolley’s two necks. Standard add-on bars may be rigid or folding. The rigid add-on bar has two long metal rods. In the rigid position, each rod has a hook that extends upward from the load bar. When a rigid add-on bar is not used on a trolley load bar, its metal rods are in the extended position. When the bar is required for use in the transport operation, employees must untangle the coupled long metal rods of the add-on bar. This leads to low employee productivity. The folding add-on bar is the second type. The folding add-on bar has two long metal rods with hooks that are designed as flexible members. To form a compact unit, these metal rods with hooks are folded down on the top of the load bar. This



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means that when the carrier extension is used on a trolley load bar, the rods are extended downward; when the carrier extension is not attached to the trolley load bar, the metal rods are folded onto the load bar. This reduces the required storage space and permits quick trolley attachment. Trolley Pull Bar or Rod. The last nonpowered trolley accessory is the trolley pull bar or rod. The trolley pull rod is a metal member that is coated with chrome, zinc, a galvanized metal, or paint. The metal rod is approximately 36 inches long. One end of the metal rod is shaped into a hook, and the other end is shaped into a handle. The hook is designed with sufficient width and length to fit around a trolley’s rear neck. The handle shape is designed to fit a human hand. When required to pull a trolley train over a tubular rail travel path from the dispatch station to another station, an operator queues four to five trolleys on the overhead tubular branch rail. At the dispatch station, the operator places the pull rod onto the rear neck of the last trolley in the train. When the pull-rod hook is attached to the last trolley, the operator grasps the pull rod handle and pulls the bar. With the pull bar, the operator walks forward in the adjacent aisle and pulls the trolley train over the overhead tubular rail travel path. In walking forward, the operator provides the power to move the train of trolleys forward over the tubular rail travel path. The trolley pull rod increases operator productivity by increasing the number of trolleys per trip between the dispatch station and the required workstation or storage area. Plastic or Cardboard GOH Piece or Customer-Order Separator. If your GOH transport operation needs to separate GOH SKUs or customer-ordered pieces on one trolley load bar, a circular or rectangular plastic or cardboard sliding separator is used to separate the pieces. The plastic or cardboard identifier has an opening in its surface to permit an employee to easily attach or remove a number of identifiers onto or off of a trolley load bar. The surface of the separator contains GOH piece or customer-order identification. Cardboard and plastic separators are flexible, reusable, and low in cost. Tubular Rail Travel Path The next component in a GOH nonpowered trolley horizontal transport system is the tubular rail travel path. The overhead tubular rail is a fixed travel path that allows the nonpowered trolley to be pushed or pulled between two facility locations. These two locations are on the same finished floor of your facility. Nonpowered trolley transport is the link between any two GOH functional locations within your facility. The components of an overhead tubular rail are the straight rail, the 30˚ curve, the 45˚ curve, the 68˚ curve, the 90˚ curve, the 180˚ curve, switches, and stops. Straight Rail. The first overhead tubular rail component is the straight rail section. The straight rail section is made of high-strength metal tubing or piping. The straight rail section provides a smooth and continuous travel path surface. To minimize transfer of any metal dirt or rust from the metal rail to the GOH piece or to employees’ hands, a metal rail has a uniform zinc or galvanized exterior coating.


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Most overhead trolley tubular rail sections are manufactured to provide a minimum yield strength of 60,000 pounds per square inch and a minimum tensile strength of 75,000 pounds per square inch. The standard overhead straight rail measurements are inside pipe size (IPS), outside diameter (OD), wall thickness, metal gauge, and length. Standard tubular rail sections have the following measurements: • • • •

3 4

/ -inch IPS, 1 1/16-inch OD, a metal gauge of 14, a wall thickness of 0.083, and a rail length of 21 feet 1-inch IPS, 1 5/16-inch OD, a metal gauge of 14, a wall thickness of 0.083 and a rail length of 21 or 24 feet 1 1/4-inch IPS, 1 3/8-inch OD, a metal gauge of 14, a wall thickness of 0.083, and a rail length of 21 or 24 feet 1 1/2-inch IPS, 1 5/16-inch OD, a metal gauge of 12, a wall thickness of 0.109, and a rail length of 21 feet

The OD is the exterior pipe diameter. It matches the trolley-spool open space and the trolley travel path structural-support members. The manufacturer determines the tubular rail OD. The factors that determine OD are combined GOH piece and trolley load weight, trolley spool, and travel path support member. The tubular rail pipe gauge is determined by the manufacturer. The metal gauge is one of the factors that determines the weight capacity of the tubular rail. The weight of the trolley rail, plus the combined weight of the trolley and the GOH pieces, is supported by the structural-support members that are attached to the ceiling, wall, or floor. The factors that the manufacturer uses to determine metal gauge are the maximum number of heavy or light-weight GOH pieces per trolley and the number of trolleys per linear foot on the overhead tubular travel path. Pipe or Rail Insert. When a straight tubular rail is longer than one pipe section, or when a curved section must be connected to a straight section, an installation crew connects two straight sections to each other with a pipe insert. To connect the two pipe sections together, the pipe insert must match the IPS. To increase the length of the straight rail travel path at the lowest cost and in the least amount of time, a preinstalled pipe insert is often used. Travel Path Curves. Most nonpowered overhead trolley transportation systems avoid building obstacles and other transportation equipment by using curves (also called bends or turn rail sections). When your trolley travel-path design requires a curve, the curve radius should match the distance between trolley spool center lines. When this distance matches the curve radius, the trolleys can travel through the curve with minimal trolley hangups or jumping from the rail. When these problems occur on the trolley travel path curve, it results in low productivity and possible GOH damage. In a pushed or pulled trolley system, the travel speed for a straight tubular rail is faster than the speed though a curved section. Another curve consideration is the choice of a lower-degree curve or a higherdegree curve. Lower-degree curves have a lower coefficient of friction on the trolley



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spools as the trolley passes through the curve. This lower coefficient of friction on the trolley spools means less physical effort is required to push or pull the trolley or train of trolleys through a low-degree tubular rail curve. To ensure good transport productivity with minimal GOH damage, most overhead trolley rail travel path designs minimize the number of tubular rail curves or use low-degree tubular rail curves. Curve types include prebent curves and bent-in-the-field curves. During installation of a predesigned trolley travel path, most tubular rail manufacturers use prebent tubular rail curves. Based on travel path design and on-site survey, the tubular rail manufacturer determines the number of tubular rail curves that are required for the travel path. The prebent tubular rail curve is bent at the factory and sent to your facility for installation. The advantages are exact curve degree and a more economical curve. The bent-in-the-field curve is made on-site by the installation crew from a straight rail section. With most tubular rail manufacturers, field-bent curves are used when the tubular rail layout has few curves, when prebent curves were not shipped or were received in damaged condition, or when the rail must bypass an unexpected building obstacle that was not shown on the layout drawings. When compared to the cost of relocating a building obstacle or revising a travel path layout with prebent curves, the field-bent curve has a lower cost and maintains the project schedule. All trolley curves are manufactured from zinc or galvanized tubing or piping with a minimum tensile strength of 75,000 pounds per square inch. Most tubular rail curve sections have a 3/4- to 1-inch IPS and are manufactured from 14-gauge steel. Tubular rail curves are made in the following measurements: 23˚, 45˚, 68˚, 90˚, 90˚/90˚, and 180˚. 23˚ Curve. The 23˚ curve is a standard prebent curve that matches a 15/16-inch OD pipe with a 13-inch radius. The 23˚ curve is used with a straight section before a master switch, or to intersect at a 45˚ angle to a straight travel path. 45˚ Curve. The second tubular rail curve is the 45˚ curve with a straight section, which is used for auxiliary switches to intersect at a 90˚ angle. The standard OD pipe has a 13-inch radius. The standard 45˚ curve pipe has a 15-inch radius, corresponding to a 1 1/16- or 1 5/16-inch OD pipe. 68˚ Curve. The third overhead travel path curve is the 68˚ curve. The 68˚ curve pipe matches a 1 5/16-inch OD pipe with a radius of 13 inches. The 68˚ curve is used with one long straight rail section before a master switch, or to intersect at a 90˚ angle to a straight travel path. 90˚ Curve. The next tubular rail travel path curve is the 90˚ curve. On the planview drawing for a tubular rail travel path, the trolley enters a 90˚ curve from a straight rail section and exits the 90˚ curve onto a straight rail section. The standard OD sizes of a 90˚ curve pipe are 1 1/16 and 1 5/16 inches with a 15- to 24-inch radius, or 1 5/16 inches with a 36-inch radius. 90˚/90˚ Curve. The next tubular rail curve is the 90˚/90˚ curve. The 90˚/90˚ curve has two 90˚ curves. The 90˚/90˚ curve has a standard 15-inch radius and a pipe OD


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size of 1 1/16 to 1 5/16 inches. The entry and exit to the 90˚/90˚ curve have a straight tubular rail section that is 36, 42, or 48 inches long. The options are a straight tubular rail section between the two 90˚ curves, a trolley that enters and exits in the same direction, and a trolley that enters in one direction and exits in another direction. 180˚ Curve. The next tubular rail curve is the 180˚ curve. The 180˚ curve comes in the following measurements: • • • •

1 1/16- or 1 5/16-inch OD pipe size with a 12-inch radius and 24-inch long straight sections at the entry and exit 1 1/16- or 1 5/16-inch OD pipe size with a 13-inch radius and 27-inch long straight sections at the entry and exit 1 1/16- or 1 5/16-inch OD pipe size with a 15-inch radius and 30-inch long straight sections at the entry and exit 1 1/16- or 1 5/16-inch OD pipe size with a 24-inch radius and 48-inch long straight sections at the entry and exit

Switches and Stops. The next overhead trolley components are the switches and stops. Switches and stops on the tubular rail travel path function to permit continuous trolley travel on the rail, to switch from one travel path to another, and to stop trolley travel at a specific location on the travel path. Switches have a moveable pipe section that is moved by a spring-loaded device or by an operator. The trolley travel path switch permits an operator to move trolleys efficiently from one rail to another. Rails and switches permit a travel path to connect two workstations to each other. Spring Switch. The spring switch is a spring-loaded, automatic switch. The switch is activated by a trolley’s lead spool. As the trolley’s lead spool rides onto the switch, the trolley’s weight and forward movement forces the spring switch into the down position. After the trolley spool travels past the switch, the spring-loaded feature causes the switch to return to the up position. To complete trolley travel through the spring switch, the trolley’s rear spool performs the same action. Manual Switch. A manual or human-operated switch requires that an operator pull the switch down and move it up. A manual switch in the down position acts as a bridge. If not required to act as a bridge for a trolley, the switch is manually moved to the up position by an operator. Switches allow an operator to move a trolley from a main travel path to a branch or spur path and back to the main path. Other switches have a removable section that creates a passageway for personnel or vehicles to travel through the trolley travel path. In the up position, the manual switch serves as a stop device. Trolley traffic switches point left or right. With a left tubular-rail switch, as the trolley travels through the switch section it begins traveling to the left of the straight travel path. With a right tubular-rail switch, as the trolley travels through the switch section it begins traveling to the right of the straight travel path.



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FIGURE 4.9 Trolley stop and support drop. (From Railex Corporation, Queens, NY. With permission.)

Trolley Stops. Trolley stops (Figure 4.9) may be manually set or fixed. Stops prevent trolley travel beyond a specific point. Manually-adjustable stops are used along the trolley path. The fixed end stop is located at the end of the trolley travel path. Various Tubular Travel Path Switches and Stops. Non-powered trolley switches and stops include the following types: • • • • • • • • • • • • • •

Spring or automatic straight switch 45˚ lever or manual switch Two-way master switch Three-way master switch Manual cross-through switch Automatic or spring-loaded cross-through switch Hinged knife-elevator or fire-door switch Removable-rail section Parallel-stacking switch Overhead-door switch Fixed end stop Adjustable end stop Swing-rail stop Manually-adjustable rail stop

Spring or Automatic Straight Switch. The first trolley travel path switch is the spring or automatic straight switch. The spring straight switch is a spring-loaded switch on an overhead tubular travel path. A spring-loaded switch places the switch section of the travel path in the raised position. This is similar to a drawbridge in the raised position. In the lowered position, the switch spring has low pressure, which allows the switch section to act as a bridge. As a fully-loaded trolley approaches a spring-loaded switch, the spring-loaded switch is activated by the trolley’s weight and by its front spool. The trolley pushes the spring switch down, permitting an operator to push or pull the trolley from a branch travel path onto a curved section of the main travel path. As the fully-loaded trolley’s lead spool travels


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onto the straight spring switch, the trolley’s weight and forward movement force the spring switch downward onto the curve. Spring-loaded switches are designed with a slight elevation in the middle, and a mechanism that lowers the end of the switch onto the main travel path. A springloaded switch is designed, in other words, with a slightly higher middle section and a lower discharge section. At the discharge section, the spring-loaded switch has a slightly lower elevation and an angle-cut end. The spring-loaded switch’s angle-cut end acts as a trolley-flow or speed-control mechanism as the trolley travels across the switch. This angle-cut discharge end allows the spring-loaded switch rail to rest on the top of the curve section. This resting feature ensures a smooth trolley-spool flow from the spring-loaded switch section to the new travel path. There are other spring-loaded switch characteristics. In the down position, they allow one-way trolley travel through the switch. In the raised position — above the main travel path — they permit unobstructed trolley travel, allow smooth and even trolley travel from a switch to a main travel path, and require minimal operator effort to move trolleys over a travel path section. When a straight spring-loaded switch is in the manual position, the spring tension moves the switch rail to the up position. With the switch in the up position, trolley travel on the main travel path is under the raised switch section. 45˚ Lever or Manual Switch. The next trolley switch is the 45˚ curved-lever or manually-activated switch. The curved-lever switch serves as a bridge for the trolley from a branch or spur travel path to the main travel path. A manually-activated switch has a slightly higher middle section and a lower discharge end. Other design features include an operator handle that is attached to the underside of the switch. The handle allows an operator to pull the switch down to a bridge position for trolley travel onto another path. A self-locking mechanism keeps the switch lever in the lowered position. At the switch’s discharge end, a manually-activated curved switch has a slightly lower travel path elevation and an angle-cut end. The manuallyactivated switch acts as a trolley travel mechanism. The switch’s angle-cut discharge end allows the switch rail to rest on top of a main travel path curve. Manuallyactivated switches allow one trolley to travel through a switch, permit uninterrupted trolley travel on a main line when the switch is in the raised position, and ensure smooth and even trolley travel from the switch to the main travel path; but because an employee must walk to a switch and pull, manual switches also lower productivity to move a trolley over a travel path section. To engage a manually-activated curved-lever switch, the operator grasps the handle and pulls the switch lever down to the lowered position. A self-locking mechanism holds the switch in the lowered position, which allows a trolley to be pushed or pulled across the travel path bridge to a new travel path. When the lever switch is not in use, an employee pushes the switch up and it is locked in the up position. In the up position, a curved-lever switch permits free and clear trolley travel on the main travel path. Depending on trolley layout, the manufacturer may specify a 45˚ manuallyactivated curved-lever switch to direct trolley travel from the branch path to the main



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path. Trolley travel moves left or right from the intersection of the main path and the branch path. Two-Way Master Switch. The next switch is the two-way master switch. The twoway master switch is a manually-activated switch that permits trolley travel from a main path to a branch path or from a branch path to a main path. Two-way master switches permit trolley travel on the main travel path, or cause the trolley to exit to the right or left from the previous travel path. These switches minimize the risk of trolley derailment as the trolley passes through the master switch. The switch is self locking after it is set. The two-way master switch has a rail section that moves to the master switch’s left or right discharge end. A lever extends to the side of the aisle adjacent to the master switch and allows an operator to push or pull the master switch rail section in the desired direction. To ensure smooth trolley transfer from an entry rail section to a master switch, and from a master switch to the main travel path or a branch trolley travel path, all rail sections are square and are set at the same elevation above the floor. After an operator stops the trolley train on the entry path, he walks past the trolley train to the two-way master switch. To activate the two-way master switch from the aisle, the operator pushes or pulls the switch lever so that the switch is set in the desired position for transfer to the exit path. The exit path permits trolley travel on one of the branch lines to the right or left of the master switch. After the two-way master switch is set and locked in the desired position, the operator walks back to the last trolley on the trolley train and moves the train through the two-way master switch. Three-Way Master Switch. The next switch is the three-way master switch, another manually-operated switch. This switch permits trolley transfer from a branch travel path to the main travel path, from a branch travel path to another branch travel path, and from the main travel path to a branch travel path. The three-way switch has a rail section that moves its discharge end to the first or second branch travel path, or permits the trolley to continue travel on the main travel path. A switch lever extends outward into the adjacent personnel aisle. In this aisle, an operator sets the three-way master switch in the desired direction to provide smooth and even trolley transfer through the three-way master switch to the branch travel path or to the main travel path. All travel path entry and exit rails and the master switch rail are square, and all travel path and switch rails are set at the same elevation above the floor. After an operator stops the trolley train’s movement on the entry path, he or she walks past the trolley train to the three-way master switch. To activate the threeway master switch from the aisle, the operator pushes or pulls the lever on the master switch. This action ensures that the switch is set in the desired position for trolley transfer to the exit path. This permits the trolley to travel on one of the branch lines that are to the right or left of the master switch, or to continue travel on the main path. After the master switch is set in the desired position, it locks itself. An operator walks back to the last trolley in the queued trolley train and moves the trolley train through the three-way master switch.


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Manual Cross-Through Switch. The manual cross-through switch is the next nonpowered overhead trolley switch. The manual cross-through switch allows trolley travel through two separate trolley travel paths that intersect at right angles. The manual cross-through switch has a lever that is connected to a rail section. At the entry to the cross-through switch, the tubular trolley rail and exit rail sections are square, and all trolley rails and switches are set at the same elevation above the floor. These rail features ensure smooth and even trolley travel from the entry rail through the cross-through switch and onto the exit rail. The cross-through switch is basically a large X that can rotate and intersect with the required exit path at a right angle. When the cross-through switch is placed in the required position, it is locked in position. Locking the switch reduces trolley derailment. Trolley derailment means that as the trolley travels through the switch, the trolley can jump or fall from the rail. After stopping the trolley train on the main path, an operator walks past the queued trolleys to the cross-through switch. To activate the cross-through switch, the operator moves the hand lever, rotating the cross-through switch rail to the proper orientation for trolley travel. After the switch is set, the employee walks back to the queued trolleys and pushes or pulls the trolley train through the cross-through switch. Automatic or Spring-Loaded Cross-Through Switch. The next switch is the spring-loaded cross-through switch. This switch allows the operator to push or pull trolleys through it and onto the next travel path without setting the switch. The spring-loaded cross-through switch is considered a one-way switch and is activated by a fully-loaded trolley’s lead spool. When an employee pushes or pulls the trolley onto a spring-loaded switch, the trolley’s load weight and forward movement cause the switch to descend onto the next travel path. The switch becomes a bridge that connects two travel paths. The spring-loaded cross-through switch consists of a spring-loaded bridge and rail section with square ends and a take-away trolley rail, which also has a square end. Hinged-Knife Elevator or Fire-Door Switch. The hinged-knife elevator or firedoor switch is the first of several special-purpose switches. The standard hingedknife switch length is 32 inches. One end is connected to the trolley travel path lead, and the other end has a break-away connection. As an elevator or fire door moves, it comes in contact with the hinged-knife switch. The fire door’s forward movement puts force on the switch, causing the break-away end to move and creating an open space in the straight travel path. The hinged-knife switch is an automatic switch that is activated by the movement of an elevator or fire door. A hinged-knife switch near a fire door or elevator door means that the trolley path runs through a fire wall or another building passageway. During a fire, the passageway or door is closed to prevent fire expansion. When the passageway door is not activated, the hinged-knife switch is a mainpath, straight-rail section that allows trolleys to pass through the open doorway. If the fire door moves, it seals the passageway. The broken locking mechanism allows the hinged-knife section to move away from the main travel path. This movement of the hinged-knife section creates an opening in the main travel path and the fire door closes the passageway.



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When designing the hinged-knife section at a fire-wall passageway, ensure that the hinged-knife switch swings in the proper outward direction and allows the fire door to close the passageway. Also note that the hinged-knife switch should be located at the entrance to the fire wall. In this location, the hinged-knife section can swing outward in response to the movement of the fire door. An activated hingedknife section acts as a trolley stop prior to an opening on the main travel path. Removable-Rail Section. The removable rail section or bar is the second speciallydesigned switch. The removable-rail switch has a standard length of 24 or 32 inches. When an operator activates the removable-rail switch, it creates an open space in the trolley travel path. This permits an operator or vehicle to move through the travel path. The removable-rail switch has a straight-rail section with two angled ends; each end is equipped with a locking device. When a personnel or mobile-vehicle passageway must be opened up in the trolley travel path, an operator lifts up on the removable-rail switch. This disengages the locks and allows the operator to remove the switch rail from the main trolley path. With this section removed from the path, a 24- or 32-inch open space is created between two main-path sections. This opening in the trolley travel path is sufficiently wide for most personnel or mobile vehicle masts to pass through it. After the operator or mobile vehicle has passed through the opening in the travel path, an operator replaces and secures the removable-rail switch in the opening, and locks the switch to the two sections of the travel path. When the removable switch is secured in the proper position on the main travel path, it becomes a travel-path section, and trolley travel continues over the main path. To ensure minimal trolley and GOH damage, the travel path has an adjustable trolley stop that is located before the removable switch on the main travel path’s lead side. An operator sets the adjustable trolley stop prior to removing the switch. In the down position, trolleys queue at the stop instead of moving forward on the travel path into the rail opening and falling from the path. After resetting the removable switch, the operator deactivates the adjustable trolley stop by moving it to the up position. In the up position, the travel path is free and clear for trolley travel across the removable-rail section. Parallel-Stacking Switch. The parallel-stacking switch is another speciallydesigned automatic switch. A parallel-stacking switch is used to store empty trolleys. The parallel-stacking switch has a specially-designed teeter-totter rail section and two parallel travel-path sections. The teeter-totter rail section is attached in the middle to a structural-support member at an elevation that is slightly above the two parallel rails. When an operator moves an empty trolley across the teeter-totter section, the teeter-totter device and the rail’s elevation causes the rail section’s charge end to raise upward, and causes the trolley’s rear spools to move onto a sloped and curved trolley-rail section. As the trolley moves over the stacking switch, each trolley spool travels a different parallel-rail section. The teeter-totter rail section’s front and rear ends are angled. The front end’s angle permits the section to nest over the main trolley path. The rear end’s angle permits the section to nest over the parallel-rail travel path. These rail ends are halfcut, and have a guide pin that is inserted into the take-away rail. These features ensure that the teeter-totter rail section accurately nests over the other rail section.


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A teeter-totter rail section’s length is determined by the center-to-center distance between a trolley’s spools. The stacking switch’s next components are the two parallel-rail paths, which are standard trolley rails. One parallel-rail section has a curve and slope change at the charge end. This slope change is downward. The second parallel-rail section is at the discharge end of the teeter-totter section. To ensure empty-trolley travel on the stacking switch, the two parallel rails have an elevation change between the charge end and the discharge end. To operate the parallel-stacking switch, an employee pushes or pulls an empty trolley to the entrance of the switch. At the entrance, the operator ensures that the trolley’s front spool travels over the stacking switch’s middle section. The trolley’s weight and forward movement causes the lead end rail of the teeter-totter to rise up above the main travel path. The height of the teeter-totter rail section above the main travel path should be sufficient to allow the trolley’s rear spool to continue traveling on the main travel path. As the rear trolley spool travels on the main travel path, the path slopes and curves slightly, taking the rear trolley spool onto a separate trolleystacking switch rail. The trolley’s front spool travels forward on the teeter-totter switch and onto a separate rail (the parallel rail). When an employee has moved a trolley through the parallel stacking switch, there will be one trolley spool on each of the parallel rails. To ensure the maximum empty-trolley queue, the rails are sloped downward from the charge end to the discharge end. If there is excessive pressure from queued trolley spools pressing against each other on the two parallel rails, an employee has the difficult task of removing an empty trolley from the parallel-stacking switch. In this situation, an adjustment is made to the slope of the parallel rail. When empty trolleys queue on a parallel-stacking switch, their length is the length of the trolley head. With a standard trolley length of 36 inches and a standard trolley-head length of 3 to 4 inches, storing an empty trolley saves 32 inches of space. Overhead-Door Switch. The next switch is the overhead-door switch. The standard overhead-door switch is 10 feet long and is an automatic switch. The overhead-door switch is moved by a door’s downward movement and weight. The door’s weight and movement applied to the switch creates a open space in the trolley travel path. The overhead-door switch has a lever arm. The lever arm is attached to the main travel path and extends upward, parallel to the main travel path. The lever’s other end extends at an angle below the main travel path. A chain is attached to this end of the lever arm. When the overhead-door switch is on the lead side of the main travel path, as the lever arm is activated it acts as an adjustable stop. The lever halts trolley travel on the main travel path and reduces any potential trolley and GOH damage. The chain is attached very tightly to the lever arm and to a sliding pin hook. A section of the trolley travel path has a sliding pin with a chain attachment device and a pivoting mechanism. As the overhead door moves in the downward direction, the door’s movement and weight forces the lever arm downward. This causes the chain to pull the sliding pin backward. This pin moves outward and away from the trolley travel path. Since the pin is not inserted into the first section of the trolley travel path, the chain’s



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movement forces the section’s pivoting side to move downward and away from the main path. This specially-designed rail section’s movement creates an opening in the main path for the overhead door to pass through as the door moves toward the surface of the finished floor. When not activated, the sliding pin extends outward into the main path. To ensure that pin connection is correct, this section of the main rail is designed to hold the pin. Trolley Stops. The next nonpowered overhead trolley devices are the fixed end stop, the adjustable end stop, the swing-rail stop, and the manually-adjustable rail stop. An end stop is used at the end of the travel path that feeds a workstation, or at the location where the trolley has completed its travel on the overhead trolley system. The end stop is a device that halts trolley travel on a main or branch travel path. The other trolleys on the travel path queue against the stopped trolley. The adjustable trolley stop is a hardened metal plate that extends downward; its end extends above the trolley travel path. The portion of the end stop above the trolley path comes in contact with the trolley’s lead head. Fixed End Stop. The first end stop is a hardened metal device that has an L shape. This device consists of a hardened metal plate that makes up the stem of the L and a travel-path pipe insert that is the base of the L. The diameter of the rail insert is slightly less than the interior diameter of the travel rail. This allows an employee to insert the end stop into the end of the trolley travel path. The hardened metal plate is 2 to 3 inches above the TOR. A Tek screw is inserted through a hole in the plate and into the bottom of the trolley travel path. The Tek screw is inserted in the underside of the travel path. In this position, the Tek screw does not interfere with the trolley spool rolling on the travel path, and it secures the end stop to the travel path. Usually the end stop is painted red. Adjustable End Stop. The second stop is the adjustable end stop. The adjustable end stop can be located anywhere along the main travel path and near a structuralsupport member. The end stop’s metal member has sufficient depth to come in contact with a trolley’s lead head as the trolley travels over the travel path. The other end of the trolley’s adjustable stop is connected to structural-support member on the travel path. Swing-Rail Stop. The swing-rail stop is the next stop device. The swing-rail stop allows the trolley to travel in one direction over the main travel path. The swingrail stop is a hardened metal, coated member that extends downward from a J-hook above the travel path. The height of the stop above the travel path is sufficient to ensure that the trolley’s front head comes in contact with the hardened metal plate. As the trolley moves forward on the travel path, the swing stop moves upward over the trolley’s front and rear heads. This allows the trolley to travel past the swing stop. The swing-rail stop is a flipper that moves in one direction. When the trolley on the overhead rail travels in the proper direction, the trolley heads strike the swing flipper. As the trolley’s front head strikes the swing stop, the swing stop flips upward and rides along the top of the trolley and over the trolley’s rear head. This flipping action permits trolleys to travel on the main rail and through the swing stop.


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When an employee moves a trolley in the wrong direction on the main rail, the trolley’s rear head strikes the flipper’s metal extension and forces the swing stop to come in contact with the J-hook. The J-hook stops the flipper, and the flipper halts trolley travel. Manually-Adjustable Rail Stop. The manually-adjustable rail stop is the last stop device. The manually-adjustable rail stop is a J-hook rail support member with an attached lever. The lever moves up (the deactivated position) and down (the activated position). The lever’s length permits an operator to control the position of the adjustable stop. The adjustable-stop attachment method and the lever’s length permit one end of the lever to become a barrier in the travel path. When an operator activates a stop, the stop halts all trolley travel on a travel path. To set a manually-adjustable rail stop to the active position, an operator pushes upward on the lever’s outside end. This causes the other part of the lever to fall across the trolley travel path. With the lever in this position, all trolleys on the travel path queue against the stop. To deactivate a manually-adjustable stop, the operator pulls downward on the lever’s outside end. This causes the other end of the lever to rise above the travel path. The deactivated lever is high enough above the travel rail to allow the trolley to travel below the rail stop. Support Structure and Structural Members The next components in an overhead trolley system are the structural members. The trolley travel path and support structure are designed by the manufacturer. The travelpath structure is designed to handle the combined weight of the trolley and the maximum number of GOH pieces. The support structure may be attached to the floor or the ceiling. Floor-Supported Method. Floor support is a very common support method because most buildings have a 20-foot-high ceiling, and the top of the trolley travel path is typically 6 feet, 4 inches above the floor. This means that there is open space between the overhead structural-support members and the ceiling; and ceilings in some buildings are not designed to carry the total load weight of structural-support members, trolleys, and GOH pieces. The floor-supported method consists of upright frames (posts or pipes) that are placed every 10 to 20 feet along the floor. These upright frames have cross clamps and pipes that make the structure sturdy and rigid. Frames are secured to the floor and support the overhead-trolley travel path. This creates open aisle on the floor between the upright posts and under the overhead travel path. The components of a floor-supported structure are floor sets or clamps, upright posts, frames or pipes, tubular joist frames, pipe clamps, braces and cross members, pipe inserts, J-hook rail supports, and Tek screws. Floor Set or Clamp. The first component is the floor set or clamp. Based on the load weight of a fully-loaded trolley and the facility’s seismic location, your manufacturer determines the appropriate floor-set type. The floor set ensures stability and rigidity in the upright posts. Floor sets anchor to the floor.



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Types of floor sets include an anchor bolt with a washer and wooden bushing, a flange and nipple with one hole, a flange and nipple with two holes, and a dish base. Anchor Bolt with a Washer. The anchor bolt with a washer and wooden bushing is the first type of floor set. This type features an anchor bolt that is drilled into the floor. The anchor bolt extends 1/2 to 1 inch above the floor; a large washer and wooden bushing are placed over the bolt. The washer spreads the weight of structural members and trolleys over a wider surface. After the upright post is placed over the wooden bushing, the wooden bushing reduces the movement of the upright post along the floor. This type of floor set is inexpensive and easy to install. It handles a light load weight. The upright post cannot withstand abuse or accidental impact. The post will move easily if it is hit by a moving vehicle, thereby jeopardizing the overhead travel path. Flange and Nipple with One Hole. The second floor set is the flange and nipple with one hole. This floor set has a large washer with one punched hole and a welded 1- to 2-inch high nipple or pipe. After the flange is set in the proper floor location, an anchor bolt is driven through the hole into the floor, or the anchor bolt can be driven into the floor first and the anchor set placed onto the bolt and secured with a nut. After the anchor set is secured to the floor, the upright post is set inside or around the nipple. This secures the upright post; the flange spreads out the total load weight of the overhead trolley. The disadvantage is that this type of floor set is more expensive. The advantages are that it handles a low-to-medium load weight and is better able to withstand abuse or accidental impact. Flange and Nipple with Two Holes. The third floor set is the flange and nipple with two holes. This set is very similar to the previous set, with the exception that the flange has two holes in its surface. This makes it easier to create a crisscross anchor pattern and, if required, to use two anchors per floor set. This anchor pattern improves stability and rigidity. Dish Base. The last floor set is the dish base. The dish base has a preformed base plate with punched holes and a post that extends upward. The post is welded onto the dish in the middle, and the dish has two secure bolts that anchor it to the floor. To reduce rusting, the dish is covered with a coating or paint. After the dish base is set on the floor, it resembles a dish that is turned over, with the high point in the middle. Anchor holes are drilled in the dish’s four corners. These are placed over the anchor bolts, securing the dish base to the floor. The dish is 20 to 22 inches square and has a 28-inch diagonal. The dish base spreads the load over a wider surface than other floor sets. With the dish base secured to the finished floor, the upright post is set inside the pipe extension in the middle of the dish. Bolts are tightened onto the upright post to keep it rigid and straight. The dish base is the most expensive floor set. It supports a heavier load and withstands accidental impact.


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POWERED HORIZONTAL TRANSPORTATION GROUP The next horizontal GOH transportation group has a travel path that is driven by an electric motor. The motor moves a trolley or an individual GOH piece over the travel path. The powered horizontal transportation group includes: • • •

Powered chain with pusher dogs and overhead path Powered screw conveyor Trolleyless method

Powered Chain with Pusher Dogs and Overhead Path The first powered horizontal transportation method employs a powered chain with pusher dogs (or pendants) and a trolley on an overhead travel path. This method is used in many GOH operations with long transport distances. After a code is entered on the trolley, the pusher dogs move the trolley along the travel path to the assigned address. At the assigned address, the transport controls divert the trolley from the main path onto a nonpowered spur, and the trolleys queue for later disposition. The components used in this method are a powered chain with pusher dogs, a powered-chain travel path and a trolley travel path, a trolley in-feed station, a nonpowered travel path, protection for the powered-chain and trolley travel paths, trolley divert devices and branch rails, and trolley and powered-chain stop/start controls. Trolley types include a trolley on a tubular rail, a trolley on an inverted-V barstock travel path, a trolley on a C-channel travel path, and a trolley on a strut travel path. Trolley on a Tubular Rail The first trolley type is the trolley that rides on a tubular rail. The tubular rail diameter matches that of the trolley spools. During trolley travel over the tubular rail, the four trolley spools ride on the tubular rail. Trolley on an Inverted-V Bar-Stock Travel Path The second trolley type is a trolley that travels on an inverted-V (or angle-iron) travel path. An inverted-V travel path requires a trolley with two sets of wheels. Each wheel’s flat surface is set at an angle and rides on the inverted-V travel path. Trolley on a C-Channel Travel Path The third trolley type is the trolley that travels in a C-channel travel path, which consists of two flat sections. The two flat sections are on the two sides of the C-channel and face toward the floor. The four trolley wheels ride on these two flat surfaces. Trolley on a Strut Travel Path The fourth trolley type is the strut trolley. The strut travel path is a metal piece with a middle crease that extends 1/8 inch above the base. The trolley has two wheels that have a deep, sharp, and concave shape. The trolley wheels ride on the middle crease of the travel path.



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Powered Chain, Chain Travel Path, and Pusher Dogs The transportation method that employs a powered chain with pusher dogs and a trolley travel path can also consist of a powered chain, a drive unit and take-up device, a powered-chain travel path with diverts, and soft and hard pusher dogs. Powered Chain. This method’s first component is the powered chain. The powered chain is a closed loop of chain links that is threaded through a C-channel, over a take-up device, and over a motor drive sprocket and other devices. The powered chain receives its power from an electric motor that runs through a drive unit. The drive unit is powered by an electric direct-current (DC) motor and provides the force to pull the chain through the C-channel. At predetermined points, links of the powered chain are attached to pusher dogs. These pusher dogs extend downward and push a GOH trolley over the trolley travel path. The powered chain is the main component in this transportation method. The powered chain has hardened metal links with two wheel sets. The wheel sets are staggered, with one set facing the C-channel’s interior sides and the second set facing the C-channel’s upper and lower interior. Each wheel has an axle and a bearing. The C-channel is the travel path for the wheels on the powered chain. Dual wheel sets ensure straight chain travel through the C-channel and provide a travel surface that has a low coefficient of friction as the chain moves through the C-channel. Other powered chain designs include one wheel set inside the link, two wheels on the outside of the link, and a pusher-dog link. Chain links are connected every five to six inches. The two link types are the center wheel link and the outside wheel link. The center wheel link has two outer wheels with a diameter of 2 1/4 inches, and two side links. The outside wheel link has two wheels with a diameter of 2 1/8 inches; the wheels are attached to the two side-wheel links. All chain links are connected with a connecting pin, which provides the chain with the necessary flexibility to travel through a curve or over an elevation change. Every five to six feet, a hard or soft pusher dog is attached to a link. The pusher dog extends downward through the C-channel’s bottom opening. During operation, the powered-chain pendant extension and the pusher dog have sufficient length to engage a trolley’s front head. When a pusher dog engages a trolley’s front head, the trolley is moved forward over the travel path. The chain is threaded through the C-channel travel path, through the motordriven sprocket, through a take-up device, and around horizontal or vertical curves. After the chain has been pulled through the C-channel travel path, the chain’s two ends are connected together to form an endless loop. The soft and hard pusher dogs extend downward through the C-channel. Drive Motor and Tooth Sprocket. The next components are the electric DC motor, the drive, and the chain sprocket. The electric motor provides power to the drive train or caterpillar drive unit. The caterpillar drive unit is on a powered-chain travel path. The chain sprocket’s drive teeth engage the openings in the poweredchain links. The drive teeth are attached to the chain sprocket; they extend outward


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and are spaced to fall between the powered-chain link openings. The chain sprocket’s drive tooth has sufficient depth to pull the chain forward through the travel path. The DC motor, caterpillar drive, and chain sprocket are located at the highest elevation on the powered-chain travel path. This location results in the least slack, ensuring proper interface between the chain sprocket and the powered-trolley chain link. The caterpillar drive unit and the sprocket pull the powered chain at 60 feet per minute through the C-channel track and move a trolley over the travel path. The size of the drive motor is determined by the powered chain and the travel path. The manufacturer figures in the number and type of horizontal curves, the number and type of vertical bends, the dimensions of the straight travel path, and the maximum number of GOH trolleys on a travel path. With these design data, the manufacturer calculates the chain-pull data and motor-power requirements. Along the powered-chain travel path is a trolley-chain lubricator. The lubricator is a track section, approximately 1 foot long, that has two nozzles. One nozzle is for air pressure and the second is for the lubricant. The two nozzles spray a mist onto the powered chain as it passes the lubricator station. Proper chain lubrication reduces the coefficient of friction, increases the life of the powered chain, and reduces maintenance problems. Take-Up Device. The next powered-chain component is the take-up device. The take-up device is basically a 180˚ turn. From its original location, the device can move up to 16 inches forward or to the rear. Proper adjustment of the take-up device ensures proper powered-chain tension. The take-up device’s forward movement eliminates a slack chain condition. If the chain take-up device is moved to the rear, the device reduces tension on the powered chain. The chain take-up device is a required component due to powered-chain wear and tear and change in environmental conditions. Environmental conditions and normal wear and tear over time cause the powered chain to stretch and develop slack. The take-up device is located at the lowest elevation on the travel path. Usually, the lowest elevation comes immediately after the drive unit and sprocket location. At this elevation, the underside of the powered chain requires a wire mesh or solid guard. Take-up devices may be manual or automatic. Automatic types include spring, air cylinder, and counterweight. Manual or Screw Take-Up Device. The first take-up device is the manual or screw take-up device. A maintenance employee adjusts the screw device to move the 180˚ curve forward or backward, in order to correct a slack or tense powered chain. Spring Take-Up Device. This is the first automatic take-up device. With a spring take-up device, tension on the powered chain keeps the take-up device at the proper location and ensures proper chain condition. Air-Operated Take-Up Device. The air-operated take-up device is an automatic take-up device. An air compressor provides air to the device, which extends or retracts the 180˚ curve to ensure proper chain condition.



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Counterweight Take-Up Device. The last take-up device is a counterweight takeup device, which is also an automatic take-up device. With cables and weights, the counterweight take-up device applies constant tension to the 180˚ curve. The counterweights are available in 25-pound increments to match the chain requirements. Soft Pusher Dog and Trolley Queue. The soft pusher dog is a stiff rubber pad that is attached to a powered chain’s hardened metal pendant. The stiff rubber pad extends downward, toward the floor, to engage a trolley’s front head, and has sufficient strength to push a trolley over the horizontal travel path. When trolleys are queued on the horizontal travel path, the stiff rubber must have the flexibility to slide over the trolley heads. Hard Pusher Dog and Trolley Queue. The hard pusher dog is a hardened metal plate that is attached to a powered chain’s hardened metal pendant. The hardened metal pendant has sufficient strength and elevation above the floor to engage a trolley’s front head and to push the trolley over a horizontal or vertical travel path. When trolleys are queued on the horizontal travel path, a hard pusher dog is not flexible enough to slide over the trolley heads. At trolley queue sections, the travel path is set at a lower elevation. This lowers the trolley heads and permits the pusher dogs to continue moving forward without engaging a trolley head. C-Channel or Enclosed-Track Section. The C-channel or chain track (Figure 4.10) is manufactured from nine-gauge metal that has a rectangular shape. The C-channel has two solid sides, a solid top, and an open bottom. The opening in the bottom is 7/8 inch wide. The C-channel’s top-to-bottom span is 2 11/16 inches, and the side span is 2 9/16 inches. C-channel track is available in 10- and 20-foot straight sections, 15˚ to 180˚ horizontal curves, and vertical bends.

FIGURE 4.10 GOH track detail. (From Railex Corporation, Queens, NY. With permission.)


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The C-channel travel path is available in 10- and 20-foot lengths. Two Cchannel track sections connected together provide a safe and secure powered-chain travel path that reduces employee injury and GOH damage. The interior bottom has a low coefficient of friction; there is a hard, smooth, and continuous surface for the wheels. The exterior surface is identified with a color code for a particular operational function. Horizontal curves and vertical bends are similar to straight track sections; their interiors are lined with wear bars made of hardened metal. As the powered chain is pulled through the C-channel, its wheels come in contact with the wear bar. The wear bar resists wear, minimizes the coefficient of friction, and increases wheel and track life. Overhead transportation professionals prefer to use the largest standard curve radius, because the largest radius increases chain life. Design factors include the center distance between two pendants and the open space between two trolleys. Other C-channel track components include a track hanger with attachment brackets, an end yoke, sway braces, hanger rods, splice fixtures, a track removal station, a chain inspection station, and expansion sections. The first component is the track hanger with attachment brackets. The hanger bracket is a 1/4-inch thick metal component that is used to connect the C-channel track section to the structural-support member. The bracket types are a U bracket and a flanged bracket. The U bracket is used on horizontal turns and vertical bends, and to support the C-channel track at splice points and at other intermediate locations. The bracket is in the shape of a U, the two sides of which straddle the exterior track section. At these locations, the hanger bracket is welded to the C-channel track section. Other U-bracket features are drilled holes in the top for thread-rod attachment and a 2inch open space between the base of the U and C-channel track. The second C-channel bracket is the flanged bracket. The flanged bracket is very similar to the U bracket. It has drilled top holes for hanger-rod attachment and is made of 1/4-inch thick metal. The flanged bracket slips onto the track section and is used to suspend the C-channel track at welded-splice or intermediate locations. The next C-channel component is the die-cut hanger yoke. The hanger yoke is 3/8 inch thick and is welded to the end of the track at locations where there is a removable splice section. Depending on the manufacturer’s installation standards, hanger yokes are used at various intermediate points to support the track. The hanger yoke straddles a track section and is welded to secure the hanger yoke to the track. Drilled holes connect two spliced track sections. At the track take-out station, the die-cut hanger yoke is part of the two track sections. This feature permits removal of the C-channel’s take-out section from the track. This removed track section exposes the chain and permits the maintenance crew to observe chain travel over the C-channel. The next part of a C-channel is the sway brace. A sway brace is a 1/4-inch thick metal bracket that is 1 3/4 inches wide and 3 1/16 inches long. Single and double sway braces are available. The single sway brace has a flat top with an extension to one side that is at a 45˚ angle. The top section has drilled holes for attachment to the



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track. The single sway brace is used with the U or flanged bracket, and is placed on the bracket’s top surface. The double sway brace is very similar to the single sway brace, except that the double sway brace has two 45˚ sections and a longer top surface. The double sway brace’s angled sections and top sections have drilled holes for threaded-rod attachment. The next component of a C-channel is the threaded rod. Threaded rods are available in standard 12-foot lengths. Threaded rods are used to connect the Cchannel track to the diagonal sway brace. Four full hex nuts are required to secure the rod to the structural-support member and to the C-channel track. The installation crew cuts the thread rod to the required length, based on the layout. The next C-channel component is the spliced-track weld fixture. The splicedtrack weld fixture is used to weld two track sections together. The weld fixture comes in two types, a 4-inch fixture and a 14-inch fixture. The 14-inch weld fixture is used to weld two standard straight-track sections together and to weld a curved section to two straight 12-inch sections (an entry section and an exit section). The 4-inch weld fixture is used to connect two straight-track sections together and to weld entry and exit sections to a curved section when the straight sections are less than 12 inches long. To ensure a smooth splice joint, clamps are used. The next C-channel component is the track take-out section. The track take-out section permits maintenance to add or remove links from the powered chain. During operation, wear and warm weather cause the powered chain’s length to increase. Cold weather causes the chain to tighten or decrease in length. Maintenance removes the four bolts and nuts on the hanger yoke, the C-channel section, and the take-out section to expose the powered chain. This permits access for repairs. The take-out section is approximately 2 feet long and has a split hanger yoke at each end. When the take-out section is open at the top and bottom, maintenance can access the powered chain. The main track sections have normal hanger yoke devices. A powered-chain C-channel track has one take-out section in its travel path. Most manufacturers place the take-out section in a location that is past the take-up device. This location is preferred because it causes less chain tension. The next special section is the chain-track inspection station. The chain-track inspection station is a 2-foot-long track section that has a standard splice-bracket hanger yoke at both ends. The straight C-channel track’s top section has a removable cover that is attached with four bolts and four nuts. Maintenance removes the cover to inspect the chain as it is moving along the travel path. The next section is the track expansion joint. The track expansion joint is used on a straight enclosed track and permits 1-inch adjustment to the C-channel. Divert Devices and Full-Line and Partial-Line Sensors. The next powered chain and trolley components are the trolley divert devices, full-line sensors, and partialline sensors. The trolley divert device is an air-operated mechanical device on the main travel path. After a programmed trolley travels past a code reading device on the main travel path, the code reader sends a message to a microcomputer. The microcomputer sends a message that activates the divert device, which diverts the trolley from the main travel path. To divert the programmed trolley to the required nonpowered spur, the divert device swings outward into the travel path. This causes the divert-device section


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to connect with the spur. This connection permits the trolley’s front spools to travel from the main travel path over the divert travel path and onto the spur. The components of a divert device are the programmable trolley, the code reader, the divert mechanism, and the spur travel path. Programmable Trolley. The first component is the programmable trolley. The programmable trolley is a GOH trolley with a hang bar and a programmable trolley neck. This nonpowered trolley has different head and neck characteristics and should not be used on a powered trolley. The trolley components are a hang bar with antislide pins, front and rear heads with spools, and front and rear necks. With a programmable trolley, the spool surface that faces in the direction of travel is slightly larger, and the trolley neck has sufficient space for attaching the code reader. These components are similar to the components of a nonpowered trolley. (We refer the reader to the nonpowered trolley section in this chapter.) The second programmable-trolley component is the code reader. The code reader is located on the trolley’s front neck. At the in-feed station, the code reader allows the dispatcher to encode the trolley’s delivery destination. After a trolley code is set, the trolley is transferred from the nonpowered travel path to the powered-chain travel path. The powered chain pulls the trolley over the main travel path. The code is read by the code reader prior to reaching the divert location. After reading the trolley code, the code reader sends the trolley identification to a microcomputer. The microcomputer activates the appropriate divert device, which diverts the trolley from the main travel path to the assigned nonpowered spur travel path. The trolley coding methods are (1) sliding pins or tabs, (2) sliding photoreflective tabs, and (3) bar code labels. Sliding Pins or Tabs. The first coding method uses sliding pins or tabs. A sliding pin is attached to the trolley’s lead neck. The sliding pin consists of an index, a metal extension, and a pin reader that runs along the main travel path. There may be one, two, or three sliding pins. Selection is determined by the number of divert locations along the travel path. The index has numeric or alphabetic character settings with a range from A to I or 0 to 9. Most trolleys use the numeric settings. The digits are printed on the face of the index and identify the numbers that can be set on the pendant. Each pin setting has an indentation on the metal face that keeps the sliding pin in its proper setting. If the GOH operation has an alphabetic identification system, alphabetic characters replace the numbers on the index face. In a single sliding-pin identification system, a metal pin extends out beyond the index face of the pendant. The metal pin moves upward or downward along the index face. When the metal pin is moved to the proper pin setting, the trolley is ready for transfer from the nonpowered travel path to the powered-chain-and-trolley travel path. On the latter path, the metal pin allows the code reader to read the trolley delivery location or pin setting on the index. The single sliding-pin system provides the trolley transport with nine different divert locations. The double sliding-pin system has two sliding pins and two series of indexes. Each pin-and-index pair has numbers that range from 0 to 9. This



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provides for 99 different divert locations. Most dynamic GOH operations use the double-pin system. A double-pin trolley neck is wider than a single-pin trolley neck. The three-pin system has three sliding pins and three indexes. Each pin-andindex pair has numbers that range from 0 to 9. This combination provides 999 different divert locations. The three sliding-pin trolley has the widest trolley neck. After receiving trolley dispatch instructions, an operator moves the sliding pin or pins upward or downward to the appropriate number. This number appears on the trolley pendant’s index face, and matches the number that appears on the trolleydelivery instruction form. After the operator transfers the programmed trolley onto the powered travel path, a pusher dog pulls the trolley forward over the travel path. As the trolley travels over the path, a code reader reads the trolley’s sliding-pin setting and communicates the information to a microcomputer. The microcomputer activates the appropriate divert device, which swings from the main travel path in the appropriate direction. With the divert device in position, the trolley moves from the powered-chain travel path onto a nonpowered spur. Sliding Photo-Reflective Tabs. The second code-setting method is the sliding photo-reflective tab. The components of this tab are an index on the trolley’s front neck, a photo-reflective tab or tabs on the end of the sliding pin, and a code reader along the main travel path. There may be one, two, or three tabs. The photo-reflective tab has a numeric or alphabetic character setting that has a range from A to I or 0 to 9. Most trolley systems use the 0 to 9 settings. The digits are printed on the index face; they identify the numbers that are set on the pendant. Each setting has an indentation on the metal face that keeps the sliding photoreflective tab in its proper setting. If your order-fulfillment operation has an alphabetic identification system, the alphabetic characters replace the numbers on the index face. In a single-tab identification system, a metal tab covered with a photo-reflective material extends outward from the index face. The tab moves up and down along the index face. When the metal pin is moved to the proper settings, the trolley is ready for transfer from the nonpowered travel path to the powered-chain travel path. The photo-reflective material on the tab’s end permits the code reader to read the trolley’s delivery location (the setting on the index). This method provides your trolley travel transport method with nine divert locations. The double-tab method uses two sliding photo-reflective tabs and two index series. Each tab-and-index pair has numbers that range from 0 to 9. This double set or numbers provides 99 different divert locations. Most dynamic GOH operations use the double-tab setting. The trolley neck in a double-tab system is wider than that of a single-tab system. The three-tab method uses three sliding photo-reflective tabs and three indexes. Each pair has numbers from 0 to 9. This combination provides 999 different divert locations. The trolley has the widest trolley neck. After receiving instructions to set the trolley delivery code with a sliding photoreflective tab, an employee moves the tab upward or downward to the appropriate


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number. This number appears on the index face and matches the number that appears on the trolley-delivery instruction form. After the operator transfers the programmed trolley onto the powered-chain travel path, a powered-chain pusher dog pulls the trolley forward over the trolley travel path. As the trolley travels over the travel path, a code reader reads the tab setting and communicates the information to a microcomputer. The microcomputer activates the appropriate divert device, which swings from the main the trolley travel path in the divert direction. With the divert device in this position, the trolley moves from the powered-chain travel path to a nonpowered spur. Bar Codes. The third code-setting method is the bar code method. Its components are a bar code label, a trolley’s lead neck or front piece hanger, and a bar-code reader or readers. Each bar code represent a delivery location. Most companies print the associated code on the label face. This human-readable code allows the operator to determine the trolley delivery location. When a problem occurs with the bar code system, the transport system can be operated with the help of the readable code and a handheld scanner. The trolley’s lead neck must have a flat surface for attaching the bar code label. After the bar code label is printed, it is placed onto the flat surface on the trolley’s front neck. In some operations the label is affixed directly to the neck; in others the label is inserted into a sleeve on the trolley’s neck. With the bar code on the trolley, the trolley is transferred onto the powered-chain travel path. As the trolley travels on the powered-chain travel path, it moves past a bar-code scanner that reads the code. The scanner sends this information to a microcomputer. The microcomputer activates the assigned divert device, which moves the trolley from the main travel path to the appropriate nonpowered spur. After the trolley with the bar code arrives at the assigned location, the bar code is removed from the trolley’s neck. One option is to use the bar code as a permanent license plate and transport code. In this system, the GOH SKU is attached to the license plate and the trolley is diverted to the assigned location. With this method, the bar codes are reusable. Another bar-code option is to hang the bar code onto the front GOH piece hanger. With this application, the bar-code readers are located above the travel trolley path to read the trolley lead GOH bar code. Code Readers or Scanners. The second programmable-trolley divert component is the code reader or scanner. The code reader is a device that is located next to or above the main travel path. When an operation uses bar-code readers, all trolleys must travel past the code-reader station at the same elevation above the floor and must face in the same direction. Depending on the code identification system and the code reader, the two requirements for obtaining proper code reads are (1) physical contact with a sliding pin or pins, or (2) a line of sight aimed at the trolley’s neck and a light beam focused on the main travel path (for photo-reflective tabs or bar codes). Sliding-Pin Reader. The first type of code reader is the sliding-pin reader. The sliding-pin reader has prongs that make contact with the metal sliding pins.



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The sliding-pin code reader is preset to identify a trolley that is assigned to its divert device. As the trolley’s neck (with the code-pin setting) travels through the code reader, it activates the code reader. The reader triggers the assigned trolley divert device to divert the trolley from the main trolley line onto a spur line. If the metal sliding pins do not trigger the code reader, the trolley travels past the code reader to the next divert device on the main travel path. Photo-Reflective Tab Reader. The second type of code reader is the sliding photoreflective tab reader. This reader has a light source, a receiver, and a reflective target. The light source is located along the side of the main travel path and faces the trolley neck. The trolley’s neck has the photo-reflective tab or target. The photo-reflective tab is attached to the end of the sliding pin and reflects the light back toward the light source. The receiver is located along the main travel path and receives the reflected light from the photo-reflective tab. Each receiver is programmed to recognize light patterns based on the setting of the photo-reflective tab. This information is sent from the code reader to a microcomputer that activates a divert device and transfers the trolleys from the main trolley line to the nonpowered travel path. If the light pattern does not match the assigned pattern for the divert device, the trolley continues to travel on the main travel path. Bar-Code Reader or Scanner. The third type of code reader is the bar-code reader or scanner. Each trolley’s bar code indicates a divert location. The bar-code scanner is similar to the photo-reflective reader, except that the bar-code scanner receives a bar code message. The scanner emits a light beam directed at the trolley travel path. This light beam is a solid or moving beam that is spread over a large area. The type of light beam depends on the type of bar-code scanner, the type of bar code, and the location of the bar code on a moving trolley. The bar-code scanner reads reflected light. As a trolley with a bar code label travels past a scanner’s light beam, the white spaces between the black bars on the code are reflected back to the receiver. The trolley tracking device and constant trolley travel speed allow the microcomputer to activate the assigned divert device at the appropriate time, diverting the trolley from the main travel path onto the appropriate spur. Divert Device, Spur Path, and Sensor Devices. The next components are the divert device, the nonpowered spur travel path, and the sensor devices. The first component of a divert area is the divert device. The divert device has an air-operated sweeper mechanism. After the divert device is activated by the code reader and microcomputer, the device moves a divert section of the main travel path in the appropriate direction. The forward movement of the trolley’s front spool, the powered-chain pusher dog, and the trolley’s travel speed cause the trolley to follow the divert travel path. As the trolley’s rear spool travels over the divert section, the trolley’s forward movement and travel speed causes the trolley’s front head to travel across the divert device and onto the spur path. At this location, the pusher dog is no longer engaged with the trolley’s rear head. Once the trolley is on the divert or spur section, gravity ensures that it will clear the main travel path and the divert device.


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After a predetermined time, the divert section returns to the main travel path. To ensure that other trolleys can travel on the main travel path, the path becomes solid and continuous. The second component is the nonpowered branch or spur travel path. The spur path is designed to connect with the divert sweeper section. After the divert section moves to the divert position, the divert section and the declined spur path form a continuous travel path. At predetermined locations along the spur path, there are line control devices. These may be line-of-sight or photo-reflective devices, or trolley- and load-activated devices. The photo-reflective full-line sensor device has a light beam at the height of the trolley’s head that is set for a predetermined trolley number on the spur path. This light beam is sent across the spur path to a reflective target. The reflective target returns the light beam to the sender/receiver. The sender/receiver has a communication line to a microcomputer that controls the divert devices. When a trolley’s head breaks through the beam, it indicates to the controller that the lane is full. The controller deactivates the assigned divert device. It takes some time for all mechanical components to communicate with each other, and during this time one or two additional trolleys may be diverted from the main travel path onto the spur path. The length of the spur path should be sufficient to handle one or two additional trolleys. The full-line trolley or load sensor device is a specially-designed section on the spur path. As diverted trolleys queue on the spur path and a trolley is stopped on the full-line sensor section, the stopped trolley’s weight depresses the full-line sensor section. When a full-line sensor section has been depressed for a predetermined time, the full-line sensor sends a message to the microcomputer to deactivate the divert device. Along with full-line control devices, some manufacturers use partial-line control devices. The differences are that a partial-line control device is located in the middle of the spur path, while a full-line control device is located closer to the spur’s charge section. In addition, a partial-line control device activates an alarm, while a full-line control device deactivates a divert device. Structural-Support Members The next powered-chain component group consists of structural-support members: a floor-supported C-channel with a cantilever or bridge structure, and a C-channel travel path that is hung from the ceiling. Floor-Supported C-Channel. A cantilever or bridge floor support requires upright posts or stands that are anchored to the floor. The upright posts support the sway braces and other overhead structural-support members. The C-channel is attached to the overhead structural-support members. Ceiling-Hung C-Channel. An optional support method is to hang the C-channel travel path from the ceiling. The building’s architect or structural engineer approves the ceiling supports. These professionals certify that the ceiling’s steel structural members have sufficient strength to support the load weight of a static and dynamic



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powered-chain travel path. Depending on ceiling material and structural components, the travel path members require headers that are bolted, welded, or clamped to the ceiling’s structural components. The headers extend across several joists to evenly distribute the additional load. Support Structure and Structural-Support Members The support structure and structural-support members are the next powered-chain transport components. The support structure is designed by the manufacturer to handle the path layout and load weights. The weight factor is based on a fully-loaded trolley with the heaviest GOH load. Most manufacturers attach the support members to the powered-chain travel path. Trolley Travel-Path Support The trolley travel-path support members are the next components of a poweredchain system. The support member is a J-hook or a header iron travel-path structural support metal member. These travel-path support members are the same as for a nonpowered travel path. We refer the reader to the nonpowered travel path section in this chapter. Trolley Travel-Path Sections The trolley travel path is the next component. The options are a tubular rail, strut travel path, inverted flat-iron travel path, and C-channel travel path. These travel-path sections are the same as for a nonpowered travel path. We refer the reader to the nonpowered travel path section in this chapter. Trolley In-Feed Methods The trolley in-feed sections are the trolley-queuing section and the pusher dog interface location. The first powered-chain transport section is the trolley in-feed station. The trolley in-feed staging area is a nonpowered travel path that serves as a trolley queuing area. An operator dispatches the trolley along with the routing instructions that identify each trolley’s assigned workstation or storage and pick location. With this information, the operator sets the delivery location on the trolley’s front neck code device. For additional trolley-queuing information, see the section on nonpowered trolley queuing in this chapter. The second in-feed section is the station where a pusher dog interfaces with the trolley’s rear head. After an operator properly sets the trolley’s dispatch code onto the trolley’s front-neck code device, the operator pushes the trolley from the trolleyqueue travel path to the pusher dog interface and trolley in-feed location. Since the powered chain has a continuous series of pusher dogs on 5- to 6-foot center spacing, the trolley pauses momentarily at the in-feed station. After this momentary pause, a powered-chain pusher dog engages the trolley’s front head and pushes the trolley over the travel path. The powered-chain pusher dog and trolley-interface options are manual, chopper (or mechanized), and hold back and release (or automatic). Manual Trolley In-Feed Method. Manual trolley in-feed to the powered-chain pusher dog is the first trolley in-feed method. The in-feed station has a manual push


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trolley. With manual trolley in-feed, an operator pushes a trolley from the trolleyqueue travel path until the trolley’s front head becomes engaged with a powered chain pusher dog. At the in-feed section, the travel path is inclined slightly to ensure that one trolley is indexed forward under the travel path. At this location, the powered-chain travel path declines to a lower elevation. At this elevation, the powered-chain pusher dog engages the rear head and the trolley is under the control of the powered chain. As the powered-chain travel path continues, it inclines to the proper elevation for horizontal travel or to an elevation that permits transfer to an elevated travel path. To operate a manual trolley in-feed station, an operator observes the movement of the powered-chain pusher dog above the trolley in-feed station and before it reaches the station. As an empty powered-chain pusher dog approaches the trolley in-feed station, the operator pushes the trolley forward on the in-feed station’s nonpowered travel path until a pusher dog engages the trolley’s rear head. Manual trolley in-feed handles a low trolley volume and requires a person to operate it. The other features are a minimum capital investment and a low probability of trolley jams. Chopper or Mechanized Trolley In-Feed Method. The second trolley in-feed method is the chopper or mechanized trolley in-feed method, which transfers a trolley from a nonpowered travel path and is pulled by a powered-chain pusher dog. The chopper in-feed method uses a chopper device and a short gravity-powered travel path. The short travel path’s incline permits the trolley’s rear head to be engaged by a powered-chain pusher dog. The short travel path section is located before the chopper device. Trolleys queue on the short path, which is long enough to hold two to six trolleys. The chopper in-feed device is an air-operated bar with trolley stops on both ends. The device is balanced in the middle and operates in a seesaw manner. On the powered-chain travel path, prior to the chopper location, the powered-chain pusher dog passes a pronged sensing device. The prong extends into the pusher-dog travel path. As the pusher dog passes the prong, the sensing device communicates the presence of a pusher dog on the powered-chain travel path to a microcomputer and then to the chopper device. When a pusher dog strikes the sensing device, the microcomputer activates the chopper device. The activated chopper device permits a trolley’s front head to be engaged by the pusher dog. After the pusher dog is moved forward on the trolley travel path, the trolley head activates a second sensing device. This sensing device communicates to the chopper device that the trolley has traveled from the chopper device section and that the chopper device is ready to accept another trolley from the gravity-powered queue section. This permits the next trolley in the queue to move forward to the in-feed station. Manual trolley in-feed requires an employee and minimal investment. The chopper in-feed method does not require an employee and requires a slightly greater investment. Hold Back and Release (or Automatic) Trolley In-Feed Method. The third trolley in-feed method is the hold back and release (or automatic) method. This method employs a device that moves up and down on the trolley travel path. A



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trolley being pushed by a pusher dog across the device controls the action of the device. The hold back and release device is an air-operated device that is located before the incline or decline of a trolley travel path and is placed on the trolley travel path so that the trolley’s rear head comes in contact with the powered-chain pusher dog. As the trolley enters the hold back and release device, the trolley head is moved downward. The trolley’s front head comes in contact with a soft pusher dog, but does not come in contact with a powered-chain pusher dog. As gravity and the soft pusher dog move the trolley forward on the hold back and release device, the trolley is moved upward and the trolley’s front spool head is at the right elevation to come in contact with a hard pusher dog. The hard pusher dog is a hardened metal component of the powered chain that extends downward toward the floor. The hold back and release device moves the trolley downward and upward. On the upward movement the pusher dog comes in contact with the trolley’s front head and is moved over the trolley travel path. With the hold back and release device in the up position, the elevation of the device ensures that a powered-chain pusher dog will engage the trolley’s front head. In the down position, the hold back and release device temporarily holds one trolley. At this elevation, the pusher dog does not engage a trolley. The movement of the powered-chain pusher dog and the trolley activates the up-and-down movement of the device across the travel path. The pusher dog activates a sensing device. As the trolley travels across the travel path, a series of soft pusher dogs allow the trolleys to queue on the rail section. The hold back and release device, acting as a temporary stop, causes the trolleys to queue. When the hard pusher dog passes a sensing device, the pusher dog activates the hold back and release device, which rises up. In the up position, the hard pusher dog engages the trolley’s front head. The hard pusher dog pushes the trolley over the short horizontal travel path section onto the inclined section. As the front section of the hold back and release device is raised to the up position, the rear section is lowered to the down position. In the down position, a trolley is placed at a lower elevation. In this location, queued trolley heads are below the elevation where a hard pusher dog can engage a trolley head and wait for a hard pusher dog to activate the hold back and release device that raises the trolley head to become engaged by a hard pusher dog. This method handles a high volume with no manpower required. It does, however, require additional investment. Nonpowered Travel Path The next powered-chain system component is the nonpowered travel path. An operator moves trolleys on a nonpowered travel path. On a nonpowered travel path, the pusher dogs are at an elevation that does not allow them to engage the trolley head. Manual power or gravity moves the trolleys over the nonpowered travel path. In most powered-chain systems, a nonpowered travel path is used at in-feed stations or as a spur after the divert location. The nonpowered travel path has the same design parameters and operational characteristics as with the nonpowered horizontal trolley transport method. We refer the reader to that section in this chapter.


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Trolley Travel Path Protection As with any powered mechanical device, the powered-chain travel path system requires guards. In this case, the guards are on the underside and on the sides. The guards are safety code requirements for all overhead powered-transport products. The purpose of the guards is to catch any GOH pieces or powered-transport components that fall from the elevated travel path. The GOH-piece characteristics and the mix determine the width and height of the side guards and the depth of the underside guard from the top of the C-channel track. Additional bottom and underside guards, structural-support members, and trolley sway on horizontal curves may also be required. In a travel path layout, the standard practice is to allow a minimum of 6 inches of clearance between the side of a GOH piece and the side guard, and between the bottom of the tallest GOH piece and the underside guard. If a GOH piece falls, trolleys continue to move GOH pieces over the travel path. The guard components are headers, which are 5 feet wide and are attached to the enclosed track’s top or structural-support members, and frames, which are 8 inches on center. This is the distance between two frames and extends downward from the header to the bottom cross-structural-support member. Bottom structuralsupport members are 5 feet wide and are attached to each frame; they extend full width under the underside guard. Runners are attached full length to both sides of the underside guards and full length on the top of the side guards. Guard material can be wire mesh, expanded metal, or sheet metal. Most manufacturers use expanded metal guards that are assembled at the installation site. These metal panels are cut to fit the guarding section’s width. The gauge and the size of the diamond pattern depends on GOH size and weight. Some guards are designed to support a maintenance staff employee and are designed according to the manufacturer’s standards. Wire-mesh guards have prefabricated sections made of welded and coated metal strands that are cut to fit the width of the guarding section and the side guard dimensions. Most wire-mesh guards are available in 8-foot long sections. Wire-mesh sections are connected with a spiral wire fastener. During installation, the wire-mesh sections are attached on 8-foot centers. The GOH dimensions determine the length and width of the wire mesh opening. Sheet-metal guards consist of a solid metal surface that is cut to fit the width of the guarding section and the side guard dimensions. The metal sheets are welded or Tek-screwed onto the bottom cross member. Most manufacturers use sheet-metal underside guards to protect the travel path under a motor. Trolley Run-Out Section On a powered-chain travel path, the next component is the trolley run-out section. The trolley run-out section is the last section on the powered-chain travel path. At this location, the powered-chain C-channel track is elevated upward. This upward elevation moves the hard and soft pusher dogs to an elevation that is above the trolley heads. This means that there is no contact between the powered chain and the trolley heads. With no contact, there is no power from the pusher dog to propel the trolley over the travel path. Past this travel-path location, trolley travel is on a



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nonpowered spur. The nonpowered spur section declines to allow gravity to move the trolley forward. Return Powered-Chain Travel Path or Track When the powered-chain C-channel track travels over a travel path with no trolleys, the direction is back to the dispatch or start location. The window of an empty Cchannel travel path has a small height. The powered-chain window height shrinks because there are no trolleys on the powered-chain travel path. When an emptytrolley travel path is compared to a powered-chain travel path, the window of the empty-trolley path has the width and depth of a C-channel, plus the added depth of a hard pusher-dog. This means that the return C-channel requires a small travel-path window and follows a more direct route to the dispatch location. Electrical Controls and Panel The next powered-chain system components are the electrical controls and the electrical panel. Some of these components are at the control panel station and others are located at key sites along the powered-chain travel path. Operating in concert, they ensure that the system functions safely, with overrides to prevent damage or injury. The remote controls along the powered-chain travel path are emergency-stop push buttons, antirunaway switches, and photo-eye controls. An emergency-stop (E-stop) device is a red mushroom-shaped push button that is placed at key site locations along (or below) the powered-chain travel path, within easy reach of an employee. When the E-stop button is activated, it sends a signal to the control panel to stop the drive motor and chain. This happens when an employee has observed a condition he or she considers unsafe. Such situations might have the potential to cause equipment damage, GOH product damage, or personal injury to an employee. After an E-stop button is activated, a red light on the main control panel is illuminated, and the system’s start button is turned off. To restart trolley transport, the E-stop button must be reset and the control-panel start button activated. Other electrical components are electric drive motors, air-operated divert devices, automatic trolley in-feed stations, sensors, and trolley stops. Description of Operations In a powered-chain transport system, an operator or a mechanical device transfers a trolley onto the trolley travel path at the in-feed station. This trolley path is located directly under the powered-chain travel path. Prior to transferring a trolley to an in-feed station, the operator ensures that the trolley spools are set on the nonpowered travel path. The operator reads the dispatch instructions and sets the proper code on the trolley’s coding device. With the trolley routing code programmed, the operator pushes or pulls the trolley over the nonpowered travel path to the powered-chain trolley in-feed station. At the trolley in-feed station, each trolley leaves the nonpowered travel path and is moved by the powered chain. As the powered-chain hard pusher dog engages the trolley’s front head, the trolley moves forward over the travel path. During travel over the travel path, the trolley’s dispatch code (on the front neck) is read by each


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divert station code reader or scanner. When the trolley code matches the code-reader setting, this information is sent from the reader to a microcomputer. The microcomputer activates a divert device to divert the trolley from the main travel path onto the appropriate spur. If the spur is full, or if for some mechanical reason the divert device does not operate, the trolley continues to travel on the main travel path past the divert location. If the trolley path is an endless closed loop that travels past all divert stations, the trolley repeats the previous activities and makes a second attempt to divert onto the divert spur. At the end of the workday, all trolleys with GOH pieces are diverted, and the GOH pieces are transferred to the appropriate location. If the powered travel path has a run-out, the trolleys that were not diverted are queued on the run-out path. The trolley run-out path requires an operator, who physically transports the trolleys or GOH pieces to the assigned divert location, or reintroduces the trolleys at the in-feed station. Powered-Screw Conveyor The powered-screw conveyor system is the next GOH transport system. Screwconveyor transport is a one-way system that is designed to move a single GOH piece on a hanger across a fixed travel path. The travel path can be hung from the ceiling or supported on the floor. A powered-screw conveyor consists of an electric drive motor, rotating rail and spiral wire strands, structural-support members, controls, guard rails, and accessories. A powered-screw conveyor is designed for either right-hand or left-hand operation. The direction on the travel path of the hook face of a GOH piece hanger determines whether your powered-screw conveyor will be a right-hand or a lefthand operation. If a GOH piece hanger’s open side faces to the right as the GOH piece moves away on a powered-screw conveyor, it is a right-hand screw conveyor. If a GOH piece hanger’s open side faces to the left as the GOH piece moves away on a powered-screw conveyor, it is a left-hand screw conveyor. Motor and Drive Unit The first powered-screw conveyor component is the electric motor and drive unit. Motor horsepower may be 1/2, 1/3, or 1/6. Revolutions per minute (rpm) may be 60, 90, or 135. A 60-rpm motor is used to transport heavy GOH pieces over a powered-screw conveyor. The 90- and 135-rpm motors are used to transport light-to-medium-weight GOH pieces. With the latter types, the entire powered-screw conveyor is 70 to 150 feet long. If heavy GOH pieces are transported, the entire powered-screw conveyor is 50 feet long. The 135-rpm motor can also be used to transport heavy GOH pieces over a short powered-screw conveyor. The powered-screw conveyor is measured from the charge station to the discharge station. GOH pieces have a high travel speed. The motor’s electrical requirements are 115 volts, 60 hertz, and single-phase power. The motor is connected to a gear unit with a reducer clutch and a cam that turns a rotating shaft.



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Rotating Shaft (Rail) and Spiral Wire Strand. The rotating shaft (or rail) and spiral wire strand are the second powered-screw conveyor components. The rotating shaft and spiral wire strand are the moving components. The motor turns a shaft. This motion turns the spacer cam and clutch through the reducer. As these items turn, the rotating shaft turns. The rotating shaft is the moving component that supports an open-faced hanger hook. Depending on the weight of the GOH piece, the standard screw-conveyor travel section is 50 to 100 feet long. As required by the powered-screw conveyor layout, horizontal screw-conveyor curves are used in the travel path to avoid columns and other building obstacles. The standard curve has a 13-inch radius with curves of 15˚, 30˚, 45˚, 90˚, and 180˚. If the powered-screw conveyor has a travel path distance that is longer than the maximum of 150 feet, two or more screw-conveyor units will be planned for the GOH transportation system. At the intersection of two screw-conveyor sections is a GOH piece transfer device. The transfer device moves a GOH hanger from the first screw-conveyor section to the second screw-conveyor section. The spiral wire strand is another part of the powered-screw conveyor. The spiral wire strand is sometimes called a helix. The spiral wire strand runs the entire length of the rotating shaft. As the rotating shaft turns around the spiral wire, a GOH hanger is placed between the spiral wire’s two strands. The shaft’s rotation causes the GOH hanger to move forward along the rotating shaft. The GOH piece hanger’s movement along the powered-screw conveyor is a controlled movement. Control is ensured by the open space that continuously revolves between the spiral wire strands. When designing a powered-screw conveyor system, factors to consider include: • • •

The open space between the spiral wire strands should match the width of the GOH hanger’s open-faced hook. The rotating shaft’s turning movement should match the direction of the GOH open-faced hanger. The wire strand’s diameter should match the dimensions of the hanger hook.

Both the rotating-shaft and spiral-wire-strand components are zinc-plated or electroplated, to reduce GOH piece damage from rust and to ensure a smooth, consistent travel surface. Structural-Support Members The screw conveyor also requires a structural-support component. The structuralsupport members are the components that provide the support, rigidity, and stability to the powered-screw conveyor. A powered-screw conveyor may be supported from the floor or the ceiling. The floor-supported method involves upright posts, cross members, and sway braces. The uprights are steel tubes 2 inches in diameter, mounted on a steel plate and a cantilevered iron base. The upright posts are secured to the cantilevered iron base using nuts and bolts; they extend outward under the powered-screw conveyor. The iron base is anchored to the floor in compliance with the manufacturer’s standards, local building codes, and seismic requirements, if any.


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A support arm is attached to the upright post at the required elevation. This support arm is welded to a bracket. The bracket has two drilled holes for a U-bolt connection. The upright post is placed inside the bolt, and the two U-bolt nuts secure the support arm connection to the upright post. The support arm extends outward from the upright post. The arm extends over the cantilevered base plate. The support arm is the structural member that supports the powered-screw conveyor. At the support arm’s end are a series of brackets and nuts and a J-hook that support the powered-screw conveyor. The spiral wire strand is secured to the J-hook. The J-hook secures the spiral wire strand in a permanent position that allows the interior rotating shaft and the stationary spiral wire strand to move the hanging garments forward over the travel path. The upright posts are spaced on 5-foot centers. At the end of the powered-screw conveyor, the conveyor requires a floor stand. Overhead braces give the poweredscrew conveyor stability and rigidity. The upright posts’ overall height is adjustable. The standard upright post sizes are 6 feet, 9 inches; 8 feet; 9 feet, 3 inches; and 10 feet, 7 inches. To determine the maximum height from the floor to the centerline of the powered-screw conveyor, subtract 7 inches from these heights. All floor components are zinc-coated to reduce transfer of rust and dirt to the GOH pieces. The floor-supported method is used when the floor area does not have heavy vehicle or personnel traffic, when the open space between the screw conveyor and the ceiling is not sufficient to permit hanging the conveyor from the ceiling, and when the ceiling’s structure is unable to support the new load weight or is restricted by other equipment. An alternative screw-conveyor structural-support method is to hang the conveyor from the ceiling. When the powered-screw conveyor is hung from the ceiling, threaded rods extend downward from the ceiling joists. At the bottom of each threaded rod, the screw-conveyor support members are attached to the rod. For a powered-screw conveyor to be hung from the ceiling, the steel in the ceiling must have the strength to support the powered-screw conveyor’s total weight. The total weight includes the screw-conveyor structural-support members, the travelpath components, and a maximum number of GOH pieces. A powered-screw conveyor that is hung from the ceiling requires a clear space between the ceiling’s steel members and the powered-screw conveyor. This clear space cannot contain building obstacles or other equipment. Hanging a powered-screw conveyor in this way gives your facility a clear floor that permits vehicle or personnel traffic or additional workstations. The relevant parts are ceiling attachment brackets; rods with threads at both ends; C-channel structural supports for the powered-screw conveyor; and washers, nuts, and bolts. Headers may also be required to spread the load across a larger area of the ceiling structure. The ceiling-attachment bracket is the component that connects the threaded rod to the ceiling’s steel members. The design of the ceiling and the policies of the manufacturer determine the type of ceiling-attachment bracket.



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All bracket types require truss joists, I-beams or angle rods, wooden beams, and a flat wooden ceiling. Most screw-conveyor manufacturers do not suspend powered-screw conveyors from flat concrete ceilings because the available concrete fasteners are not adequate to support the screw conveyor’s load weight, and it is possible that the ceiling might not withstand the dynamic load (i.e., vibrations) from the screw conveyor. When the ceiling has truss joists, a threaded rod is inserted between the two metal joist members. A washer and nut secure the rod to the joist from above. The washer and nut are wider than the open space between the two metal joists. When the manufacturer attaches brackets to an I-beam or angle rod that is up to 1/2-inch thick, a steel C-clamp is used. A nut and bolt secure the C-clamp to the I-beam or angle rod. Washers and nuts secure the threaded rod to the C-clamp. In a facility with wooden beams, the screw-conveyor support has 90˚-angle metal brackets. The angle bracket’s base is secured to the wooden beam with wood screws. The leg side of the angle bracket extends outward. The bracket is predrilled for attaching the threaded rod. One end of the threaded rod is inserted through one hole. Washers and nuts on both sides secure the threaded rod. In a facility with a flat wooden ceiling, a flush ceiling mount is used to support the threaded rod. The flush ceiling mount has a 3-inch long nut that is welded to a flat metal plate. The flat metal plate has two predrilled holes. Wood screws and lock washers secure the metal plate to the flat wooden surface through these holes. Lock washers and nuts secure the threaded rod to the 3-inch nut. To provide a stable, rigid powered-screw conveyor, the ceiling hanger supports are located on 5-foot centers at both ends of the powered-screw conveyor. The lower threaded-rod end, which extends downward from the ceiling attachment device, is connected to the powered-screw conveyor structural-support member. The powered-screw conveyor support members are J-hooks or C-channels. Nuts and washers secure the connection. Depending on the screw-conveyor design and the seismic location, sway braces are used to ensure a stable, rigid powered-screw conveyor. Sway braces are metal members that are connected to the ceiling’s steel members, and the threaded rod or screw conveyor is supported by a J-hook or C-channel. Brackets, nuts, and bolts are used to connect the sway braces to the other structural-support members. Most manufacturers recommend 3 sway braces for the first 20 feet of the screw conveyor, and 2 sway braces for each additional 10-foot section. Controls. Screw-conveyor controls determine when hangers move across the travel path. The screw-conveyor controls are solid-state controls, auxiliary controls, and manual controls. The solid-state control is used in conjunction with an automatic GOH bagging device, or any other machine that has a solid-state printed circuit board. The other components are a solid-state relay and a circuit breaker installed on the conveyor drive. Power cords and control cables are the other control components. The auxiliary control is used on a screw-conveyor application that has an automatic GOH device. The automatic device is a loader or a queue device. The screwconveyor auxiliary device control receives its signal from a switch that is located


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on the other automatic device. To transmit this signal, a solid-state printed circuit board and relay must be located on the screw-conveyor drive. The other hardware control components are power cords and control cables. The last screw-conveyor control is a manual control. With a manual screwconveyor control, an operator activates the screw conveyor. The manual control components are an on/off switch mounted to the screw conveyor drive, an overload protection device, and a power cord. Guardrail and Accessories. Screw-conveyor system components that reduce GOH damage and improve employee productivity are guardrails, loaders, and diverters. The guardrail resembles a metal cap and is attached at various locations along the powered-screw conveyor. The guardrail is attached to the J-hook or C-channel; there is a clear space between the spiral wire strand and guardrail. This space permits the hanger to move forward over the travel path. The guardrail is used on curves or at a transfer location to prevent a GOH piece from falling or jumping from the rotating shaft and spiral wire. The loader is an automatic device that transfers hangers onto the powered-screw conveyor. The loader operates by means of a cam mounted on a motor drive shaft. As the screw-conveyor spiral wire and rotating shaft make one complete revolution, one GOH hanger is released onto the screw conveyor. A divert device is another screw-conveyor component. The divert device splits the GOH flow from one powered-screw conveyor to another device. Description of Operations. A screw-conveyor transport operation requires that an operator place an open GOH piece hanger, facing in the correct direction of travel, onto the screw conveyor. At the in-feed station, the operator places a GOH piece with the open-faced hanger hook between the spiral wire’s two strands and resting on the rotating shaft. With the hanger on the powered-screw conveyor, the operator turns on the screw conveyor and the GOH piece comes under the screw conveyor’s control. As the rotating shaft revolves and the exterior spiral wire strand remains fixed on the rotating shaft, the GOH piece moves forward along the powered-screw conveyor. This travel path runs between two spiral wire strands that run the full length of the rotating shaft’s travel path. At the end of the powered-screw conveyor, a GOH piece is automatically or manually transferred to a second screw conveyor or workstation. The GOH screw-conveyor transport system is used to transport GOH pieces from a workstation to an automatic GOH-piece bagging device, or to another workstation such as a steam tunnel. The disadvantages of a screw conveyor are increased capital investment, limitation to a specific hanger type (hangers with an open-faced hook), GOH travel in only one direction, limited travel path distance, and slow travel speed. The advantages are that the system is easily installed, operates quietly, can be easily automated, handles hangers, interfaces with dangerous workstations, and does not require an operator to move GOH pieces.



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TROLLEYLESS GOH TRANSPORT CONCEPTS A trolleyless GOH transport concept moves individual GOH items overhead between two facility locations by a powered material handling system. When we compare a trolleyless GOH transport concept with a trolley GOH transport concept, the similarities are that both (1) move GOH items between two facility locations; (2) have powered and overhead travel paths; and (3) have programmable carrier and travel path divert locations. Differences are (1) trolleyless GOH transport moves an individual or a small group (up to 15 GOH items) per carrier and a trolley concept carrier moves 25 to 50 items per trolley; (2) trolleyless transport travels over a steeper sloped travel path; and (3) the trolleyless carrier is permanently attached to a travel path whereas the trolley system is removeable from the travel path. When used to transport multiline or multiquantity GOH SKUs per order, each GOH piece requires a discreet identification.

VARIOUS TROLLEYLESS GOH TRANSPORT CONCEPTS The trolleyless GOH transport concepts are the modular transport system (MTS) and 200 G GOH trolleyless system. Modular Transport System The modular transportation system is considered an automatic GOH single item transport/storage/pick concept. This GOH single item transport/storage/pick concept has each GOH item on an individual carrier. Each carrier has a storage/pick position on a power and free conveyor travel path. This feature is similar to the horizontal carousel GOH concept. The MTS concept has (1) individual- and discreet-coded carriers or downward extending pendants, each of which has a special designed hanger hook carrier; (2) powered and free conveyor travel path; (3) in-feed and outfeed slick rails or travel paths with special ends for carrier and GOH hanger hook interface; and (4) a GOH item on a specific hanger with a standard hook. Key Components. The first major MTS components are the individual- and discreet-coded carriers with a special designed hanger hook carrier that has six sections, the first of which is the carrier connection to the power and free pendant. This component is a molded, hard plastic pendant that extends downward from the power and free conveyor travel path and has sufficient depth and width for attachment of a ladder-oriented bar-code symbology. The hard plastic-molded component has several harden plastic wheels that interface and roll over the hard, smooth and continuous metal travel path. At the base of the hard plastic carrier component is a hole for the rivet connection of the special designed molded harden plastic hanger hook carrier or device. The second major MTS component is the power and free conveyor travel path, which is powered by an electric powered sprocket drive motor that interfaces with a drive chain. The drive chain interfaces with the power and free conveyor chain sprocket. As the drive train turns or revolves, these components pull the power and free conveyor chain forward through the travel path. As a power and free conveyor


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chain are pulled forward, the pendants that are attached to the power and free chain are pulled foward over the travel path. The powered and free conveyor travel path has curves to avoid building obstacles and to change elevation above the floor to complete a GOH pick-up and delivery transaction. The MTS in-house transportation travel path has the ability to travel with a GOH item over an incline or decline travel path that is steeper than the standard trolley travel path slope of 30 degrees. The third component is the forward and reverse moveable special designed hook or GOH hanger carrier. The hook is a molded hard plastic component with a predrilled hole for rivet connection to the hard plastic carrier component or pendant base. The two-component connection allows the hook to be moveable and complete the various required pick-up, transport and delivery transactions. The specially designed hook or carrier is C-shaped. It has a bottom finger or extension, open space between the top and bottom fingers or extensions, and top finger or extension. As the hook is pulled over the travel path, the shape permits the hook (1) to pick-up a GOH hanger at the in-feed or pick-up station, (2) to securely hold a GOH hanger in the cavity during travel over the travel path, and (3) to drop-off or discharge the GOH hanger at the delivery or discharge station. When the ‘C’-shaped carrier is pulled over the pick-up area, it faces downward with the bottom finger at the lowest extension. The shape, slick rail design, and forward movement permits the hook bottom finger or extension to engage a GOH hanger. During carrier travel over the travel path, a GOH hanger hook slides within the ‘C’-shaped carrier, and the GOH weight causes the carrier to assume the transport ‘C’ Shape. The transport ‘C’-shaped carrier has the ‘C’ open space facing forward and the GOH hanger resting on the ‘C’ bottom finger. When a ‘C’-shaped carrier is pulled forward over the delivery area, it faces downward with the bottom finger at the lowest extension. The ‘C’-shaped carrier shape, slick rail design, and forward movement then permits the hook’s bottom finger or extension to release the GOH hanger. The fourth major MTS components are the carrier’s two-coated and hard metal travel paths. Between the two metal travel paths is an open slot. The travel path sections are attached to overhead structural support members. These metal travel paths are coated, smooth and continuous. This type of metal travel path permits the carrier’s hard plastic wheels a low co-efficient of friction travel path. As a power and free conveyor pulls the carriers or pendants forward, the carrier or pendant rides in the slot between or is guided between the two metal travel path sections. The fifth major MTS components are the GOH pick-up and delivery stations. The GOH pick-up and delivery stations are slick or slide rail sections or travel paths. At the pick-up end and delivery station is a specially designed end. The pick-up or in-feed slick rail is sloped downward, permitting GOH hangers to accumulate at the slick rail end. This end section, constructed of hardened molded plastic, has a cavity between the two slick rail sides or runners. The cavity is designed with an angled, downward pitch to the end. This end section has a wedge shape with two full height sides. The pick-up slick rail wedge end feature permits an open space for the GOH hanger and the cavity bottom. During an MTS carrier pick-up activity, this open space permits the carrier hook’s bottom finger to become flat and to engage the GOH hanger.



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The delivery or discharge slick rail end has a hard plastic end that has two upward sides or runners. The sides have sufficient height to interface with an MTS carrier hook and the GOH hanger that is on a slick rail. As a GOH hanger is pulled forward, the two sides and slick rail space between the two sides assure that the GOH hanger is removed from the carrier. After GOH removal from the carrier, the slick rail gravity sloped slick rail travel path assures that the GOH item moves away from the delivery location. The sixth major MTS component is the GOH hanger. A GOH hanger hook or opening end is contructed of hard metal. For best MTS performance your operation has a standard GOH hanger hook. Prior to your GOH hanger purchase or vendor standard, your manufacturer tests your GOH hanger or vendor hanger or you can test your vendor’s hanger on your MTS concept. The final major MTS components are the controls — the bar-code scanners and microcomputers that control the order pick requirements and GOH item association to a MTS carrier’s bar-code symbology. Per your customer orders, the devices direct the appropriate MTS carrier movement over the travel path to the assigned discharge location. Description of Operations. After a GOH delivery truck has the GOH items transferred onto your delivery dock, the GOH individual hangers are approved and are transferred onto the MTS pick-up slick rails. From the discharge end, the GOH items slide on the slick rail to the pick-up end. The GOH item discreet description or code is associated with the MTS carrier bar-code symbology. As the power and free conveyor travel path pulls the MTS carrier hook forward over a slick rail pick-up section, the MTS carrier hook becomes flat with a ‘C’-shaped open face facing downward. As an MTS carrier is pulled forward to pick-up slick rail transfer section, the carrier bottom finger engages the GOH metal hanger. The carrier’s forward movement has a GOH hanger to move to the ‘C’-shaped carrier rear. After a GOH hanger is removed from a slick rail pick-up section, a carrier with the GOH hanger becomes vertical and hangs down toward the finished floor. In this position, a GOH is securely transported over the power and free travel path. As the power and free conveyor moves over the travel path, each MTS carrier has a GOH item. Therefore, each MTS carrier is a storage/pick position. When there is customer order for a GOH item, the microcomputer has power and free conveyor move the appropriate MTS carrier to the delivery or discharge location. As the MTS carrier with the GOH item is pulled forward over the discharge section, a GOH hanger becomes flat and the ‘C’-shape carrier open section faces downward. A GOH hanger interfaces with travel path components that move the hanger into the ‘C’-shape open space and onto the delivery slick rail. The slick rail gravity slope assures that the discharged GOH item slides forward on the slick rail from the MTS interface section. Disadvantages and Advantages. The disadvantages of the MTS are that it (1) requires a bar-code symbology and scanner, (2) operates best with a WMS, (3) completes receiving detail at the dock or entry, (4) requires uniform hangers and (5) performs QA after the GOH items are in the storage/pick area. The advantages are that it (1) is an automated storage and pick activity, (2) requires few employees, (3)


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does not require a trolley, (4) does not require an employee walkway, thus providing improved space utilization, (5) does not require utilities, (6) is able to travel over a travel path with steep inclines or decline sections, and (7) is easy to operate. 200 G GOH Trolleyless GOH Transport Concept The 200 G GOH powered trolleyless transport concept is basically an endless powered conveyor and slick rail travel path that moves carriers with open spaces for GOH items. For each SKU group on the travel path, the lead GOH item has a transport unit identification. Along the travel path that has scanners and divert devices, there are powered and slick rail GOH in-feed stations and divert slick rail travel paths. The 200 G GOH powered trolleyless transport concept is used to move a large quantity of single SKUs en masse or as a group between two facility functions or locations. When the 200 G GOH powered trolleyless transport concept is used to transport GOH orders that are multiline or multiquantity pieces for one customer order or a single SKU customer order, the 200 G GOH concept requires several modifications. Each SKU of a multiline, multiquantity or single SKU customer order requires a transport discreet identification, and betwen the pick area and the pack area, there is a customer-order sortation concept that has a travel path, divert devices and divert travel paths. Major components of the 200 G GOH powered trolleyless GOH transportation concept are: • • •

•

• • • • • •

Endless ‘C’-shaped channel powered conveyor and carrier travel path and drive train ‘C’-shaped conveyor travel path structural components Four-wheel carriers that are interlocked the full length of the conveyor travel path to form an endless train. A carrier rides on a slick rail travel path and has four pendants that create three GOH carrying spaces, extended downward, and connected to the carrier surface. Powered vertical inclined travel path and slick rail gravity in-feed station with control devices and GOH item stop and start flows to assure controlled and proper interaction between the GOH items and carrer open spaces Slick rail in-feed travel path Individual SKU or SKU group discreet identification GOH discreet identification readers or scanners GOH divert devices with a divert slick rail decline travel path GOH hanger and hanger orientation on the travel path For multiline or multiquantity customer orders, a customer ordered and picked piece sortation concept.

Endless ‘C’-Shaped Channel Powered Conveyor and Carrier Travel Path. The 200 G GOH powered trolleyless transportation concept is an endless ‘C’-shaped powered conveyor and carrier travel path with a drive train to pull the powered



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conveyor. The 200 G ‘C’-shaped powered conveyor is a powered endless loop chain that has a series of downward extensions or pendants that are equally spaced and attached to each carrier’s forward and rear ends. As the powered conveyor drive unit pulls the conveyor chain forward through the ‘C’ channel, with the powered chain pendants attached to a carrier as the chain is pulled forward over the travel path, the GOH carrier is pulled forward over the travel path. As required to complete the GOH conveyor travel path, the “C’ channel and conveyor travel path use 45, 90, or 180 and other degree angled horizontal and vertical bends in order to avoid building, to access elevated finished floors and operational equipment, and to connect in-feed and divert stations. The ‘C’-shaped conveyor travel path is attached at the top to structural support members. This structural arrangement has the ‘C’-shaped open space between the two ‘C’ legs facing the finished floor. In this position, the two ‘C’-shaped channel legs each provide an enclosed carrier wheel travel path consting of two solid, smooth, flat and continuous four-wheel carrier travel paths. The open space permits the conveyor pendants or fingers to extend downward. For additional ‘C’-shaped channel travel path and drive train information, we refer the reader to the ‘C’-shaped channel travel path and drive train section in the powered trolley component section. ‘C’-Shaped Conveyor Travel Path Structural Support Members. The second 200 G GOH powered trolleyless concept is the ‘C’-shaped channel conveyor travel path structural components that provide the conveyor travel path rigidity and structural support. Per the GOH transportation concept, building physical characteristics, and operational design parameters, the structural support components are supported from the ceiling or finished floor. The 200 G GOH powered trolleyless concept structural components are similar to the powered trolley concept. For additional structural support component information, we refer a reader to a conveyor travel path structural component section in the powered trolley concept section. Four-Wheel GOH Carrier. The third 200 G GOH powered trolleyless concept component is a four-wheel carrier connected to the endless powered conveyor travel chain extension or pendant. This connection assures that the four-wheel carrier is pulled through the ‘C’ channel travel path. The four-wheel carrier has four hard plastic smooth wheels, each of which is attached to an axle and located each carrier side. In this position, a set of front and rear wheels ride on one side of the ‘C’-channel leg travel path. The carrier wheels roll over a smooth, flat and continuous metal travel path, assuring a low coefficient travel path for the carrier travel. The travel path arrangement assures proper carrier support and the enclosed ‘C’-channel travel path provides control travel direction through an enclosed travel path. The second four-wheel carrier component is a hard metal top bar. From the powered chain pendants that extend downward, through the open space between enclosed ‘C’-channel, two legs are attached to the top bar front and four-wheel carrier rear. A front and rear couple concept allows carriers to form an endless and continuous carrier train the full length of the travel path.


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The GOH carrying surface is securely attached or riveted to the four-wheel carrier. It is a hard-coated metal member that consists of four fingers or pendants. At each pendant bottom a hard metal tube or the GOH carrying surface is attached. The GOH metal carrying surface is separated into three GOH carrying compartments. The length of the metal carrying surface permits an open space to carry up to five GOH pieces. At the end of the carrier is an open space that does not carry GOH pieces. Below the carrier top bar the four finger downward extension is a 4- to 5-inch square open space assuring that a GOH item is easily transferred, one to five GOH pieces at an in-feed station or divert station. The metal carrying bottom section is a hollow tube with two open ends. The metal carrier bottom has several important characteristics: • •

• •

The external tube diameter provides sufficient solid round space to assure that a GOH hanger is retained on the carrying surface. The internal tube dimension or diameter has sufficient open space between the tube and the slick rail to assure that a carrier slides over the slick rail travel path. A carrier has the structural strength and rigidity to support the designed GOH maximum load weight. The tube internal surface is a smooth, continuous, flat and even surface to assure a low co-efficient of friction between the bottom carrier and slick rail.

The next 200 G GOH powered trolleyless concept major component is the slick rail travel path, a hard metal smooth, rail, continuous, flat and even surface that runs the full length of the powered trolleyless concept travel path. As the powered conveyor pulls the carrier forward over the travel path, the travel path assures a low coefficient of friction between the bottom carrier and slick rail. In-Feed Station. At the GOH in-feed station an employee assembles the GOH garments for one SKU as a group that is behind a transport label. The transport label is attached to the lead garment. There is one GOH piece per transport label or one transport label is used to identify up to 100 pieces. The GOH garments are evenly spaced on the in-feed spur. As an employee or powered conveyor moves the GOH garments forward, the GOH pieces move upward over a vertical travel path. At the peak elevation above the floor path, the GOH garments are released on a predetermined time onto a decline slope slick travel path. With a large SKU number behind one transport label and just past the in-feed travel path peak elevation, a control device assures that a single SKU is released as a group of five GOH pieces onto the in-feed slope travel path. At the decline in-feed travel path slope end, the travel path discharges the individual labeled GOH piece or five pieces of a single group of SKUs onto the carrier open space. After an in-feed employee has collected the GOH SKU as a group or ‘en masse’ with one transport label on the lead GOH piece, the SKU group is moved forward on the in-feed travel path. Either a powered conveyor or an employee physically



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moves the GOH pieces forward. The GOH pieces travel over an inclined travel path. At the in-feed travel path peak, the GOH pieces are separated into a pre-determined group of pieces per transport label or a predetermined five-piece group. The pieces are mechanically or employee held until there are sufficient empty carrier numbers on the trolleyless travel path to handle or carry the GOH piece number as individual pieces or five-piece groups. As required, a control device on the in-feed decline travel path assures trolleyless carriers move forward on powered conveyor travel path to the in-feed station. As the trolleyless carriers with the required number of open carriers move forward, they in-feed onto a gravity or declined slick rail travel path. As the GOH pieces flow over the slick rail travel path, the GOH pieces arrive at the discharge end where they are automatically transferred from the discharge end onto a trolleyless carrier open space. The GOH piece transfer is completed in a group or five batches or five GOH pieces. The next GOH single or an en masse five-piece group, the GOH pieces are transferred one at a time or are moved forward for the next empty carrier open space. Discreet Identification. The transport label is required to discreetly identify one individual piece or SKU or the lead GOH piece for an en masse or a group of SKUs. In most applications, the transport unit label is a bar-code label that has the black bars and white spaces between the black bars that are presented to a bar-code scanner. For the maximum number of good reads, the bar-code label is presented in the picket fence orientation, which has the black bars and white spaces between the black bars perpendicular to the floor. Other important bar-code label features are (1) the black bars are long, (2) human readable code at the bottom of the black bars, (3) sufficient quiet zones or white space between the first and last black bar’s edge and the label edge to increase the number of good reads, and (4) a hole at the paper top for easy attachment over the hanger hook. Discreet Identification Scanner or Reader. Prior to a divert location, bar-code readers are strategically located above a main trolley travel path. Bar-code scanners are angled to have a line of sight to read each bar code. After a bar-code scanner reads the bar-code transport label, the bar-code scanner sends the information to a microcomputer that controls a trolleyless travel path discharge or divert device. The divert device transfers the individual transport label or piece or a transport label en masse or a SKU group from the main trolleyless travel path onto a divert slick rail travel path. GOH Travel Path Divert Devices and Travel Path. The slick rail travel path is top hung and extends from the main travel path divert location and ends at a pack or work station or storage rail. The slick rail travel path is smooth, even and continuous to assure a low coefficient of friction on the GOH hanger travel path. As the GOH hanger is moved by gravity or employee power over the slick rail travel path, the slick rail travel path diameter assures that the GOH hanger is retained on the travel path. If the GOH hangers have a potential to slip from the slick rail travel path, to minimize GOH pieces falling from the slick rail travel path, a full length gap plate is placed above the slick rail travel path.


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GOH Hanger and Hanger Orientation. The GOH hanger divert device is located to interface with the trolleyless travel path. It is activated and microcomputer controlled by a bar-code scanner reading a bar-code label and sending the bar-code data to a microcomputer. When the microcomputer activates a divert device, the divert device transfers an individual transport label or en masse transport label or a SKU group behind one transport label from the trolleyless carrier main travel path onto the divert slide rail travel path. Multiline or Multiquantity Customer Order Sortation Concept. The GOH hanger provided by your GOH vendor or your order fulfillment transfers each GOH piece from a nonstandard hanger onto an approved GOH hanger. A GOH hanger neck and hook are designed specifically for use on your 200 G GOH trolleyless transport concept. The 200 G GOH concept manufacturer provides the specific hanger hook height from the hanger arms and hanger hook height and width. The features assure that the GOH hanger is transferred from an in-feed station onto a trolleyless carrier open space and from the carrier onto a divert travel path. The second hanger characteristic is that each hanger hook has a specific direction as the hanger is placed onto the in-feed spur. When a GOH hanger is transferred onto the in-feed spur, the hanger hook open space or side faces the slick rail for the GOH direction of travel. 200 G GOH Powered Trolleyless Concept in the Storage Area. W h e n t h e 200 G GOH transport concept is used in the storage area, each entrance to a storage aisle or area requires a divert device and declined slick rail travel path. The horizontal slick rail travel path extends the full length of the storage aisle. This feature permits an employee to move a GOH piece through the entire aisle and complete a GOH storage transaction at any location. After a transport label as an individual piece or en masse or SKU group is diverted onto the slick rail, per the storage area procedure an employee moves and transfers the transport label from the slick rail onto a static storage rail. In most storage applications the entire transport label GOH piece or SKU en masse quantity is transferred from the slick rail to the storage location. 200 G GOH Powered Trolleyless Concept Used as a Single SKU Pick Concept. When the 200 G GOH trolleyless concept is used to pick single line, single quantity SKUs or customer orders, the order picker picks the SKU en masse or as group. After an employee transfers a required SKU quantity from the storage static rail onto the slick rail travel path, the pick employee places a transport label onto the lead GOH piece. With a transport label on the lead GOH piece, an employee pushes the entire SKU quantity on the slick rail travel path to the infeed station. There the pick employee transfers through the in-feed travel path the entire picked SKU quantity from the slick rail travel path onto the required number of trolleyless carriers. As the trolleyless carrier travels from the transport/storage/pick area and arrives in the pack area the transport label (bar code) on the lead GOH piece is read by a bar-code scanning device. This bar-code data is sent to a microcomputer that activates the appropriate trolleyless travel path divert device. The activated divert device



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extends forward and transfers the entire SKU group or en masse from a trolleyless main travel path onto the pack station divert slick rail travel path. This unique divert travel path feature requires that the divert travel path length limits the GOH piece number (meter or feet length) that is associated with one transport label. The disadvantages are that it requires (1) a WMS, (2) employee training, (3) a one pack station receiving one SKU, and (4) a specific hanger and hanger orientation on the travel path. The advantages are that it (1) has a similar investment, (2) does not require trolleys, (3) does not require employees to transfer trolleys onto the travel path, and (4) is easy to operate. 200 G GOH Powered Trolleyless Concept Used as a Multiline or Multiquantity SKU Pick Concept. When the 200 G GOH trolleyless concept is used as a multiline or multiquantity SKU pick concept, it requires a transport label on each GOH piece and a customer ordered and picked sortation area. Since a multiline customer order has two or more GOH pieces and a multiquantity of a single SKU, each GOH piece has the potential to be picked in different storage/pick aisles and locations. To have an effective and cost efficient pick activity and customer order pack station activity, the customer ordered and picked individual pieces require a transport label, and these individual pieces are combined or placed in a sequential order on the pack station divert slick rail travel path. During the GOH piece pick activity by a RF device, the pick employee attaches a transport label to a customer ordered or specific SKU bar code label. This transport label and SKU bar code association is sent from the RF device to the sortation microcomputer. To combine these two transport-labeled individual pieces that are selected from different storage/pick aisles or areas, the 200 G GOH powered trolleyless GOH concept requires a customer order sortation area. After each transport label or GOH piece is transferred from a slick rail travel path onto a carrier empty space or opening, the trolleyless carrier transports the GOH pieces or transport labels from the transport/storage/pick on a powered trolleyless carrier travel path past a bar-code scanner. The bar-code scanner sends the bar-code data to the microcomputer, which has the customer order SKU bar-code data and quantity and the associated transport label. As the GOH SKUs or transport labels travel on the main travel path, the microcomputer activates the appropriate divert device to transfer each transport label onto the sortation travel path divert location. In the trolleyless multiline or multiquantity customer order concept, each GOH piece transport label is transferred from the storage/pick aisle onto a carrier that travels on the main trolleyless travel path. Per a customer order, the appropriate GOH pieces or transport labels are transferred from the main trolleyless trravel path onto the sortation concept travel path. As the transport label piece or GOH item travels on the sortation travel path, each transport label travels past a bar-code scanner, which sends the transport label data to the sortation microcomputer. Per the customer order, the microcomputer activates the appropriate divert device. As each piece or transport label of a customer travels past the bar-code scanner and divert device, the divert device transfers each required customer order transport label


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from the sortation travel path onto a pack station divert slick travel path. All pieces or transport labels or customer orders are diverted to complete a customer order before the next customer ordered and picked pieces or transport labels are diverted onto a pack station slick rail travel path. The disadvantages of this method are that it requires (1) an additional sortation travel concept investment, (2) additional space, and (3) individual piece transport labels. The advantages are that (1) the concept handles both single line and multiline customer ordered and picked SKUs, (2) there are simple pick employee instructions, and (3) each SKU has an identification.

VERTICAL GOH TRANSPORTATION Many existing and proposed GOH order-fulfillment facilities have multiple floor levels. The use of multiple floors or mezzanines within an order-fulfillment facility takes advantage of the airspace above or below the ground floor and lowers the total building investment. GOH vertical (incline or decline) transport systems move GOH pieces on a load-carrying surface between two activities on different elevations. The benefit from these additional levels enables the operation to move GOH pieces costeffectively and efficiently. Compared to horizontal GOH transport systems, vertical GOH transport requires additional safeguards and increased carrier control. The safety requirements are handrails, kick plates, and fire doors around floor penetrations. Additional controls include GOH piece-flow controls to minimize line pressure, travel path underside guarding and side guards, and architectural and structural facility design appropriate to dynamic and static loads and the seismic location. Vertical transport moves GOH pieces between two floors that have different elevations. Most powered vertical incline or decline transports move an individual GOH piece or a GOH trolley in a controlled manner over a fixed travel path. This minimizes GOH damage and ensures a constant GOH piece flow between the two floors. Most nonpowered vertical decline transport systems use gravity or human power to move a GOH trolley or a single GOH piece with uncontrolled flow from a higher to a lower level.

VERTICAL TRANSPORTATION OBJECTIVES The vertical transportation objectives are to move GOH pieces between two floors over a fixed travel path; to ensure that the maximum GOH quantity is delivered per trip, on time, and to the correct location; and to move GOH pieces at the lowest possible operating costs with the minimal GOH piece, building, and equipment damage and employee injury. Common to the various GOH vertical transport systems is the movement of GOH pieces between two locations that are located on different floors. The variables include: • •

An incline or decline travel path The power source required to propel the GOH piece carrier



• • • •

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GOH piece weight and cube load carrier capacity Required GOH piece and load-carrier surface travel path or window Average and peak GOH piece volume and mix per trip GOH piece carrier ability to load and unload GOH pieces

VERTICAL TRANSPORTATION DESIGN PARAMETERS An important GOH vertical-transport design consideration is to ensure that the proposed GOH piece travel path satisfies transport objectives, method design parameters, and building codes. To ensure that the proposed GOH piece vertical transport meets these design objectives, develop order-fulfillment and GOH transport plan-view and detail-view drawings and written functional specifications. The plan-view and detail-view drawings show the company’s management team, vendors, and local building authorities how the GOH transport system will look and operate. The written functional specifications provide the history of the operation and tell the proposed GOH transportsystem story. These drawings and written specifications turn the vertical GOH transport system into a physical link between two floors. Most GOH transport method plan-view drawings are done on a small scale to show the entire vertical GOH travel path from a ground-floor horizontal travel path, through the elevated floor penetration, and onto an elevated-floor horizontal travel path. The plan-view drawing shows the clearances for each GOH piece travel path between other equipment travel paths, order-picking equipment, and building obstacles; the number and slope for each travel path transition location; each floor’s horizontal GOH travel path interface and run-outs; and the total vertical travel path height and the depth between floors. Most detail-view drawings are done on a larger scale than the plan-view drawing. The large-scale drawing shows a plan view or elevation view for a specific location or section on a GOH travel path. The GOH transport design and drawing review process ensures that there is no interference between order-fulfillment equipment and other transport methods, building obstacles, and building floors; that there are the required horizontal travel path run-outs; and that specific GOH transport elevated-floor penetrations include the required personnel safety and fire protection. Prior to initiating GOH transport design, purchase, and implementation, clearly define the GOH transport design parameters. These design parameters are in the written functional specifications and are the basis for the GOH transport drawings. These design parameters include the direction of travel with incline and decline movement; GOH piece characteristics (minimum, average, and maximum length, width, and height; weight; and volume); GOH pieces per trip including surges, average, and peaks; GOH mix and characteristics such as protected or unprotected and destination identification method; travel path distance or total vertical transport system length, including run-outs and transition angle; power requirements; required vertical travel-path carrier clearance from equipment, building obstacles or elevated floor; side and underside guards; elevated floor thickness and structural-support members; elevated floor penetrations; employee safety and fire protection; power


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source and other utilities including air-compressor location, type, quantity and water drain; load-carrying surface support methods and facility seismic location; employee travel path and emergency exits; and other operational factors such as work hours.

COMPUTER SIMULATION

OF A

GOH TRANSPORTATION SYSTEM

A powered, highly mechanized, automated, or high-volume GOH vertical transport system design should be validated by a complete computer simulation of the proposed system. A computer simulation is performed for the existing system, if any, and for the proposed GOH vertical transport system. To develop a computer simulation for your GOH vertical transport system, provide the plan-view and detailview drawings and the written functional specifications for the existing and proposed GOH vertical transport. In addition, provide the simulator with as much data as are available. Where hard data are not available, the simulator can use manufacturer specifications, projections, or estimates of the proposed operation. Clearly state all the assumptions made about data related to the operation that is used in the simulation. When you provide these drawings and data, a computer simulation of the GOH vertical-transport method can be performed in less time and provides more accurate results. The model can test system performance for volumes projected in the company’s growth plan. After the previously mentioned GOH vertical-transport volume data, other GOH transport information and layout drawings are entered into the computer simulation model. The computer program determines the number of trolleys that will move over the travel path, projects potential trolley queue areas, requires additional queue areas or a faster trolley travel speed, and determines the required number of employees for the GOH volume of your operation’s daily work schedule. A good simulation study of the project should include sensitivity analysis of key assumptions and critical operations. Typically, several days, weeks, or months of simulation runs are made and averaged to get a realistic result. It should be stressed, however, that the quality of the final result is directly related to the quality of the data and assumptions that are made about the real system. Simulation in itself is the subject of many books, and the reader should refer to them for more a detailed treatment of the subject.

VERTICAL TRANSPORTATION DESIGN FACTORS When a GOH order-fulfillment operation moves GOH pieces between two floors, and there are constraints that do not permit powered vertical transportation, nonpowered vertical transportation should be considered. The factors that contribute to an efficient, cost-effective, and economical nonpowered vertical transport system are making sure only a few trips per hour are required to handle the volume, the facility or GOH transport layout does not permit a powered GOH vertical transport, there is a low labor wage rate and a large labor pool, the average and peak GOH volume and mix can be moved by a human or gravity force, there is a short vertical travel path distance, no space is available for horizontal travel path run-outs, there is low maintenance capability, and there are limited capital investment funds.



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VARIOUS VERTICAL TRANSPORTATION SYSTEMS These vertical transportation systems move GOH pieces between two floors within a facility. A GOH vertical-transport travel path may be an incline between two floors or a decline between two floors. When vertical transport moves GOH pieces from a lower floor to an elevated floor, it is considered an incline system. When vertical transport moves GOH pieces from an upper floor to a lower floor, it is considered a decline system. The various GOH vertical transport systems are (1) above-floor nonpowered vertical GOH transportation, (2) overhead nonpowered decline GOH transportation, and (3) overhead powered GOH transportation. Above-Floor Nonpowered Vertical GOH Transportation Above-floor nonpowered vertical GOH transport moves your GOH pieces between two floors. The power source is human power. Human-Carried Vertical Transport Human-carried vertical transport is the first vertical transport method, and it is considered the most basic above-floor nonpowered vertical transport method. The unique feature of human-carried vertical transport is the ability to move GOH pieces over a decline or incline vertical travel path. With potential employee injury problems and the low volume that can be handled by the human-carried method, the method is not to be considered for dynamic order-fulfillment operations. For a more detailed review, see the section on human-carried horizontal transportation in this chapter. Overhead Nonpowered Decline GOH Transportation Each of the nonpowered decline methods transfers GOH pieces from an elevated floor to a lower floor. These GOH nonpowered decline methods move your GOH pieces over a fixed travel path in a noncontrolled GOH piece flow; the power source is gravity. The nonpowered decline methods are (1) slick or slide rail and (2) trolley on a tubular rail, strut, C-channel, or inverted bar stock. Slick or Slide Rail The first GOH nonpowered decline transport is the slick or slide rail. The slick rail is the more common name. This is a fixed travel path for single GOH pieces that requires an elevation change between the charge end and the discharge end. The travel path has sufficient clearance on its two sides and its underside to allow long or short GOH pieces to flow over the travel path without hanging up. Since gravity moves GOH pieces over a slick-rail travel path, it is considered a noncontrolled GOH flow method. Key Components. The slick-rail components are open-faced hangers; rail caps; the degree of slope, pitch, or angle; structural-support members; side and underside guards; top and bottom transition locations; bottom-level run-outs and stops; and GOH protection and flow controls.


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The first slick-rail component is the open-faced hanger. The open-faced hanger has two arms and a hook section. The two arms provide support for the GOH piece. The hook section permits the operator to place the hanger onto the slick rail. The hanger’s hook-section diameter matches the slick-rail diameter to ensure that the operator can easily transfer the GOH hanger between the elevated-floor horizontal GOH transportation system and the slick rail, and that the hanger will remain on the rail as it flows over the slick-rail travel path. After a flow test on a slick-rail system, the proper degree of slope and a choice of wood, metal, or plastic hangers are determined for your proposed slick-rail transport. The second slick-rail component is the metal slick-rail travel path. The slick rail is made from hardened metal with a zinc or galvanized exterior. This coating serves to minimize metal-dirt transfer from the operator’s hands to a GOH piece, to ensure a smooth and even hanger travel-path surface, and to provide the minimum coefficient of friction for hanger movement over the travel path. The slope elevation change between the charge end and the discharge end ensures that gravity will pull small, lightweight summer GOH pieces and large, heavyweight winter GOH pieces over the slick rail. The degree of slope for a slick-rail system should not be steep, so that the hangers remain on the slick rail as they travel from the charge end to the discharge end. An inverted-V or curved cap is placed full-length above the slick-rail travel path to prevent hangers from jumping or falling from the travel path during piece flow down the slick rail. An open space between the cap and the slick rail is sufficient to allow hanger flow over the rail travel path. During GOH piece flow over the decline rail travel path, the cap helps to keep hangers on the path. The third set of components includes structural-support members, side guards, and underside guards. These components ensure that the slick-rail travel path is rigid and stable. If GOH a piece falls from the slick-rail travel path, these components minimize GOH piece damage and employee injury. The slick-rail travel path structural-support members are the various hanging, bracing, and piping components supported from the ceiling or on floor stands. To ensure a clear travel path, most slick-rail travel paths have a J-hook. The J-hook is connected by Tek screws to the underside of the slick rail. These structural-support members are similar to those of the nonpowered GOH trolley. For additional information, see the nonpowered GOH trolley section in this chapter. The side guards and underside guards are the next components. The side guards and underside guards are wire- or nylon-mesh components that are attached to the structural-support members. As the GOH pieces flow down the slick-rail travel path, the side guards and underside guards serve to ensure that no one walks into the GOH travel path, and to prevent injury from a moving GOH piece. They also prevent GOH damage if a GOH piece falls from the travel path. The fourth set of slick-rail components consists of the two transition locations. The first transition location is on the elevated floor or slick-rail travel path. At this transition location, the elevated-floor horizontal slick-rail travel path makes a downward bend to start the slick rail’s decline toward the lower floor. This slick-rail bend radius or angle is very slight. The bend radius ensures that hangers flow



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through the bend or crown and that the hanger does not jump or fall from the slickrail travel path. The second transition location is on the lower-floor portion of the slick-rail travel path. At this transition location, the decline slick-rail travel path makes a bend upward to begin the lower finished-floor horizontal run-out travel path. This bend radius is important because hangers travel through this curve at maximum travel speed. With this hanger-flow characteristic, the lower floor transition bend has a low angle. The next slick-rail components are the lower-floor run-out travel paths and end stops. The lower-floor run-out travel path is a slick-rail travel path that has a very gradual slope. This gradual slope provides a travel path section that reduces a GOH piece’s travel speed and provides a length of rail for GOH queuing. The end stop is attached to the slick-rail travel path’s run-out end. The end stop permits GOH pieces to queue on the slick rail run-out travel path. The last slick rail components are the flow control devices. The flow control device is a photo eye. The photo eye is located at a predetermined location along the slick-rail travel path. When the photo eye is blocked by a GOH piece on the slick-rail travel path, the photo eye sends a message to a microcomputer to activate an alarm. The audio or visual alarm indicates to the charge operator that the slickrail travel path is full and that the operator should stop transferring GOH pieces onto the slick-rail travel path’s charge end. At the discharge station, the alarm tells the operator to remove GOH pieces from the slick-rail travel path. Description of Operations. GOH slick-rail transport requires an operator to transfer individual GOH pieces onto the charge end of the slick-rail travel path. As the GOH pieces flow over the travel path, the in-feed station operator continues to transfer GOH pieces onto the slick-rail travel path. Gravity moves the GOH pieces over the travel path. When the GOH pieces arrive at the end of the run-out, they queue against the end stop. The disadvantages of a nonpowered system are that GOH piece flow is not controlled, it requires an elevation change between the charge end and discharge end, it moves GOH pieces only a short distance, it handles a low volume, the openfaced hanger must match the slick-rail diameter, and it requires a large area. The advantages are that it does not require energy, there is a minimal investment, and it is easy to operate and maintain. Tubular Rail, Strut, C-Channel, or Inverted Bar-Stock Travel Path The next nonpowered overhead GOH transport method is the nonpowered trolley on a tubular rail, strut, C-channel, or inverted bar-stock decline travel path. This method moves trolleys from an elevated floor to a lower floor. Nonpowered trolley transport relies on gravity to move the trolleys between two floors and ensure proper trolley flow. To minimize GOH damage, it requires antislide pins on the trolley’s load bar, devices along the trolley travel path to slow travel speed, a gradual slope on the decline travel path, a run-out travel path, underside and side guards, and a photo eye along the trolley decline travel path to indicate when the travel path is full. The GOH overhead nonpowered decline trolley transport method is similar to the GOH above-floor nonpowered transport method. For additional information, see the above-floor overhead nonpowered trolley transportation sections in this chapter.


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Overhead Powered Vertical GOH Transportation Methods Each GOH nonpowered vertical transportation method transfers GOH pieces between two floors. These GOH nonpowered vertical transportation methods move GOH pieces over a fixed incline or decline travel path in a controlled GOH flow. An electric motor is the power source that moves GOH pieces on a hook, on a trolley, or in a trolleyless system. The overhead powered vertical transportation methods are: •

• • • • •

Travel path for a powered chain with pusher dogs. Each pusher dog moves a trolley with pegs over a tubular rail, strut, C-channel, or inverted barstock travel path. Horizontal GOH carousel. Vertical GOH lift. Vertical GOH trolley lift. Vertical GOH carousel. Trolleyless travel path.

Powered Chain with a Trolley The first vertical incline or decline transportation method is the powered chain with pusher dogs and trolleys on a travel path. The options are a tubular rail travel path, an inverted bar-stock travel path, a strut travel path, and a C-channel travel path. Key Design and Operational Considerations. A powered chain with pusher dogs and trolley requires a slope, bend radius, or tangent point for the travel path; structural supports, side guards, underside guards, and employee safety and fire elevated-floor penetrations; a trolley in-feed location to the vertical travel path and the rear head interface; a GOH piece hang bar with antislide pins; and E stops and other stop and start controls. The elevated floor’s opening size and thickness, and the elevated- and lower-floor horizontal travel paths must be considered. The first design factors are the vertical travel-path slope and the bend radius or tangent point. The key components are travel paths for the powered chain with pusher dogs and for the trolley. These travel paths have similarities and differences. The vertical travel-path requirements are that the trolley is moved over the vertical travel path and remains on the travel path, and that the GOH pieces remain on the trolley’s load bar. The first decline or incline travel-path consideration is the travel-path slope or angle between two floors, meaning the decline or incline degree of slope for the straight line between the lower and upper floor’s horizontal trolley travel path. The pitch of the travel path may be (1) too steep, (2) too shallow, or (3) exact. The first degree-of-slope condition is that the travel path slope is steep. The potential travel-path problems are that the trolley falls from the incline or decline travel path, or that GOH pieces fall from the trolley’s load bar due to uncontrolled piece-line pressure on the load bar. The second degree-of-slope condition is that the travel-path slope is shallow. A potential travel-path problem is the requirement for extended travel-path length, and



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thus additional investment in travel path and side and underside guards, as well as additional lower-floor space are required. A shallow degree of slope presents minimal risk of a trolley falling from the trolley travel path and of piece-line pressure on the load bar. When the travel path between two floors has a 30˚ slope, no trolley travel path problems are apparent, and the vertical transport system requires a minimal investment. Most trolley travel-path manufacturers prefer a 30˚ slope; acceptable degrees of slope range from 20˚ to a maximum of 45˚. During powered-chain and trolley-layout design, most trolley manufacturers develop a standard straight vertical travel section. The straight-vertical travel-path section is between the lower-level vertical turn and the elevated-floor vertical turn. The straight travel-path section has a 30˚ slope in relation to the vertical incline or decline travel path, requires a 12-foot, 6-inch opening in the elevated floor (for a 4foot, 6-inch GOH piece), and requires a 12-inch elevated floor. The next overhead powered-chain design factors are the trolley travel-path bends, turn radii, tangents, and transition points. A trolley travel-path tangent point is located at each floor’s horizontal and vertical trolley travel path. At these two trolley travelpath tangent locations, the trolley travels between a horizontal trolley travel path and a vertical trolley travel path. The trolley travel-path vertical-bend design factors are (1) vertical trolley travelpath incline or decline degree of slope, and (2) trolley spool center-to-center spacing. The vertical trolley travel-path incline or decline degree of slope determines the tangent point to the vertical turn. When a trolley travels over a vertical travel path, the tangent points are (1) at the lower floor and (2) at the upper floor. The lower-floor tangent point has a trolley travel from the lower-floor horizontal trolley travel path onto the vertical trolley travel path. During trolley travel through this tangent point, the vertical bend’s internal radius allows the trolley spools to travel through the vertical bend. If the vertical bend’s internal radius is short compared to the dimension between the trolley spools, as the trolley moves through a vertical bend there is a possibility that the trolley spools will fall from the trolley travel path. The upper finished-floor tangent point has a trolley travel from the vertical trolley travel path onto the upper-floor horizontal travel path. During trolley travel through this tangent point, the vertical bend’s external radius allows the trolley spools to travel over the vertical bend. If the external radius is long compared to the dimension between the trolley spools, as a trolley moves through a vertical bend there is a possibility that the trolley spools will fall from the trolley travel path. The next travel-path components are the degree of slope (or pitch or angle) and the vertical travel-path bends. To have an effective GOH vertical trolley transport system, the powered-chain travel path must have a slope and tangent (or transition) points. The powered-chain travel path degree of slope is the straight line between the two floors’ horizontal travel paths. This is also spoken of as the elevation change between the two floors’ horizontal travel paths. Most trolley travel path and poweredchain travel path manufacturers specify a 30˚ line between the two floor elevations. The minimum trolley and powered-chain travel path degree of slope is 20˚ and the maximum is 45˚.


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With the powered chain in a C-channel enclosed track on a vertical travel path, the vertical travel path considerations are (1) tangent locations for the lower horizontal travel path and the incline or decline travel path, (2) tangent locations for the incline or decline travel path and the upper finished-floor horizontal travel path. The powered-chain transition location considerations are (1) the straight vertical incline or decline powered-chain travel path on the last point of the lower finishedfloor vertical incline or decline turn and the start point of the upper finished-floor vertical turn, and (2) the total vertical distance between the lower-floor and elevatedfloor tangent points. Smooth powered-chain flow over a vertical incline or decline travel path is ensured by (1) at least a 12-inch straight horizontal powered-chain travel-path section prior to the vertical incline or decline turn, (2) a standard degree of slope on the vertical bend (20˚, 30˚, or 45˚), (3) the overall rise of the vertical turn arc (the elevation difference between the horizontal powered-chain travel path’s center and the straight vertical powered-chain travel path), (4) the overall elevation change between the lower-floor horizontal powered-chain travel path and the upper-floor horizontal powered-chain travel path, and (5) the radius for the lower- and upperfloor vertical bends. Depending on whether your vertical powered-chain incline or decline travel path is at a slope of 20˚, 30˚, or 45˚, your powered-chain manufacturer has standard vertical turns with radii of 2, 3, 4, 5, 6, 7, 8, 10, or 13 inches. The next components are the structural-support members, side guards, and underside guarding; and the employee safety and elevated-floor penetration risk management factors for both travel paths. A ceiling- or floor-supported vertical powered-chain travel path transportation system’s structural-support members, side guards, and underside guards are the same as those for a horizontal powered-chain travel path transportation system. For a review we refer the reader to the powered-chain and trolley horizontal travel-path section of this chapter. Concerns about employee safety and fire-management protection on the elevated floor are the next vertical-path design factors. When an overhead powered chain in a C-channel track with a trolley travel path enters the elevated floor, employee-safety handrails and kick-plate barriers may be around all four sides of the opening, or in the shape of a coral. The coral design has handrails on two sides and kick plates on four sides. The kick plate is located 4 to 6 feet from the elevated floor opening’s end. A kick plate in this location acts as a trip bar for an employee who walks toward the opening. With no handrails on this fourth side, the GOH pieces have an unobstructed travel path onto the elevated floor. Both of these elevated-floor penetration employee-safety designs require approval by the local building code inspector and your company’s insurance company. The elevated-floor opening fire-protection options are (1) the vestibule or doghouse method and (2) the deluge method. A deluge fire-sprinkler system directs a high concentration of water at the desired location. The vestibule or doghouse method’s components are a two-part fire door, smoke detectors with controls, overhead powered-chain controls, and photo eyes or other trolley sensing devices.



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In the vestibule method, when the smoke detectors sense smoke and the photo eyes ensure that there is no trolley in the fire-door path, the control system stops the overhead powered-chain movement. With the overhead powered-chain movement halted, the fire door has an unobstructed path to close the passageway. The next considerations are (1) the trolley in-feed locations and (2) the poweredchain hard pusher-dog interface with the trolley’s front spool. At the trolley in-feed location, a trolley is transferred from the finished-floor horizontal nonpowered travel path onto the powered-chain-and-trolley travel path. At this location, lower-floor horizontal trolley travel is directly under the poweredchain travel path. As the powered-chain travel path gradually declines, the poweredchain hard pusher dog declines toward the finished floor. As the hard pusher-dog elevation becomes lower, a powered-chain hard pusher dog comes in contact with the trolley’s front head. After the powered-chain hard pusher dog comes in contact with the trolley’s front head, the trolley is pushed by the powered-chain hard pusher dog over the vertical or incline travel path. The trolley in-feed options are (1) manual, (2) mechanized, and (3) automatic or hold-back and release. These options are reviewed in the powered-chain and trolley section in this chapter. The next factors are the trolley load-bar antislide pins. Trolley load-bar antislide pins are galvanized, zinc, or coated metal pins that are inserted by the manufacturer into the trolley load bar’s top surface. There are four to five pins per load bar. These pins extend upward approximately 3/4 to 1 inch above the trolley’s load bar surface and create a section between two pins. During vertical trolley travel with several GOH pieces in a section between two pins, the pines serve to (1) minimize GOH piece-line pressure and falling from the trolley load bar, and (2) reduce hanger entanglement. The next considerations are the E stops and other powered-chain movement controls. The E-stop devices are red push buttons that are strategically located on the lower and upper floors. The E-stop locations provide an employee with a trolley travel-path view and with easy access to the E-stop push button. The push button locations are reviewed by you and your manufacturer for potential trolley jams or trolley transport problems. Another decline travel method control device is the antirunaway limit switch. The antirunaway limit switch is located on each powered-chain decline travel path. If there is a break in the powered chain or another uncontrolled chain movement, the control system activates the antirunaway switch, which stops the drive motor and the powered chain’s movement and turns the start button to the “off“ position. To restart the system requires a turn-on procedure similar to the normal E-stop turnon procedure. The other powered-chain controls are located on the control panel. These controls are reviewed in the horizontal powered-chain and trolley section in this chapter. The final factor that affects powered-chain travel path design is the elevated-floor penetration length and width and the elevated-floor thickness. The elevated-floor opening’s length must be sufficient to permit the powered chain with pusher dogs, trolley travel paths, and GOH pieces to travel from the lower floor, through the opening, and onto the upper floor. The factors that determine the elevated-floor opening’s length are (1) the powered chain with pusher dogs and the trolley travel-path


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slopes, (2) the powered-chain travel path overall length, (3) the GOH piece length, plus travel-path structural support and safety members, and (4) the elevated floor’s thickness. The factors that determines the floor opening’s width are (1) the maximum GOH piece width and number and (2) structural support and support members. GOH Carousel The next GOH powered vertical-transport method is the GOH carousel-transport method. The GOH carousel method is a motor- and sprocket-propelled transport method that moves wheel-hung slots or opening sections. These wheel-hung slot sections are connected to form an endless loop. Each slot section is moved by a motor-driven tooth sprocket that interfaces with the wheel-hung slot section necks. This interface and the sprocket’s turning action moves each wheel slot section over a fixed travel path. The wheel-section fixed travel path is a tubular rail that directs the wheel slots’ travel past a GOH piece in-feed station and a GOH piece pick station. The GOH piece travel-path height and side clearances are determined by GOH maximum length and width. Design Parameters and Operational Characteristics. With the previously mentioned GOH-piece carousel design parameters and operational characteristics, the GOH carousel method’s flexibility permits the method to be designed as a horizontal and vertical GOH transportation method. The GOH carousel is an endless loop; the GOH carousel design and operational characteristics are the same for an incline or decline GOH travel path. In considering a vertical GOH carousel, the design parameters are (1) the travelpath incline and decline degree of slope, (2) travel-path structural-support members, (3) side guards and underside guards for employee safety and protection for the elevated-floor penetration, and (4) E stops and other travel-path control devices. The first GOH carousel factor is that the travel path is required to incline and decline between two floors. The facility’s ceiling-height requirement for a standard overhead GOH carousel travel path is 10, 11, 12, 13, or 14 feet above the floor. With an elevated GOH travel path at a high elevation, to transfer GOH pieces between the in-feed or pick station and the GOH carousel carrier, the GOH carouselcarrier travel path declines to a lower elevation. At this elevation, the GOH carousel carrier is at the proper elevation for an employee to perform a GOH piece deposit or pick transaction. When the overhead GOH-carousel travel path declines to access the transfer station or inclines to the normal overhead travel-path elevation, the GOH carousel travel path becomes a vertical decline or incline travel path. The GOH vertical travel path is the transport link that connects each floor’s GOH horizontal travel path to any GOH activity. The maximum slope of the GOH vertical travel path is 30 to 45 degrees. The carousel travel path has the flexibility to travel on one floor level or between two floor levels. The carousel travel path can have an L, T, four-finger, U, E, or F shape. The next overhead vertical GOH-carousel transportation method factors are the travel-path structural-support members. The structural-support members are the hardened metal pipes, posts, angle irons, stands, and racks that provide support,



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rigidity, and stability to the GOH-carousel travel path and other components. These structural-support members are welded or connected with nuts and bolts. The structural-support members are floor-supported or ceiling-hung. The GOH-carousel travel-path structural-support member factors are (1) vertical travel-path slope and available facility space, (2) verification by an architectural or structural engineer that the ceiling or finished floor can support the system, and (3) ability to design employee safety and fire protection for the elevated-floor travel path. The next components are the cross support members, side guards, underside guards, employee safety features, and fire protection of the elevated-floor penetration. The carousel’s cross support members, side guards, underside guards, employee safety features, and fire protection of the elevated-floor penetration are the same as for the powered-chain-with-a-trolley travel path method. These are reviewed in the powered-chain and trolley vertical transportation section in this chapter. Vertical GOH Lift or Conveyor The next vertical-powered GOH transportation method is the vertical GOH lift. This method moves an individual GOH piece between two floors of a facility. The verticalpowered GOH lift method uses an electric motor to pull a closed-loop linkage chain with hanger hooks over a fixed travel path. This fixed travel path is from a lower floor over a vertical travel path to an elevated floor. When vertical GOH lift is compared to the standard powered-chain pusher dogs and trolley method, the vertical GOH lift features are (1) it handles one GOH piece per peg; (2) the peg extends outward; and (3) the GOH travel path is vertical, which requires less floor space. Key Components. The vertical GOH lift method components are (1) upright posts and structural-support members; (2) electric motor, take-up device, and sprocket; (3) closed-loop linkage chain with pegs; (4) controls and safety features; and (5) on each floor, horizontal GOH travel-path in-feed and out-feed stations. The first vertical GOH lift components are the upright posts and structuralsupport members (Figure 4.11). The upright posts are hardened metal members that provide a rigid and stable travel path over the entire length of the vertical lift. These upright posts are designed to fit your vertical GOH lift application. The structuralsupport frame designs are (1) wall mounted or (2) lower-floor supported. The wallmounted design has welded members that are connected to the rear side. These members are attached to the facility’s interior wall. The wall material, seismic location, and manufacturer standards determine the number, location, and wall connection method for mounting to a wall. With the floor-supported design, the upright posts’ base plates are anchored to the floor at predetermined intervals along a wall. Depending on the wall material, seismic location, and manufacturer standards, the vertical GOH lift is floor supported or wall mounted. The other structural-support members are at the GOH vertical lift’s top and bottom. These top and bottom members are connected to the upright posts by welds or nuts and bolts. These members provide rigidity and stability to the vertical GOH lift travel path. The top members provide a location for an electric motor, sprocket, and take-up device.



FIGURE 4.11 Examples of GOH mounting methods. (From Railex Corporation, Queens, NY. With permission.)

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The other upright posts and structural members are made from standard 1/2- to / -inch gusset-reinforced steel and have a coated exterior finish. Depending on the available space, GOH piece dimensions, and manufacturer standards, the vertical top members range from 30 to 38 inches in width. The second vertical GOH lift transport method components are the electric motor, sprocket, and take-up device. These devices are the components that pull the linkage and peg (and thus GOH pieces) between the two floors. The standard electric motor is 1/3 to 1/2 horsepower, 115 volts, and single phase. Your design parameters, peg number, and travel path distance enable your manufacturer to determine the motor horsepower. The sprocket drive unit is a standard ball-bearing type that is pre-lubricated and sealed with an enclosed gear head and a 1-inch diameter drive shaft. The linkage take-up device is a manually adjustable type. The third vertical GOH lift component is the closed-loop linkage with pegs. The linkage is an endless loop with pegs that is the transport link between the two floors. The linkage’s open spacings match the sprocket teeth and allow the linkage to move over the travel path. The other linkage characteristics are that it is prelubricated, self-lubricating, and prestressed; it also has an ultimate strength of 6000 pounds and a travel speed of 45 to 60 feet per minute. The powered linkage is propelled through several bends, and the linkage moves at an angle. The linkage’s articulation feature minimizes or resists wear. The closed-loop linkage travel path is a standard C-channel hardened metal member with the C’s open face toward the employee workstation. The GOH peg is attached to the linkage and extends outward from the C-channel opening. The peg diameter matches your open-faced hanger’s opening diameter. Your GOH piece width, operation type, or GOH piece out-feed transfer and your manufacturer’s standards determine the peg’s outward extension. The standard peg load capacity ranges from 10 to 20 pounds and spacing on the linkage ranges from 5 to 6 feet on centers. Your GOH piece length, travel path configuration, and manufacturer standards determine the peg spacing on a linkage. The standard structural-support member lengths and linkage lift heights are: 10 feet with an 8-foot linkage lift; 11 feet with a 9-foot linkage lift; 12 feet with a 10foot linkage lift; 13 feet with an 11-foot linkage lift; 14 feet with a 12-foot linkage lift; 15 feet with a 13-foot linkage lift; 16 feet with a 14-foot linkage lift; 17 feet with a 15-foot linkage lift; 18 feet with a 16-foot linkage lift; and 19 feet with an 18-foot linkage lift. The next vertical GOH lift method components are the controls and safety features. These components are the off/on controls, electric wiring, E-stop devices, and enclosures. An enclosure consists of a coated 12-guage metal material with four sides and a 10-inch width. The final components of the vertical GOH lift system are the GOH piece infeed transfer station and the pick station. These stations are for the operator to transfer a GOH piece between the workstation and the vertical GOH-piece peg. The vertical lift transfer stations are (1) a manual in-feed transfer station, (2) a manual pick station, and (3) an automatic out-feed transfer station. In a manual GOH piece in-feed transfer station, as one vertical GOH lift’s empty pegs pass the transfer station, the operator transfers a GOH piece with an open-faced 3 16


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hanger from the workstation onto an empty peg. The workstation has a cartload bar, a trolley hang bar, or a slick rail. With an automatic GOH vertical lift out-feed transfer station, as a powered linkage peg with a GOH piece approaches the out-feed transfer station, the GOH piece slides onto a slick rail. The slick rail extends outward into the GOH vertical lift peg’s travel path. GOH piece transfer occurs as the peg travels past the slickrail extension. The extension automatically transfers the GOH piece from the peg onto the slick rail. Description of Operations. After a GOH piece on an open-faced hanger is moved to the in-feed transfer station, an employee places an individual GOH piece onto an empty vertical GOH lift peg. The peg with the GOH piece is pulled downward to the bottom of the vertical GOH lift and upward to the highest elevation. From the highest elevation in the linkage travel path, the GOH piece travels downward to the out-feed station. As the powered linkage passes the discharge station, the operator manually removes the GOH piece from the peg and places the GOH piece onto a cart load bar, trolley hang bar, or slick rail. An optional discharge transfer method is the automatic discharge transfer method, where a GOH piece is transferred from the peg to a slick rail. As a powered linkage passes through the elevated floor, the linkage travel path makes a 90˚ turn inward and downward toward the lower-floor in-feed transfer station. The disadvantages are that the system (1) handles a low volume, (2) handles only one GOH piece per peg, (3) requires an employee to transfer a GOH piece onto an empty peg, and (4) requires another GOH transport method on each finished floor. The advantages are that there is (1) powered transfer of GOH pieces between two floors, (2) complete vertical transport activity in a small building area, (3) possible automatic GOH piece discharge, (4) floor or wall support, and (5) a quiet operation. Vertical GOH Trolley Lift The next vertical powered GOH transportation method is the vertical GOH trolleylift method. The powered vertical GOH trolley-lift transportation method moves a GOH trolley between two floors. The vertical trolley lift has the capacity to move a fully loaded trolley up an incline or down a decline. The vertical trolley-lift components are (1) a vertical moving trolley rail with two adjustable end stops and travel guides; (2) structural-support members and guide tracks; (3) an electric drive motor with a nonpowered guide sprocket and a closed-loop endless chain with two trolley-lift bar studs; (4) a start/stop control and other controls; and (5) on each finished-floor level, a GOH horizontal transportation system. The first vertical trolley-lift components are the trolley-lift bar and trolley-lift rail with two adjustable end stops. Each of the vertical trolley-lift support arms is securely attached to the square or H-frame structural-support member’s base. Each arm extends outward and provides a location for secure trolley-rail attachment. The two adjustable end stops are manually activated stops. These stops ensure that the trolley is moved onto and off the lift bar; that the trolley-lift bar is stopped properly; and that during travel, the trolley remains on the trolley lift bar.



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The second vertical trolley-lift components are the structural-support members and studded travel guides. The structural-support members are the hardened metal members that provide rigidity and stability to the vertical trolley-lift travel path. These members are welded together to form a rectangular frame. Each upright post’s front has two studded travel guide openings (or C openings). To ensure a rigid structure, there are top and bottom cross members, and between the top and bottom members (as required by the height) are one or two evenly spaced cross members. When installed against a wall, the cross members serve as anchor locations to secure a vertical trolley lift to a wall. Your vertical trolley-lift lower-floor design feature is that the base legs are attached to each upright post’s base. These legs have predrilled holes to anchor the frame to the floor. The standard vertical trolley-lift frame has several overall design features. The first features are a bottom-located motor with a top frame at 10 feet above the lower floor for an upper trolley at an 8-foot elevation above the lower floor, a top frame at 15 feet above the lower floor for an upper trolley at a 13-foot elevation above the lower floor, or a top frame at 20 feet above the lower floor for an upper trolley at an 18-foot elevation above the lower floor. The second features are a bottom-located motor with a top frame at 14 feet above the lower floor for an upper trolley at an 8-foot elevation above the lower floor, a top frame at 19 feet above the lower floor for an upper trolley at a 13-foot elevation above the lower floor, or a top frame at 24 feet above the lower floor for an upper trolley at an 18-foot elevation above the lower floor. The next vertical trolley-lift component is the H- or square-shaped frame member with two travel guides. The H- or square-shaped frame member has two arms attached to the frame. The square- or H-shaped frame support member’s two horizontal cross bars interface with the motor-powered chain stud to ensure that the trolley is moved over the travel path and that the trolley-lift rail is even and level. Both travel guides extend outward from the square-shaped frame member and are inserted into the C opening in the track. With the travel guides in the C-opening track, and as the vertical trolley lift moves between two elevations, these travel guides inside the C opening in the track serve to ensure accurate travel over the vertical travel path. The next vertical trolley-lift components are (1) the electric drive motor with a sprocket, (2) the guide sprocket, and (3) the endless closed-loop chain with trolleylift bar studs. The electric motor has forward and reverse movement capability. The drive motor provides the power to turn the sprocket. As the drive sprocket turns and interfaces with the endless closed-loop chain, the chain is moved over the fixed travel path. Connected to the chain are two hardened metal studs. These studs extend outward to a dimension that permits the studs to come in contact with the vertical trolley-lift cross member. As the chain is moved over a travel path, the chain stud comes in contact with the trolley-lift bar’s H-frame member and moves the trolleylift bar to the appropriate finished-floor level. The powered-chain travel path is an elliptical travel path with two straight runs over two sprockets. The first sprocket is the powered sprocket, and the second is the


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nonpowered sprocket. The nonpowered sprocket serves as a guide to the chain as the chain travels over the travel path. The next vertical trolley-lift components are the stop/start controls and other controls that move the trolley-lift bar. Each floor level has a stop/start control. These devices start and stop the drive motor. Another control feature is a brake motor control to ensure accurate position of the trolley-lift bar. The bar at the proper elevation above the appropriate floor ensures a smooth, even, and easy trolley transfer onto the floor’s horizontal trolley transport system. The last vertical trolley-lift component is each floor’s horizontal trolley-transport system. Each floor’s system ensures that (1) the appropriate trolley is ready for transfer onto the vertical trolley-lift bar, and (2) the trolley on the bar is transferred onto the appropriate floor’s horizontal trolley transport system. The disadvantages are that the method (1) requires a high capital investment, (2) handles one trolley per trip, (3) requires an employee to operate it, and (4) has limited elevation-change ability. The advantages are that it (1) requires no run-out, (2) is easy to operate, (3) handles a trolley, and (4) requires a small square-foot area.

GOH STATIC-RAIL STORAGE AND PICK METHODS The objectives for a GOH storage and pick static-rail method are to (1) provide storage and pick positions for GOH pieces and (2) ensure that the pick-position inventory quantity is sufficient to satisfy a customer-order.

VARIOUS GOH STORAGE AND KEY COMPONENTS

AND

PICK DESIGN PARAMETERS

GOH storage and pick method design parameters, capacity, and key components are determined by the physical GOH piece features: length, width, depth or bulk, the number of GOH pieces per linear foot, and weight. The GOH storage and pick position lengths are 5 2/3 to 6 1/2 feet for a long GOH piece and 3 1/4 to 3 1/2 feet for a short GOH piece. The GOH piece width is 27 inches. The depth for summer GOH pieces or dresses is 12 to 16 pieces per linear foot. The depth for winter GOH pieces or coats is 8 to 10 pieces per linear foot.

GOH STORAGE

AND

PICK POSITION DESIGN CONSIDERATIONS

The design objective for a GOH storage and pick rail method is to provide the storage and pick positions for GOH pieces. The method’s components are a storage rail, a storage-rail support structure, and an employee walkway. Standard pallet-rack frames, cantilevered rack posts, tubular pipes, and pallet containers are the most common GOH rail support members. The GOH storage and pick rail is attached to a single or double cantilevered arm. The cantilevered arms are attached with Tek screws to the posts and extend outward toward the pick aisle. The individual GOH pieces are hung on this rail. The rail is approximately 1 5/16 inch in diameter and is supported every 6 feet. When long GOH pieces are placed into the storage and pick



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area, the rail is set at 81 inches above the floor. With short GOH pieces, there are two rail levels. The lower rail is set at 3 1/4 to 3 1/2 feet above the floor and the upper rail is set at 6 1/2 to 7 feet above the floor. To minimize GOH damage and the risk of employee injury, rubber caps are placed on the rail ends.

GOH STORAGE

AND

PICK RAIL CAPACITY

The GOH storage and pick rail capacity is 150 pounds per foot; rails can hold 8 to 10 thick GOH pieces and 12 to 16 thin GOH pieces. If a GOH rack has a rail-arm support member, the GOH load is carried between the two posts.

VARIOUS STATIC-RAIL STORAGE

AND

PICK METHODS

The various static-rail storage and pick systems are (1) a standard pallet rack with load beams, cross members, and rails, with a powered-vehicle travel path or an employee aisle; (2) a cantilevered rack with support arms and rails; (3) a tubular pipe with support arms and load rails; and (4) a pallet container with a load rail. Standard Pallet-Rack Method The first static-rail storage method is the standard pallet-rack GOH storage and pick method. The standard pallet-rack GOH storage and pick method’s components are upright frames, load beams, GOH piece rail retainers, and cross members. When a standard pallet-rack method is designed for a GOH storage and pick system, the options are to use a powered vehicle that operates in a guided aisle, or an employee and a GOH cart or overhead trolley. The powered-vehicle method is a simple method to design. The powered-vehicle method has standard pallet-rack upright frames that have base plates with anchor holes. The upright frame depth is 30 to 60 inches between the two post interiors. Per the manufacturer and the seismic location, the appropriate load-beam levels and back-to-back space device are used to ensure the structure’s stability and rigidity. Upright-frame internal cross members with predrilled holes secure the storage and pick rail. Connection devices and a guided, powered vehicle are the final components. The first standard pallet-rack component is the upright frame. The standard palletrack upright frame has two upright posts, horizontal and diagonal cross members, and a base plate with predrilled anchor holes. To handle a 27- to 30-inch wide GOH piece, rack row and aisle layout design includes two upright-frame options. If your GOH storage and pick area layout has a single deep GOH rack row, the upright frame members are a minimum of 27 to 30 inches deep. The 30-inch deep upright frame has one GOH rail in the center of the rack. If your GOH storage and pick area layout has back-to-back GOH rack rows, the layout options are to first use back-to-back single 30-inch deep upright frames. This design has maximum flexibility to handle GOH length changes but has a slight cost increase. The single deep upright frame was previously reviewed in this section. The other option is to use a 60-inch deep frame or two 30-inch deep frames. The 60-inch upright frame has two GOH rails that are evenly spaced, and provides


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sufficient clear space between the two upright posts for two GOH pieces. This design has limited GOH size flexibility but a lower rack cost. With the 30-to-60-inch pallet-rack method, from an aisle-guided, powered-vehicle platform, the operator has access to any GOH piece on a storage and pick rail. The second standard pallet-rack components are load beams and GOH retainers. The load beams are standard pallet-rack components that have two end plates. These end plates connect to the upright posts to form a stable and rigid structure. The load beams are not designed to support a load weight; they have the longest possible center-to-center span and are varied to compensate for building columns. As required by your manufacturer, local codes, and seismic location, the appropriate back-to-back ties, overhead ties, wall ties, and load-beam levels are installed to build a stable and rigid system. The next standard pallet-rack GOH component is the GOH retainer. The GOH retainer is a rope, a piece of plastic or cardboard, or a pipe that is attached to the face of the upright frame across the full length of the aisle. As the powered vehicle travels in the aisle, the vehicle creates wind, and the GOH retainer minimizes the swinging of a GOH piece’s bottom section, which causes GOH piece damage. The final standard pallet-rack components for a GOH storage and pick system are the cross member with a rail, the rail secure device, and the storage and pick rail. The cross member is a piece of angled iron that spans the two upright posts. The cross member extends downward and secures the GOH rail 2 inches below the load beam. Two cross members per rack opening provide a location for GOH rail attachment and some stability and rigidity. These angled iron members ensure connection to the load beams, provide structural strength to support a fully loaded rail, and include a predrilled hole or holes for the secure rail attachment or to permit Tek-screw drilling to secure the device on the cross member. The next component is the rail secure device. The rail secure-device options are a U bolt and nuts that require predrilled holes in a cross member, and a hooked clamp device that is Tek-screwed into the cross member. The final component is the storage and pick rail. The storage and pick rail is a standard GOH storage and pick rail with storage and pick position identifiers. The rail and position identifiers were previously reviewed in this chapter. The various GOH rack depths maximize space utilization and rack and aisle layout; the racks surround the building columns. The second standard pallet-rack method is an employee-aisle GOH method. This method has the same pallet-rack design and components, but an employee walkway replaces the powered-vehicle travel path as the method to complete GOH piece transactions. With an elevated employee aisle as part of the standard pallet-rack GOH method, the additional components are (1) structural-support members and a deck surface; (2) kick plates and full-length handrails; and (3) per local code, wire-mesh “cargo-tainer“ or solid barrier in any cavity, plus fire sprinklers and light fixtures. The employee-aisle methods are the floor method and the floor method with GOH cavities. The options are for GOH pieces to hang on a rail above a solid or wire-mesh surface cavity, and for GOH pieces to hang below the aisle where there is a solid deck for an elevated walkway.



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Aisle or Floor Method The floor method has an employee aisle as the building floor. In this method all GOH rails are reachable by an employee. This method has one long GOH rail and two short GOH rails. The various aisle material groups are (1) the solid group, which includes plywood, coated plywood, masonite on plywood, tile on plywood, polytexture, metal plate, and solid grating; and (2) the open group, which includes grating bars, preformed deck gratings, open planks or grip struts, and perforated metal or expanded metal. The plywood aisle surface is a solid material. The disadvantages are that, with high employee traffic, it wears quickly and the bare plywood surface is difficult to clean. The advantage is that it is inexpensive. The coated plywood aisle surface has the same characteristics as the bare plywood aisle surface. Additional advantages are that it is easier to clean and the surface reflects light. The masonite-on-plywood aisle surface is plywood with a masonite overlay. The masonite overlay is placed in the high-traffic aisles to provide a surface that resists wear. The slight elevation change between the masonite and plywood creates a housekeeping problem and may cause employees to trip. The tile-on-plywood aisle surface is a plywood aisle with a tile cover. This solid aisle surface is a long-wear surface and is even along the entire aisle. These features permit easy housekeeping and minimal employee tripping. The aisle requires additional installation time, even floor support, and an adhesive that is applied between the plywood and floor support. The next aisle surface is polytexture material. This aisle material has a textured high-density polyethylene overlay attached to the plywood. This feature creates a smooth and even walkway surface with less installation time. The polytexture surface provides an easy aisle to clean. As part of the installation work, any gaps between two polytexture aisle sections are filled with an epoxy filler and are smoothed even with the aisle surface. All fastening-screw tops are coated to match the polytexture color. With the five previous aisle surfaces, the aisle material is fastened to a steel roof deck with flathead self-tapping screws that are spaced on 12-inch centers along the two sides and between two walkway sections. The plywood material is a minimum of 3/4 inch thick; it is interior, APA class 1 or 2 plywood and is square cut or tongueand-groove on all edges with the C side up. Fire-treated tongue-and-groove plywood has a potential for uneven edges and creates installation problems that result in an uneven aisle surface. The next solid aisle surface material is the metal floor-plate type. This aisle surface has a solid metal plate with diamond shapes on its surface. The final solid aisle surface material is the plank grating type. To improve rigidity on the plank grating aisle, additional cross-aisle members are required and planks are crimped or welded together. The first open aisle material is the grated-plank type. Grated-plank types include bar grating, grip-strut grating, and open-plank grating. Each type provides sufficient support for an employee aisle. When using the deck types, the deck requires addi-


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tional cross-aisle structural members, and for rigidity all planks are crimped or welded together. The next aisle surface is perforated metal or expanded metal. This material consists of metal sheets that are supported by cross-aisle members. The first components are the aisle structural-support members. The walkway’s basic structural-support components are standard rack load beams and cross-aisle members. The rack load beams are standard pallet-rack components with one load beam on each side of the aisle. The center-to-center load-beam dimension is determined by your projected total structural and aisle weight, manufacturer standards, your desired aisle rigidity, and any requirement to avoid building columns. Box-step or H load beams are an optional design. The box or H load-beam types provides additional surface for aisle deck support. For additional aisle deck security, self-tapping screws are used along the deck and at the load-beam location. The next aisle component is the cross-aisle member. Cross-aisle members are metal members that span the distance between the two load beams. Each cross-aisle member is Tek-screwed or hook-attached to the load beam’s top surface. At each walkway deck joint there are at least two cross-aisle members. One cross-aisle member is under each end section of the aisle deck material. Per your company and manufacturer standards, additional cross-aisle members are added to the walkway. The next aisle components are the kick plates and handrails. The kick plates and handrails are hardened and coated metal components that lie full-length on the aisle sides. The kick plates and handrails are prewelded members. The heights of the kick plates and handrails are per local code. The kick-plate or handrail section is the length that fits between two upright support members. During installation, this section is secured by nuts and bolts or welded to the posts and load beams. Per local code and your company’s risk-management policy, fire sprinklers, light fixtures, and stairways are installed. This system requires a slightly higher capital investment and a maximum number of order pickers per shift. It permits easy employee access to all SKUs on the storage and pick rail and does not require a battery-charging station. The upright post keeps GOH pieces from sliding over the storage and pick rail. The system is used in facilities that have a high ceiling. Cantilevered Rack Storage and Pick Method The next GOH structural-support method employs a cantilevered rack with support arms. Cantilevered rack components are (1) upright posts and base plates; (2) support arms with a GOH rail; (3) bracing; (4) a powered, guided vehicle with vertical and horizontal travel capability; and (5) light fixtures and fire sprinklers. The cantilevered rack method has one or two rows. Between two rows is the powered-vehicle aisle. At the required elevations, support arms are attached to the cantilevered rack’s upright posts. These arms extend outward toward the poweredvehicle aisle. Each arm is a location where the storage and pick rail is attached with Tek screws. To complete GOH storage and pick transactions, the operator drives a guided vehicle in the aisle. As the vehicle travels in the aisle, the vehicle has the ability to



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move in both vertical and horizontal directions. The feature ensures that the order picker has access to all GOH storage and pick positions. Per the local code or your company’s risk-management standards, fire sprinklers and light fixtures are installed in the aisle. The system has limited rail levels and a high cost per position. It is used only with a powered, guided vehicle. The cantilevered rack method is not to be considered for a dynamic GOH operation. Pipe-with-Rail Storage and Pick Method The third GOH storage and pick structural-support method is the pipe-with-a-rail method. In a multilevel facility with a 12-foot clear ceiling height on each finished floor, pipe structural support is used to support a GOH storage and pick rail. The pipe-with-rail components are (1) upright support pipes; (2) floor or ceiling upright pipe anchors; (3) overhead cross structural-support members; (4) connection parts including suspensions, flanges, braces, cross clamps, and Tek screws; (5) single-arm brackets, double-arm brackets, and wall brackets; (6) storage and pick rails with rubber ends; and (7) position identification devices. Key Components The first component of the method is the upright support pipe. The upright support pipe is a tubing section that is cut to fit into the open space between the finished floor and ceiling. The standard pipe is coated with zinc, chrome, or paint. This feature minimizes dirt transfer from an employee’s sweaty hands. The GOH pipe installation design has the pipes spaced on 5- or 6-foot centers. Per your maximum GOH load weight, height, seismic location, storage and pick area layout, and manufacturer standards, your manufacturer determines the spacing centers. The next standard upright pipe features are the support member gauge, the wall thickness, the yield and tensile strength, and the outside dimensions (OD). The upright pipe yield is 60,000 psi at a minimum, and the tensile strength is a minimum of 75,000 psi. The upright pipe’s standard OD, gauge, and wall thickness are as follows: •

•

•

•

For lightweight GOH pieces 1 to 3 levels high or heavyweight GOH pieces 1 to 2 levels high, and at an 8-foot maximum height, the OD is 1 1/16 inches, the gauge is 14, and the wall thickness is 0.083. For lightweight GOH pieces 1 to 3 levels high or heavyweight GOH pieces 1 to 2 levels high, and at a 10-foot 6-inch maximum height, the OD is 1 5/16 inches, the gauge is 14, and the wall thickness is 0.083. For lightweight GOH pieces 1 to 3 levels high or heavyweight GOH pieces 1 to 2 levels high, and at a 12-foot maximum height, the OD is 1 1/4 inches, the gauge is 12, and the wall thickness is 1.09. For lightweight GOH pieces 1 to 3 levels high or heavyweight GOH pieces 1 to 2 levels high, and at a 14-foot maximum height, the OD is 1 1/4 inches, the gauge is 14, and the wall thickness is 0.083.


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•

•

•

For lightweight GOH pieces 1 to 3 levels high or heavyweight GOH pieces 1 to 2 levels high, and at a 14-foot maximum height, the OD is 1.9 inches, the gauge is 14, and the wall thickness is 0.083. For lightweight GOH pieces 1 to 3 levels high or heavyweight GOH pieces 1 to 2 levels high, and at a 20-foot maximum height, the OD is 2 1/4 inches, the gauge is 11, and the wall thickness is 0.12. For lightweight GOH pieces 1 to 3 levels high or heavyweight GOH pieces 1 to 2 levels high, and at a 20-foot maximum height, the OD is 2 1/4 inches, the gauge is 14, and the wall thickness is 0.12.

The pipe’s OD, gauge, and wall-thickness factors are maximum GOH load weight, storage elevation, seismic location, and manufacturer standards. The last upright pipe factor is the upright pipe overall length. The pipe length is determined by the manufacturer and spans the distance from the finished floor to the ceiling. The next GOH storage and pick rail structural-support components are the floor and ceiling anchors. The ceiling and floor anchors are determined by your manufacturer and are based on pipe size, ceiling or floor type, seismic location, and manufacturer standards. The next GOH storage and pick rail structural-support component is the connection device, which includes suspensions, flanges, braces, cross clamps, and Tek screws. These components are determined by your manufacturer and are based on the previously-mentioned design parameters. The next GOH storage and pick rail structural-support components are the singlearm bracket, the double-arm bracket, and the wall bracket. The arm bracket is clamped with bolts and nuts and Tek-screwed to the upright pipe. The arm extends outward and has a shaped and rounded end with predrilled holes that is used to support the storage and pick rail. The single-arm bracket is designed to support one GOH storage and pick rail. The bracket has two predrilled holes for Tek screws to secure the rail and bracket connection, and four predrilled holes for a clamp with nuts and bolts to secure the upright post attachment. In a GOH storage and pick area layout, the single-arm bracket is used along the wall or to make the rack and aisle layout fit in the building area or between the building columns. The standard single-arm bracket measurement for an upright pipe center to a rail center is 9, 12, 13 1/2, 15, or 18 inches. The bracket has the capacity to support 30 pounds. The double-arm bracket is designed to support two GOH storage and pick rails. The bracket has, at the end of each arm, two predrilled holes for Tek screws to secure the rail and bracket connection, plus eight predrilled holes for a clamp with nuts and bolts to secure the upright post attachment. In a GOH storage and pick area layout, the double-arm bracket is used in the middle of the rack and aisle layout, which fits in the building area or between the building columns. The standard double-arm bracket measurement from upright post center to rail center is 18, 24, 27, 30, or 36 inches. The wall bracket is designed to support one GOH storage and pick rail. The wall bracket has two predrilled holes for Tek screws to secure the rail and bracket connection, and two predrilled holes for a clamp to ensure secure attachment to the



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wall. In a GOH storage and pick area layout, the single-arm bracket is used along the wall in the rack and aisle layout. The measurement from upright pipe center to rail center is 12 or 18 inches. The next structural storage and pick rail components are the storage and pick rails with rubber ends and the position identification devices. The standard GOH storage and pick rail is the 1 1/16-inch OD pipe that was previously reviewed in this section. If the GOH extends beyond the arm bracket, the pipe end is considered a potential safety problem with possible employee injury or GOH piece damage. To minimize this problem, most manufacturers place a rubber cap over the hanger pipe end. The various GOH storage and pick position rail identification options were reviewed earlier in this chapter. Pallet-Container Storage and Pick Method The last static GOH storage and pick method is a pallet container with one or two hang bars. The pallet and load bar method has each GOH piece transferred to a hang bar. After transfer-activity completion, or with a full hang bar, the pallet receives an identification label and is transferred by a forklift truck to the pallet storage position. Per the customer-order, a pallet is transferred by a forklift truck from the storage position to a pick position, or an employee travels to the pallet position and completes the pick transaction. This system includes (1) a pallet as the base support member, (2) a pallet rack position and storage vehicle, (3) structural side walls to ensure a stable and rigid hang-bar support, and (4) a GOH piece transfer and pick location. The first component is the pallet. The pallet is made of wood, metal, plastic, or another hardened material that has fork-entry openings and structural-support members. The fork-entry openings permit a forklift truck to transfer the pallet. The structural-support members provide structural support and a base for the side walls and for a fully loaded GOH hang bar or bars. The pallet dimensions and deck components match the forklift truck and pallet rack requirements. The second pallet-container components are the pallet rack storage position and the forklift truck. The pallet-rack storage position has hardened and coated metal upright frames, load beams, and members that provide pallet storage positions. The pallet position’s opening length, width, and height match the pallet container’s dimensions. A mobile forklift truck or captive aisle AS/RS crane completes a palletstorage transaction to any pallet position. The third pallet-container components are the structural sidewalls and hang bar or bars. The structural sidewalls are made of hardened and coated metal, wood, plastic, or another material. These members are permanently attached to the pallet and are preformed devices that are placed onto a pallet deck. The vertical sidewall members have the structural strength and height to accommodate one long GOH level or two short GOH levels. The hang bars are secured to the sidewalls. The design of the pallet container permits an employee to access the GOH hang bar. The pallet-container design has two or three sidewalls. The final pallet-container component is the GOH transfer and pick location. The GOH transfer and pick location is the physical location for an employee to complete


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a GOH storage and pick transaction. The order picker must travel to the palletcontainer storage and pick location. At the storage and pick location, the employee completes the GOH storage and pick transaction. During the storage and pick transaction, the pallet container remains in the storage and pick position. A forklift truck travels to the pallet-container storage and pick position, withdraws the pallet container from the storage and pick position, and travels with the container to a transfer and pick location. At the transfer and pick location, the order picker removes the required GOH pieces from the pallet container and places them on the customerorder device. If the forklift vehicle is an AS/RS vehicle, the pallet container is transferred to the pallet conveyor for travel to the storage and pick transaction location. After completion of the storage and pick transactions, the forklift truck returns the pallet container to a storage and pick position. The disadvantages to this method are that whether full or empty, the GOH pallet container requires a storage position; there is low container utilization; and the system requires additional pallet transactions or a vehicle to transport an employee to the pick position. The advantages is the ability to use multiple pallet storage-area use and batch picking, which provides the best order-picker productivity. AS/RS Trolley Storage/Pick Concept The AS/RS trolley storage/pick concept stores and picks a trolley of GOH items. The GOH AS/RS trolley concept has an AS/RS crane with a special designed trolley carrier, a special trolley, a specially designed trolley storage position, and microcomputer systems. GOH AS/RS Key Components The first AS/RS trolley concept is the AS/RS crane, a standard pallet or miniload AS/RS crane with a specially designed carrier. It is an electric motor microcomputercontrolled vehicle that travels horizontally on a rail through an aisle and vertically on a mast to complete a storage/pick transaction to an elevated storage/pick position. The AS/RS crane has a specially designed carrier attached to the mast and two ‘C’ channel sections per carrier side. The carrier with the two ‘C’ channel sections has the ability to move vertically to the required elevated storage/pick position or pickup delivery station. At the appropriate position, the crane has the ability to move the carrier horizontally or extend outward from the crane carrier center. The two set, ‘C’ channel-shaped carrier feature permits the AS/RS carrier to complete a storage/pick transaction on both sides of the aisle. The second component is a specially designed GOH trolley that is very similar to a regular GOH trolley with a few exceptions. The first unique feature is that the open space or necks between the hand bar and trolley heads or wheels are longer. This additional depth permits a hard metal rod to be attached between the load and trolley heads or wheels. The hard metal rod length extends beyond the two trolley necks. On the AS/RS carrier and in the storage position, the second trolley hard metal rod has sufficient structural strength to support a fully-loaded trolley supported on the metal rod’s two ends. The metal rod extension beyond the two necks has sufficient length on each end, allowing the AS/RS carrier’s two ‘C’ channel-shaped devices to slip onto the two



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metal rod ends. After the AS/RS carrier’s two ‘C’ channel device has secured a trolley in the ‘C’ channel cavity, then the AS/RS carrier moves the trolley to complete a storage/pick transaction. The second unique trolley feature is that the trolley load bar has at least one peg or pin at 1 to 2 inches prior to each neck and with other pegs on normal centers along the load bar. During AS/RS crane travel in the AS/RS aisle, these trolley-load bar pegs stabilize the GOH items on the trolley load bar. The third unique trolley characteristic is that on the trolley travel path the second metal rod extension has the same outward extension as the trolley heads or wheels. This feature permits the trolleys to accumulate on a nonpowered trolley travel path. The next major AS/RS trolley storage/pick concept is the trolley storage/pick concept. The trolley storage/pick position consists of two ‘C’ channel-shaped devices. Each ‘C’ channel-shaped device is attached to an upright post and has sufficient structural strength to support a fully loaded trolley supported on the metal rods’ two ends. The distance or open space between each two ‘C’ channel-shaped device permits the AS/RS carrier with a trolley to complete a trolley storage/pick transaction and assures that a fully loaded trolley is secured in the storage/pick location. The next AS/RS trolley storage/pick concept is the microcomputer that controls the AS/RS crane aisle travel and AS/RS carrier’s storage/pick transactions at a storage/pick position and a P/D station. To complete a trolley storage/pick position transaction the AS/RS crane with its two ‘C’ channel-shaped carrier extends outward from the AS/RS crane to the appropriate aisle side. With the AS/RS carrier full extension, the AS/RS carrier moves upward on the AS/RS mast and the two ‘C’ channel-shaped devices are properly interfaced to the trolley’s hard metal rod ends. With the two hard metal rod ends secured on the AS/RS carrier’s two ‘C’ channel-shaped ends, the AS/RS carrier, with a fully-loaded trolley, is moved upward. This upward movement is sufficient distance to allow the trolley to clear the support device. At this AS/RS elevation, the AS/RS carrier is withdrawn onto the AS/RS crane. In the proper position on the AS/RS crane, the crane is ready to travel in the aisle to complete a trolley deposit or withdrawal transaction. When the AS/RS trolley storage/pick concept is compared with the other GOH trolley storage/pick concept, the AS/RS trolley storage/pick concept features are that it (1) is a fully automated storage/pick concept, (2) assures maximum cube utilization, (3) handles fully loaded trolleys, (4) requires a WMS, (5) requires a specially designed trolley, storage/pick position and AS/RS carrier, (6) requires a high capital investment, and (7) requires a high investment to modify the AS/RS from a GOH trolley to a carton or pallet AS/RS concept. GOH SKU Pick-Position Identification Method The next GOH storage and pick component is the pick-position identification method. The pick-position identification method includes a human-readable, machine-readable, or human- and machine-readable code that distinguishes one SKU from another. The pick-position code matches the order picker’s instructions.


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The various GOH storage- and pick-position identification methods employ (1) printed self-adhesive labels, (2) plastic placards, (3) preformed plastic or cardboard doughnuts, (4) large cardboard doughnuts, (5) rectangular placards, (6) clip-on labels, and (7) cardboard triangles. Printed Self-Adhesive Labels The first identification method is a printed human- and machine-readable code that is printed with black ink on a white background. The identification label is printed onto paper with a self-adhesive back, or onto plain paper. To ensure minimal damage, the printed label has a protective coating. After an employee removes the label’s backing, the employee applies the label to the rail system’s support member. For easy and quick label recognition by the storage and pick employee, the label faces the aisle. The disadvantages are that to change a position, a new label is required; the storage and pick position is a fixed location; and there is the possibility of damage. The advantages are the method’s easy implementation and low cost. Plastic Placards The second identification method is the plastic placard and printed self-adhesive label. This identification label is printed onto paper or cardboard with a white background. The plastic placard has a curved, transparent, and hardened plastic member and a flat, straight member. The flat, straight member’s back side has selfadhesive tape; and the front curved side is transparent. With the front side facing the aisle, an employee attaches the plastic placard to the rail system’s top support member. With a label’s side facing the aisle, an employee inserts a paper or cardboard label into the plastic placard. This method permits an employee to remove an old label and insert a new label. The disadvantages are that the position is a fixed location, and that there is possible damage to the plastic placard. The advantages are the method’s easy installation, low cost, and ease of changing position identifications. Preformed Plastic or Cardboard Doughnuts The third identification method is the preformed plastic or cardboard doughnut method. The preformed plastic or cardboard doughnut is a circle with a 1/2- to 1inch wide opening in the center and a slit in the radius. So that it can be slipped onto a GOH storage and pick rail, the circle is not complete but has a 1/8-inch slit. The circle has sufficient width for identification label attachment. The circle’s opening is large enough for easy attachment to the storage and pick rail. The circle’s interior is hollow so it can slide on the storage and pick rail. This feature permits the storage and pick rail to be separated into smaller sections or multiple storage and pick positions. This identification method is best used to identify storage and pick positions in a static GOH system. In a two- or three-high storage and pick rail method, for an employee to see or RF-scan the doughnut, the doughnut’s height must extend above the rail and GOH pieces. When GOH pieces are stored in a plastic bag, the bag’s bottom does not block identification on the rail below.



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The disadvantages are that it is difficult to maintain a readable location and that the identification component must fit on a circular or curved member. Advantages are that it is easy to implement the system and to change position identifiers, the cost is low, and multiple locations are permitted on a rail. Large Cardboard Doughnuts The next identification method is the large cardboard doughnut method. The large cardboard doughnut method has the same characteristics as the preformed plastic doughnut method, but the circle members are larger. The cardboard doughnut is made by an employee or vendor. The large-doughnut identification method has the same advantages and disadvantages as the previous method. Rectangular Placards The next identification method is the plastic rectangular placard method. The rectangular plastic placard has a circular center, two short sides, and two long sides. At an angle from one corner, a slit is made up to the hollow circle. The hollow circle is slightly beyond the center of the rectangle’s long side. The rectangular section beyond the center hole is solid. With the placard on a rail, the slit design permits an employee to slip the plastic placard onto the rail. The majority of the plastic placard’s weight is at the slit end; the plastic placard design and weight location permits the placard’s top part to extend upward from the rail. The placard extension has sufficient space above the rail for position identification. As previously mentioned in the doughnut identification method, the elevation of the GOH rails allows an employee to read each level’s identification. The disadvantages are that there is some possibility of sliding from the rail and there is a slight cost increase. The advantages are that it is easy to implement and to hang position identifications and that the method permits multiple locations per rail. Clip-On Labels The next identification method is the clip-on identification method. The clip-on identification method’s components are a plastic C-clamp that is attached to the storage and pick rail, and a clip device that extends upward from the clamp section. The clip device holds the identification. After an employee places the clamp section onto a storage and pick rail, the clamp is held firmly onto the storage and pick rail. Next, an employee places the identification item onto the clip section. The clip section and identification extends upward above the storage and pick rail. In this position, the identification is above the GOH pieces on the storage and pick rail. The clip-on identification method is used to identify storage and pick position in a static GOH method. In a two- or three-high storage and pick rail method, for an employee to see or scan the position identification, the clip-on member’s height must extend above the rail and GOH pieces. The GOH pieces above the clip do not block the identification on the rail below. The disadvantages are a slight cost increase, the need for an employee to move the clamps, the potential for clamp or clip damage, potential that the identification will slip from the clip, and the time required to relocate labels on a rail. The


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advantages are that it is easy to implement, the cost is low, it is easy to change position identifications, and multiple locations are permitted on a rail. Cardboard Triangles The next identification method is the cardboard triangle identification method. The cardboard triangle identification method’s components are a rope, pipe, or cable that is located in the rear of the storage and pick position and is parallel to the GOH storage and pick rail; and employee- or vendor-cut cardboard triangle identification placards with an identification section. One section of the triangle placard has a slit that slips over the storage and pick rail. The triangle must be deep enough to have the triangle’s rear rest against the rope, pipe, or cable. The third triangle placard section extends above the top side. This top-side section is the location for storage and pick position identification. This identification method is best used to identify storage and pick positions in a static GOH module system. The disadvantages are that it is difficult to maintain the position identification in a readable location, and that it is used with a GOH module method. The advantages are that it is easy to implement, the cost is low, it is easy to change position identifications, and multiple locations are permitted on a rail. GOH SKU-Identification Considerations At a GOH storage and pick location, an important consideration is the ability to have an employee see or scan the GOH identification. Most GOH SKUs have a plastic cover that hangs downward beyond the GOH bottom by approximately by 6 to 10 inches. In many operations that have multiple-level GOH storage and pick position locations, the higher-level GOH plastic cover’s downward extension covers the lower-level GOH SKU identification. This plastic cover extension creates a problem in reading the lower-level GOH identification. The plastic cover problems are minimized when the plastic bags on all GOH pieces are sealed or knotted at the bottom. This option has an employee to tie or seal the plastic cover that extends beyond the GOH SKU. With additional labor expense, the sealed or knotted plastic cover improves line of sight to the GOH identification. Problems are also minimized when there is an adjustable mesh net or solid deck below each GOH storage and pick level. With an adjustable mesh net or solid deck under each GOH level, a barrier is provided to hold the plastic cover extension. The method provides line of sight to the GOH identification and minimizes the required elevation for a GOH storage and pick position. The method has an additional cost, and the barrier is moveable upward or downward to handle a long or short GOH SKU.

HANGING GARMENT STORAGE AND ORDER-FULFILLMENT METHODS The next GOH order-fulfillment operation activities are the storage and pick methods. A GOH storage and pick method permits an employee to complete a storage or customer-order pick transaction at a storage and pick position.



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The GOH storage and pick methods are (1) an employee travels to the GOH storage and pick position and (2) the GOH storage and pick position is moved to the employee.

EMPLOYEE TRAVELS

TO THE

PICK POSITION

This method has an employee to walk and push or pull a GOH cart over a floor, or push or pull a trolley on an overhead travel path through aisles to the required customer-ordered SKU storage and pick locations. If the employee does not have a GOH cart or trolley as the transport device, the employee hand-carries the GOH pieces. At the required location, the operator completes the required customer-order pick transactions. The pick transaction has an employee to transfer the required GOH piece quantity from the pick position to his or her hands, a cart load bar, or a trolley load bar and verify the transaction. The employee-traveling methods are (1) static rail and (2) dynamic rail. Static-Rail Hanging Garment Pick-Position Method With this method, the GOH SKU pick position may be: • • •

On a fixed rail — The pick positions are separated by one of the previously mentioned identification methods. In an aisle — The inbound GOH pieces are transferred from the transport trolley or cart load bar onto a static rail storage and pick position. In an aisle — The picked GOH pieces are transferred from a static rail pick position onto a transport trolley or cart load bar.

The method handles long or short GOH SKUs with a small, medium, or large inventory quantity per SKU. After the GOH pieces are delivered by GOH carts or overhead trolleys to the storage and pick area, the GOH pieces are manually transferred from the transport vehicle load bar to a static storage and pick rail position. The basic GOH static storage and pick rail method has one, two, or three rails high above the floor. Various methods are shown in Figure 4.12. Among these are the following floor-level storage and pick methods: one rail deep and one or two rails high, two or three rails deep, a raised walkway, rails above a pit, three rails high with a rolling ladder or long rod with a hook, a rail module, a hang rail in a rack or shelf bay, and a push back. Multilevel storage and pick methods are appropriate for the following: a multiple-floor building; a tubular, equipment- or columnsupported mezzanine or floor that has a regular, level walkway and GOH pick positions, or a raised walkway with GOH pieces above a cavity; and an order-picker truck with cantilevered racks, standard racks, or tubular pipes. The various floor-level methods use storage and pick rails that are located on the floor, with a 10- to 13-foot high ceiling. With this method, the operators have direct access to GOH storage and pick rails. The long GOH pieces are one level high and the short GOH pieces are one to two levels high.


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FIGURE 4.12 GOH order picking methods. (From Railex Corporation, Queens, NY. With permission.)

One Rail Deep and One or Two Rails High The first floor-level storage and pick method is one rail deep and one or two rails high. This setup is used in a facility that has a low ceiling height. In this design the storage and pick area has an aisle between two storage and pick rail rows. The aisle has sufficient width for an employee to complete storage and pick transactions. The GOH storage and pick rails include one high rail for long GOH pieces, one or two high rails for short GOH pieces, and one storage and pick rail deep from the aisle. The disadvantages are that it requires a large area and that it provides low storage density. The advantages are the method’s easy access to the storage and pick rail positions, suitability for a building with a low ceiling, and low cost. Two or Three Rails Deep The next floor-level storage and pick method is two or three rails deep. This method is very similar to the one-rail-deep GOH storage and pick design. The two- or threerails-deep design has a deep rail that is fixed, and the rails adjacent to the aisle are fixed or removable rails. This method requires that the rail support arm has the design and structural support strength for the two- or three-deep rail attachment. The two-deep GOH design is 54 to 60 inches deep from the aisle to the rear upright



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support member. A three-deep GOH design is 81 to 90 inches deep from the aisle to the rear upright support member. The two-deep rail design is coupled with a one-deep rail method to make a three-deep rail storage and pick position method. This GOH design feature permits design flexibility. The two- or three-deep rail GOH storage pick method is preferred for SKUs that have a large piece quantity per SKU. The disadvantages are the method’s limited access to all SKUs and difficulty of inventory control. Advantages are its dense storage and a small space requirement. Raised Aisle or Walkway The next GOH storage and pick method is the raised-aisle method. An elevated aisle is placed between the two GOH storage and pick rails. The raised-aisle method is used with the one-deep and two-or-three-high GOH storage and pick level method. The increased employee height from the elevated aisle permits employee access to the two or three elevated GOH storage and pick levels. With the GOH pieces on the lowest level hanging below the aisle, three high, short GOH levels and one high, long GOH level with one short GOH level are permitted. To ensure employee safety and minimize GOH damage, kick plates and handrails are installed full-length along each aisle side. The raised-aisle material is a solid deck or meshed deck, and all step elevations are per the local building code and the fire code. Per local code, kick plates, handrails, and fire sprinklers are required under the aisle. The disadvantages are the method’s higher investment and increased housekeeping problems. The advantages are its improved employee access to the elevated GOH storage and pick levels and improved cube utilization. Rails above a Pit The next GOH storage and pick method has rails that are above a pit in the floor. The pit in the floor is in the facility or is created in an equipment-support mezzanine. On the lower GOH level, GOH pieces hang into the pit. This arrangement with a kick plate and handrails along the pit perimeter makes it easier for an employee to complete storage and pick transactions on the two long GOH levels and the three short GOH levels. If the pit-in-the-floor method is used in an equipment-supported mezzanine, the pit has a solid or meshed bottom and side walls. The solid or wiremesh material selection is based on the local codes. The disadvantages are the method’s higher investment and increased housekeeping problems. The advantages are its improved employee access to the elevated GOH storage and pick levels, improved storage and pick employee productivity, and improved cube utilization. Three Rails High with a Rolling Ladder or a Long Rod With a Hook The next GOH storage and pick method is the rolling ladder or long rod with a hook method. With one or two rails deep and two or three GOH storage and pick levels high, the rolling ladder or long rod with a hook permits an employee on the floor to perform storage and pick transactions at the elevated GOH storage and pick levels. A disadvantage is a decrease in employee productivity because an employee moves the ladder or hook from an aisle location to the required aisle location. The


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advantage is an increase in the storage density per aisle. For additional information on the various rolling ladder designs, we refer the reader to Chapter 7. Rail Module The next GOH storage and pick method is the GOH storage and pick rail module. The GOH storage and pick rail module is used for a small-volume operation that is housed in an existing facility. The GOH storage and pick rail module is a freestanding structure that has handrails, structural tubing, pipe and angle iron members, and solid or meshed walkway decks and kick plates. The GOH storage and pick rail module has two or four high rail levels. Each rail level provides GOH storage and pick positions. The tubing, pipe, and angle iron members provide structural support for the hang rails, handrails, walkway decks, and kick plates. The pipe or rope is on the far side of each storage and pick level, and the rope retains the storage and pick position identification device. The walkway deck material, kick plates, and handrails provide a walkway and decks for employees to perform storage and pick transactions at third or fourth GOH levels. The facility floor gives an employee access to perform transactions at the first and second GOH storage and pick levels. When the horizontal and vertical members and decked aisles are connected together, they establish stable and sturdy freestanding GOH storage and pick positions. Hang Rail in Rack or Shelf Bay The next GOH storage and pick position method is the hang rail in a rack or shelf bay method. When you have a low-to-medium GOH volume that fluctuates, you need flexibility in your storage and pick area. Flexibility provides that a storage and pick rack or shelf-rack opening is converted for GOH storage and pick positions or hand-stacked master cartons. Each SKU has unique characteristics, and the storage and pick methods have different requirements and seasonal volume fluctuations. The labor that is required to adapt a storage and pick position to handle a particular SKU’s storage and pick characteristics is a tremendous expense. The storage and pick position characteristics are that the master carton requires a flat surface and that GOH pieces require a pipe as a hanger and open space for the garment to hang. To achieve flexibility, the rack or shelf bay opening requires a solid or mesh deck with two eyehole hooks that extend downward into the lower rack or shelf opening. The eyehole hooks are for GOH hang bars and GOH pieces. If wood, fiberboard, or metal is used as the single-item or carton hand-stack deck surface, two holes are drilled through the deck surface. The space between each hole and the rack or shelf upright frames permits master cartons to be handstacked onto the deck. If wire mesh is used as the deck surface, the straight part of the eyehole is located in one of the openings of the wire mesh. The distance between the bolt and the upright frame allows for hand-stacking of master cartons. To secure the bolt, large washers are used on the bolt. The bolt’s eyehole extends downward into the rack or shelf bay below. The hang bar is inserted through the two bolt eyeholes and creates the hanging garment storage and pick positions. To reduce any horizontal movement of the pipe through the eyeholes, tape is applied to the pipe at each eyehole’s exterior side.



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When the GOH volume is lower and the master carton volume is high, the additional storage and pick levels are installed in the rack or shelf bay. Push-Back Method The next GOH storage and pick method is the GOH push-back method. The GOH push-back method has telescoping carriages that contain hooks for GOH hangers. Each telescoping carriage is considered one lane. Each lane is one or three carriages deep from the aisle and has one SKU per lane. As the first carriage becomes empty, the empty carriage queues against the lane stop, the second carriage queues inside the first carriage, and the third carriage queues inside the second carriage. An employee transfers individual GOH pieces onto the third carriage’s hooks. When the third carriage is full, the employee pushes the carriage into the lane and it is held in place by the second carriage. When the GOH piece transfer is completed on the second carriage, the second carriage is pushed into the lane. Next, an employee places GOH pieces into the first carriage. When required to complete order-pick transactions, the order picker transfers GOH pieces from the first carriage. When the first carriage is empty, the second carriage is moved forward until it is adjacent to the pick aisle and the third carriage moves forward. GOH transport between the storage and pick lanes and areas is completed by overhead trolleys or GOH carts. For maximum return on investment, the operation requires a GOH piece with a large quantity per SKU. The fire-sprinkler design for a push-back method is per the local codes. The disadvantage is a higher capital investment. The advantages are that it increases storage density and requires fewer aisles. Various Multilevel Storage and Pick Methods The next group of static GOH storage and pick methods are the multilevel storage and pick methods. The various GOH arrangements are used in a building with a clear ceiling height above 20 feet. This clear space permits you to use the space for GOH storage and pick positions on multiple levels. Multiple-Floor Building Method The first multilevel GOH storage and pick method involves a building that has multiple floors. Each finished floor has the clearance for floor-level storage and pickmethod design. The vertical incline and decline transport travel paths and elevatedfloor penetrations require safety and fire protection. The multiple-floor building design includes the required incline and decline vertical GOH and personnel transport methods; compliance with your company’s risk-management standards or local codes; per local code, the appropriate restrooms, water fountains, lighting, and other building features; and appropriate air circulation and ventilation. Equipment- or Column-Supported Mezzanine Method The next multilevel GOH storage and pick method is the equipment- or columnsupported mezzanine method (or freestanding mezzanine method). Freestanding mezzanines provides the structural support for an elevated floor. The various struc-


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tural support methods are independent columns with cross members that support an elevated floor, and order-fulfillment equipment including racks or pipes that provides the connection locations for the cross members that support an elevated floor. Mezzanines also provide the structure for GOH storage pick rails. The GOH storage and pick rails are supported from arms that extend outward from a pipe or rack upright member. Load beams or arms that extend from the pipe or rack members are each floor level’s surface support member. On each mezzanine floor, a one- or two-deep GOH storage and pick rail design is used for the storage and pick positions. On these elevated floors, the GOH storage and pick position designs are (1) with a raised platform as an aisle that has full-length kick plates and handrails, or (2) with a cavity adjacent to the aisle that has full-length kick plates and handrails. The cavity design has a wire-mesh cargo container or solid decking material installed along the cavity’s four sides and bottom. The cavity design has structural-support members to catch loose GOH pieces that fall or to catch an employee who might fall or walk into the cavity. Per local code, the cavity requires a fire barrier that is made of approved treated wood or sheet metal. Order-Picker Truck with Multilevel Rack Method The next multilevel GOH storage and pick position method is the high-rise orderpicker truck or guided narrow-aisle vehicle method. With this method, the powered vehicle has the ability to travel vertically and horizontally in the aisle, and to elevate the operator and the GOH carrying surface. This permits the operator to complete a GOH storage and pick transaction between the storage and pick location and the vehicle GOH carrier. This GOH storage and pick position design uses a cantilevered rack with a rail, a standard pallet rack with a rail, a pipe with a rail, or a pallet container with a hang bar in a pallet storage position. Prior to implementation of a multilevel GOH storage and pick method, your storage and pick design is approved by fire and employee risk management, the company insurance underwriter, and local authorities. Dynamic-Rail Hanging Garment Pick Position Method The dynamic-rail GOH group characteristics are that the GOH SKU’s pick position is a mobile trolley, and that the inbound SKUs remain on the trolley and the trolley is transferred to a trolley flow lane. The trolley travels on the trolley flow lane by means of gravity from the charge aisle, over the lane, and to the pick aisle. The trolley is considered the GOH storage and pick position. In the pick aisle, the picked GOH pieces are transferred from the dynamic trolley pick position onto a transport trolley or cart load bar. The method handles a GOH SKU with a large inventory quantity per SKU. Each trolley flow lane is allocated to one SKU, which means the design has many lanes. The various dynamic GOH storage and pick methods are employed on a single floor or an elevated mezzanine level. Both of these dynamic storage and pick methods have similar design parameters and operational characteristics. The dynamic storage and pick method design has a charge aisle with a transport trolley travel path and diverts, trolley flow lanes and protective aisle and adjustable



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end stops, and an order pick aisle with a trolley travel path and a completed order take-away trolley travel path. With a multilevel structure, the wire-mesh cargo container serves as a maintenance aisle and a protective aisle along the trolley flow lanes and between the two main travel paths and aisles. An employee or powered chain pushes or pulls a GOH trolley over a main traffic rail past the various divert locations. At the proper location, an employee activates a divert mechanism manually or with a code reader, and the assigned trolley is diverted from the main travel path onto a spur for travel to the trolley gravity-flow storage and pick lane. Per the trolley transport method, each trolley has a discrete identification. The identification is human, machine, or human/machine readable. Each trolley gravity flow storage and pick lane is assigned one SKU. To ensure trolley travel over the gravity flow lane, the gravity flow lane is sloped at 3˚ from the charge end to the end stop at the lane pick position. The trolley travel lane is powered by gravity until it reaches the end stop. Other trolleys on the gravity flow lane queue against the stopped trolley. The trolley at the end stop is the GOH SKU pick position, and the trolleys that queue against the front trolley are considered the GOH SKU ready-reserve pieces. Per the order-pick method, each trolley flow lane’s end stop has a discrete identification that is human readable, machine readable, or human and machine readable. After a SKU trolley fills the first flow lane, the additional SKU trolleys are transferred to another flow lane. Per the customer-order instruction method, an employee removes a GOH piece from the pick-position trolley and transfers the GOH piece onto a pick trolley or GOH cart. During the customer-order pick activity, customer orders may be picked in bulk onto the trolley load bar or as a full trolley. If a bulk customer-order pick method is used in the dynamic-pick method, a manual drop switch at the flow lane’s end permits a fully loaded trolley to transfer from the flow lane onto the pick travel path. This feature improves employee pick productivity. Customer orders may also be picked with load bar separators: customer orders are batch-picked onto the trolley load bar. The pick trolley is on a pick trolley travel path. After the pick trolley is full, the trolley is transferred from the pick trolley travel path onto a main out-feed trolley travel path. To remove an empty trolley from a dynamic trolley gravity lane, one employee option is to adjust the end stop or manual drop switch that permits an empty trolley to flow from the storage and pick lane onto the main out-feed travel path. Another option is to leave the engaged end stop and physically remove and transfer the empty trolley from the gravity flow lane to the empty trolley cart or take-away trolley travel path. Disadvantages of the method are high investment and difficulties with inventory control. The advantages are that this method handles a large inventory for one SKU, provides dense storage, ensures high pick concentration and density, ensures high order-picker productivity, and requires few order pickers. Key Components The various dynamic-rail method components are:


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• • • • • • • •

Trolley identification In-feed aisle and trolley travel path Structural-support members Dynamic trolley gravity lane and adjacent aisle Adjustable end stop Pick spur and aisle or walkway Out-feed or pick trolley travel path and aisle Empty trolley cart and full trolley take-away travel path

Trolley Identification. The first component of the dynamic-rail GOH storage and pick position method is the trolley identification method. In a dynamic-rail GOH storage and pick method, there is one SKU per gravity flow lane, and the gravity flow lane has a storage and pick position identification. In the sort and count area, the trolley identification (human, machine, or human/machine code) is placed onto the trolley or is a permanent trolley component. During trolley travel through the dynamic flow system, the trolley identification remains on the trolley and identifies one trolley from the other trolleys. At the dynamic flow system’s charge side, the identification instructs the in-feed employee as to the assigned gravity flow lane, and at the pick side the identification shows the order pickers the proper SKU for a customer-order. Other trolley storage and pick identification methods are used for the transport and divert activity. These trolley transport and divert methods are wire prong, photoreflective tab, bar code, and placard. These transport and divert methods are reviewed in the transport section in this chapter. In the dynamic storage and pick flow lane, the GOH pieces remain on the trolley, which is considered the SKU’s storage and pick position. The trolley storage and pick identification methods are (1) placard with a hole and (2) bar code. The placard with a hole is a rectangular white cardboard or thick paper item. The placard has a prepunched hole at one end and a black printed human- or machinereadable code at the other end. Colored cardboard or paper may be used to identify different lanes. The human-readable code contains human- or machine-printed alphabetic characters or numeric digits. If your operation requires identification on each GOH piece, the options are to have the vendor attach the placard to each GOH piece; to have your receiving or sort-and-count employee attach a placard onto each GOH piece hanger; to have the sort-and-count employee attach the placard to the trolley neck; or to have the sortand-count employee attach the placard with a plastic seal to the trolley neck. Per your operational procedures, your operation may require each individual GOH piece to be identified with a code and to have an identification placard on a trolley’s front neck or around the hanger. After an employee transfers the GOH pieces onto the trolley load bar, he or she ensures that the placard is on the front or lead trolley neck or GOH piece hanger, the SKU identification matches the SKU on the trolley, and the identification faces in the trolley’s direction of travel. With the proper identification match to the SKU, the employee places the placard onto the trolley’s lead neck. The placard attachment options are to slip the first GOH piece hanger through the placard hole and place the GOH piece on the trolley’s



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front; or to insert a plastic seal through the placard hole, around the trolley’s front neck, and secure the seal. With the SKU identification attached to the front neck or first GOH piece on a trolley load bar, the trolley is transported and transferred to the assigned dynamic gravity flow lane. After trolleys are queued on the dynamic gravity flow rail, a placard is attached to each trolley. During the customer-order picking process, to have accurate SKU identification, the placard remains on each trolley’s front neck. The operational concerns are to require an order picker to avoid removing the first GOH piece from the trolley and, when required, to complete a pick transaction to remove a GOH piece from behind the front GOH piece; or to remove the placard from the front GOH piece hanger and to attach the placard securely to the next GOH piece or trolley neck, or onto the pick position structural-support member. Prior to the order-pick employee transferring the last GOH piece from the trolley, the employee removes the placard and places the placard into the trash. With the plastic-seal method, this operational feature requires the employee to either cut the seal or tear the placard from the plastic seal and place the items in the trash. The disadvantages are that identification is not reusable, SKU identification may accidentally slip from the trolley neck or GOH piece, placards must be removed from the trolley neck or hanger and thrown in the trash, there are possible transposition errors, and some written numbers or alphabetic characters are difficult to read. The advantages are that the method works well as an identification code in a humantransport method, the cost is low, and color coding can be used for a lane or SKU. The second GOH storage and pick trolley identification method makes use of a bar code on the trolley’s lead neck or on the GOH piece. The bar code method is the most popular automatic identification method and it is used in many distribution operations. Its popularity results from its simple operation, high degree of flexibility in handling a large number of SKUs, method to track the trolley and SKUs, low cost and reusability, accuracy, and online, high-speed information transfer. The GOH bar-code automatic identification method consists of a bar code on each GOH piece or trolley’s lead neck. The bar code is a series of black lines and white spaces between the black bars that vary in width. For use on a trolley’s lead neck, these black bars are printed onto a self-adhesive white paper label and are attached to the trolley’s lead neck with the bar code in the ladder arrangement. A handheld bar-code scanner permits an employee to focus an intense laser beam over a bar code or an overhead fixed-position and fixed-beam bar-code scanner to focus an intense laser beam at a specific location on the trolley travel path. At this location, the laser beam travels over a bar code. Each gravity lane’s end is identified with a bar code and each SKU trolley is allocated to a specific gravity lane. The bar code is placed onto a structural-support member with the code facing the aisle so an employee can scan the bar code. To complete a customer-order pick transaction, an order-picker employee uses a handheld bar code scanner to verify the transaction. On the trolley travel path, the light beam from the scanning device is reflected back to the scanner device from the white spaces and sensed by the scanning device. The white space is between two black bars. This light reflection is a signal that is sent directly by the scanner device to the microcomputer or held in the scanner device’s memory for later download to the computer. This data transfer verifies the


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completion of the transport, replenishment, or order-pick transaction. During transport, replenishment, storage and pick, and return to the receiving area, the bar code label remains on the trolley’s lead neck. The bar-code identification can be placed on each GOH piece, on each trolley’s lead neck, or on a combination of both. The selection of the identification method is based on your operational requirements and your vendor’s ability to identify each GOH piece per your company requirements. As previously discussed, at the charge and discharge ends of each dynamic trolley lane there is a bar-code label on the structural-support member. To ensure proper trolley assignment and transfer to a dynamic flow lane, the method requires a bar code instruction for the replenishment employee and an identification that discretely identifies the SKU or trolley. With the bar-code label identification method, an employee scans each trolley as it enters the dynamic flow lane. The trolley’s direction of travel over the dynamic flow lane has the trolley neck with the bar code label as the lead neck. Per the customer-order pick instruction and verification requirement, and for each orderpick transaction, the order-pick employee scans the pick position bar-code label, trolley bar-code label, or individual GOH bar-code label. With an empty trolley in a pick position, the order-picker employee transfers the empty trolley from the dynamic flow-lane pick position to an empty trolley transport cart or travel path. The disadvantages are that the trolley neck accepts a bar-code label, and the method requires a handheld bar-code scanner. The scanner has data memory capacity, or the data transfer is online to the microcomputer. Another disadvantage is that an employee must follow the procedures. The advantages are that the method is used as the identification code in a human-transport method, it is reusable, it employs lowcost labels, and it provides online, accurate information and transaction verification. In-Feed Trolley Travel Path. The next GOH storage and pick dynamic-rail component is an in-feed trolley travel path. An in-feed trolley travel path is an overhead trolley travel path that conveys trolleys from the sort and count area to a GOH dynamic pick area and past a code reader and all dynamic lane in-feed locations. The in-feed trolley travel path permits an employee or a mechanical device to transfer a trolley from the main travel path to the appropriate dynamic lane spur. The overhead in-feed trolley travel path divert options are human-powered trolley and powered chain with pusher dogs and trolley. The overhead trolley travel-path design considerations and operational characteristics are the same as those outlined in the in-house transportation section of this chapter. For more detailed information, we refer the reader to the GOH horizontal in-house transportation section. The dynamic flow-rail divert location is set at a high elevation. The dynamic flow-rail method has gravity force move the trolleys over the flow-rail trolley travel path. To have gravity move a trolley over the trolley travel path, the charge end is at a higher elevation than the order-pick side. The trolley travel-path elevation above the floor factors are trolley number or dynamic lane overall length, GOH piece overall length, a 3˚ slope for the dynamic lane. To achieve the proper dynamic-rail slope and to permit an employee to access the in-feed transfer switch, under the in-feed trolley travel path is a raised aisle. The



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raised aisle has the employee walking surface set at a higher elevation. If the dynamic-rail method’s finished floor is a building floor, the raised aisle is designed as a solid deck or wire-mesh “cargo-tainer“ deck for the in-feed walkway surface. If the dynamic floor is a multilevel method that has a wire-mesh “cargo-tainer“ floor under the in-feed and out-feed sections, the wire-mesh “cargo-tainer“ is adjacent to the dynamic flow lane. To minimize investment, one wire-mesh “cargo-tainer“ aisle serves two dynamic flow lanes. Structural-Support Members. The next GOH dynamic gravity-lane and trolley travel-path components are the structural-support members. Since these members are the same as those reviewed in the nonpowered and powered overhead transport methods, we refer the reader to those sections in this chapter. Dynamic Gravity Lane or Rail. The next GOH dynamic gravity-lane method component is the dynamic trolley gravity-lane travel path and aisle underside. The dynamic trolley gravity lane is a nonpowered overhead trolley travel path. The trolley travel path’s degree of slope between the charge end and discharge end ensures trolley travel from the in-feed section, over the dynamic gravity lane, and to the order-pick side. The trolley gravity lane has a 3˚ slope, which ensures proper trolley travel over a gravity lane and minimal line pressure on the trolleys that queue on the dynamic trolley lane. Each dynamic trolley flow-lane’s pick side has an end stop. The end stop is located on the trolley flow lane prior to the manually-operated drop switch and ensures that the trolleys queue on the dynamic lane. The first trolley in the flow lane queues against the end stop and ensures that the SKU is in the pick position for the customer-order selection. The second gravity-lane component is the floor that is under the dynamic gravity lane. If the GOH dynamic storage and pick method is installed on a solid floor, the building floor is the dynamic gravity lane’s underside. When a trolley hangs up on the dynamic trolley gravity lane, or when a GOH piece falls from a trolley’s load bar to the floor, the floor lets an employee retrieve the GOH piece or unclog a trolley hang-up. If the GOH dynamic storage and pick method is installed above a wire-mesh “cargo-tainer“ floor, this floor is the dynamic gravity lane’s underside. When a trolley hangs up on the dynamic gravity lane, or a GOH piece falls from a trolley’s load bar to the floor, the wire-mesh “cargo-tainer“ floor provides an employee aisle to retrieve the GOH piece or unclog a trolley hang-up. With this wire-mesh “cargotainer“ floor, structural-support members are designed with sufficient structural support and provide a safe employee aisle. Per local code or your company, the employee aisle is made from several materials. These various materials were reviewed in the pallet-rack aisle section in this chapter. For additional information on the aisle materials, we refer the reader to this section. Adjustable End Stop. The next GOH dynamic trolley gravity-lane storage and pick component is the adjustable end stop. The adjustable end stop is located at each dynamic gravity-lane’s end. The end stop ensures that the trolleys queue on the


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dynamic lane prior to the manually-operated drop switch. The first trolley queues against the end stop and the trolley provides the SKU in the pick position for customer-order selection. Pick Spur and Aisle or Walkway. The next GOH gravity-lane storage and pick method components are the pick spur and employee aisle. In a pick-spur design, each trolley flow lane has a manual drop switch or a manual adjustable stop for trolley transfer from the trolley flow onto the pick spur. The pick spur is an overhead nonpowered travel path that is parallel to the dynamic flow lane’s discharge end. It permits an employee to push or pull an order-pick trolley past each pick position. At predetermined locations, manual drop switches permit the order-pick employee to transfer a trolley with a completed customer-order from the pick spur to the takeaway trolley travel path. All dynamic-lane discharge ends face an employee pick aisle. The employee aisle has sufficient space between the dynamic lane’s end stop and the pick spur. Per the customer-order, the aisle permits an employee to transfer the required GOH pieces from the various dynamic lanes onto the customer-order trolley. The customer-order trolley is pushed or pulled along the pick-spur travel path. With a completed customer-order, the order picker activates a manual drop switch to transfer the completed order trolley from the pick-spur travel path onto the takeaway trolley travel path. Out-Feed Trolley Travel Path. The last GOH dynamic-lane storage and pick method component is the out-feed trolley travel path. The out-feed trolley travel path is a nonpowered or a powered overhead trolley travel path that extends along all dynamic lane ends. The trolley out-feed travel path design is set at the standard TOR height above the floor and located at the standard distance from the pick spur path. The out-feed trolley travel path permits an employee or a poweredchain pusher dog to move a trolley with completed customer orders from the pick area, over a trolley transport travel path, and to the order-check and pack area.

STOCK TRAVELS

TO A

PICK-POSITION METHOD

The second major GOH storage and pick method group is one in which GOH pieces or stock travels to a pick position, or stock travels to the employee. A powered GOH transport method brings a GOH piece to a pick station. At the pick station, an employee is directed by a pick light, an RF device, or a paper-pick instruction to transfer a customer-ordered GOH piece or pieces from a powered transport pick location onto a cart or trolley load bar. The methods are (1) horizontal carousel and (2) vertical carousel. Horizontal Carousel The first carousel type is the horizontal GOH carousel. The horizontal carousel is an electric carousel that is top-driven by an electric motor and a sprocket wheel with teeth. As the sprocket turns, the cavity between two teeth interfaces with each trolley neck. As the sprocket turns, the powered chain or GOH hook sections are moved forward or in reverse over the fixed travel path.



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The GOH carriers are connected together to form an endless closed loop that is directed past a deposit or order-pick station. The GOH horizontal carousel carriers are designed to handle one GOH piece or several GOH pieces. The GOH horizontal-carousel operational considerations are the method to drive the carriers and the method to control the carrier movement. Top-Driven Carousel The first GOH horizontal-carousel consideration is the method used to drive the GOH horizontal-carousel carriers. The most frequent GOH horizontal-carousel drive method is the top-driven type. The top-driven carousel unit has structural-support members that provide the support for the GOH carousel drive unit, an endless chain track, and a GOH piece carrier travel path. The endless chain may be pulled through a track by motor-driven sprocket teeth. These sprocket teeth interface with the chain link openings. Alternately, the GOH piece carrier neck may be pulled by the motordriven sprocket teeth. As the sprocket teeth turn, a sprocket tooth moves the GOH carrier neck. This interface and sprocket rotation propels the GOH carriers over the fixed travel path. This travel path has two straight-run sections, two 180˚ curves, and a GOH piece transfer station. The bottom-driven horizontal unit is used to handle small items or flat-wear apparel and is not considered for a GOH application. Hanging Garment Horizontal-Carousel Control The next GOH carousel consideration is the method used to control the horizontalcarousel carrier’s movement past the transaction station. The GOH carousel control options are intermittent and continuous. Each group may be manually controlled or microcomputer controlled. Intermittent Carousel Unit. The first GOH horizontal-carousel carrier movement control method is the intermittent carousel method. The intermittent carousel method moves the GOH carriers over a travel path past a transaction station. With an intermittent carousel unit, the required GOH piece carrier travels over the fixed travel path in the shortest travel distance to a pick station. The carrier travel direction is forward or in reverse to the pick station. In a dynamic GOH pick operation, the intermittent carousel unit is the preferred control option. Continuous Carousel Unit. The second method used to control the carrier over a travel path is the continuous carousel method. The continuous carousel unit indicates that the carousel GOH carriers are constantly moving over the travel path. The continuous carousel unit is a manually-controlled unit with a motor-driven sprocket. The drive motor and sprocket have variable drive speeds. The continuous carousel unit moves GOH carriers slowly past the pick station. This slow carousel-carrier travel speed permits the pick station employee to perform a GOH piece pick transaction between the pick station and carousel carrier. In a dynamic GOH orderfulfillment operation, the continuous carousel unit has limited application. Manual Carousel Unit. The next GOH horizontal-carousel unit-control method is the manual carousel unit. The manual carousel unit has an employee positioned at the transaction and control station. The control or pick station is the location where


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a GOH piece is transferred between the workstation and a GOH carousel carrier. At the station, the carousel employee has the ability to control carousel carrier movement over the travel path to the workstation. The employee has the controls to stop or start the carousel carrier at the pick or control station. The carousel pick-station designs include a hand-controlled device with a bidirectional toggle switch; a footcontrolled switch with two buttons, one button for the carousel carrier’s forward travel and one for reverse; a numbered dial and push button that allows an employee to set the dial and activate the carousel to revolve the appropriate carrier to the pick station; and a keypad and digital display unit with several push buttons. These buttons have numbers from 0 to 9, revolve, and entry that allows the control-station employee to enter the required hook or carrier number into the keypad. This carousel movement instruction causes the carousel unit to move the appropriate carrier over the travel path to the pick station. Microcomputer-Controlled Carousel Unit. The final GOH carousel is the microcomputer carousel. The microcomputer-controlled GOH carousel method has the memory and capability to handle approximately 500 commands for up to six carousel units. The microcomputer carousel method permits several carousels to serve one pick station. Because at least one carousel unit provides the required GOH piece at the pick station and the other carousels are moving other GOH piece pick positions to the pick station, there is higher employee productivity. Most GOH horizontal-carousel applications today are microcomputer controlled and have the capability to revolve multiple carousels carriers in a forward or reverse travel direction to bring the appropriate GOH piece carrier to the pick station in the minimal time. Horizontal-Carousel Key Components Electric GOH horizontal-carousel components include an electric motor-driven unit with a tooth sprocket, a support structure and frames, hooks or carriers, and controls. Electric Motor-Driven Unit. The first GOH carousel component is the electric motor-driven tooth sprocket drive unit. The top motor-driven carousel has a tooth sprocket device that is located on the inside of one or both of the carousel’s two 180˚ turns. A carousel application with a long travel path has two motor-driven sprockets, per manufacturer design. With one motor-driven carousel, one turn is a nonpowered sprocket turn. The nonpowered sprocket turn provides excellent tracking of the closed-loop carriers as they travel over the travel path. The tooth sprocket has spacings between two tooth centerlines that create open space between the two teeth. This open space matches a carrier-neck or chain-link opening. When this open space and neck match, and as the tooth sprocket revolves, a carrier neck can enter into the open space and the sprocket tooth can move the carrier forward or in reverse over the travel path. The carrier’s forward or reverse movement is the same as the sprocket turning direction. The teeth per sprocket and sprockets per carousel are determined by manufacturer standard according to the following design factors: the motor horsepower, the spacing between two carrier necks, the combined weight for GOH pieces and carriers, the turn number, the carousel application, and the carousel travel path with elevation changes.



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Track and Support Structure. The second carousel components are the travel path and support structure. The travel path and support structure allow the carousel carrier hooks to move GOH pieces over the travel path past a pick station. The enclosed chain is moved through the travel path by the tooth sprocket. The travel path components include a straight run and 180˚ turns with metal tubular-pipe or chain-link sections that form an endless loop. The GOH carousel manufacturer’s standard length ranges from 14 to 110 feet. A carrier also has two wheels or a grooved wheel that travels over a hardened metal track. The carrier’s hardened metal or plastic wheels have a low coefficient of friction so that the carrier wheel can have a smooth and continuous movement over a metal travel path. With the top-driven GOH carousel, metal brackets that extend outward are attached to each carrier wheel, and all the brackets are connected together at the bracket bottom by a series of hardened metal links. The thickness of the link matches the openings between the sprocket teeth. Chain Link, Neck, or Arm. The GOH carousel chain link or neck is the next carousel component. The carrier chain link is a hardened metal section with an opening and a link that is a hardened metal extension. The link serves to interface with the opening space between motor-driven or nonpowered sprocket teeth and provides the connection location for a carousel carrier hook. Each carrier link and carrier device is connected together to form an endless closed-loop chain. In the top-driven carousel, the carrier device is a hook that is attached to the chain link or neck bottom. The link shape for a GOH carrier connection is determined by carrier shape, top connection location, and GOH piece and carrier weight. The next carousel component is the support structure. The support structure design is determined by the horizontal carousel type and the carousel application. The top-driven GOH carousel support structure is a frame that is supported by at least two upright posts. The post base plate is wide to spread the load weight and to ensure stability. These base plates have predrilled holes for anchor bolt locations. The upright support number, base plate size, and metal gauge for the structuralsupport members are per your manufacturer’s standards, carousel application and weight, and seismic location. Carrier (Hook or Trolley). The next GOH carousel component is the GOH piece carrier or hook. A GOH piece carrier is a single hook, a plane with several hooks or slots, or a trolley. Each device carries one open-faced hanger per hook or slot; a plane has several hangers or several GOH pieces on a load bar. Multiple-Carousel Layout Considerations. There are several multiple GOH carousel designs. For additional review we refer the reader to the small-item carousel section of Chapter 3. Description of Operations. A microcomputer-controlled multiple GOH carousel operation unit is simple. With the microcomputer-controlled GOH carousel, the fixed travel path with GOH hooks or carriers travels past a GOH piece pick station. The company’s host computer transfers the customer-order requirements to the carousel microcomputer. With these customer orders, the microcomputer controls the forward


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and reverse GOH piece-carousel carrier movement past the pick station. After the order-pick employee starts the carousels, the microcomputer rotates the first carousel. The first carousel rotates the GOH carriers until a required GOH piece carrier arrives at the pick station. As the order picker completes the first carousel pick transaction, the microcomputer has the other carousels rotate forward or in reverse to bring the next GOH piece carrier that is required by a customer-order to the pick station. The multiple-carousel rotation design ensures that as one carousel is stopped at the pick station and the employee is performing a pick transaction, the other horizontal carousels are rotating to bring required GOH piece carriers to the pick station; the design also ensures that, at the pick station, the stopped GOH carousel carrier has a customer-ordered GOH piece. The constant presentation of customer-ordered GOH pieces at the pick station means there is very little unproductive employee waiting time between two picks and higher picker productivity. Vertical Carousel The next method for moving a GOH pick position to an employee storage and pick location is the vertical carousel method. The GOH vertical carousel method consists of two endless powered chains that pull load bars over a fixed travel path. Each powered chain is driven by an electric motor-driven sprocket. The load bars follow a vertical and horizontal fixed travel path that is enclosed in a wire-mesh or solidwall enclosure. At the enclosure front is an employee GOH piece pick and transfer transaction station. After an employee transfers GOH pieces to the vertical carousel load bar, the vertical carousel is directed to move the full load bar over the travel path and to move the assigned full or empty load bar to the pick station. Per your customer-ordered SKUs, the appropriate GOH piece load bar is delivered to the pick station for an employee to complete a GOH piece pick transaction. The GOH vertical-carousel components are a GOH carrier, load bar, or hook; two endless closed-loop chains with the GOH carriers, load bars, or hooks; electric motors, drives, and sprockets; start and stop controls, a carousel chain command entry device or keypad, and a GOH piece-transfer transaction access door; structural support upright posts, horizontal support members, and a shell (a wire-mesh or solidwall shroud or housing); and a floor-level horizontal GOH transport method. Carrier Load Bar or Hook The first GOH vertical-carousel component is the GOH load bar or hook. The vertical-carousel carrier features are carrier spacing, load bars or hooks, orientation, and identification. The first feature is that the carrier is attached to each powered chain and provides a GOH piece carrying surface. The carrier is designed to permit an employee to perform a GOH piece pick transaction and to have proper SKU identification on the carrier. The vertical GOH carrier’s centerline spacing permits a GOH piece to extend downward without striking another carrier or vertical carousel component. The centerline distance permits a fully loaded carrier to travel the vertical and horizontal travel path through the vertical carousel enclosure access door. The next feature of a GOH piece carrier permits an employee to perform a GOH piece SKU pick transaction through the access door.



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The last important feature is that the carrier requires a SKU to have the proper storage and pick position identification. The carrier has a fixed placard or bar code that identifies the storage and pick position. The GOH piece identification options are human-readable, machine-readable, or human- and machine-readable code; a plastic doughnut; or a plastic rectangle. These identification devices are for SKU identification. They permit a maximum number of SKUs per carrier and ensure that the identification is retained on the carrier. Electric Motors, Drives, and Sprockets The next important components are electric motors, drives, and sprockets. These carousel components provide the power to move the two closed-looped endless chains with carriers over the travel path. Each electric motor has a shaft that has a tooth sprocket attached to the end. Over each tooth sprocket is a short closed-loop chain, and each chain interfaces with a second sprocket. Each motor-driven sprocket’s short chain is looped over the two sprockets on a shaft. This tooth sprocket has two long closed-loop endless chains with carriers. The carousel carrier is moved by each electric motor turning its shaft and tooth sprocket. As each electric sprocket turns the short chain, the short chain turns the sprocket that is connected to the endless closed-loop chain. As the endless closedloop chain turns, the GOH carriers move over the fixed travel path. The GOH vertical-carousel standard DC motor sizes are 1 1/2, 2 1/3, and 3 horsepower. The appropriate motor is matched to the vertical carousel application and is based on the carrier number and the carrier’s maximum GOH piece carrying weight. Other features on some GOH vertical carousels are the guide rollers and sleeves. These guide rollers or sleeves improve the vertical-carousel carrier travel over the travel path, and minimize vibration. Start, Stop, and Control Devices The next GOH vertical-carousel components are the controls that start and stop the endless chain’s and carrier’s movement over the travel path. These controls are an emergency stop button or cords, a manual carrier chain that moves up or down, chain movement starting and stopping, and other switches and indicators such as off/on and carrier number. GOH vertical-carousel carrier movement control options are a keypad and computer. Keypad

The manual-control option is the keypad data entry device. Keypads have 10 buttons that have numbers from 0 to 9, a digital display, an emergency stop, and keys that cause the carousel chain to bring the required carrier over the shortest route (on a forward or reverse travel path) to the pick station. A manual-control option is a handheld bar-code scanner that reads a carrier’s identification into an automatic vertical-carousel control system. A vertical-carousel controls are programmed to accept up to 250 carrier movements or GOH picks. Microcomputer

The next GOH vertical-carousel control option is an interface with a microcomputercontrolled system. With this control-system option, the vertical-carousel microcom-


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puter-controlled memory system accepts approximately 1250 carrier movements or GOH picks. Structural-Support Members The structural-support members are the structural upright posts and horizontal support members. These coated metal members serve to provide the support for the endless closed loop chain, GOH carriers, guide track and transfer station, and protective shell or housing. The protective shell or housing is wire mesh or solid material. The shell or housing material is determined by the local code and designed to minimize employee injury, reduce noise from the carousel’s moving parts, and minimize fire risk. The next GOH vertical-carousel component is the associated GOH finished-floor horizontal transport method. This method moves the GOH pieces between the vertical-carousel pick station and the packing location. The previously mentioned GOH floor horizontal transport methods are pushed GOH cart, nonpowered overhead trolley, and powered chain and overhead trolley. The disadvantages to using this method are a capital investment; one pick station; clear space between the floor and ceiling; and, when downtime occurs, difficulty in picking a GOH piece. The advantages are that the method uses the facility cube or air space, has a small footprint, provides a GOH storage and pick area, offers excellent security, and minimizes employee injury. GOH Pick-Position Method Order-Fulfillment Operational Considerations The various employee-to-stock GOH order-fulfillment operation considerations are the pick instruction method, the pick vehicle, the pick-position identification method, the order-picker routing and travel path, the storage and pick position design, the order-pick philosophy, and the picked-SKU transport method. Order-Pick Instruction Methods The various components of a GOH customer-order pick instruction method indicate to the order picker the customer-ordered SKU and associated piece quantity. The order-pick instruction methods are: •

• •

Manual printed paper document or label. The label can be self-adhesive and attached to a paper identifier or plastic cover, or made of thick paper with a hole that is slipped over the hanger neck. Pick to light. Pick with an RF scanner.

Paper Pick Document in Plastic Bag with an Attached Loop If your GOH order-fulfillment operation uses a paper pick instruction document, to protect the document from damage and to secure the document to a GOH piece or multiple GOH pieces, your order-fulfillment operation uses a plastic bag with an



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attached-loop method. The GOH pick-instruction method has a paper printed document or card that is inserted into a plastic bag with an attached loop. Before an order picker travels to the pick area, each order-pick instruction is placed into a plastic bag with an attached loop. The plastic bag with attached-loop method consists of a heavyduty transparent bag that has an open mouth and side and is sealed on the other side and the bottom, an attached heavy-duty plastic loop on the plastic bag, a GOH piece with a hanger, and a paper order-pick instruction that is placed inside the bag. Prior to the order-fulfillment activity, the GOH customer-order pick instruction and other customer delivery documents are placed inside the plastic bag. The plastic bag permits the order picker to read the order-pick instruction easily, and retains the order-pick instruction inside the plastic bag. After the order-pick employee arrives at the appropriate pick position, the employee transfers the GOH piece from the pick position and places the plastic bag loop over the GOH hanger. With the plastic bag loop over the hanger, the plastic bag faces the trolley’s lead travel direction. Per your GOH order-fulfillment operation, from the bag the order picker removes the paper document, places a mark adjacent to the customer-ordered GOH piece, and returns the paper document to the bag. If there are several GOH pieces for one customer-order, the order picker travels to the appropriate pick position, transfers the appropriate GOH piece from the pick position, and inserts the GOH hanger onto the plastic bag loop that contains the customer-ordered and picked GOH piece. This pick activity is repeated for each customer-ordered GOH piece. After the final customer-order GOH piece pick transaction, the order picker ensures that the plastic loop is over all the customer-ordered and picked GOH hangers. The disadvantages to this method are that it requires an employee to insert the pick instructions into the plastic bag, and there is additional plastic bag expense. The advantages are that pick instructions are easily read, the method is easy to use, it keeps the order documents clean, it is reusable, and it secures the documents and GOH pieces as one unit. The second pick-instruction component is the GOH pick-position identification. The pick-position identification identifies one specific location on a static GOH pick rail, on a dynamic-method trolley’s lead neck, or on a carousel carrier. The GOH pick-position identification methods are (1) human-readable, machine-readable, or human- and machine-readable alphabetic characters or numeric digits or both; (2) digital pick-to-light or RF devices; and (3) bar-code labels. Each order-pick instruction and pick-position identification method is used in the employee to stock or pick-position group and the stock-to-employee or pickposition group. These order-pick instruction and pick-position methods are used in a small-item order-fulfillment operation, and so we refer the reader to the smallitem pick section in Chapter 3. Order-Pick Vehicle The next stock-to-employee GOH order-fulfillment method consideration is the vehicle that is used to pick customer-ordered GOH pieces and to transport picked GOH pieces from the pick area to the customer-order packing area. The order-pick vehicle methods are the pushed or pulled GOH cart with a hanger load bar, pushed


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or pulled GOH cart with a trolley load bar, overhead trolley, and high rise order pick system (HROS) or man-up vehicle. With multiple GOH storage and pick levels in an order-fulfillment operation, a moveable ladder and an order-picker-elevating GOH pick vehicle are considered order-pick vehicles. The moveable ladder is a safety stepladder that has several steps. These steps permit an order picker to easily complete pick transactions that are above the order picker’s normal reach. The ladder is mobile to any aisle. The safety stepladder options are a ladder attached to the pick cart, a ladder top-attached to the top structural-support members, a four-wheel rolling ladder, a four-wheel rolling ladder with a collapsible platform, and a stepstool. Stepladder Attached to the Pick Cart. The first order-pick vehicle is the stepladder that is attached to the pick cart. The safety stepladder is a hardened and coated metal structure that is attached to the rear side of a rectangular four-wheeled pick cart. The safety stepladder has several stairs and two handrails that extend to a predetermined elevation. As an order picker steps onto a stair, the order picker’s weight causes the two handrail-extension-bottom rubber tips to come in contact with the floor. While an order picker is on the stepladder, the rubber tips are in contact with the floor. This feature stops the cart and permits the order picker to reach the elevated level. The stepladder method is considered a mobile-aisle method. Top Attached to the Structural-Support Members. The next order-picker method for reaching an elevated GOH storage and pick level is the rolling ladder method. When the GOH pick positions are elevated above a normal employee’s reach, the rolling ladder rides on and along a fixed travel path to the required pick position. An employee pushes the rolling ladder with a safety bottom step to the required pick position. At the required pick position, the employee stops the ladder and steps onto the bottom step. The spring-loaded safety steps secure the ladder in the aisle, and the employee climbs the ladder to reach the elevated pick position. This rolling ladder’s components include a hardened and coated metal structure and two top wheels that are attached to a top travel and guide rail. During travel in the aisle, this provides ladder aisle guidance. The ladder has a slight slope that extends into the aisle, is considered captive to the aisle, and serves one side of the pick aisle. Four-Wheel Rolling Ladder. The four-wheel rolling ladder is a hardened and coated metal structure that is used in a GOH order-fulfillment operation that handles GOH in elevated storage and pick positions. Like the safety stepladder with handrails, the rolling ladder permits the employee to safely complete pick transactions at the elevated positions. The ladder method increases the number of storage and pick positions and linear feet per aisle. The four-wheel rolling ladder is considered a mobile aisle vehicle. Four-Wheel Rolling Ladder with a Collapsible Platform. In a GOH orderpick area that has an overhead trolley transport method, the hardened and coated metal structure of the four-wheel ladder with a collapsible platform and safety steps is used to access the elevated GOH storage and pick positions. The collapsible platform permits an employee to move the four-wheel ladder to an adjacent aisle and under an overhead trolley travel path.



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Stepstool. The safety stepstool is a hardened metal structure that is a one-step-high device. After an employee moves the stepstool to an aisle location, the employee’s weight on a stepstool secures the stool to the floor. The stepstool is low in cost, creates a mobile aisle, and increases an employee’s reach by 8 to 10 inches. There may be several stepstools in one pick aisle. HROS or Man-Up Powered Vehicle. The next multilevel GOH pick vehicle is the HROS or man-up powered vehicle method. The high-rise order-picker truck vehicle types are the counterbalanced truck, the straddle truck, the platform truck, and the very narrow aisle (VNA) man-up vehicle. These vehicles are manually controlled and operated vehicles. In a guided aisle, an electric battery-powered vehicle elevates an order picker as it travels horizontally or vertically down an aisle between two pick rows. The pick positions are located on a pick aisle’s both sides and, per the vehicle type, are up to 35 feet high. Some vehicles handle a GOH cart or a three-wall pallet structure with a load bar. At a pick position an employee completes a transaction and moves to the next required aisle location. For additional information on these HROS man-up order-picker vehicles, we refer the reader to Chapter 3. These GOH order-pick vehicle methods are the same as the GOH transport method that is used to move GOH pieces to an operation storage and pick area. For a review of these GOH transport methods, we refer the reader to the GOH transportation section in this chapter. GOH Pick-Position Identification Method The GOH pick-position identification method is the method that is used to discretely identify one GOH SKU pick position from the other SKU pick positions. A manual GOH storage and pick area has several aisles and static rails. The aisles are between two static rails and permit an employee to complete a storage and pick transaction to an assigned GOH storage and pick position. The static rail is basically a coated pipe that has structural-support members and a diameter to match the GOH hanger hook. To complete a GOH storage and pick transaction, an employee places or removes a GOH hanger between the static rail and the mobile in-house transportation device. To ensure identification of a GOH piece pick position, the static rail requires a GOH storage and pick-position identification method. The basic GOH pick-position identification methods are fixed position identification, sliding position identification between two fixed structural-support posts, and sliding identification on the entire rail length. Fixed Position Identification The first GOH pick-position identification method is the fixed storage and pickposition identification method. With the fixed GOH storage and pick-position identification method, the storage and pick position identification is attached to the static rail. To relocate the fixed identification position device, an employee must physically loosen the identification device, move the identification device to the new location, and physically attach the identification device to the new location.


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The fixed identification method requires additional time to expand or shrink the static rail space that is allocated to a GOH item and has a slightly higher cost per identification device. The method is flexible because it is used on any static-rail length. The pick-position length is determined by the GOH static rail structuralsupport member. Sliding Position Identification between Two Fixed Structural-Support Posts The second GOH pick-position identification method employs a sliding GOH storage and pick position identification between two structural-support members. The static rail is supported by posts. Each post has a unique identification that defines a GOH storage and pick zone. Within each pick zone or static-rail area and between two structural-support posts are several GOH storage and pick identification position devices. These identification devices slide along the static rail between the two posts to separate the pick zone into a series of GOH storage and pick positions. There are several advantages to this method. Minimal time is required to expand or shrink a static-rail space within a zone’s limits. The cost per identification device is low. The identification device slides along the static rail without falling from the static rail. Expansion of the GOH storage and pick positions is restricted to the static-rail length that is between the two support posts. The GOH storage and pick static rail is separated into several zones. All GOH put-away and storage transactions start at the highest numbered position from the pick-zone identification post or main traffic aisle. Pick positions that end with even-numbered digits on the right side of the aisle and pick positions that end with odd-numbered digits on the left side of the aisle establish an order-picker routing pattern through the aisle. Sliding Position Identification for the Entire Rail Length The third GOH pick-position identification method is a sliding GOH storage and pick-position identification device that slides along the static rail’s entire length. The components include a static rail that is full-aisle length and a GOH static-rail structural-support member support-post design and mobile GOH storage and pickposition identification design that permits each storage and pick-position identification device to slide full-length along the static rail or aisle. The storage and pickposition identification slides over the static rail, the storage and pick-position identification device is retained on the static rail, and the entire static-rail or aisle-side length is considered one pick zone that is separated into several GOH storage and pick positions. The method’s features are similar to the previous sliding method except for the following. The identification device slides the entire static-rail length. A GOH storage and pick-position expansion is the entire static-rail length. All GOH storage and putaway transactions start at the highest numbered position on the rail or at the main traffic aisle. The method permits a one-side order-picker routing pattern through the aisle and automatic “ABC” inventory allocation or profiling for the GOH pieces or SKUs on the static rail. To create empty storage and pick positions at the aisle’s beginning, the method requires periodic GOH inventory transfers from the lower storage and pick positions to higher storage and pick positions.



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The various GOH pick-position identification methods are (1) printed selfadhesive label on the structural-support member, (2) plastic placard attached to the structural-support member, (3) preformed plastic or cardboard doughnut, (4) large cardboard doughnut, (5) rectangular placard, (6) clip-on method, and (7) cardboard triangle. For additional information on the various pick-position identification methods, we refer the reader to an earlier section in this chapter.

GOH ORDER-PICKER ROUTING PATTERNS The next important GOH order-fulfillment consideration is the order-picker routing pattern. The GOH order-picker routing pattern is an arithmetic progression to the pick-position numbers through each order-fulfillment area aisle. In any order-picker pattern, the order picker starts at the first required SKU pick position in a pick aisle and, as the order picker travels through the pick aisle to the end, the next required GOH SKU pick position is as close as possible to the previous GOH SKU pick position. In a GOH order-fulfillment operation, the preferred order-picker routing pattern is a sequential routing pattern that directs the order picker through the various order-fulfillment pick-area aisles. These aisles are between GOH rails that have GOH SKU pick positions. These GOH SKU pick positions contain SKUs that appear on a customer-order. The routing pattern should reduce unproductive employee time, lower employee fatigue, decrease employee confusion, and increase employee productivity. To ensure an efficient and cost-effective order-picker group, the various GOH order-picker methods are matched to the order-picker routing pattern. The first order-picker routing patterns are used when an employee walks or rides in a pick aisle. They are (1) the single-side order-picker pattern with one picker, (2) the single-side order-picker pattern with two order pickers, (3) the loop, (4) the U or horseshoe, (5) the Z, (6) the block, (7) the stitch, and (8) the various high-rise order-picker patterns. For information for the various pick-position identification methods, we refer the reader to an earlier section in this chapter.

OVERHEAD TROLLEY PICKING

IN THE

PICK AISLE

The second order-picker routing patterns are used with an order picker moving an overhead trolley through the pick area. To complete a customer-order, the order picker is routed in the pick aisle, and the options are as follows. The order picker may be directed with a pick trolley from the main traffic aisle into the pick aisle. This order-picker routing pattern has an employee to walk between the various aisles and the main traffic aisle. This method’s features are increased trolley-rail and switch investment and decreased employee walking distance and time. Alternately, the order picker may be directed to leave the trolley in the main aisle; walk into the pick aisle; complete all pick transactions; and, with the picked GOH SKUs, walk from the pick aisle to the main aisle and transfer the picked GOH SKUs onto the trolley. This method’s features are low cost and additional employee walk distance and time.


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Other order-picker routing pattern considerations are as follows. As your order picker travels through the aisle, pick-position numbers that end with an even digit are located on the right side of the pick aisle, and pick-position numbers that end with a odd numbers are located on the left side of the pick aisle. There is an arithmetic progression through the pick aisle. The picker should be in the pick aisle as long as possible. The routing method should improve the GOH SKU hit concentration and hit density, start the order picker in the fast-moving SKU section, separate the pick activity to the cart or trolley hang bar, keep the pick aisles clear, and maintain good housekeeping and illumination. Light fixtures may be hung directly above the pick-aisle center. The fixtures are supported from the ceiling support members or from the pick-position structural members, permitting maximum light in the pick aisle and easy light bulb replacement, or the fixtures are hung perpendicular to the pick aisle and above the GOH storage and pick rails. In this method, the light fixtures are hung from the ceiling structural members, increasing the difficulty of replacing light bulbs. Some light is absorbed by GOH pieces.

STORAGE AND PICK-AREA DESIGN CONSIDERATIONS The next major GOH order-fulfillment design factors are the storage and pick-area design considerations to improve employee productivity and maximize the storage and pick positions per square foot. These factors are the pick-position type (fixed or random), the GOH or SKU location on the pick aisle, and the pick-aisle characteristics.

TYPES

OF

PICK POSITION

The GOH pick position in a GOH order-fulfillment aisle contains a GOH SKU quantity and, per a customer-order, an order picker transfers a GOH SKU quantity from the pick position to an order-pick vehicle. The pick position options are (1) fixed and (2) random, floating, or variable. Fixed Pick Position With a fixed GOH pick position, as the GOH SKU enters the pick area, the computer has a specific SKU quantity placed in one fixed pick position; the remaining SKU quantity is placed into reserve positions. As a depleted fixed GOH SKU pick position occurs on a static rail, the GOH SKU replenishment activity occurs in the reserve area to transfer a GOH SKU quantity from a reserve position to the GOH SKU pick position. The fixed pick position is designed to have one GOH SKU that is assigned to this permanent pick position. The disadvantages are additional labor, an increase in GOH SKU handlings and potential damage, and possible replenishment errors and stock outs. The advantages are an increase in GOH SKU hit concentration and hit density, family grouping, and higher replenishment and pick-employee productivity.



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Random, Floating, or Variable Pick Position The random or floating pick position is the GOH SKU pick position that is randomly located within the pick aisle or aisles of the facility. As a GOH SKU is received at the facility, the computer places a quantity of the new GOH SKU into a vacant pick position in one pick aisle, and the other inventory is placed in other pick positions in the same aisle or other pick aisles. Each SKU position is entered into the WMS or computer inventory files. When the order pickers deplete the present SKU pick position, the computer prints the future customer-order pick instructions for one of the other pick positions. The disadvantages are employee walk distance and time, a large floor area, and low picker productivity. The advantages are minimal replenishment labor, few GOH SKU handlings, and low GOH SKU damage.

GOH SKU LOCATION

IN THE

PICK AISLE

The GOH order picker routing pattern factor is the GOH SKU’s physical location in the pick aisle. The GOH SKU’s location along the pick aisle is the SKU pick position in the pick aisle. The factors are SKU profile, pick zone or pick area, pickposition philosophy (ABC; season, pairs, or family group; or value), length, and special or promotional SKUs. SKU Profile The first factor to determine the GOH SKU location in the pick aisle is the SKU profile. The GOH SKU profile factors are the SKU historical customer-order volume, physical characteristics, family or seasonal group, and promotional classification. These factors determine each SKU’s pick position in the pick aisle. The GOH SKU profile technique is the same as the small-item SKU profile technique. For additional review we refer the reader to Chapter 3. Pick Zone The GOH pick zone is the next GOH pick-area design factor. The pick zone is the pick-aisle section that is allocated to an order picker. The most frequently used pickzone method is the cube-out activity, an order-picker activity. The cube-out activity involves the customer-ordered GOH SKUs that are easily transferred to the trolley hang bar or GOH cart load bar. This pick-zone type is considered a variable pick zone. The pick zone determines the GOH SKU picks per aisle and the pick aisles that are required to fill a trolley or cart load bar to complete a customer-order. Per the customer GOH order-pick volume and SKU size, the order-picker pick zone changes per day. Pick-Area Layout Philosophy The GOH pick-area layout philosophy is a factor that influences the GOH SKU location in the pick aisle. The pick-area layout philosophy is a design factor that


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determines the SKU location in the pick aisle and impacts the order-fulfillment employee productivity. The various pick-area layout philosophies are (1) ABC or Pareto’s law (the 80/20 rule); (2) seasonal, pairs, or family groups; (3) SKU value; (4) SKU length (short or long); and (5) special or promotional SKUs. ABC or Pareto’s Law (80/20 Rule) When a GOH order-fulfillment operation’s pick area is based on the SKU popularity or proposed popularity, the pick area is based on Pareto’s law. This law states that 85% of the wealth is held by 15% of the people. In the order-fulfillment industry, this law indicates that 85% of the volume shipped to your customers is derived from 15% of the SKUs. Many studies have indicated that another 10% of the volume shipped to your customers results from another 30% of the SKUs and that an additional 5% of the volume shipped to your customers is attributed to 55% of the SKUs. If your are in the catalog or direct-mail business, 90 to 95% of your business is from 5% of your SKUs, because two to four catalogs are introduced within a year. Each catalog has different SKUs. In recent studies, the results show that 95% of the volume shipped to your customers is obtained from 55% of the SKUs. This method is referred to as “Pareto’s law revisited.” When an order-fulfillment professional refers to the three zones of Pareto’s law, their reference is to the ABC theory. This theory simply states that the A pick zone is allocated to the fast-moving SKUs. These SKUs are few in number and have a large inventory quantity per SKU. The B pick zone is allocated to the normal-moving SKUs. These SKUs are medium in number and have a medium inventory quantity per SKU. The C pick zone is allocated to the slow-moving SKUs. These SKUs are large in number and have a small inventory quantity per SKU. If a GOH order-fulfillment facility has the pack stations in the front side of the facility and the SKU pick zone is based on the ABC theory, the fast-moving SKUs are at the facility’s front. Season, Pairs, or Family Group The next GOH pick philosophy is the season, pair, or family group philosophy. The seasonal (spring, summer, fall, and winter), family-group, or pairs philosophy is a predetermined criterion. The SKUs are assigned to specific pick positions in one pick aisle or pick zone within the order-fulfillment facility. By hit density and hit concentration, the pairs or family-group layout philosophy improves your orderpicker productivity. Value The next GOH pick-area philosophy is the value of the SKU. Per your company’s criteria, the high-value GOH SKUs have several pick positions and the low-value GOH SKUs have separate pick positions. When high-value GOH SKUs are separated into a security area, there is potential low productivity. Length The next GOH pick-area philosophy is the length of the SKU. Most order-fulfillment operations separate long GOH SKUs from short GOH SKUs. When long GOH



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SKUs are separated to specific pick aisles and short GOH SKUs are located in specific pick aisles, this feature improves space utilization, in-house transport, and order-picker productivity. Special or Promotional The special or promotional pick philosophy is sometimes referred to as power or fast-moving SKUs in one pick area. The power or fast-moving SKUs in one pick area or zone philosophy has an inventory (SKU) allocation program that locates all fast-moving SKUs in specific pick positions. These pick positions are adjacent to one another. This philosophy has all your promotional, seasonal, special sale, or fast-moving SKUs in one pick zone. This SKU arrangement increases your order picker’s hit concentration (number of hits per aisle) and hit density (number of hits per SKU). A high hit concentration and hit density means high order-picker and putaway and replenishment productivity due to a very short travel distance between two pick positions

PICK-AISLE CHARACTERISTICS The next GOH pick-area factors are the pick-aisle characteristics. The pick-aisle characteristics impact your order-picker walk time, distance, and SKU number per aisle. The major factors are aisle direction flow, which may be parallel to the pack table or perpendicular to the pack table, and pick-aisle length (long or short).

AISLE DIRECTION

OF

FLOW

The first static GOH pick-rail layout philosophy is based on the direction of flow to pack stations. The aisle direction of flow options are parallel to the pack table and perpendicular to the pack table. Parallel to the Pack Table The first method is a static GOH rail and aisle direction-of-flow method that is parallel to the pack stations. With this method, at least two turning aisles at the rows’ ends and a middle traffic aisle are required in the layout. These aisles lead the order picker to the pack stations. This arrangement increases the order-picker travel between the pick area and the pack stations. Perpendicular to the Pack Table The second static-rail and pick-aisle flow layout has the static-rail and aisle direction of flow straight from the pick area to the pack stations. In this design, each pick aisle provides access to the pack area and the main traffic aisle serves as an orderpicker turning aisle. A middle cross aisle ensures good order-picker productivity in transferring to an adjacent aisle and performing a transaction for a SKU in a different aisle. With this design, the order-picker travel distance is short, improving orderpicker productivity. Aisle Length The next GOH order-fulfillment layout philosophy involves a layout that is based on the GOH pick-aisle length. The philosophies are short aisle and long aisle.


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Short Aisle Length The short-aisle philosophy specifies that the static rails and aisles run in the short facility dimension or the short width of a rectangular facility. This method requires turning aisles at each static-rail row’s end. When compared to the long-aisle method on a SKU-per-square-foot basis, the short-aisle method provides fewer pick positions per aisle and lower employee productivity, due to an increase in aisle turn numbers. Long Aisle Length With the long static-rail and aisle philosophy, the static-rail rows and pick aisles are arranged to flow in the long direction of a rectangular facility. The long-aisle method does have a cross aisle in the middle of each static rail row to provide easy and quick access to other pick-area aisles. The long static-rail and aisle method does provide maximum pick positions per aisle and fewer unproductive employee turning aisles. GOH Storage and Pick Position Aisle Barrier When your GOH storage operation has a low-level static storage rail, or moving GOH storage positions that are adjacent to an employee or mobile equipment aisle, a solid-aisle barrier along the aisle’s edge has the following benefits. In the bottom storage positions, it prevents the bottom of a GOH plastic bag from creeping into the aisle and becoming damaged. It also reduces the possibility that airborne dust will flow through the plastic bag opening and onto the GOH piece. The aisle solid-barrier methods are as follows. First, with a static storage method that uses upright rack or shelf posts attached to the floor, a 12- to 18-inch length of cardboard or a hardened plastic high-solid sheet that extends upward or rope strands may be attached to the upright rack or the side of a shelf post that faces the aisle. Second, with a static storage method that uses cantilevered arms to support the GOH storage rails, a solid 90˚-angle piece of hardened plastic or sheet metal, or posts with rope strands, is installed on the floor. With the 90˚ method, one leg is secured to the floor and the other leg serves as the barrier. Lastly, with a mobile or dynamic horizontal-carousel storage method, along the storage area perimeter a solid 90˚angle piece of hardened plastic or sheet metal is installed on the floor. With the 90˚ method, one leg is secured to the floor and the other leg serves as a barrier. Hanging Garment Order-Pick Philosophy The next GOH order-pick consideration is the GOH order-pick philosophy. The GOH order-pick philosophy is the method by which the customer orders are presented to the order-pick employee. The order-pick transaction options are (1) single customer-order completed by one order picker and (2) batched customer orders that are picked by one or several order pickers. These order-pick philosophies are similar to the small-item or flat-wear apparel order-pick philosophies. For a detailed review, we refer the reader to the small-item flat-wear apparel section of Chapter 3. Batch-Pick Hanging Garment Sorting Methods In a batch-pick GOH order-fulfillment operation, the computer groups customerordered pieces into one group or wave. Prior to the customer-ordered and picked



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GOH pieces’ delivery to the pack stations, the customer-picked GOH pieces are mixed, and require a separation or sorting by customer-order. In a GOH batched customer-order pick operation, the next important order-fulfillment activity is the customer-order separation or sorting activity. The batched customer-ordered and picked SKU separation or sorting activity methods are (1) manual sorting or (2) mechanical sorting. Hanging Garment Manual Sorting Method. The first GOH batched customerordered and picked SKU method is the manual sorting method. The manual GOH sorting method has the customer-ordered and picked GOH pieces separated and sorted from a mix of customer-ordered and picked SKUs to the individual customerordered and picked SKUs. The manual sorting methods are the GOH cart and nonpowered trolley. The first GOH sorting method employs a pushed or pulled GOH cart with a hanger load bar. Each order-pick cart load bar holds the mixed or batched customerordered and picked GOH pieces. Along each aisle side are empty GOH carts. Each cart has a hanger load bar that has several rectangle or doughnut dividers. Each rectangle or doughnut divider has a customer-order identification on its surface. The two empty GOH cart rows are considered the customer-order locations or the sorting locations. The sorting locations are arranged in numerical sequence from the lowest customer-order number to the highest customer-order number. As an employee pulls or pushes a GOH cart with mixed or batched customer-ordered and picked GOH pieces through the sorting aisle, per the sorting instruction (which is the customerorder number), from a full cart with mixed customer-ordered and picked GOH pieces the sorting employee sorts or transfers the customer-ordered and picked GOH SKUs to the appropriate customer-order cart or section on a cart. To enhance employee sorting productivity and accuracy, the customer-ordered and picked SKUs are in SKU number sequence, the customer-order locations are in customer-order sequence, and the customer-order sorting instructions are printed in SKU number sequence. The second manual GOH sorting method has a nonpowered trolley sorting aisle. The sorting aisle has three overhead nonpowered trolley rails. The middle trolley travel path is for trolleys of mixed or batched customer-ordered and picked GOH SKUs. Each outside trolley travel path has empty trolleys on the appropriate overhead rail. Each trolley is considered a customer-order assembly location. If the operation has a large number of customer orders with few GOH pieces per order, each trolley load bar has several rectangle or doughnut dividers. Each rectangle or doughnut divider has a customer-order identification. As an employee walks through the sorting aisle, the employee pushes or pulls a mixed or batched customer-ordered and picked trolley with GOH pieces on the middle trolley rail. Per the sorting instruction, from a full trolley with mixed or batched customer-ordered and picked GOH pieces the sorting employee sorts or transfers the customer-ordered and picked GOH SKUs to the appropriate customer trolley or section on a trolley. To enhance employee sorting productivity and accuracy, the customer-ordered and picked SKUs are in SKU number sequence, the customer-order locations are in


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customer-order sequence, and the customer-order sorting instructions are printed in SKU number sequence. Since the manual GOH piece-sorting method is similar to the manual sort methods that were reviewed in the receiving section, for a detailed review we refer the reader to the receiving section in this chapter. GOH Mechanical Sorting-Method Group The second GOH sorting-method group is the mechanical sorting-method group. The methods are (1) the Promech method, (2) the powered chain and trolley method, and (3) the trolleyless method. Promech. The Promech GOH piece sorting method moves a GOH piece (or six GOH pieces on a ring) from an in-feed (or charge) station over a fixed travel path and to a customer sorting and packing station. The standard Promech GOH piecesorting method handles approximately 5000 GOH pieces per hour. The Promech GOH piece-weight carrying capacity is up to 11 pounds per GOH piece, and the method can handle both short and long GOH pieces. Some new Promech GOHpiece sorting methods are designed with GOH hooks on closer centers to increase the sorting capacity. The Promech GOH piece sorting method’s components are (1) two wheel trolleys in a C-channel or on an I-beam with a powered endless closed-loop wire rope and pendant carriers; (2) structural-support members; (3) hooks or individual GOH piece carrying devices, or an optional ring that carries up to six GOH pieces; (4) drive motor, sprocket, and take-up units; and (5) in-feed and out-feed stations and controls. Some Promech components are similar to the powered wire rope material handling method. These similar features include the following. First, there are twowheel trolleys or carriers in a C-channel or on an I-beam with a powered wire rope and pendant GOH transport component. The two wheel trolleys are attached to the wire rope. As the powered wire rope is pulled by the drive motor, the wheels are pulled over the C-channel or I-beam fixed travel path. Second, there are structuralsupport members. These hardened and coated metal members are floor-supported posts with base plates. The base plates are anchored to the floor. With a ceilinghung method, adjustable rods and saddle brackets are used to hold the travel path. Third, there are the drive motor, sprocket, and take-up device. The drive motor and sprocket provides the power to pull the wire rope forward over a fixed travel path. A nonpowered sprocket on 90˚ or 180˚ turns ensures that the wire rope carriers and wheel trolleys complete travel through a curve. The Promech method’s unique components are (1) a hook or individual GOH piece-carrying device, or an optional ring that holds six GOH pieces; (2) the GOH piece in-feed station; and (3) the slick rail divert station. The first unique Promech GOH piece-sorting component is the specially designed hook or GOH piece-carrying device. The hook is a hardened metal member that is attached to the bottom of the powered wire rope and has a spring-loaded lever. As the Promech powered wire rope propels the hooks over the travel path at 100 feet per minute, the hook is designed to interface with the GOH piece in-feed station and divert or packing station.



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The hook features are that the intersection of the spring-loaded lever and fixed metal hook section is at the lowest hook level, and that the hook handles a metal open-faced hanger or a ring. The Promech GOH piece-sorting method wire rope presents the hook to the infeed station. A GOH piece open-faced hanger is automatically transferred or placed onto a hook. Open-faced hanger transfer is achieved because the metal hook of the open-faced hanger is slightly held back by a small depression at the in-feed station slick rail component, and because of the forward movement of the wire rope and hook. At the customer-order divert or packing station, the GOH piece is transferred from the Promech wire rope hook onto a divert or packing station slick-rail section. At each packing station along the wire-rope travel path, a trigger plate is positioned to open a wire-rope hook spring-loaded lever. The spring-loaded lever’s opening action releases the GOH piece onto the packing station’s slick-rail section. The Promech GOH piece-sorting method’s wire-rope hook design arrangements are on 14.5 in centers and on 7.5 in centers. When the Promech wire-rope hooks are on 14.5 in centers, the Promech method sorts 5000 GOH pieces per hour. When the Promech wire-rope hooks are on 7.5 in centers, the Promech method sorts 10,000 GOH pieces per hour. To handle the additional in-feed volume requires a dual charge or in-feed station method. If you increase the number of GOH pieces (or decrease the distance between two wire rope hooks or wire rope hook centers) on the Promech method, you increase the load weight on the Promech GOH piece-sorting method’s travel path. This loadweight increase requires additional structural-support member design and increases the drive motor horsepower. The second Promech components are the GOH piece in-feed station and the divert or packing station. The Promech method in-feed station designs are (1) manual in-feed and (2) automatic in-feed. Manual In-Feed Station and Packing Station. The manual in-feed station is the basic Promech GOH piece-sorting in-feed station. At the in-feed station, a GOH piece is manually attached to a Promech hook. The hook is connected to the Promech wire rope, which is an endless closed-loop conveyor system. The wire-rope travel path is past the in-feed and divert or packing stations. After your in-feed station employee enters the GOH piece SKU identification number into the induction terminal, each customer-order quantity or the total number of GOH pieces appears on the display screen, and the in-feed station employee transfers one GOH piece onto each wire-rope hook. At the manual GOH piece in-feed station, the wire-rope travel path declines. This decline causes the wire-rope clasp to open. When the wire-rope hook is open, an employee places an open-faced hanger or ring onto the wire rope hook. After the GOH piece is on the wire rope hook, the employee presses the dispatch button that sends the GOH piece over the travel path to the appropriate packing station. If the ring is not used in the GOH piece-sorting operation, the multiple GOH pieces require one hook for each GOH piece. With the GOH piece on the wire-rope hook, the hook passes a photo eye that activates the appropriate solenoid magnetic divert device. The solenoid magnetic


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divert device is the first packing or divert station that requires the GOH piece SKU. As the wire rope hook with the GOH piece approaches the appropriate packing or divert station, the divert station device lifts the appropriate trip bar in the direct path of the wire rope levered hook wheel. As the hook wheel travels onto the elevated trip bar at this travel-path location, the wheel travels up the trip bar. This travel direction permits the hook clasp to move upward. The clasp’s upward movement releases the GOH piece open hanger or ring from the clasp onto the packing or divert station’s slick-rail section. As the wire-rope hook continues its forward travel on the travel path and through the packing station section, the hook’s wheel passes to the upper end of the trip bar and the wheel forces the trip bar to return to the lowered position. In this lowered position, the trip bar permits the hook to complete travel through the packing station section. This action disengages the trip bar magnet, so that the packing station discharge components are in the neutral position. The discharge station in the neutral position permits other hooks with GOH pieces that are assigned to other packing stations to travel through the unassigned packing station to the appropriate packing station. Automatic In-Feed Station and Packing Station. In the Promech automatic infeed method, one GOH piece at a time is fed onto the wire-rope hook’s travel path. The automatic in-feed station is controlled by a microcomputer. The microcomputer controls a spindle that is driven by an electric motor. The control system regulates the spindle speed in sequence with the travel speed of the wire-rope hook. The travel path of the wire rope elevates and declines before it reaches the GOH piece in-feed station. The wire-rope hook’s clasp opens due to the location and wheel weight. When the clasp is open, a GOH piece slides onto the hook. Special sensing devices are located in the spindle area to determine the existence of two hangers (or GOH pieces) on the same spindle. If this situation occurs, an alarm is activated and sorting is stopped to prevent damage. An employee removes the extra hanger and reactivates the system. Multihanger Ring. If your customer orders have multiple GOH pieces of the same SKU, the multihanger ring is used on the Promech GOH sorting method. The ring has the capacity to carry six GOH pieces. If there are six GOH pieces per pack station, the ring increases the GOH piece throughput volume to 20,000 pieces per hour. Description of Operations. The operation of the Promech GOH sorting method requires that the GOH pieces be delivered to the in-feed station on open-faced hangers. At the in-feed station, depending on your control system, an in-feed station employee enters the SKU number into the data-entry device and places a GOH piece onto a Promech open hook. In the alternative SKU data-entry method, an employee places the GOH piece onto an open Promech hook to allow a scanner device to read the GOH piece bar-code label. If there are multiple SKUs per delivery or packing station, a ring is used to attach the appropriate number (up to six GOH pieces) to a hook. An alternative in-feed station method is an automatic GOH piece in-feed method.



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After the GOH piece is under the Promech control system and is on the wire rope hook, the GOH piece travels over the wire-rope travel path to the assigned packing station. Given the constant wire-rope travel speed and the GOH piece encoded data, at the assigned packing station the Promech device and controls permit the GOH piece to divert from the wire rope hook onto the appropriate packing station’s slick rail. The disadvantages are that the Promech method only handles one to six GOH pieces per hook, it requires an encoding station and device, it has a short travel distance, it has one or two charge stations that require a GOH piece in-feed queue area or a constant GOH piece flow to the in-feed station, and the open-faced hangers match the Promech method specifications. The advantages are that it frees up the floor below the travel path, handles a medium volume, reduces sorting errors, sorts per encode instruction or entry, has reusable carriers, requires low maintenance, is simple to operate and requires few employees, and requires minimal employee training. Powered Chain and Programmable Trolley. The second mechanical GOH sorting method is the powered-chain and programmable-trolley method. The programmable trolley is a device that is used to sort GOH pieces on a trolley; the trolley’s front neck has a destination code that is set by an employee. The trolley has a load bar that carriers GOH pieces, and the load bar is attached to two spools. The two spools ride on a rail, strut, C-channel, and inverted iron angle travel path. The trolleys are pulled by an endless closed-loop powered chain. The powered chain is propelled by an electric motor-driven sprocket with a series of teeth that interface with chainlink openings. The powered chain is pulled through a C-channel track that is directly over the trolley travel path. In this location and at a predetermined elevation, the powered chain has a series of metal downward-extending pendants (pusher dogs). After the pusher dog engages the trolley’s front head, the powered-chain pusher dog pulls the GOH trolley over a fixed travel path. Along the trolley travel path is a reading device that reads a trolley code, sends a message to a microcomputer, and triggers a divert device on the trolley travel path to divert the trolley from the main travel path to a branch spur. The programmable-trolley code devices are (1) sliding retro-reflective tabs, (2) wire prongs, and (3) bar-code labels. For additional programmable trolley information, we refer the reader to the GOH in-house transportation section in this chapter. The disadvantages of this method are that there is a large quantity of GOH pieces per trolley, and that it is difficult to efficiently and cost-effectively handle a single GOH piece or SKU. The advantages are that it handles a high volume and is reusable. Trolleyless Sorting We refer the reader to the section on trolleyless sorting earlier in this chapter. Hanging Garment Accumulation Prior to a Pack Station is a Must. The packing station activities include GOH packing and sealing, and attaching the customer address to the delivery container. Other activities include transferring the completed customer-delivery container to the take-away transport method or onto a cart or pallet. To have an efficient, cost-effective, and on-time customer-order pack


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activity, an important pack-area design parameter is to provide a sufficient in-feed GOH piece queue prior to each pack station.

VARIOUS IN-HOUSE HANGING GARMENT TRANSPORTATION METHODS The various customer-ordered and picked GOH piece transport methods are: • • • •

GOH cart with a load bar Nonpowered or powered overhead trolleys with a load bar Trolleyless method Totes on a powered or nonpowered conveyor travel path

When GOH pieces are delivered to a packing station, there must be sufficient space for at least two transport devices, a constant GOH piece flow, and an empty transport device take-away travel path. Packing supplies have temporary storage between the cart lanes. The completed and packaged customer-order take-away is on the packing table’s far side or behind or adjacent to the packing table.

GOH CART METHOD If your GOH operation uses a GOH cart as the GOH transport method, your packing station layout has an inbound cart lane and an empty cart lane. The inbound cart lane has the carts flow from the main traffic aisle to the packing station. One corner of the rectangular cart meets a packing table corner. The outbound cart lane has the rectangular empty cart positioned at a packing station corner or directly behind the packing station. The cart flow starts at the packing station and ends at the main traffic aisle intersection. Each cart lane holds two to three carts and intersects with a main traffic aisle.

NONPOWERED OVERHEAD TROLLEY METHOD If your GOH operation uses a nonpowered overhead trolley as the GOH transport method, your packing station layout has an inbound trolley travel path and an empty trolley cart or trolley travel path. The inbound trolley travel path has the trolleys flow from the main travel path to the packing station. The trolley travel path ends with the trolley positioned at the packing station so that the trolley’s front meets a packing table corner. The outbound trolley travel path or empty trolley cart is positioned at the packing station corner or directly behind the packing station. The empty trolley lane or cart flow starts at the packing station and ends at the main traffic aisle intersection. The inbound trolley travel path or empty trolley cart lane holds two to three trolleys and intersects with a main traffic aisle.

TROLLEYLESS METHOD If your GOH operation uses a trolleyless method as the GOH transportation, your packing station layout has an inbound GOH slick-rail trolley travel path. The inbound



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slick-rail travel path has the GOH hangers flow from the main travel path to the packing station. The GOH hanger slick-rail travel path ends with the lead GOH piece at a packing table corner. With the hanger in the customer-order carton, there is no transport device return queue lane.

TOTE

ON A

NONPOWERED

OR

POWERED CONVEYOR

If your GOH operation uses a tote on a conveyor travel path as the GOH piece transport method, your packing station layout has an inbound tote-conveyor travel path and an empty tote travel path. The inbound tote-conveyor travel path has the totes flow from the main conveyor travel path to the packing station. The rectangular tote position at the packing station has the tote intersect at a packing-table corner. The outbound tote has the rectangle totes stacked on the floor directly behind the packing station or placed onto the conveyor travel path that is positioned along the packing station front.

COMPLETED CUSTOMER-ORDER PACKAGE TAKE-AWAY METHOD The next important GOH packing station consideration is the transport method for complete customer-order packages. The completed customer-order package may be (1) placed into a bulk-mail carrier (BMC) or four-wheel cart or (2) carried on a nonpowered or powered conveyor travel path. BMC or Four-Wheeled Four-Sided Cart The BMC is sometimes referred to as a specially-designed four-wheeled cart. The BMC’s components include four swivel wheels; a square, solid, or wire-mesh loadcarrying surface or bottom; and four mesh or solid walls with holes. One wall is hinged to open and close and, per your operation, is lockable. Other BMC features include rigid side walls or carriers that can be nested. BMCs are easily moved by an employee and easily towed by a powered vehicle. BMCs are 60 by 60 inches with a wall height of 6 feet. The BMC load-carrying surface accommodates your customer shipping box. After the BMC is loaded with your customer-order cartons, an employee moves the BMC to the dock staging area or directly onto your customer delivery truck. The BMC is handled at your orderfulfillment facility and at your freight company facility. The BMC disadvantages are that full or empty carts require a staging area, the loading station requires several cart positions, and an employee must move the carts. The advantages are minimized pressure on cartons and no conveyor investment. Nonpowered or Powered Conveyor The next GOH customer-order package transport method is the nonpowered or powered conveyor travel path method. With a slight slope and with an employee’s force, a GOH customer-order carton is moved over a nonpowered conveyor travel path. The powered conveyor travel path has an electric load-carrying surface that moves your GOH customer-order packages between two locations.


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The nonpowered or powered conveyor travel path options are a skate-wheel conveyor travel path or a roller conveyor travel path. These conveyor travel-path designs have differences and similarities. The differences are that the skate-wheel method has skate wheels as the load-carrying surface and the roller method has rollers as the load-carrying surface, they have different investment costs but handle the same volume, rollers are considered more durable, and skate wheels and roller axles are different. The nonpowered and powered conveyor travel-path methods were reviewed in other chapters. For additional information we refer the reader to Chapter 3. Packing Station Surface The next GOH packing station design consideration is the GOH packing station surface and temporary packing supply storage at the packing station. In the GOH catalog and direct-market industry, the packing station may have a plain flat-top table or a specially designed table with drawers and shelves. In the retail store industry, the packing station design options are manual transfer to the retail store delivery device and mechanical transfer to a hang-bar box. Plain Flat-Top Table The first GOH packing station method is the plain flat-top table method. The plain flat-top table is a 3-by-6-foot surface with fixed or adjustable legs. This table provides the packing employee with the necessary work surface to complete the GOH piece preparation and packing activity. The packing activity includes carton makeup; pick accuracy check; invoice, GOH piece fold (with an insert, if required), and placement into the carton; customer shipping address label placement on the carton; sealing the carton; and easy package transfer onto the completed order-transport method. Shelving adjacent to or above the table surface provides temporary shipping supply storage. Shelving or a four-wheel cart is considered a problem order station. The completed customer-order take-away conveyor travel path is set slightly below the pack surface, and rubber mats on the floor at each packing table’s front improves employee productivity by reducing employee fatigue. The completed customer-package transport method options are a BMC located adjacent to or behind the packing table, or a take-away conveyor located on the table’s far side. Specially Designed Table The second packing surface is the specially designed table that has drawers, shelves, and temporary carton-storage locations. The table surface has adjustable legs and sufficient surface space to complete the GOH piece preparation and packing activity that were mentioned in the plain flat-top table section above. When we compare the two packing station methods, the specially designed packing table has a higher cost. Manual Transfer to Delivery Device In a retail store’s GOH order-fulfillment operation that sends GOH pieces on GOH carts to the retail stores, the GOH pieces are picked directly onto a GOH cart.



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With this method, the order picker (a check and pack employee) completes all packing activities. If the GOH pieces are sent by rope loops in a delivery truck, the GOH pieces are picked onto a transport device and transferred directly into a delivery truck. In the delivery truck, an employee transfers the GOH pieces from the transport device onto a delivery truck’s rope loop. Packing Machine for a Hang-Bar box In a retail store’s GOH order-fulfillment operation that sends GOH pieces in a hangbar box to the retail stores, the GOH pieces are transferred from the pick device into the hang-bar box. With this method, the GOH piece packing activity has two options: manual transfer into a hang-bar box and mechanical transfer into a hang-bar box. Manual Transfer to the Hang-Bar Box. If a retail store’s GOH order-fulfillment operation sends GOH pieces in a hang-bar box, the GOH pieces are picked onto a GOH cart or trolley and transported to a transfer station. At the transfer station, an employee transfers the GOH pieces individually or in bundles from the transport device’s load bar to the hang-bar box. This activity requires an employee to raise and lower the GOH pieces onto the hang bar in the box. Mechanical Transfer to the Hang-Bar Box. If a retail store’s GOH order-fulfillment operation sends GOH pieces in a hang-bar box, the GOH pieces are picked onto a GOH or trolley and transported to a transfer station. At the transfer station, an employee transfers the GOH pieces individually or in bundles from the transport device’s load bar to the mechanical boxing load bar. The mechanical load bar is attached to a vertical device that raises the load bar above an empty hanger box. The employee controls the load bar to lower onto the carton sides. This mechanicaltransfer device requires minimal employee effort to load the GOH pieces onto the hang bar in the box. The mechanical-transfer method requires an investment, electrical power, and minimal employee effort. Packing Materials and Methods The customer-order shipping container that is used by your GOH order-fulfillment operation is determined by the quantity or number of GOH pieces per order, GOH value, the customer delivery method, and the container’s reusability. A GOH piece operation’s customer-order shipping container is determined by your customer type. The GOH piece packing activity and requirements are different for catalog or directmarket customers and retail store customers. If your GOH order-fulfillment operation services catalog and direct-market customers, the type of customer-order shipping containers is a very important factor because the shipping container’s exterior appearance influences customer opinion. Most catalog and direct-market companies use another company to transport the customer-order package to the customer delivery address. To achieve optimum employee packing productivity, efficiency, GOH piece protection, and package exterior presentation, the customer-order shipping container selection factors are GOH pieces per order, other customer-ordered merchandise in


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the package, package cost, and security of the GOH piece inside the package. A container of appropriate size is indicated on the customer packing slip (or display screen); this becomes an instruction to a packing employee, improving packing productivity and package appearance. In the catalog and direct-market industry, the possible GOH piece shipping container types are cardboard boxes (one piece and two piece) and two-piece chipboard boxes. In most catalog or direct-market companies, the cardboard carton or chipboard box has two sizes. One carton size is for one GOH piece and the other carton size is for two GOH pieces. One-Piece Corrugated Box The first GOH piece cardboard or corrugated carton is the one-piece carton or pizzabox type carton. The one-piece carton requires a packing employee to fold or form the carton. This activity is very similar to a pizza chef preparing a pizza delivery box. After forming the one-piece carton, the GOH piece is placed into the carton interior and the cover is folded down. This encloses the GOH piece inside the carton. To secure the GOH piece inside the carton, plastic bands or tape secures the carton cover. The one-piece carton requires a larger packing station area, causes decreased employee productivity, does not require additional equipment investment, and features slightly lower carton cost. Two-Piece Corrugated Box The second GOH piece cardboard or corrugated carton is the two-piece corrugated carton. The two-piece cardboard carton consists of a bottom section and a top or cover section. The two-piece cardboard carton requires a carton-forming machine to form (or make up) both of the two-piece carton’s sections. To provide cartons at the pack station, the carton makeup and supply options are to have both carton sections restocked on a periodic basis, or to have an employee or powered-conveyor method provide a constant supply of carton sections to a pack station. With the two-piece carton, the pack employee places the GOH piece into the bottom section and places the cover onto the bottom section. The cover on the bottom section encloses the GOH piece inside the carton. Plastic bands or tape secures the GOH piece inside the carton. The two-piece carton provides increased employee productivity and requires fewer employees, investment in a carton-forming machine, and a transport method to deliver empty carton bottoms and tops to a pack station. The packing station can reuse clean and solid bottom sections from customer returns. There is a slight cost increase, and there is increased side wall and corner strength. The corrugated carton features are slightly higher material cost, an equipment investment, additional time to make up cartons or to deliver made-up cartons to the pack station, increased side wall and corner strength, and ability to handle all GOH piece types. Two-Piece Chipboard Box The second GOH piece packing option is the two-piece chipboard box. The chipboard box has thin pressed-cardboard walls, bottom, and top. At the pack station,



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both the top and bottom sections are collapsed in a bundle. This requires the pack station employee to pop or form the bottom section and to form the top section. After the bottom is formed, the employee places the GOH piece into the chipboard box and forms the cover. The cover is placed on top of the bottom to enclose the GOH piece. Plastic bands or tape secures the top and bottom box sections. The chipboard box features slightly lower material cost. It is preferred for medium to lightweight GOH pieces. There is less side wall and corner strength, no additional equipment investment, and higher productivity. When to Make Up Cartons The two options are to make up the two-piece carton sections and have made-up cartons staged at the pack station or in a constant flow to the pack station, or to deliver the carton sections to a pack station on demand. This carton makeup issue is the same as for small-item and flat-wear cartons. For additional information, we refer the reader to that section in Chapter 3.

CUSTOMER-ORDER CHECK METHODS No matter what the customer-order-fulfillment method (single customer-order or batch), one aspect of the GOH piece packing activity is a check activity to ensure the customer-order pick accuracy and the GOH piece quality. To ensure that the quality and quantity are correct, the options are (1) manual or visual checking and (2) bar-code scanning. Manual or Visual Method The manual or visual-check method requires a packing employee to make a visual comparison of the actual picked GOH piece quality and quantity to the customerordered GOH piece quantity that appears on the customer-order pack slip. The method requires that each SKU has a human-readable label. To make the comparison, an employee uses a printed customer-order packing slip, a handheld scanner, and a display screen that shows the customer-ordered piece quantity. To verify the picked GOH piece quantity and quality, the packing employee reads the SKU description identification number and piece quantity that are printed on the packing slip. If there is a match with the actual and pack-slip GOH piece figures and if the SKU quality is good, the packing employee prepares the GOH pieces for shipment to the customer’s delivery address. If there is no match with the actual and pack-slip GOH piece figures or the SKU quality is poor, the packing employee places the picked GOH pieces and packing slip together onto a problem order station. If there is no match due to an excess of GOH pieces, the packing employee prepares the customerorder package for shipment and places the surplus picked GOH pieces onto a problem order station. The disadvantages are that the method requires an employee to read and that it requires a preprinted packing slip. The advantages are that the method verifies the pick accuracy, handles a large volume, entails easy employee training, requires a human-readable code on each SKU, and is easy to install.


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Handheld Bar-Code Scanning Method The second customer-check method requires a packing employee to use a handheld bar-code scanning device to scan each picked GOH piece label. The method requires that each SKU has a human- and machine-readable label. To verify the GOH piece quantity and quality, the packing employee uses a handheld scanner to scan each customer-ordered and picked GOH piece. After a personal computer (PC) or RFdevice display screen indicates customer pack-slip SKU quantity, the employee verifies the SKU quantity and quality. With a match, the employee packs the GOH pieces into the customer-order shipping container. If there is no verification and the SKU quality is poor, the packing employee places the picked GOH pieces with a note onto a problem order station. If there is no match due to an over-pick, the packing employee prepares the customer-order package for shipment and places the surplus picked GOH pieces onto a problem order station. The disadvantages are an additional investment, packing station communication to the microcomputer, employee training, a human- and machine-readable label requirement on each SKU, and an employee performing a quality check. The advantages are that the method verifies pick accuracy, handles a large volume, has a high degree of accuracy, does not require an employee to read, and handles a wide SKU mix.

PACKING INSTRUCTION

AND

SHIPPING LABEL PREPARATION

At the packing station, a customer delivery package requires a packing slip inside the package and a customer delivery-address label on the package’s exterior surface. The packing slip is required in the package because it allows the customer to verify that the customer-order is complete and that the ordered SKU pieces are in the package. At the packing station, the customer-delivery address label is attached to the package’s exterior surface. To print a customer packing slip and a customerdelivery address label, a GOH piece order-fulfillment operation’s options are to print the labels at a central print station and deliver the correct label to the appropriate pack station (the central print method), or to print the customer delivery label at the packing station (the remote print method). The decision to print your GOH customer-order manifest and shipping documents at the pack station or at a central location is determined by the following: •

•

• •

Order-fulfillment method. At a start station the customer-manifest and shipping documents are placed in the customer-order pick container; a pick, sort, and pack method can be used for delivery to a pack station; or a pick, transport, and sort method can be used at the pack station with the customerorder manifest and shipping documents delivered to the pack station. Ability to purchase and install a communication network connecting pack stations with a computer, and time to communicate the customer-order information between the computer and the remote pack station printer. Economics. Employee training.



• •

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Available space at the pack station. Pack-area existing environmental conditions.

Central Print Method The first option for printing customer packing slips and shipping labels is to have these documents printed at a central location. After printing and combining the documents, the documents are delivered to the appropriate picking station. Prior to the customer-order pick activity, the documents are placed into the customer-order pick container. After the order pickers have completed all customer-order pick transactions that include the customer-order documents and shipping label, the order picker delivers the customer-ordered and picked SKUs and the manifest and shipping documents to a pack station. Per your order-fulfillment operation, your packing employee performs a customer-order pick quantity and quality check. Advantages include high speed, minimal installation expense, central inventory, increased control, and additional space at the pack station. The method does not add to the pack-station activity. Without a backup printer, the pack-station activity shuts down. Per the order-fulfillment, picking, and sorting methods, there are potential print document distribution errors. Relocating or remodeling the pack area involves minimal difficulty and cost. Print at the Pack Station The customer-order manifest and shipping document may be printed at each pack station. After an order picker has completed all required customer-order GOH picks, the customer-ordered and picked SKUs are delivered to a pack station. At the pack station, the packing employee scans the customer-order discrete code. This customer code is sent to the computer that tells the pack-station printer to print the customer manifest and shipping documents. The packing employee, per your company procedures, completes a customer-ordered and picked SKU quality and quantity check. The method requires a large number of print machines. There is the expense of wire installation between the computer and the pack-station printers. Manifest and shipping document supplies minimal control. The method adds to the required space at the pack station, adds a pack-station employee activity, requires backup printers for pack-station printer problems, and involves no print document distribution errors. There is difficulty and additional cost associated with remodeling or relocating the pack area. Printers affect pack-area environmental conditions.

HANGING GARMENT PACKING CONSIDERATIONS The next GOH piece order-fulfillment activity is the packing activity. For each type of customer, the GOH piece packing activity is different. Catalog and Direct-Market Customer Packing Options When your catalog or direct-market customer GOH piece order-fulfillment packing activity folds the customer-ordered and picked GOH piece into a shipping container, the options are:


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• •

• •

To have the GOH piece remain on the hanger and drape or fold the GOH piece into a shipping container To have the GOH piece remain on the hanger, place the hanger in a cardboard insert notch, fold the GOH piece around the insert, and place the GOH piece into a shipping container To remove the GOH piece from the hanger and drape or fold the GOH piece into a shipping container To have the GOH piece remain on the hanger, place the hanger on a cardboard insert side, fold the GOH piece around the insert, and place the GOH piece into a shipping container

Hanger Remains on a Hanging Garment with No Insert The first GOH piece packing option is to have the GOH piece remain on the hanger and to drape or fold the GOH piece into a shipping container. With some long GOH pieces, the drape or fold activity requires packing-employee training and time to ensure the proper GOH presentation. When your GOH piece remains on its hanger and is placed into the customer shipping container, the GOH piece has the potential to get wrinkles. As the customer-order container is handled by the customer delivery company, the hanger weight causes the GOH piece to move toward the shipping container’s bottom. In this position wrinkles occur in the GOH piece. A wrinkled GOH piece at the customer delivery location has the potential to create a customer return. Hanging Garment with Hanger Folded around a Notched Insert The second GOH piece packing option is to have the GOH piece remain on the hanger, fold the GOH piece around a cardboard insert with a notch, and place the GOH piece into a customer-order shipping container. When your GOH piece remains on its hanger, the hanger hook is placed into a cardboard insert notch, folded around the insert, and placed into the customer shipping container. The GOH piece remains folded around the insert. With the cardboard-insert feature, the hanger stays in one location and there is less potential for the GOH piece to get wrinkles. As the container is handled by the customer delivery company, there a lower possibility for the GOH piece to become wrinkled by the hanger weight and its position in the shipping container. The features are a slight cost increase for the cardboard insert, improved packing-employee productivity, and improved GOH piece presentation to your customer. Hanging Garment with No Hanger Folded in the Container The third GOH piece packing option is to have the GOH piece removed from the hanger and drape or fold the GOH piece into a shipping container. When your GOH piece has the hanger removed and is placed loose into the customer-order shipping container, the GOH piece has the potential to get wrinkles. As the container is handled by the delivery company, the GOH piece gets wrinkled by its movement toward the shipping container’s bottom. A wrinkled GOH piece at the customer delivery location is a potential customer return. Hanging Garment with Hanger Folded around an Insert The fourth GOH piece packing option is to have the GOH piece removed from the hanger, fold the GOH piece around a cardboard insert, and place the GOH piece



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into a shipping container. When your GOH piece is removed from its hanger, the GOH piece is folded around the insert and is placed into the customer shipping container. During transport to the customer delivery address, the GOH piece remains folded around the insert. With this feature, the GOH piece has a good potential to stay in one location and there is less potential for the GOH piece to get wrinkles. As the container is handled by the customer delivery company, there is a lower possibility for the GOH piece to become wrinkled by the GOH piece moving inside the shipping container. The features are a minimal cost increase for the cardboard insert, improved packing-employee productivity, and improved GOH piece presentation to your customer. When compared to the notched insert method, the plain insert method requires some additional packing time. Various Retail-Store Customer Packing Options Your retail-store customer GOH piece order-fulfillment packing activity options are to have GOH pieces hung on a four-wheeled cart’s load bar with a cardboard cap, on a four-wheeled cart’s load bar with a self-adhesive tape on the hangers, on a hanger bar in a hang-bar box, and on a delivery truck’s rope loop. Hanging Garments Hung on a Cart’s Load Bar and Secured with a Cardboard Cap The first retail-store GOH piece packing method is to place the GOH piece with a cardboard cap onto the hang bar of a GOH cart. Another term for this GOH cartdelivery method is the rolling rack. With a GOH cart method, the GOH pieces are hooked onto the GOH cart’s load bar. After the load bar is full, to secure the GOH pieces onto the load bar an employee places the retail-store identification onto the cart and places a cardboard cap on the top of the hangers. The cardboard cap runs the full length of the load bar. To secure the cardboard cap and GOH pieces to the load bar, an employee wraps self-adhesive tape around the cardboard cap and load bar. After the tape is applied to the cart, the cart is ready for transport to the retailstore customer. To minimize uncontrolled cart movement inside the delivery truck and GOH piece damage, inside the delivery truck the uncontrolled cart movement is restricted by load-locking bars or other securing devices. The disadvantages are as follows. There is additional cardboard and tape cost, the hangers must be secured to the hang bar, carts must be returned to the orderfulfillment facility, there must be a load-locking device inside the delivery truck, and the empty carts require storage space at the retail store. The advantages are that this is a reusable transport device, it handles a large GOH piece quantity, it can be moved to the retail store sales floor area, and no tape residue remains on the hangers. Hanging Garments Hung on a Cart’s Load Bar and Secured With Tape The second method is to place the GOH pieces directly onto the hang bar of a GOH cart. After the load bar is full, to secure the GOH pieces onto the load bar an employee places the retail-store identification onto the cart and wraps self-adhesive tape around the hangers and load bar. After the tape is applied to the cart load bar and hangers, the cart is ready for transport to the retail store customer.


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The disadvantages are as follows. There is additional tape cost, the hangers must be secured to the hang bar, carts must be returned to the order-fulfillment facility, there must be a load-locking device inside the delivery truck, the empty carts require storage space at the retail store, and there is potential tape residue on the hangers. The advantages are that this is a reusable transport device, it handles a large GOH piece quantity, and it can be moved to the retail store sales floor area. Hanging Garments Hung on a Hanger Box The next method is to place GOH pieces on a hang bar in a hanger box. The hanger box contains a hanger bar. The hanger box is a cardboard box with four sides and flaps on the top and bottom. After the bottom flaps are sealed with tape, the hanger bar, a hardened metal bar, is attached to the box’s two sides, permitting a GOH piece hanger to be hung on the bar. The box height or depth allows the GOH pieces to hang in the box’s interior and not accumulate on the bottom. The typical hanger box is 36 inches high, but 6-foot boxes are available. The box height permits a long GOH piece to hang in the interior open space that is between the hanger bar and the box interior’s bottom surface. To reduce the likelihood of a GOH piece falling from the hang bar to the box interior, a sleeve (or cap) is taped over the GOH piece hangers and the hanger bar. A cap and tape secure GOH pieces to a hang bar and leave tape residue on the hangers. After the hanger box is full, the top flaps are sealed with tape or plastic bands. Prior to leaving the packing station, the customer delivery label is placed onto the appropriate location. With the label on the hanger box, the hanger box is ready for retail-store delivery. A hanger box minimizes GOH piece damage. In many retail-store supply-chain strategies, at the retail store the hanger boxes and hang bars are collected and returned to the order-fulfillment facility. This recycling strategy minimizes the hanger box cost. In a GOH piece operation, the hanger box is used to place GOH pieces into a pallet storage position. The disadvantages are high cost, the need for a hanger, and the need to secure GOH pieces to the hang bar (for best results). In addition, at the retail store, return boxes require space. The advantages are that the method reduces GOH piece wrinkles, transports a medium GOH piece quantity, minimizes dust and dirt on the garments, can be in the pallet storage area, and is reusable. Hanging Garments Hung on Rope Loops The next method is to bundle GOH pieces onto a delivery truck’s rope loop. An employee ensures that a GOH piece is in a plastic bag. An employee collects and identifies five to ten GOH pieces with the retail-store identification, and transfers these bundles to a delivery truck. From the delivery truck’s roof or load-locking bar hang rope strands with loops. In a delivery truck, the employee hangs a GOH bundle onto a rope loop. Per the retail-store order GOH piece quantity, the employee hangs additional GOH piece bundles onto other loops. The rope delivery method is used for retail-store customers or for a company that has its own delivery-truck fleet. This method does not require the return of a shipping container, does not require retail store storage space, requires the delivery truck’s roof or load-locking bar to



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support the GOH piece load weight, minimizes potential delivery damage, and does not require packing material and labor. Package-Securing Methods The next GOH piece packing activity is to secure the customer-order package. The package-securing activity ensures that shipping containers’ top and bottom flaps or top covers are secured to the cartons’ side walls. During delivery to the customer address, the securing or sealing shipping-carton top and bottom protect the GOH pieces from damage, improve security, and improve the carton’s exterior appearance. In the catalog and direct-market GOH piece order-fulfillment industry, the shipping container sealing or securing options are (1) gummed tape, dispensed by a manual or electric machine; (2) self-adhesive tape; and (3) plastic bands. If bands are used, the container requires one or two bands, applied in the same direction or in a crisscross pattern. In the catalog and direct-market GOH piece order-fulfillment industry, most companies use gummed tape or self-adhesive tape with corrugated or cardboard cartons and plastic bands with chipboard cartons. The tape’s exterior surface has the company’s name or logo. Gummed Tape Gummed tape is tape that contains glue on one side and has moisture applied to the glue surface. The moisture activates the glue and the tape adheres to the shipping container’s exterior surface. The gummed tape options are a manually operated tape machine and an electric machine. The manually operated tape machine requires an employee to pull the machine handle. When the handle is pulled, the tape is fed through a moisture applicator; the tape’s length is equal to one pull. The disadvantages are low packing-employee productivity, increased tape waste, potential paper cuts or glue on employee’s hands, and the need for a water supply. The advantages are that it requires a low capital investment and that the gummed tape activity can be done anywhere in the facility. The second gummed tape method is the electric tape-machine method. The packing employee sets the desired tape length on the tape machine selector dial or button. After the employee presses the hand- or foot-operator button, the tape is automatically fed through the moisture applicator. The tape machine dispenses the desired tape length. If the tape machine has a heated water supply, the glue is easier to apply to the package. The additional disadvantages of the electric tape machine are increased investment and the need for an electric outlet. The additional advantages are higher employee productivity and less tape waste. Self-Adhesive Tape Another tape method is to seal a carton with self-adhesive tape. Self-adhesive tape is available in many different materials and widths and is applied to the carton by your packing employee or by machine. In most GOH piece packing operations, the manual self-adhesive tape roll dispenser with an attached tape-cutting edge is


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used at the packing station. With the single-piece or two-piece shipping carton, semiautomatic or automatic tape machines have limited application at a GOH piece packing station. The disadvantages are some tape waste, no standard length for a shipping carton, and low productivity in sealing three or four carton sides. The advantages are that the tape handles all carton sizes, there are fewer employee complaints, and sealing can be performed anywhere in the facility. Plastic Bands The next GOH piece shipping-container securing method is the plastic-band method, which involves one or two bands. The two-band method has bands applied in the same direction or in a crisscross pattern. With the plastic-band method, a plastic band surrounds the customer shipping carton. The plastic band is applied by an employee-operated machine (mechanized method) or by an automatic strapping machine (automatic method). The plasticstrapping machine’s sealing layouts are similar because the machine applies a plastic strap around the customer shipping carton in a direction that is perpendicular to the carton’s travel direction on the conveyor travel path. Prior to the strapping station, the container is momentarily stopped on the conveyor travel path to ensure proper gap between two cartons. The gap ensures that the carton on the strapping machine is properly strapped with the plastic band. If your GOH piece order-fulfillment operation requires one plastic strap around the cardboard or chipboard carton, the activity is standard. If your GOH piece orderfulfillment operation requires two plastic straps around the cardboard or chipboard carton, the band activity is more complex. The double-strapping options are two plastic straps that are perpendicular to the carton’s direction of travel on the conveyor travel path, and two plastic straps that have a crisscross pattern relative to the carton’s direction of travel on the conveyor travel path. When your operation requires two plastic straps per carton that are perpendicular to the carton’s direction of travel on the conveyor travel path, your plastic strap application options are the manual and the mechanical method. Manual Plastic-Band Method. With the manual plastic-strap method, after the carton arrives at the strapping station, the employee-operated strap machine applies two plastic straps in the same direction on the shipping carton. After the carton arrives at the strap station, the employee applies the first strap to the shipping carton. To apply the second strap, the employee moves the carton slightly forward on the strap machine’s surface and applies the second plastic strap to the carton. Each plastic strap surrounds the shipping carton in the same direction around the shipping carton. The method offers low employee productivity, handles a low to medium volume, and results in straps that are not uniform on every package. Mechanical Plastic-Band Method. The mechanical plastic-strap machine is an electric device that bridges a conveyor travel-path section. Prior to reaching the strap machine, the shipping cartons accumulate and are moved forward one by one onto the strapping-machine surface. After a shipping carton is on the strapping-machine bridge, the strapping machine applies one or two straps to the shipping carton. To



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ensure proper shipping-carton forward movement across the strapping-machine bridge, rollers are on the bridge surface. With the machine plastic-strap method, one large strapping machine is required to apply two straps in the same direction on the shipping carton. After the container arrives on the conveyor travel path at the strapping station, the machine applies two plastic straps to the shipping carton. Each plastic strap surrounds the shipping carton in the same direction around the shipping container. The mechanical strapping machine requires few employees, handles a high volume, and results in straps that are uniform on every package. When your operation requires two plastic straps per carton in a crisscross pattern relative to the carton’s direction of travel on the conveyor travel path, your plasticstrap application options are the manual method and a method in which the conveyor turns the shipping container. With the manual plastic-strap method, to apply two straps in different directions on the shipping carton, after the carton arrives at the first strapping station, an employee at the plastic-band machine station applies two plastic straps to the shipping carton. After the carton arrives at the strap station, the employee applies the first plastic strap to the shipping carton. To apply the second plastic strap, the employee turns the shipping carton 90˚, moves the shipping carton forward slightly on the strap machine’s surface, and applies the second plastic strap to the shipping carton. Each plastic strap surrounds the shipping carton and has a different direction around the shipping carton. The method leads to low employee productivity, handles a low to medium volume, and results in straps that are not uniform on every package. With the machine plastic-strap method, to apply two straps in different directions on the shipping carton, the strapping method requires two strapping machines. After the carton arrives on the conveyor travel path at the first strapping station, the machine applies the first plastic strap to the shipping carton. After the shipping carton leaves the first strap machine, the shipping-carton conveyor travel-path options are as follows. First, the shipping carton can travel over a skewed-roller conveyor travel path (one that is set at a slight angle) and strike a round, fixed side guard. This method turns the shipping carton perpendicular to the original direction of travel. When the shipping carton arrives at the second plastic strapping machine, the shipping carton has the proper direction of travel to receive a second plastic strap. After the second strap is placed around the shipping carton, the two plastic straps are in a crisscross pattern. Each plastic strap surrounds the shipping carton in a different direction. Second, after the first strapping station, shipping cartons accumulating on the conveyor travel path can be moved forward one by one to an electric turntable with a conveyor surface. After the shipping container travels over the turntable, the shipping carton is turned perpendicular to the original direction of travel. The carton in this direction of travel arrives at the second plastic strapping machine and receives the second plastic strap. The second plastic strap completes the strapping process; the two plastic straps are in a crisscross pattern on the shipping carton. The method requires a larger conveyor travel-path investment, requires few employees, handles a high volume, and results in straps that are uniform on every package.



5

Planning a Carton or Full-Case OrderFulfillment Operation INTRODUCTION

A carton order-fulfillment operation is less complex with fewer value-added activities when compared to a small-item or flat-wear apparel or a garment-on-hanger (GOH) order-fulfillment operation. This is because stock-keeping units (SKUs) are received in pallets or multiple carton quantities and sent to customers in pallets, several cartons, or individual carton quantities. This chapter’s objective is to identify and evaluate carton handling equipment applications, methods, and technologies that make a carton order-fulfillment operation more efficient and cost effective. These factors improve an order-fulfillment operation’s profits and customer service. This chapter reviews the key order-fulfillment operation receiving, storage, order-picking, sorting, manifesting, loading, and shipping activities; it also reviews the various manual, mechanized, and automatic pick and sorting methods. This includes an analysis for each order-pick and sorting method’s design factors, operational characteristics, disadvantages, and advantages.

CARTON OR HANDLING UNIT A carton (or vendor master carton) is a basic piece that is handled at a carton orderfulfillment operation. If there are large carton volumes, the cartons are handled on a four-wheeled cart, a slip sheet, a pallet, or another material-handling device. The pallet, four-wheeled cart, or slip sheet permits an employee or machine to move the carton or cartons from receiving through the storage and pick areas to the customer shipping dock and into the customer delivery vehicle.

BASE OPERATIONAL DATA AND PICK-AREA INFORMATION The first steps in designing a new or remodeling an existing carton order-fulfillment operation or facility are to collect, evaluate, review, project, and approve the present and proposed carton pieces and customer-order volumes, the SKU quantity and

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characteristics, and other operational parameters for each order-fulfillment activity. The other operational design parameters are as follows: • • • • • • • • • •

• • • • • •

Customer-order number per day (average, most frequent, and peak) Customer carton number per order (average, most frequent, and peak) Shipping cartons, pallets, slip sheets, or carts per order (average, most frequent, and peak) Cartons per pallet, cart, or slip sheet and size (average, most frequent, and peak) Customer-order mix, including SKU type (length, width, height, weight, family group or pairs, value, and velocity for one year) Hit density or SKUs per line on a customer-order, and hit concentration or lines per customer-order (average, most frequent, and peak) Your present transport conveyor or vehicle travel speeds and number of linear feet The present customer-order shipping method and size for carts, slip sheets, or pallets Delivery truck customer-order carton number (average, most frequent, and peak) Information Management Systems (IMS)-required customer-order processing and IMS download time and time required to communicate directly to the pick line or to a microcomputer Customer-order priority Customer service time or customer-order and delivery-cycle time SKU profile for a pick line or pick area Proposed pick-line or pick-area conveyor design or aisle layout, with all required activities and simulations Proposed pick-area block, and plan-view and detail-view drawings that include all order-fulfillment activities Your order-fulfillment and other pick-area activity employees’ average height

Data collection and analysis ensures that the proposed carton pick-area layout is designed to handle the projected customer-order volume, pieces per customerorder, total daily volume, and customer-order delivery-truck volume. This ensures a cost-effective carton order-fulfillment operation that provides the lowest operational cost and accurate and on-time customer service.

PEAK, AVERAGE, AND MOST FREQUENT CARTON ORDER VOLUMES

OR

CUSTOMER-

To project carton order-fulfillment operations, the important volumes are carton volumes, lines per order, and SKUs per line. These represent the number of picks for pick employees. A pick employee’s productivity determines the employee number in a pick area. Also important is the number of orders that will flow from a pick area to a shipping area.


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If your carton order-fulfillment operation has an increase in the number of cartons handled by the pick activity, with an increase in the number of cartons per customerorder and with no increase in the number of customer orders, this may lead to higher employee productivity. If the number of cartons handled by the pick activity remains constant, with a decrease in the number of cartons per customer-order and with an increase in the number of customer orders, this may lead to lower employee productivity. The peak, average, and most frequent monthly carton or customer-order volumes are used to project your carton order-fulfillment operation’s future carton or customerorder volume. These future carton or customer-order volumes are based on the cartons or customer orders that were handled by the company’s carton order-fulfillment operation for a specific time period. This time period can be a day, a week, a month, or a year. The future carton or customer-order volume components are the past cartons or customer-order volumes and your company’s carton order-fulfillment operation’s anticipated real growth rate. These future carton or customer-order volumes are key factors in projecting or scheduling the labor quantity and equipment that are required to handle a projected carton or customer-order volume. Projection also helps to plan annual and other operational expenses for the annual operating budget. It also helps predict the potential labor quantity, labor costs, labor savings, and other associated operational expenses that justify a capital expenditure request. Peak Carton or Customer-Order Volume The first carton or customer-order volume is the peak carton or customer-order volume. The peak carton or customer-order volume is the highest carton or customerorder volume that is handled by the operation for a specific time period. This peak carton or customer-order volume usually occurs as a result of a final customerpurchase increase. On a periodic basis, this customer-order carton increase does recur and is a result of a customer income-flow increase, customer membership criteria, or another customer motivational factor. Average Carton or Customer-Order Volume The second carton or customer-order volume is the average carton or customer-order volume. There are two average carton or customer-order volume calculation methods. One is the total time period which is the customer-order volume. This customerorder volume is calculated by taking the total annual volume and dividing it by the number of days, weeks, or months in a year, to derive the average daily, weekly, or monthly volume. For the other method, a specific time period, take the total for the highest and lowest carton or customer-order volumes and divide by two. Most Frequent Carton or Customer-Order Volume The third carton or customer-order volume is the most frequent carton or customerorder volume. The most frequent volume for a given time period occurs or repeats most frequently at the order-fulfillment operation. In a bell curve presentation for the carton or customer-order volumes, the most frequent carton or customer-order


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volume typically occurs between the average carton or customer-order volume and the peak carton or customer-order volume.

FACILITY DESIGN INFORMATION AND CONSIDERATIONS For the best carton order-fulfillment facility design and operation, the second step is to complete the building design information and operational department considerations. A carton order-fulfillment building’s size, shape and floor number are determined by the following: • •

•

• • • • • •

Site size and shape and site location, along with access road. Required square footage, based on the projected storage inventory, pickline design, required pick-position number and other required pick-line space requirements. Soil condition and ability to support the imposed dynamic and static building. Usually the greatest loads are the storage and pick-line area loads. The geographic location; the local building codes and restrictions; seismic location; and wind, rain, and snow loads. Available funds. Number of female and male employees per shift, along with employee, vendor, and customer delivery-truck parking requirement. Average and peak delivery vendor and customer delivery-truck requirement. Required electricity and other utilities. Fire protection and employee emergency-exit requirements.

The other carton order-fulfillment facility design and operational considerations include the building’s shape, expansion capability, and expansion direction; and the local code’s allowable clear-ceiling height and operational acceptance for a singlefloor facility or multiple-floor facility or a facility with an equipment-supported mezzanine. Included in the building height and floor square footage are the vertical carton travel-path slope and length run-outs. Per the carton or customer-order transport method, there may be a requirement for a pit in the floor surface along with personnel protection along the pit perimeter, and a fire wall or elevated wall or floor penetration for the carton or customer-order transport method. Other features include fire protection, employee emergency exits, and required walkways for each exit, as well as lighting fixtures with a light level or lumens at 30 inches above the floor surface. Light fixtures are turned on and off by a photo eye or activity sensor, and there are various lighting levels for each workstation on a manual, mechanized, or automatic pick line. When pits are installed in the floor surface and are not being used with the transport method, the pits are covered with hardened metal structural members and plates that support employee or vehicle traffic. Rubber mats should be on the floor surface at each employee activity location. This includes the pick line and each employee workstation. Ceiling fans or floor-



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level fans circulate the air on each floor. In a geographic area that has high humidity, the moving fan blades improve the employee working environment and minimize moisture buildup on the floor surface. This feature reduces a potential employee injury. In most carton operations with a mezzanine method, fans are required to circulate the air. Also required is an uninterruptible power supply (UPS), which during a brownout or electrical power failure provides sufficient electric power to prevent a computer crash and to permit the facility to operate all pick-line electrical equipment for a predetermined time period. This time period is a shift portion or the entire shift. The other UPS considerations include the source of electricity — battery power, which is connected to specific electrical equipment and is designed to operate for a short time period, or a diesel-powered generator that is designed with the capacity to provide the entire pick line or all of a facility’s electrical equipment for a long time period — and the method used to activate the UPS (a manual start-up or online start-up). Since most UPS systems are designed to protect a microcomputer or host computer, most UPS systems are started by an online method. Also important are the communications between two microcomputers or between the host computer and a microcomputer controlled piece of equipment. The various communication factors are communication method (radio frequency [RF] or hardwire) and communication distance. With RF, the desired frequency is approved by the local and federal government and is tested in a building that has a high metal content. With hardwired communication over a long distance, the communication wire requires short-haul modems or relays to ensure a clear and good communication. In many hardwired communication applications between two computers, four factors are an electric spike protector, a low electrical voltage protector, an electrical power filter to minimize undesired noise on the electrical power line, and a dedicated communication line between two computers. To minimize the total investment and ensure the required standards, the electrical power supply should be sent through the UPS. This achieves most or all of the electrical power-supply considerations. The last consideration is the carton or customer-order flow or travel path through the facility or carton pick operation. The objectives are to have the shortest travel distance and time between two locations; to require the fewest handlings with minimal carton, customer-order, building, or equipment damage or personnel injury; and to ensure the maximum carton or customer-order quantity is delivered accurately, to the correct location, and on schedule.

CARTON ORDER-FULFILLMENT FACILITY LAYOUT CONSIDERATIONS Carton order-fulfillment facility-layout considerations determine your order-fulfillment operation’s ability to control operational costs, earn a profit, and satisfy and increase your customers. In addition to the carton-flow consideration, the orderfulfillment facility layout considerations are layout philosophy or layout principle, building shape and size, and storage space.


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LAYOUT PHILOSOPHIES

Order-Fulfillment Concepts, Design, and Operations AND

PRINCIPLES

Your order-fulfillment layout philosophies and principles are the factors that influence your material handling equipment arrangement and your order-fulfillment activity locations, including the storage and pick areas. The two most important areas in a carton order-fulfillment operation are the storage area and the pick area. These order-fulfillment activities require a large floor area and have the largest number of employees. The order-fulfillment layout philosophies and principles are SKU popularity or Pareto’s law (80/20 rule); ABC theory; unloading and loading ratio; power or fastmoving SKUs in one pick area; family group; product rotation; rack-row and aisle direction; aisle length, an adequate number of aisles, and aisle width; building height; and customer-order-fulfillment and sorting philosophy. SKU Popularity or Pareto’s Law (80/20 Rule) When a carton order-fulfillment operation’s layout is based on SKU popularity, it is based on Pareto’s law. This law states that 85% of the wealth is held by 15% of the people. In the order-fulfillment industry, this law indicates that 85% of the volume shipped to your customers is derived from 15% of the SKUs. Many studies have indicated that another 10% of the volume shipped to your customers results from another 30% of the SKUs, and that an additional 5% of the volume shipped to your customers is attributed to 55% of the SKUs. If you are in the catalog or direct-mail business, then 90 to 95% of your business is from the 5% of your SKUs, since two to four catalogs are introduced per year with different SKUs. A recent study shows that 95% of the volume shipped to your customers is obtained from 55% of the SKUs; this is referred to as “Pareto’s law revisited.” ABC Theory When an order-fulfillment professional refers to the three zones of Pareto’s law, their reference is to the ABC theory. The ABC theory simply states that the A pick zone is allocated to the fast-moving SKUs. These SKUs are few in number and have a large inventory quantity per SKU. The B pick zone is allocated to the normal-moving SKUs. These SKUs are medium in number and have a medium inventory quantity per SKU. The C pick zone is allocated to the slow-moving SKUs. These SKUs are large in number and have a small inventory quantity per SKU. If a carton order-fulfillment operation’s layout has the receiving and shipping docks on the facility’s front side, and if the SKU pick location is based on the ABC theory, the fast-moving SKUs will be at the facility’s front. If the receiving and shipping docks are located on opposite sides, the fast-moving SKUs are located by the SKU unloading and loading ratio. Unloading and Loading Ratio The unloading and loading ratio compares the number of trips that unloading employees and loading employees require to handle a vendor truck. When the number of unloading trips equals the number of loading trips, the SKU pallets (pick



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positions) are located near the shipping docks or in any location in the rack row. When the unloading trips are more numerous than the loading trips, the SKU pallet loads (pick positions) are located near the receiving docks. This reduces the employees’ total travel distance. Power or Fast-Moving SKUs in One Pick Area The power or fast-moving SKUs in one pick-area philosophy has an inventory allocation program that places all fast-moving SKUs in pick positions. These pick positions are adjacent to one another. This philosophy has your entire promotional, seasonal, special-sale, and fast-moving SKUs in one area. This SKU arrangement increases your order-picker hit concentration (the number of hits per pick aisle) and hit density (the number of hits per SKU). High hit concentration and hit density mean high order-picker and replenishment-employee productivity because there is a very short travel distance between two pick positions. The key to an accurate, efficient, and on-time order-fulfillment operation is to have the replenishment carton or pallet available for pick-position replenishment and a picked customer-carton take-away method. Family Group The next order-fulfillment operation layout philosophy is the family-group philosophy. The family-group philosophy is dictated by your company’s requirement that SKUs are located in a pick aisle with other SKUs that have the same inventory classification. With this philosophy, by a predetermined criterion the SKUs are assigned to specific locations (pick aisles or areas) within your facility. This layout philosophy requires that the facility and material-handling method is designed to accommodate SKUs that have similar dimensions, weights, and SKU components; are located in the same aisle in the retail store; require normal, refrigerated, or freezer conditions; require high security; are from toxic or nontoxic materials; include edible or inedible substances; include flammable or inflammable materials; include stackable or nonstackable products; and include crushable and noncrushable packages. Product Rotation The next order-fulfillment operation layout philosophy is the product-rotation philosophy. The product rotation is dictated by the product life cycle and the requirement for a specific product. The product rotation philosophy options are first-in, first-out (FIFO) rotation and last-in, first-out (LIFO) rotation. FIFO Rotation In FIFO product rotation, the SKU that is received first in the order-fulfillment operation is shipped out first from the operation. This indicates that the product has a predetermined life (or a time limit) before it spoils. After a specific date, the SKU is not withdrawn from the inventory for customer orders. A carton order-fulfillment operation layout that is designed to have SKUs with a FIFO product rotation requires


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access to all pick positions in the pick area and ensures that the oldest product is withdrawn first from the pick position. If there are many SKUs and few cartons for each SKU, gravity flow lanes or pallet-rack pick positions are used in the facility. When there are few SKUs and many pallets, pallet flow racks are used in the facility. LIFO Rotation In LIFO SKU rotation, the carton that is last received in an order-fulfillment facility is shipped out first from the facility. This product type does not have a specific shelf life. The order-fulfillment facility’s design does not provide access to the oldest carton. This feature allows the order-fulfillment operation layout to use dense storage and pick positions that reduce the building square footage. Rack-Row and Aisle Direction The next order-fulfillment operation layout philosophy is based on the direction of rack rows and aisles in relation to the shipping docks. The two philosophies are parallel to the shipping docks and straight to the shipping docks. Parallel to the Shipping Docks The first rack-row and aisle direction method has the rack rows and aisles flow parallel to the shipping docks. The rack-row and aisle flow includes at least two turning aisles at the pick-aisle end; rack rows and a middle traffic aisle are in the layout. These aisles lead to the shipping docks. This arrangement increases orderpicker travel time from the pick area and to the shipping docks. Straight to the Shipping Docks In the second rack-row and pick-aisle flow layout, the rack-row and pick-aisle direction of flow is straight from the pick area to the shipping docks. In this design, each pick aisle provides access to the shipping dock area, and the main traffic aisle serves as a vehicle-turning aisle. The middle cross aisle ensures good employee productivity, permitting employees to perform a pick transaction in a different pick aisle. Aisle Length The next carton order-fulfillment operation philosophy is based on the pick-aisle length. The two philosophies are short pick aisle and long pick aisle. Short Pick Aisle The short pick-aisle length philosophy specifies that the rack row and pick aisles run along a rectangular facility’s short dimension. This method requires turning aisles at each rack-row and pick-aisle end. The short pick-aisle method provides lower density and employee productivity due to unproductive pick-aisle end turns. Long Pick Aisle The rack rows and pick aisles are arranged to flow in a rectangular facility’s long direction. This long pick-aisle method does have a middle aisle in the rack row to



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provide easy and quick transfer to another pick aisle. The long pick-aisle method provides greater density and fewer unproductive employee-turning aisles. Customer Order-Fulfillment and Sorting Philosophies The next carton order-fulfillment philosophies are the customer-order pick and sorting philosophies. The carton order-pick method has an employee or machine transfer cartons from a pick position onto a load-carrying surface. The carton orderfulfillment method determines the building square footage and height. The orderpick design factors are pick-position type, inventory in the pick position, active SKU number, and order-picker routing pattern. The order-fulfillment methods are manual, mechanized, and automated. Manual Order-Fulfillment Method The manual carton order-fulfillment method requires all pick positions to be at a maximum elevation of 5 feet, 6 inches to 6 feet high (from the carton top to the floor). In a carton order-fulfillment operation, this height permits a maximum of two pallets or four to five hand-stacked carton levels. The manual order-pick method requires a wide aisle because employees walk or ride a vehicle through the facility pick aisles. With these travel-path parameters, the method requires a large picker number, increasing the required functions and square foot area. With these design factors, a manual order-pick method building has the largest square-foot area. Mechanized Order-Fulfillment Method The mechanized carton order-fulfillment method requires a medium-sized facility because it utilizes a conveyor method and permits elevated-floor construction or mezzanines for additional pick levels. In a two- or three-level facility, pick-position replenishment is performed by a narrow-aisle forklift truck. The pick-position number per square foot is increased. The SKUs are separated into the mechanized (or conveyor travel path) section and the manual (nonconveyable SKU) section. The mechanized method requires a medium square-foot building and a medium orderpicker number. Automated Order-Fulfillment Method The automated carton order-fulfillment method requires a small square-foot facility because the order-pick positions are narrow and long and there are multiple levels in a stack. These pick positions are replenished by a narrow-aisle forklift truck and the pick positions release cartons onto a conveyor travel path. The facility has a manual carton order-pick section for nonconveyable SKUs. Order Sorting Method The next carton order-fulfillment layout philosophy is used in a mechanized carton order-fulfillment operation. The customer-ordered and picked carton-sorting method has a minor influence on a facility’s square footage or height. The factors that determine a sorting are customer number, customer-order size, customer-order number per batch, and sorting method.


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The sorting methods are manual and mechanical. Manual Sorting Method The manual sorting method handles a low carton volume and a low customer-order number, but requires the largest employee number and the largest square-foot area. Mechanical Sorting Method The mechanical sorting method handles a high carton volume and a large customerorder number, but requires the lowest employee number and a medium square-foot area. Building Height The next carton order-fulfillment facility layout philosophy is based on the building height. The building height is determined by the construction costs; available land; the local codes and shadow laws; and seismic, wind, and land conditions. A highbay building has a roof at least 40 feet above the ground level. In most carton orderfulfillment operations, a high-rise building is used for storage operations. A medium building height is 30 to 40 feet above the ground level. This building is designed as a rack-supported facility or a conventionally constructed building with multiple floors. The low-bay building is no more than 30 feet above the ground level. The building height has space for elevated floors. Many order-fulfillment facilities are designed with multiple floors. These floors are used for offices, administrative areas, and other value-added activities. When considering a multiple-level facility, remember that the elevated-floor support for your imposed dynamic and static loads and the lower floor require additional large building columns. These large additional building columns occupy additional space and are potential obstacles to carton travel paths. Building Shape and Size The order-fulfillment facility’s shape and size are the second design considerations. A carton order-fulfillment building’s size and ceiling height are determined by carton pick-position number, order-pick method, and receiving and shipping dock areas. A building’s clear ceiling height is 20 to 25 feet, though some buildings (square or rectangular facilities) have a clear ceiling height up to 40 feet. The building considerations are building construction, facility shape, floor type, and building infrastructure. Building Construction The next carton order-fulfillment layout philosophy is determined by the building’s architectural and structural design. Architectural factors include the building’s exterior material or skin, column size, bay spacing and direction, floor levelness and type, roof type, and interior walls. The building material alternatives are conventional (brick, concrete, or air-supported) and tilt-up (metal, concrete, underground, racksupported, rib-paneled, wood, or open-air). The rack-supported facility’s storage racks along with studs and purlins supports the roof and walls, and provides a greater storage-position number per square foot



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than does the conventional building. When a rib-panel or tilt-up building is used, the racks along the exterior walls fit around the building columns and project inward, reducing the storage-position number. The wood structure is a low building and is not standard construction. The air-supported building has a treated fabric cover supported by metal ribs and forced air. The building is quickly constructed, requires a slab, accommodates most storage-rack methods, and handles both cartons and pallets. This facility type handles cartons that require separated storage or special storage conditions. The underground facility is a storage system that is installed in natural or manmade caves or caverns. These caverns have a flat-floor, rack-storage method and a naturally controlled temperature. Some require a vertical transport method to deliver cartons or pallets between the delivery area and the storage area. Facility Shape The next order-fulfillment operation layout philosophy is the facility shape. The facility shape has a significant impact on the order-fulfillment equipment layout, carton flow, and future expansion capabilities. The factors that determine the building shape are land shape and size and dimensions of any existing building; inventory level, carton characteristics, and pickposition number; carton flow pattern; and operation type and value-added activities. The building shapes are square, L, rectangle, oversized rectangle, U, round, and triangle. Square Building A square building provides the best balance between wall area and floor area. This building design has a low wall-area to floor-space ratio and creates an efficient structure for pick areas. The square building requires a good balance between the SKU number and storage units per SKU. It is normal as the order-fulfillment operation expands for a square building to become a rectangular building. L-Shaped Building In an L-shaped order-fulfillment facility, the receiving and shipping docks are located at the base, with the pick functions in the stem. The building shape creates an increase in carton transport costs throughout the facility. The building shape is best designed for a processing facility with an attached order-fulfillment function. Rectangular Building A rectangular building provides an increased wall-square footage to floor-square footage ratio. This building provides additional wall space for an increase in the number of dock doors. This large wall-area feature permits efficient transport from the docks to the storage and pick areas. The method allows a facility to handle an inventory storage requirement that has any mix (any ratio of SKUs to storage units). It is an excellent shape for an order-fulfillment operation that provides service to industrial, catalog, direct-mail, and retail-store customers. As the order-fulfillment operation’s business increases, expansion occurs at the rectangular building’s ends


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(or short walls). After this expansion, an oversized rectangle-shaped building has a greater length than width. Oversized Rectangular Building An oversized rectangular building design has the maximum ratio of wall squarefoot area to floor square-foot area. This wall-area feature provides the most efficient transport path from the docks to the storage and pick areas. The oversized rectangular building allows the facility to handle an across-the-dock carton flow pattern. U-Shaped Building In a U-shaped facility, the shipping docks are in one U-leg and the receiving docks are in the other leg. The storage and pick activities are located in the remaining area between the two legs and the U-base. Round Building In a round building, the receiving and shipping docks are located along the walls or in the building’s center. The building method has excellent transport paths to any interior area. The round building does not provide the maximum space utilization with square or rectangular cartons or pallets. Triangular Building In a triangular facility, the receiving and shipping docks are located on the triangle’s base and the order-fulfillment function is between the triangle’s legs. With the two legs connected at the tip, the triangle shape does not provide the maximum space utilization with square or rectangular cartons or pallets. Building Floor Type The next order-fulfillment operation layout philosophy is the type of building floor. The floor provides support for imposed dynamic and static loads and a smooth surface for carton and equipment movement. The floor type is the factor that determines a floor surface’s flatness or levelness. The type of floor surface determines the type of storage equipment and installation time. The floor options are conventional floor, flat floor surface, and very flat floor surface. Conventional Floor The first order-fulfillment facility floor type is a conventional floor surface. The conventional floor surface is a floor type for an order-fulfillment operation. The conventional floor is a standard-construction flat floor that has unevenness in certain sections. Your order-fulfillment equipment installation crew adds shim plates or adjusts each leg’s length to compensate for the unevenness. The conventional floor construction has a lower cost per square foot. Flat Floor The second order-fulfillment facility floor type is a flat floor surface. The flat floor surface is a floor that is more level or even than a conventional floor. Industry standards rank a flat floor surface as an F-50. The flat floor requires an additional investment, but equipment installation does not require as many shims.



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Very Flat Floor The third order-fulfillment facility floor type is a very flat floor surface. A very flat floor surface is a floor that is very even and level. The deflection is 1/8 inch within a 10 foot area. This floor type requires a large investment, but features easy equipment installation. The equipment installation usually does not require shims. Building Infrastructure The next carton order-fulfillment layout factor is the building infrastructure. The infrastructure ensures that sufficient resources are provided for the workstation or for operating a piece of equipment. The infrastructure items are electrical power and water for fire protection. Electrical Power An important carton order-fulfillment facility building factor is the electrical power. The electrical power is required to operate material-handling drive motors, illuminate the light fixtures, and operate computer equipment and other equipment. The important electrical factors are the total kilovolt-amperage (KVA) for the facility and material handling equipment; the electrical power amperage at each location; the required hookup of UPS, spike filters, and low voltage protectors; and the ability to add additional power. Fire Protection The next important carton order-fulfillment facility building factor is the fire protection. The fire protection minimizes equipment, building, and inventory loss due to fire. The fire protection items are smoke detectors; fire sprinklers (regular ceiling sprinklers, early-supression fast-response (ESFR) ceiling sprinklers, in-rack sprinklers, and sprinklers under solid surfaces); emergency lights; emergency exits; protection for floor and fire wall penetrations; and an alarm system connected to a central fire department. Inventory Storage or Reserve Space The next facility layout philosophy involves storage type and storage-space utilization. The SKU number and storage number of pallets or cartons determine the storage method, the inventory rotation, and the quantity requirement. In a carton orderfulfillment operation, the storage method and area are major factors that determine a facility’s square footage. The factors that influence your storage-area space requirements are the carton or pallet storage method and the storage vehicle. Carton or Pallet Storage Method The next carton order-fulfillment facility philosophy is carton or pallet storage method. The carton or pallet storage method holds the reserve inventory that exceeds the pick-position inventory quantity. In a carton order-fulfillment operation, there


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are ready reserve, remote reserve, and off-site reserve carton or pallet storage methods. The carton or pallet storage method is a factor that determines the building’s square footage. The carton or pallet storage methods are (1) hand-stacked carton or pallet one-deep rack storage, (2) low-bay building dense storage, (3) two-deep storage, and (4) high-rise storage rack. Hand-Stacked Carton or Pallet One-Deep Rack Storage The hand-stacked carton or pallet one-deep rack storage method is a common storage method. If the cartons are hand stacked onto decked pallet racks, employees from the floor or from an order-picker truck complete the storage transactions. If the building has a 40-foot clear ceiling height, a level floor, and an aisle-guided storage vehicle, per the aisle’s width a one-deep pallet rack storage method is serviced by any forklift truck. A hand-stacked carton and one-deep pallet rack method provides maximum access to all SKUs and low storage density, and requires a large building. Low-Bay Building Dense Storage Methods The next pallet storage methods are the low-bay building dense storage methods. The dense storage methods have multiple pallets per storage lane or face. The methods include floor storage, drive-in racks, drive-through racks, stacking frames or tier racks, mobile racks, and air- or gravity-flow and push-back racks. These dense storage racks interface with manually operated forklift trucks. They require a small building and few storage aisles, and provide a large pallet number per building footprint. Two-Deep Storage Rack The next pallet storage-rack method is the two-deep or double-deep storage method. This method allows your storage-area design person to plan a medium-sized building and to place building columns in the proper location. When the two-deep storage method is compared to other dense storage methods, the two-deep storage method requires additional aisles and a two-deep forklift truck. It provides storage density and low cost per pallet position, and uses the floor-position or the up-and-over (raised first-pallet position) method. High-Rise Storage Rack The next carton or pallet storage method is the carton or pallet high-rise storage method — for cartons, a mini-stacker crane or mini-load, and for pallets, an automated storage and retrieval system (ASRS). The high-rise or very-narrow-vehicle storage method utilizes a rack storage system and requires a good quality pallet. The high-bay method provides an increase in storage density due to an increase in the storage position number in a vertical stack and to the very narrow aisles. Storage Vehicle The next factor in a facility’s storage-area layout philosophy is the storage vehicle that is planned for the storage-area operation. The storage vehicle is the second most important factor in determining the storage area’s required square footage. If we include the hand-carrying of cartons as a storage transport method, there are six basic



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storage methods: hand-carrying, wide aisle (WA), narrow aisle (NA), very narrow aisle (VNA) and carton or pallet ASRS, captive aisle (CA), and mobile aisle (MA). Hand-Carrying Method The hand-carrying storage method is used to handle cartons and does not require a vehicle investment or a battery-charging area. The storage method requires a great number of employees and has a restrictive stacking height. These facts make the hand-carrying storage method as a very labor-costly method that requires a large building square-foot area and a high annual operating expense. Wide-Aisle Storage Vehicles The WA storage vehicle method uses a variable travel-path vehicle that requires, at a minimum, a 10-to-13-foot wide stacking or replenishment aisle. The most common storage vehicle is the counterbalanced forklift truck that handles a pallet. These design parameters provide a large square-foot building with a low clear ceiling height and with a 20-to-25-foot clear stacking height. Narrow-Aisle Storage Vehicles The NA (or straddle) storage vehicle method requires a minimum 7-to-10-foot wide storage transaction aisle. The vehicle is considered a variable travel-path vehicle; the first pallet-storage level is on the floor or is raised onto two load beams. This design provides a medium square-foot building with a 25-to-28-foot clear stacking height. The NA storage vehicle is very common in a hand-stack carton or pallet storage method. Very-Narrow-Aisle Storage Vehicles The VNA storage vehicle method requires a 5-to-8-foot wide storage transaction aisle. For maximum efficiency and effectiveness, this storage vehicle group requires rail or wire-guide aisle travel with storage positions on both aisle sides. Included in this group are man-down vehicles, man-up vehicles, high-rise order-selector (HROS) trucks, and carton and pallet ASRS vehicles. The design parameters provide a small square-foot building with at least a 40-foot clear ceiling height. Some buildings are designed with an 80-foot stacking height or above. Captive-Aisle Vehicles With a CA storage vehicle method, the storage vehicle remains in one storage aisle. These vehicle methods include carton ASRS and pallet ASRS vehicles that are manually controlled, PC controlled, or automatic or computer controlled. The CA design parameter reduces the number of end-turning or traversing aisles, which in turn reduces the building’s square footage. The CA design requires additional equipment investment, thus increasing the total facility investment. Mobile-Aisle Vehicles With the MA storage vehicle method, the storage vehicle enters and exits through any storage aisles. This turning-aisle or transfer-aisle requirement results in a larger building. The facility requires fewer storage-equipment pieces, reducing the total facility investment. Some VNA ASRS storage vehicles require a transfer car (T-car) that moves the storage vehicle from one aisle to another.


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SKU LOCATION ON THE PICK LINE OR IN THE PICK AISLE The next carton pick-line or pick-aisle design focuses on the SKU’s physical location on the pick line or pick aisle. The SKU location along the pick line, on a pick aisle, or in a pick-position sequence must be determined for a carton-pick activity that uses a manual method or a mechanized method. The pick-position philosophy depends on several factors. The first is due to a high volume within a short period — the SKU seasonal item. In most carton-pick applications, the seasonal SKUs are located at the pick line’s start. The second factor is the SKU velocity, sales, or physical movement for one complete fiscal year. In a pick line, the fast-moving SKUs are located at the pick line’s start, the medium-moving SKUs are located in the pick line’s middle, and the slow-moving SKUs are located at the pick line’s end. The third factor is the SKU’s physical characteristics (long or short). On most pick lines, the long SKUs are located in one area and the short SKUs are located in another area. The fourth factor is that SKU value, a characteristic that determines the SKU pick-position design. In carton-pick operations, the high-value SKUs are located in a pick position where there is limited or controlled access to the pick area, or to a pick position and has a security camera. The camera is directed at the pick area. The fifth factor is that some SKUs require specific environmental storage conditions (e.g., leather must be stored in a low-humidity area.) A sixth factor is to provide optimal customer service, some pick-line applications place SKUs on the pick line by family group. This philosophy has SKUs with similar characteristics located in sequential pick positions on the pick line. Sometimes this pick-line philosophy is referred to as the kit philosophy. Reasons for family-group allocation are that the SKUs are located in the same retail aisle, such as dresses and shirts that have one color with various sizes; SKUs are picked for a specific customer group, such as a centralized order-fulfillment facility that services several countries with different languages; or that there are pants that match a jacket. The seventh factor is the historical SKU movement determines the possibility of identifying one or several SKUs with high movement per customer-order as candidates for bulk picking. The eighth factor is the pick-position elevation on the pick line. Pick-line professionals consider the “golden zone“ to be the preferred manual pick-position location for individual cartons. In a manual or mechanized carton order-fulfillment operation, the golden zone involves a pallet on the floor surface or lowest rack-position load-beam level, and, if the pallet rack levels are not high, the second load-beam level. With a carton flow rack or decked pallet rack, the golden zone has an elevation ranging from a low 34-to-20-inch high elevation above the floor surface to a high 70- to 110-inch elevation above the floor surface. With most carton heights, the golden-zone consists of one to four one-carton-high pick levels. Prior to your pick line’s final design or layout, the golden-zone pick positions are finalized as design parameters. Another factor is the pick-line profile. This profile is the method for locating each SKU to a pick position on the pick line or in the pick aisle. Finally, the last two considerations are the pick-position type and the pick-position identification. These factors have an impact on employee pick and storage productivity and



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accuracy. The pick-position types and pick-position identification methods are reviewed later.

PICK-AREA DESIGN Next in a carton order-fulfillment facility design are the steps in developing a pick line or pick aisle. Pick-line or pick-aisle development has your design team fit the pick line or pick aisle, carton flow pattern, and customer-order flow pattern into an existing facility, or fit a facility’s four walls, building columns, columns spans, and roof around the pick line or pick aisle, carton flow pattern, and customer-order flow pattern. To fit a pick line or aisle into an existing facility is a more difficult task, because an existing building’s columns, column spans, walls, and roof are constraints. The steps in completing a pick-line or pick-aisle development are as follows. First, project the annual number of SKUs and associated inventory, the pick volume and customer-order volume, the carton flow pattern, and the customer-order flow pattern. Next, review the various carton pick methods and select a method. Then identify the building-column clear span, the column size, and clear ceiling height; locate the passageways through walls and floors; and identify the various utility locations and the quantity and pattern of light fixtures. Next, with block layouts and drawings, develop and refine the pick-line or pick-aisle layout, the carton flow pattern, the customer-order flow pattern, and other building items. Develop and finalize the building drawings and pick-line drawings. Next, complete a simulation that is based on carton flow patterns, customer-order flow patterns, pick volumes, and customer-order volumes. Review the building layout and pick-line layout drawings for compliance to local codes, company policies, and operational procedures. Complete the process for requesting quotes or bids, and select a carton order-pick method vendor. Next, develop building construction, remodeling, or pick-line installation plans and schedules. Install, test, and debug all building equipment and pickline equipment and complete a building and pick-line punch list. Lastly, start up the facility and pick line or turn it over to operations.

PICK-LINE

OR

PICK-AISLE DESIGN

The next step in a carton order-fulfillment facility design is to develop the pick line or pick aisles. The pick-line or pick-aisle development has your design team fit the pick line or pick aisle and the carton and customer-order flow patterns into an existing facility, or fit a facility’s four walls and roof around the pick line or pick aisle and the carton and customer-order flow patterns. To fit a pick line or pick aisle into an existing facility is a more difficult task because the existing building’s columns, column spans, and walls are constraints.

CARTON

AND

CUSTOMER-ORDER FLOW

The next design consideration focuses on the carton and customer-order flow patterns through the facility. The first carton order-fulfillment consideration is the carton flow pattern. Carton flow runs from the receiving dock, through the quality-assurance (QA) activity and


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value-added activities, through the storage/pick/sorting area, and ends at the shipping area. The carton or customer-order flow pattern through a carton order-fulfillment facility is termed a store-and-hold carton flow method. The carton flow patterns are (1) horizontal one way (or straight), (2) horizontal two way with a V or W shape, and (3) vertical up and down. Horizontal One-Way Flow Pattern The horizontal one-way or straight carton or customer-order flow pattern through a carton order-fulfillment facility is also referred to as “in one side and out the other.” In the straight-flow pattern, from one facility side cartons enter the facility and from the facility’s opposite side cartons exit the facility. On one building side, the carton operation receives SKUs and, with transport equipment, the cartons are moved through the storage, pick, sorting, and manifesting and loading areas to the other building side. On the other building side, these carton orders are loaded onto a customer delivery truck. The carton and customer-order flow method requires that the carton travel the entire horizontal distance through the facility between the receiving docks and the shipping docks. The facility is a conventional facility that has a vendor delivery truck yard on one building side and a customer delivery truck yard on the other building side. This additional truck yard does not optimize site utilization, but a facility may be designed with elevated floors to utilize the air space. The straight carton and customer-order flow pattern is best for a carton operation that handles across-the-dock carton or customer-order flows. Horizontal Two-Way Flow Pattern In the horizontal two-way carton or customer-order flow pattern through a carton operation, the cartons enter the facility from one building side and exit on the same building side. The horizontal two-way carton and customer-order flow pattern is a good arrangement for a carton order-fulfillment operation. With the receiving docks and shipping docks on one building side, only one road and truck yard are required. This improves site utilization. The horizontal two-way flow pattern in requires less truck yard and roadway surface than a one-way pattern. This feature means that less land is required; a facility can be designed with or without elevated floors; facility investment costs are lower; and there is an increased potential for dual cycles, which means a lower perunit labor cost. The horizontal two-way carton or customer-order flow pattern options are the U-flow pattern and the W-flow pattern. U-Flow Pattern The first horizontal two-way carton or customer-order flow pattern is the U-flow pattern. The U-flow pattern has cartons unloaded or received on the facility’s right and transported to the storage area and pick area, which are located in the facility’s middle. Customer orders are loaded on the facility’s left side. The carton or customerorder flow through the carton order-fulfillment facility makes a U pattern.



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W-Flow Pattern The second horizontal two-way carton and customer-order flow pattern is the W (or double U) flow pattern. In the W-flow pattern the cartons are unloaded and received in the building’s middle and transported to the storage and pick areas along one of the building’s sides. On the facility’s same side the customer orders are loaded onto the delivery vehicles. This carton and customer-order flow pattern creates a W flow pattern through the facility. Vertical Up-and-Down Flow Pattern The next carton and customer-order flow pattern is the vertical up-and-down carton or customer-order flow pattern. This flow pattern has the cartons received on the facility’s lower floor and transported over a vertical travel path to the facility’s elevated floor. On the elevated floor, the storage and pick-line activities are sequenced to ensure an efficient and cost-effective carton or customer-order flow across the elevated floor to the decline travel path for transport to the lower floor. The customer orders are sent to the lower-floor staging area or placed directly onto a customer delivery vehicle. With the vertical up-and-down flow pattern, the carton-receiving or customerorder-shipping activities are located on one facility side or on opposite sides. The vertical up-and-down flow pattern’s characteristics are as follows. A vendor or customer delivery truck yard on one side of the facility means that the facility occupies a small site and so there is a lower land cost. Vertical material-handling equipment requires an investment, and there is a slightly higher facility investment for additional light fixtures, stairways, and fire sprinklers.

DRAWINGS To assist with understanding the carton and customer-order flow patterns and the pick method, professionals develop block drawings and detailed plan-view drawings and list the activities that are performed in the facility. Block Drawing A block drawing or lined presentation has lines that connect two or more operational activities together. These lines permit the design person to trace the carton and customer-order flow. Each order-fulfillment operational activity is included, and these activities are arranged in the required sequence to ensure a cost-efficient and effective carton order-fulfillment operation. Also included are the square footage that is required for each carton order-fulfillment operation activity and for the total facility, and the various functions or floors that require fire walls. A block drawing should be easy to understand. Plan-View Drawing The second step in understanding the carton or customer-order flows through a facility is to develop a detailed plan-view drawing. The drawing is to scale and shows each order-fulfillment activity area. This drawing includes equipment and all


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building items. From the detailed drawing you can understand the interrelationships between the various order-fulfillment activities and the required space. List of Activities The third step is to list and define the various carton order-fulfillment activities that are performed by the order-fulfillment operation to complete a customer-order. The activity list ensures that the design team and the operations manager have included all the required order-fulfillment activities to provide the required customer service at the lowest possible operational cost. The carton order-fulfillment activities are: •

• • • • •

• • •

• • •

Vendor delivery truck or ocean container yard control, delivery assignment to a receiving dock, and customer delivery truck spotting at a shipping dock. Receiving, unloading, SKU quantity and quality control, and carton identification. Internal transport between the various carton order-fulfillment activities. Storage deposit transactions and inventory control. IMS customer-order processing, cubing, and downloading to the pickarea microcomputer. Manual or mechanized SKU quantity transfer from the pick-position cart, pallet truck, or conveyor travel path. As required by the pick activity, this includes SKU identification with a discrete customer code. With a bulk or batched customer-order pick method, several customerordered and picked SKUs are sent to a sorting area. Manual or automatic manifesting of the customer discrete identification. Customer delivery truck loading, where the customer-ordered, picked, and sorted cartons are sent to the shipping-dock staging area or directly loaded onto a customer delivery truck. Trash removal form the pick-line area and from the facility. Handling of customer cartons and out-of-season, damaged, or obsolete SKUs, which includes processing, transportation, and carton storage. Security, risk management, sanitation, and maintenance, to ensure that the building and material-handling equipment perform and protect assets and inventory from damage.

PICK-LINE OR PICK-AISLE DESIGN PARAMETERS To design an employee-to-stock (manual) or stock-to-employee (mechanized) carton pick line or pick area, the design factors to determine the SKU location on the pick line or in the pick aisle include the employee’s ability to complete a transaction; the methods used to transport cartons to storage and pick positions and to transport customer orders over the travel path and the required travel-path window; carton customer-order pick volume, customer-order volume, and customer-order shipping



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delivery-vehicle volume; and SKU physical characteristics, velocity, and value. Another factor is how the SKU is picked or transferred from the pick position. The final considerations are to determine the carton pick volume and customerorder volume, the carton type, and the customer-order delivery-truck volumes. The carton pick volumes and customer-order volumes may be average, most frequent, or peak. SKUs are grouped according to cube (length, width, and height), weight, and product classification. The next SKU consideration is the SKU’s physical characteristics. The SKU’s physical characteristics include the carton’s physical dimensions, the product classification, and the carton packaging strength. The first SKU characteristic is the carton’s physical dimensions: length, width, height, and weight. When designing a carton order-fulfillment activity area, you must obtain the dimensions for the slip sheet or pallet. The second carton characteristics are the product and carton physical classifications: value; whether the piece is crushable; family group; aisle in a retail store; environmental storage conditions; whether the piece is edible, toxic, hazardous, or combustible; and other classifications as required by local or insurance-company codes. The next carton packaging characteristic is structural strength, or the ability of the carton’s exterior packaging material to protect the SKU, support the weight of another carton, and travel across a conveyor travel path and queue without damage. The final SKU characteristic has to do with how the SKU is picked or transferred from the pick position. The options are (1) an individual piece on a four-wheeled cart, pallet, or conveyor travel path; (2) in bulk on a pallet or a group of cartons on a four-wheeled cart or pallet; (3) batch-picked and separated or sorted onto a fourwheeled cart, slip sheet, or conveyor travel path; and (4) hand-carried by an employee.

PURPOSE OF A CARTON ORDER-FULFILLMENT OPERATION A carton or case order-fulfillment operation’s purpose is to ensure that the right SKU is available at the appropriate time, in the correct condition, and in the correct reserve or pick position. SKUs must also be order-picked on schedule and in the correct quantity, and delivered to the required delivery address to complete your customer-order.

CARTON ORDER-FULFILLMENT ACTIVITIES To obtain an efficient, accurate, and profitable carton order-fulfillment operation, you must arrange operational activities and carton-handling equipment according to a preferred layout; establish procedures; and organize and motivate your employees and management staff so as to optimize the operation’s activities. These activities include: •

Preorder selection activities: • Truck yard control


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•

•

• Unloading • Receiving and checking • Carton or SKU identification • Internal transport • Deposit in storage Order-pick activities: • Carton pick and identification • Transport • Sorting Postorder pick activities: • Storage withdrawal • Replenishment • Internal transport • Manifesting • Loading and shipping • Customer returns

TRUCK YARD CONTROL ACTIVITY The first order-fulfillment activity is the truck yard control activity. Truck yard control involves assigning a vendor delivery truck to a temporary storage or holding area, assigning a delivery truck or rail car to an unloading dock, and moving the delivery truck from the temporary holding area to the assigned dock. The truck yard control activity is the first of the receiving and shipping activities. The receiving activity starts with a delivery vehicle or truck network schedule and a customer delivery schedule. The vendor delivery truck, oceangoing container, or railcar schedule is a delivery vehicle arrival time that is agreed upon by the trucking or railcar company and your receiving department. The customer delivery truck activity starts with the order and delivery cycle: the time it takes to pick and load a customer-order onto a delivery truck, to drive the truck, and to have the truck arrive at the customer delivery address. With a railcar delivery system, the receiving department, per the product on the railcar, assigns the railcar along the facility spur or track at the dock that is as close as possible to the facility’s product-storage location.

UNLOADING ACTIVITY The second order-fulfillment activity is the delivery-vehicle unloading activity. Delivery vehicles include common carrier trucks, vendor trucks, express delivery trucks, oceangoing containers, company backhaul trucks, and railroad cars. A nonemployee truck driver unloads a common carrier delivery truck, express delivery truck, or vendor delivery truck. A company employee is responsible for unloading a railroad car, oceangoing container, or company backhaul truck. For additional unloading information and a review of unloading equipment and methods, we refer the reader to the unloading section in Chapter 7.



RECEIVING

AND

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CHECKING ACTIVITIES

The third order-fulfillment activities are the receiving and checking (or QA) activities. Receiving and checking activities fulfill several objectives. They ensure that the delivery vehicle, per the assigned shipping notice (ASN), matches your company’s purchase order (PO). They verify that the delivery documents match your company’s PO, the SKU quantity per carton, the carton quantity per pallet. They ensure that each pallet contains cartons that have the same SKU quantity. They ensure that there is a license plate and a label for each pallet or carton. They verify that the carton and pallet quality matches your company’s standards. They ensure that the product quality and SKU shipping data (length, width, height, and weight) are per your company’s standards. They ensure that the pallets and cartons are transported from the receiving area to the storage area. They ensure that the SKU delivery quantity is communicated to the warehouse management system (WMS) or inventory file. Checking also involves completing the delivery company’s documents and ensuring that any rejected pallet or carton quantity is sent to the purchasing department for proper disposition. If your company is involved in a pallet exchange program, these activities ensure that the proper quantity and quality pallets are transferred and signed for by the delivery company. Per your company policy, they ensure that the proper sample number is sent to the department. The receiving-employee carton-count methods are manual and mechanized. The first vendor carton-delivery method is the manual carton-count method. With the manual-count method, your receiving employee’s options are to handle each individual carton and to determine the slip-sheet or pallet-load quantity (or “ti and hi”) and calculate the total quantity. (“Ti” is the carton number per layer and “hi” is the number of layers high.) The second carton-count method is the count-on-the-fly method. The count-onthe-fly method has a bar-code scanner or a mechanized counter count or register each carton as the carton travels on a powered-conveyor travel path past a count station. With the bar-code scanner count-on-the-fly method, each carton requires a bar code that faces in the proper travel direction. For maximum efficiency, both mechanized count methods require a gap or open space between two cartons. The next important receiving activity is to ensure that the proper carton sample quantity is sent from the receiving department to the QA department. The sample quantity options are a 100% quality check, a random check of 7 to 10% from randomly-selected pallets, and a 100% accept.

IDENTIFICATION ACTIVITY The fourth order-fulfillment activity is the pallet or carton identification activity. This identification activity ensures that the receiving department applies a license plate or identifier to each pallet or carton. The license plate or identifier is preprinted or printed on demand. When the license plate is applied to a carton or to a pallet, the license plate is placed in a physical location that permits an employee with a hand-held scanner to


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read the license plate. Most pallet license plates are applied to a pallet board’s stringer end, to a block, or onto a carton on the bottom layer. This carton is the extreme leftor right-hand carton. In a carton pick location, this carton is the last carton to be removed from a pallet.

INTERNAL TRANSPORTATION ACTIVITY The fifth activity is internal pallet or carton quantity transportation from the receiving area to the assigned storage area or delivery station. As required by your company, WMS or paper tracks the manual or powered material-handling method’s pallet or carton transport and storage transactions.

DEPOSIT

IN

STORAGE ACTIVITY

The next activity is depositing cartons or pallets in a storage-area delivery position or storage location. The assigned delivery position is assigned manually or by computer. Deposit to a delivery position is ordered, determined, and verified by an employee on a document or with an RF device. In an automated storage retrieval method, a scanning device reads a bar code label to verify delivery. Delivery to a storage position is delayed or updated online in the inventory files.

PICKING

AND IDENTIFICATION

ACTIVITY

The order-pick and picked-carton identification activity is the next order-fulfillment activity. The order-pick activity is the most important activity in a carton orderfulfillment operation because it is the first step in the process of satisfying your customer with an on-time schedule and accurate order delivery. In most orderfulfillment operations, an on-time and accurate order-fulfillment activity ensures a satisfied customer and an efficient and cost-effective operation; in most order-fulfillment operations, the activity requires the greatest number of employees.

IN-HOUSE TRANSPORTATION ACTIVITY The next carton order-fulfillment activity is the transport activity. Horizontal and vertical transport runs from the receiving dock to the storage area, from storage to the pick area, and from the pick area to the shipping dock.

SORTING ACTIVITY The next activity is the customer-ordered and picked carton sorting activity. When the carton order-fulfillment activity uses a batch-picking philosophy, the sorting activity separates one set of customer-ordered and picked cartons from your other customer-ordered and picked cartons.

STORAGE WITHDRAWAL

AND

REPLENISHMENT ACTIVITY

In a carton order-fulfillment operation that uses a fixed-position method, storage withdrawal and pick-position replenishment is considered the next activity. This



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activity has an employee- or computer-controlled machine withdraw a carton or pallet from the storage position and transfer the carton or pallet to a pick position or a workstation.

MANIFESTING ACTIVITY The next activity is the manifesting activity. The manifesting activity ensures that each customer-ordered and picked carton’s label is registered and sent to a customer delivery truck. The manifesting activity verifies that the customer-ordered and picked carton is sent from your order-fulfillment facility.

LOADING

AND

SHIPPING ACTIVITY

The loading and shipping activity is the next order-fulfillment activity. This activity has an employee transfer an individual carton, slip sheet, pallet, or four-wheeled cart from your order-fulfillment facility’s shipping dock onto a customer delivery truck.

CUSTOMER-RETURNS ACTIVITY The next carton order-fulfillment activity is the handling of customer returns. This activity ensures that your customer-returned carton was received at your facility, that the customer received credit, and that the returned carton is properly handled in the facility.

ORDER-PICK ACTIVITY The order-pick or order-selection activity is the order-fulfillment activity that completes the customer-order. To complete a customer-order, an employee or machine is directed, per the customer-order, to transfer the customer-ordered SKU quantity from a pick position to a manual or mechanized load-carrying surface. To have an effective and cost-efficient order-fulfillment operation, the pick or order-fulfillment activity requires a customer-order pick philosophy and order-handling method, order instructions, an order-selection method, an order-picker routing pattern, and a transport method. Order-Pick Philosophy and Order-Handling Method The first order-picking factor of a carton order-fulfillment operation is how the customer orders are handled in the order-pick or selection area. The factors that determine the pick philosophy and order handling method include the number of order pickers or pick machines per aisle or area, the pick routing or release pattern through an aisle or along a pick machine’s faces, and the hit concentration (the number of picks or lines per aisle) and hit density (the number of picks per SKU). The customer-order handling methods are as follows: a single customer-order handled by one order picker or pick machine, a single customer-order handled by multiple order pickers or pick machines (the zone pick method), and multiple customer orders handled by multiple order pickers or pick machines (the batched or grouped customer-order method).


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One Customer-Order and One Order-Picker or Pick Machine This method has one order picker or pick machine pick all cartons for one customerorder. In the single-customer-order-picker method, one order picker travels the entire order-fulfillment operation aisle and picks all items for one customer-order. With a large SKU number, this customer-order handling method is most frequently used in a manual order-pick operation. The disadvantages are that the method handles only a low volume, there are employee errors, and employee productivity is reduced due to long travel distances. The advantages are that employees become familiar with all SKUs, no sorting labor or building area for sorting is required, no computer program is required, and customer-order integrity is maintained. Single Customer-Order Handled by Multiple Order Pickers The next order-handling method is the single customer-order that is handled by multiple order pickers. When multiple order pickers handle a single customer-order, a computer program separates a customer-order into random or predetermined sections. Each customer-order section is given to an employee who performs all orderselection transactions. The random method separates a customer-order into a cube or SKU quantity that equals one pallet or cart, and is used with a manual-pick method. The predetermined separation method separates a customer-order per a pick-zone requirement. This method is used with a mechanized order-pick-to-conveyor system. The disadvantages are that the method requires a computer program and that it increases management control. The advantages are that employees can pick and travel any facility aisle, the method handles a large volume and a large customerorder quantity, it handles different SKUs, and it completes a customer order in a short time period. Multiple Customer Orders Handled by Multiple Order-Pickers The next order-handling method involves multiple customer orders that are handled by multiple order pickers. When multiple order pickers handle multiple customer orders, a computer program separates a group of customer orders into random or predetermined SKU sections. Each customer-order section is given to an employee who performs all order-pick transactions. Multiple customer orders handled by multiple order pickers are used with a mechanized order-pick-to-conveyor system. The disadvantages are that the method requires a computer program and management control. The advantages are that employees can pick and travel any facility aisle, that the method handles a large volume and a large customer-order quantity, that it handles different SKU types, and that it completes a customer order in the shortest time period. Order Instruction A carton order-pick method requires an order-picker instruction method. The orderpicker instruction method directs an order picker or automatic pick machine to the customer-ordered SKU pick position and indicates the case quantity that must be transferred from the pick position to a vehicle load-carrying surface or conveyor surface.



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For the most cost-effective, efficient, accurate, and timely order-fulfillment operation, the order-picker instruction method should be matched with the proper order-pick method. The order-pick instruction is determined by the manual, mechanized, or automatic carton order-pick method that is used in your carton orderfulfillment operation. The various manual order-pick instruction types include paper or card documents (printed manually or by machine); computer-printed paper labels; paperless systems that use a pick-to-light display, a bar-code scanner, or an RF device; and voicedirected systems. With an automatic order-pick method, a computer controls the customer-order pick instruction. The computer releases a pick impulse to the pick machine. As the impulse travels along the pick-position faces, per the customer-order the impulse releases a carton from the pick position onto the take-away conveyor travel path. In an automatic pick method, pick-position replenishment is an order-pick activity. Another carton order-pick instruction method factor is how your customer orders are handled in the pick area. This factor determines the number of order pickers in an order-fulfillment aisle. The various customer-order handling methods include using no method, single customer orders with a single order picker, single customer orders with multiple order pickers, variable or fixed pick zones, batched customer orders with multiple order pickers, and automatic sequential order-picking. In the manual or mechanized employee-to-stock and mechanized stock-toemployee methods, the ability to assign an order-picker number to the order-fulfillment activity is determined by cost per carton and the importance of on-time and accurate order selection and satisfied customers. The manual or mechanized employee-to-stock method and some mechanized stock-to-employee methods require an order picker to be routed through the orderfulfillment facility’s aisles. These aisles are between rows of racks or shelves that have carton pick positions. To maintain an accurate, cost-effective, and efficient automatic order-pick system with no stock-outs, the replenishment activity requires a order-picker routing pattern. Order-Picker Routing Patterns The next factor in a manual carton order-pick method is how the order picker is routed through the order-fulfillment facility’s aisles to the appropriate carton-pick positions. This factor determines the order-picker travel time between two pick positions. The various order-picker routing methods may be nonrouted or routed; they include a single-side order-picker with one or two order-pickers per aisle, a loop routing pattern, a horseshoe or U-routing pattern, a Z-routing pattern, a multilevel HROS pattern with one-way or two-way vehicle traffic and four or six levels, and variable or fixed zones. The next factor that influences carton order-picker productivity is the SKU locator system that is used in the order-fulfillment operation. Inventory location determines the SKU pick position in the order-fulfillment operation aisle; the methods are the fixed slot and the floating slot method. The fixed SKU pick-position method requires fewer aisles, causes an increase in potential stock-outs, and


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improves the customer-ordered SKU hit concentration and hit density. The floating pick-position method requires 20 to 25% more pick positions and floor area, reduces the stock-out potential, and lowers the customer-ordered SKU hit concentration and hit density. Other important considerations are a SKU’s cube, weight, and fragility; SKU velocity or movement; the family group, kit, or pair; the golden zone; and the number of SKUs. Order-Selection Method The order-selection method incorporates the rack or shelving layout, the materialhandling equipment, and the employees who read your order-pick instruction document and physically transfer the customer-ordered carton from a pick position to a vehicle load-carrying surface or conveyor travel path. With an automatic orderfulfillment system, the order-fulfillment equipment interfaces with a microcomputer to release the customer-ordered cartons from a pick position onto a conveyor travel path. Per the manual, mechanized, or automatic order-fulfillment method, these cartons are sorted to a staging area or directly loaded onto a customer delivery vehicle. The carton order-pick method is considered the key to a successful orderfulfillment operation. A carton order-fulfillment operation’s objective is to withdraw on schedule cartons from inventory that are on a customer’s order instruction document or a microcomputer download. An accurate and on-time order-fulfillment activity maintains a satisfied E-commerce, catalog, or direct-market customer group; allows the manufacturing department to maintain its production schedule; and permits the retail store to have product on hand for retail sales, which satisfies customers. An order-fulfillment operation’s annual budget review indicates that the order-pick labor line item has the highest budget or dollar-expense value and, correspondingly, in an order-fulfillment operation the order-pick activity requires the largest number of employees.

VARIOUS ORDER-PICK METHODS The basic carton order-pick systems are manual, mechanized, and automatic. In a manual carton order-pick system, an employee walks or rides on a vehicle through a series of pick aisles to the customer-ordered SKU’s pick position, removes the appropriate carton quantity from the pick position, and transfers the carton quantity onto a vehicle load-carrying surface. The vehicle load-carrying surface or conveyor travel path transports these picked cartons to a dock staging area or directly onto your customer delivery truck. In a mechanized carton order-pick system, an employee may travel to a pick position, manually remove the carton quantity from the pick position, and transfer the carton onto a powered conveyer travel path for transport to a sorting area and to the dock staging area or directly onto your customer delivery truck. Alternately, a mechanized device delivers the stock or pick position to an employee pick station. At the pick station, the employee transfers the carton quantity onto a vehicle loadcarrying surface or onto a conveyor travel path. The vehicle load-carrying surface or conveyor travel path transports these picked cartons to the sorting area, the dock staging area, or directly onto your customer delivery truck.



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Automatic carton-pick systems use a computer to control the entire carton orderpick activity. According to the SKUs on your customer-order, from the various pick positions the computer network automatically or mechanically releases the appropriate cartons from the pick positions onto a take-away conveyor travel path. The conveyor travel path transports these picked cartons to the sorting area and then to the dock staging area, or directly onto a customer delivery truck. If this basic carton order-pick method is to make your order-fulfillment operation highly productive and efficient, your order-fulfillment facility must be designed with an understanding of the proposed carton storage and pick methods, carton flow patterns, and carton replenishment requirements. The basic carton order-pick methods available for design and implementation in a new or existing order-fulfillment operation is the manual method. For best operational results, the mechanized and automatic order-pick methods are designed for implementation in a new order-fulfillment operation and facility. These new facilities are designed and constructed to house the carton order-pick area; the storage and replenishment areas; and the receiving, shipping dock, and support areas. Conveyable and Non-Conveyable Cartons During the process of selecting a carton order-fulfillment method, your design team determines the carton or SKU pick faces and customer-order volumes that lead to an operation with conveyable or nonconveyable cartons or SKUs. A conveyable carton is defined as a carton that has the physical characteristics (length, width, height, and weight) and exterior surface necessary for transport over a powered-conveyor travel path or with a vehicle load-carrying surface. A nonconveyable carton is a carton with physical characteristics and an exterior surface that prevent the carton from being moved by a powered-conveyor travel path. A vehicle with a load-carrying surface handles the nonconveyable carton. Manual order-pick methods can handle both conveyable and nonconveyable cartons. Mechanized stock-to-employee pick methods can handle both conveyable and non-conveyable cartons in tote. Mechanized employee-to-stock, pick-to-conveyor methods handle only conveyable cartons and require a manual pick method for non-conveyable cartons. Automatic pick methods handle only conveyable cartons and require a manual pick method for nonconveyable cartons. Designing and operating a manual or mechanized stock-to-employee pick method is less complex because there is only one pick method. Designing and operating an employee-to-stock, pick-to-conveyor, or automatic carton order-pick method is more complex because two pick methods are required in the operation, and because the customer-ordered and picked cartons from the conveyable and nonconveyable pick systems are loaded onto one customer delivery truck or onto a staging area. Manual Order-Pick Methods Manual carton order-pick methods are the simplest carton order-pick methods. With a manual order-pick method, an employee walks or rides a manual or remotecontrolled mobile order-pick vehicle through 150-to-300-foot-long aisles. These pick


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aisles are between two pick-position rows. These pick positions are floor stacks, pallet racks, or shelf rows that are one or two levels high. With a manual carton order-pick method, all inbound pallet or carton quantities are deposited into storage positions. Per customer orders, replenishment pallet or carton quantities are transferred from the reserve position to the pick positions. The replenishment aisle’s clear width is designed to accomodate pallet or carton-handling vehicle right turns and to permit two-way order-picker vehicle traffic. The manual order-pick method’s components include carton pick positions and a method for moving the order picker and picked cartons through the pick aisles. An employee may walk or ride on a manual or powered vehicle. Various Pick Positions The carton pick positions are the order-fulfillment locations that contain a SKU inventory. Per customer-ordered SKUs, the order-picker is instructed to transfer the required carton quantity from the pick position to a manual or powered vehicle’s load-carrying surface. The carton pick positions include: • • • • • • • • • •

A one- or two-high floor stack A one- or two-high pallet cage or stacking frame Several shelf or carton rack levels One level of pallet drive-in or drive-through racks One level of pallet gravity or air-flow racks One level of push-back pallets A standard pallet rack with one or two levels Decked or hand-stacked racks A mobile rack with one pallet level A cantilevered rack with one or two levels

Floor-Stacked Carton or Pallet or Block-Pick Position The first carton or pallet pick position is the carton or pallet floor-stacked position. The carton or pallet pick position has the cartons or pallets set in a series of rows on the floor surface. An aisle is located between two rows, and the order picker has access to the cartons in the pick position. With the carton or pallet floor-stacked position method, the SKU carton has sufficient strength to support additional stacked carton or pallet load weight, and floor stack-lane depth is determined by pick area, layout, and inventory quantity. The options are a stack set at a 90º angle to the pick aisle and a stack set at a 45º angle to the pick aisle. The 90º-angle floor-stacked method is the first floor-stack method. This method is the most common floor-stack design. The carton or pallet squarely faces the pick aisle. The method features the greatest number of SKU pick faces per aisle and requires a wide aisle. The 45º-angle floor-stacked method is the second floor-stack method. This method has the carton or pallet face the pick aisle at a 45º angle. The 45º-angle



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method requires a narrow aisle and provides the lowest number of SKU pick faces per aisle. Other floor-stacked pick position considerations are as follows. The floor-stacked pallet lane is two to six pallets or cartons deep per lane. A storage lane is a single row or several back-to-back rows. At the aisle position, the pick position is one pallet or several cartons high, which permits the order picker easily to reach the carton quantity for a customer-order, but this lowers the space utilization. To utilize the cube or air space, the pallets or cartons that are deeper in the lane are the readyreserve pallets or cartons, which are stacked two to four pallets or several cartons high. In most operations, the SKU in the pallet or carton lane serves as the SKU for the entire pallet or carton lane. The individual cartons or cartons on a pallet are able to support the stacked weight. The floor-stacked pick position’s features are as follows. The position provides a high pallet or carton ready-reserve quantity. It is used for large-cube or very fastmoving SKUs. The position provides a LIFO product rotation, requires a low capital investment, provides a good SKU hit density and hit concentration, and is used in a manual order-pick operation. Pallet-Cage, Tier-Rack, or Pallet Stacking-Frame Pick Position The second carton pick method is the pallet-cage, tier-rack, or pallet stacking-frame pick-position method. When a SKU that is placed in a floor-stacked pick position is crushable, is larger than a pallet, or is not self-supporting, one of these methods is used to make stackable and uniform unit loads. These unit loads are stackable to optimize the cube. The pallet cage is a wire-mesh four-walled container that is attached to a pallet. At each wire-mesh container’s corner is an upright support member with a pad. This pad is designed to support another pallet cage. To ensure access to the cartons inside a pallet cage, one wire-mesh wall has a hinge or is not full height. The tier rack has four legs at the four corners of its base. Each base is attached to a pallet. The four legs are connected or intersect in the middle, at the top. Nails are driven through the tier-rack base plate. This feature gives the tier rack a more secure attachment to the wood pallet. When tier racks are not used in an operation, they are disassembled and stacked to reduce storage space, but this requires employee assembly and disassembly time. The stacking-frame method consists of a hardened, welded, and coated metal structure. The metal structure has four upright legs that are permanently attached to a base and have the strength to support three fully loaded stacking frames. The leg’s top has horizontal structural-support members and devices to support other stacking frames. The base has two fork openings for forklift trucks. The stackingframe clearance between the four legs and the base handles a full pallet or handstacked cartons. The stacking-frame method’s components are permanently attached to the base and extend straight upward from it. At the top, there are four horizontal cross members that tie the four legs together. The stacking frame, which can be nested, has three horizontal upright members that connect the four legs at the top. This


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feature creates one open side. When a stacking frame is not being used in an operation, the stacking frames are nested in groups of eight to ten. During transport, or when completing a storage transaction, this feature reduces the amount of required storage space. To prevent metal stacking frames from sliding on a forklift truck’s metal forks, fork sleeves or stir-ups are added to the base’s bottom. The fork sleeve or stir-up’s downward extension, width, and opening permit the truck’s forks to enter the fork sleeve or stir-up fork opening. The sleeve or stirup base is slightly above the floor surface. To prevent cartons from accidentally falling from a stacking frame or tier rack, rubber bands, stretch wrap, or netting is wrapped around the stacking frame or tier rack’s four sides. These pick-position devices have a wood pallet, a structural member, or a solid base. If it is required to have no indents on a carton’s exterior surface from cartons that are hand-stacked onto a stacking frame’s ribbed base, a solid base is used on the ribbed base. The pallet-cage, stacking-frame, or tier-rack operational and design characteristics are the same as for the floor-stack method. Your local fire codes should be reviewed prior to implementation of any of these methods in your order-fulfillment operation. Disadvantages are that there is an additional capital investment and when building a stack, there is lower forklift truck-driver productivity. Another disadvantage is that, when not used in an operation, the cage, frame, or rack takes up space as well as employee time for assembly and disassembly. Carton Gravity-Flow Rack Pick Position The next carton pick-position method is the carton gravity-flow rack pick-position method. In most carton order-fulfillment operations, the carton gravity-flow rack method is used for slow-moving SKUs. The carton gravity-flow rack has carton conveyor travel lanes and structural-support members and frames. Each travel lane has a carton stop device, connecting top and bottom braces, and connection components. The conveyor lanes are sloped from a replenishment aisle to the order-pick aisle. Your carton weight and the carton’s bottom surface finalize the conveyor flowlane slope. This allows gravity force to move a carton from the entry side to the exit side. With a normal 24-inch-long, 10-inch-wide, and 11-inch-high carton, a 4-to-5level-high flow rack and a 5-foot-wide carton gravity-flow rack bay provides 20 to 25 pick faces per rack bay. A 10-foot, 6-inch-deep flow-rack lane provides 10 to 12 cartons in ready reserve. The carton gravity-flow pick-position designs include the standard rack with nonpowered conveyor sections, the straight-back rack, the slant-back rack, and the tilt-back rack. The first gravity-flow rack pick-position method is to place nonpowered roller or skate-wheel conveyor sections into a standard rack bar. Each conveyor section is attached to the standard pallet-rack load beams. The charge end of the load beam is set at an elevation above the floor that is higher than the load-beam elevation at the discharge end. The load-beam elevation difference creates the required slope to move the cartons over the flow lane.



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In the straight-back flow-frame design, each flow lane is located directly above the lower flow lane. This design is considered the best flow-rack method for handling cartons. The slant-back flow-rack design has a series of flow lanes. The flow lanes at the floor level extend furthest into the pick aisle. Each additional flow lane is set back into the flow rack, and the pick positions resemble steps. The tilt-back flow-rack design has a series of flow lanes. The flow lane at the floor level extends furthest into the pick aisle. At the end and at the face the flow lane is tilted downward toward the finished floor. Each additional flow lane with its tilted front is set back into the flow rack. This makes it easier to remove a carton from a flow-rack lane. The slant-back and straight-back carton gravity-flow methods are used for carton pick positions, and the tilt-back method is preferred for single-item pick positions. To ensure carton flow through the carton gravity-flow pick-position method, the flow lane’s charge end has a higher elevation than the discharge end. The each flowlane discharge end has an end stop to prevent uncontrolled carton discharge from the carton flow lane. Some carton flow pick-position methods use full-length lane guides to ensure guided carton travel and minimize carton hang-ups in the flow lane. Other carton flow-rack features are as follows. The structural members should be strong enough to provide pallet or hand-stacked ready-reserve positions on the structural members above the top flow lane. Carton flow-racks may be implemented as single-level, multilevel, or mezzanine operations. In a multilevel operation, the flow rack’s upright structural-support members support the elevated floor and pick positions. You must ensure that the flow-rack structural members have sufficient structural strength and are properly anchored for your proposed application. With the carton flow-rack method, slow-moving SKUs are replenished from the replenished aisle at the flow lane’s rear. Gravity force moves the cartons over the flow lane to the pick position that faces the pick aisle. Per the customer-order pick instruction, from a pick aisle at the flow-lane discharge end, order-pickers remove the appropriate carton quantity from the pick position. The picked carton is placed onto a take-away conveyor travel path or onto a vehicle load-carrying surface. The flow-rack carton design provides carton reserve storage. At the charge end, an aisle requires a set-down spot for flow-lane replenishment. Alternative replenishment methods include having cartons conveyed or transported on four-wheeled carts to the replenishment aisle, and having a conveyor transport-and-sorting system sort the appropriate carton into the appropriate flow lane. Disadvantages are capital investment and limited carton quantity in ready reserve. Advantages include that for very slow-moving SKUs, there is excellent SKU hit concentration and hit density. The system also features good order-picker productivity, FIFO product rotation, and excellent SKU access. Push-Back Pick Position The pallet push-back rack method is the next pick-position method. This method features a depth and height of three to four pallets per lane. The designs include standard pallet gravity-flow racks with end stops on both flow lane ends, and racks with nesting carriages that ride on two rails. Both push-back rack methods provide


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one high pick position with ready-reserve pallet positions behind the pick position, and there is one SKU per push-back flow lane. The push-back rack method requires that a forklift truck from the pick aisle set a new pallet load in the first rack position of the flow lane. If there are additional pallets, the forklift truck sets the new pallet load at the flow-lane aisle position. Until space is created for a new pallet, the forklift truck pushes against the existing pallet in the flow lane. After space is created in the flow lane, the forklift truck deposits the pallet in the push-back lane. To complete a carton pick transaction, an orderpick employee travels in the pick aisle, stops at the appropriate pick position, and is directed by a pick instruction to remove a carton quantity from the pallet in the pick position. The carton quantity is transferred to a mobile-vehicle load-carrying surface. When the pick pallet becomes depleted, an order picker removes the empty pallet from the pick position and transports the pallet to an empty-pallet accumulation location. Gravity force moves the next pallet in the flow lane to the pick position. The push-back pallet-rack method is a stand-alone rack method that is placed along a building wall or has back-to-back rows. The method requires a forklift truck to complete a replenishment transaction in the pick aisle. The pick aisle runs along the front of the pick positions. The method features LIFO product rotation and one SKU per lane. It requires an empty pallet location, handles a high carton volume for high-cube SKUs, provides a low number of pick faces per aisle, requires a large carton ready-reserve, and uses one aisle for replenishment and pick activities. Drive-In or Drive-Through Pallet-Rack Pick Position The next carton pick method is the drive-in or drive-through pallet-rack pick position. A drive-in or drive-through rack has upright frames, upright posts, support arms, guide rails, support rails, and required side and top bracing members that form storage lanes. Drive-in racks have an end stop at the lane end as an additional component. At the entrance to each storage lane, drive-through racks have additional top bracing members. The differences between the drive-in and drive-through rack are the required forklift aisles and product rotation. The drive-in rack method requires one forklift aisle along the face of the rack rows. This aisle is used to complete a forklift replenishment transaction and order-picker transactions. The drive-through rack method requires two forklift transaction aisles. These aisles are at both sides of the rack rows. In most operations, for FIFO product rotation one aisle is used for forklift deposit transactions and the other aisle is used for order-picker transactions. For an operation that requires LIFO product rotation, one aisle is used to complete both forklift replenishment and order-picker transactions. Each aisle or drive-in or drivethrough rack-bottom pallet position is considered a pick position. With the drive-in rack, a forklift enters and exits the storage lane from one aisle. In the storage lane, the forklift places the pallet in the innermost position and fills all rack positions in each lane or rack level until all storage positions are full. To maintain good inventory control, this feature requires one SKU per lane. The drive-in rack is best used as a single-rack row against a wall or in a back-to-back



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row arrangement to provide positions for nonstackable SKUs. In a drive-in rack design, the storage lane is no more than two or four pallets deep. An order-pick employee with a mobile vehicle travels in the aisle between or along drive-in or drive-through pick faces. Per the order-pick instruction, the employee removes the required carton quantity from the pick position and transfers the carton quantity onto the vehicle load-carrying surface. Empty pallets are physically removed from the pick position to an empty-pallet queue position. To complete additional order-pick transactions, the order-pick employee or forklift truck moves another pallet from an inner position to the pick position. This method’s features are LIFO product rotation, fair SKU hit concentration and SKU hit density, nonstackable SKUs, good ready-reserve quantity, and a forklift truck or pallet truck that moves pallets forward to the pick face. This method is used in a manual order-pick system with a carton-carrying vehicle. Pallet Gravity or Pallet Air-Flow Pick Positions The next carton pick-position method is the pallet gravity or pallet air-flow rack method. The pallet gravity-flow rack has short rollers or skate-wheel conveyor travel lanes. On each side of the conveyor lane, there is one roller path, skate-wheel path, or mesh skate-wheel path. Other components include structural-support members and frames, an end-stop device, a pallet-load separator, connecting top and bottom braces, and structural-member connection components. Some manufacturers use pallet flow retarders and pallet runners. The conveyor lanes are pitched or sloped from a forklift replenishment aisle to an order-pick aisle. The pallet’s height and weight, the pallet’s bottom surface deck boards, and manufacturer standards finalize the conveyor flow-lane pitch. This feature allows gravity force to move the pallets from the flow-lane entry side to the exit side. The pallet gravity-flow rack is designed as a stand-alone system that is a minimum of 2 pallet loads and a maximum of 20 pallet loads deep and 3 to 4 pallet levels high. The method requires one aisle for forklift pallet or SKU deposit and a second aisle for SKU order-pick transactions. An alternative to the pallet gravity-flow rack method is the pallet air-flow method. The air-flow method is designed with similar structural-support members and flowlane pitch characteristics as the gravity-flow rack method. The unique characteristic of the air-flow system is that there are tiny air holes on the entire length of the two travel-path support members. An air compressor pumps air into the pallet-rail structure, and the pallet is moved forward through the rack lane. Forklift trucks make pallet deposits at the flow-rack lane’s entry end, and order pickers remove cartons from the pallet at the flow lane’s exit end. When a pallet is empty, the order picker removes the empty pallet from the pick position and moves the empty pallet to an accumulation position. This empty-pallet removal transaction creates an empty position at the pick face. The open position allows the pallet airflow method to move the next pallet load forward to the pick position. The movement on the gravity-flow rack is created by gravity and the pallet load weight. Along the pick position is a sensor device to activate the open-pallet pick position and to activate the air compressor to move a pallet forward into the pick position.


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The method’s features are FIFO product rotation, fewer forklift truck transactions, one lane for each SKU, and low equipment and product damage. The method requires an investment. One or Two Levels of Standard Pallet Racks The next carton pick position is the standard pallet-rack method. The standard palletrack method design includes two upright frames. Each frame has two upright posts with horizontal braces, diagonal braces, and base plates. There are two load beams per level, as well as connecting components. Other options include two cross members per pallet position, solid or wire-mesh decks, floor anchors, back-to-back ties, and (as required by code) overhead ties. The pallet-rack method is designed with single rack rows or back-to-back rack rows. With the pallet-racking method, each rack bay has one, two, or three pallet pick positions, and the pallets are transferred to the pallet position by forklift truck. The pick position is one pallet deep, and is designed with the first pallet on the floor and the second pallet supported by two beams. In many order-fulfillment operations, to improve employee safety and product protection the second pallet bay has a wire-mesh deck or cross members. The pallets in a rack bay are the SKU pick positions. Per each rack bay, the SKU pick positions are one or two levels high and one, two, or three pick positions wide. If there is an elevated pick position, the height and depth of the carton in the elevated pick position lowers your employee productivity. The various pick position methods are as follows: Two pallets wide, with the 48-inch dimension facing the pick aisle — For some cartons, an order picker must reach into the rack position. With a very tall floor pick position, this limitation is minimized. The method creates two pick positions per bay. There are fewer pick positions per aisle and, since a forklift must handle the pallet from a nonstandard side, additional time is required for the forklift truck to complete a replenishment transaction. Good forklift truck driver skills are required. Two pallets wide, with the 40-inch dimension facing the aisle — For some cartons, an order picker reaches deep into the rack position. With a very tall floor pick position, this limitation is minimized, but there are two pick positions per rack bay. There is a greater number of pick positions per aisle. With the pallet having a standard orientation, less time is required to complete a forklift truck replenishment transaction. Three pallets wide, with the 32-inch dimension facing the aisle — This is not a standard pallet size. It holds a smaller carton quantity. This design is good for slow-moving SKUs, and provides the maximum number of pick positions per pick aisle. With a standard opening for a forklift truck, it is easy to complete a replenishment transaction. If the elevated pick position requires a deep reach, the bottom pick position is made taller with three pallets per rack bay. After the order picker receives the customer-order-pick instructions, the order picker with a mobile vehicle travels in the pick aisle between the two rack rows.



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At the appropriate pick position, the order picker transfers the appropriate carton quantity from the pick position onto the vehicle load-carrying surface. If there are depleted pallets in the pick position, the order picker transfers the pallet to an assigned empty-pallet location, and a forklift truck driver transfers a full pallet to the empty pick position. The system provides good SKU density and hit concentration, excellent SKU accessibility, and FIFO product rotation. It requires a medium capital investment. The pick position contains a large carton quantity. Decked or Hand-Stacked Cartons in Standard Pallet Racks The next carton pick position consists of decked or hand-stacked cartons in a standard pallet-rack bay. The decked or hand-stacked cartons in a standard pallet-rack bay method includes the one-deep pallet-rack method and its components, plus a wiremesh or solid deck in the rack bay. The deck material is metal, wood, pressed board, or plywood. To ensure minimal bowing of the deck material, two to four cross members are placed between the load beams. There are two design options for the decked or hand-stacked cartons in a standard pallet-rack bay method. The first option is that the rack bay is divided by a barrier, pick positions facing one pick aisle, and pick positions facing another pick aisle. The barrier in the middle is a wood, rope, or pipe barrier. Second, the rack-bay pick position faces one pick aisle. The decked or hand-stacked cartons in a standard pallet-rack bay method’s operation characteristics are as follows. The method is for slow-moving, lightweight, and small-cube SKUs. The operational procedures are the same as with the pallet rack, except that the pick-position replenishment is made by an employee handstacking cartons onto the deck. The method’s features are medium SKU hit concentration and hit density, a medium pick-face number per aisle, and additional time for pick-position replenishment. The method works best for slow-moving, lightweight, and small-cube SKUs. There is a limited carton quantity in the pick position. Multiple Levels of Shelves or Slotted-Angle Shelves The next carton-pick method has standard shelf or slotted-angle shelf methods. The standard shelf or slotted-angle shelf method includes upright posts, shelving or decks, and bracing and connecting components. The shelving method is designed with open or closed sections and single or back-to-back rows. The open section has cross bracing along the sides and a cross-braced back, and the closed section has solid sides and a solid back section. The slotted-angle shelf method consists of an open section. The open shelf or slotted-angle method is used for stackable cartons, and the closed method is used for nonstackable cartons. The method has limited application in a carton order-fulfillment operation, handles minimal weight, and features fair SKU hit concentration and hit density. The cost is low, and the method provides a small carton quantity in the pick position. Carton or Pallet Mobile or Sliding Rack The next carton pick-position method is the carton or pallet-mobile or sliding-rack method. This method has a moving shelf or moving pallet-rack bases; pallet rack


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structures that are attached to the motorized, mobile bases and permanent rack rows; safety devices; and a forklift truck. In most carton order-fulfillment operations, the carton or pallet mobile or sliding rack is used in the storage area. Cantilevered Rack The next carton pick-position method is the cantilevered-rack method. The cantilevered-rack method includes upright posts, support arms and legs, bracing, deck material, and wire-mesh baskets. The cantilevered-rack method provides pick positions for long cartons and is designed with single-arm or double-arm rows. In most carton order-pick operations, a cantilevered rack has limited application. Pick Tunnel The next carton-pick method is the pick-tunnel method. The pick-tunnel method is designed with gravity-flow or push-back racks as the pick and reserve positions. The pick tunnel is created in the floor’s middle or on an elevated floor level for a manual pick method or employee-to-conveyor method. For the manual order-pick method, the sections include an elevated floor level or pallet reserve section with gravity-flow racks that span the pick aisle, as well as the pick positions, which are gravity-flow racks that face the pick aisle. This design creates an aisle for a pick-aisle operation with ready-reserve positions. A pick-tunnel side view shows that the elevated gravity-flow racks or elevated floor level form the pick tunnel’s top, and the floor gravity-flow racks are the pick tunnel’s sides; the pick aisle is through the pick tunnel. Your pick-tunnel design specifies that the floorlevel rack positions flow to the pick tunnel middle aisle, upright frame posts protection and additional structural support members to span the pick tunnel. HROS Pick Method The HROS method has two rack or shelf rows and an electric-guided vehicle with an employee platform and a cart or pallet that has the ability to travel horizontally and vertically in the aisle to the required pick position. After pick transaction completion, the employee places the picked carton onto a cart or pallet. The high-rise order-pick method is considered one in which an employee rides to the pick position.

EMPLOYEE

AND

PICKED-SKU IN-HOUSE TRANSPORTATION METHODS

The second component of the manual order-pick method is the employee and pickedSKUs travel transport method. The picked-SKU transport method moves the orderpicker through the various aisles to the customer-ordered SKU pick positions, and moves picked cartons through the facility’s pick aisles to the customer-order staging area. The order-picker and picked-carton transport methods are as follows: an employee walks with a cart, and an employee rides on a manually powered and controlled vehicle. Employee Walks with a Cart to the Pick Positions The first employee-to-stock method has the employee walk with a cart to the pick position or to the stock. The method has an employee push or pull a human-powered



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vehicle, or steer an electric battery-powered three- or four-wheeled load-carrying vehicle through the pick aisles to the pick positions. At the appropriate pick position, an employee, per the customer-order pick instruction, transfers the carton quantity from the pick position onto the vehicle load-carrying surface. The subdivisions in this group include human-powered employee walk methods — employee carry, two-wheeled hand truck, platform truck or dolly, four-wheeled cart, and manual pallet truck or jack — and electric battery-powered employee walk methods: “walkie” pallet truck and “walkie” tugger or tractor with a cart train. Employee-Carry or Two-Wheeled Hand-Truck Methods The employee-carry method has an employee physically carry the picked carton from the pick position to the required customer-order staging area. The employee powered two-wheeled hand truck method has an employee push or pull the picked cartons on a two-wheeled hand truck from the pick position to the required customerorder staging area. The employee-controlled and powered two-wheeled hand truck design has an H-frame that has two handles on the upper end. To retain small-cube cartons, one or several horizontal bracing members are required between the frame legs. There are two wheels with an axle at the H-frame’s lower end, and a loadcarrying surface that has a lip or nose ahead of the wheels. The two-wheeled hand-truck method has an employee transfer the customerordered required carton quantity from the pick position onto the two-wheeled hand truck’s lip. With the cartons secured and balanced on the two-wheeled hand truck’s lip, the employee walks the hand truck from the pick area to the required customerorder staging area. For best results, this method requires a smooth and even finishedfloor surface with no debris in the travel path. This method is used for a quantity of cartons that fit onto the two-wheeled hand truck’s H-frame and lip. The method transports a small carton number per trip, and requires an employee’s physical effort. There is only a very small load-carrying surface, which can lead to SKU damage. The method requires either no investment or only a minimal investment; it requires no battery-charging area or fuel-storage area, very little maintenance, and minimal employee training. It is best used in a single customer-order handling system. The employee-carry method is not preferred for most dynamic carton orderfulfillment operations. Platform Truck or Dolly Methods The second employee-to-stock method is the platform-truck or dolly method. The employee-powered platform truck or dolly method has an employee physically push or pull a four-wheeled platform truck or dolly with the picked cartons from the pick position to the required customer-order staging area. Both methods require a smooth and even floor surface with no debris in the pick aisle. The platform truck has four large-diameter wheels, one wheel under each corner of the platform. The front wheels are rigid wheels or casters and the rear wheels are swivel wheels or casters. There is a push handle and a solid or slatted rectangular load-carrying surface. The load-carrying surface’s elevation is approximately 12 inches above the floor surface.


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The dolly has three or four small-to-medium-diameter swivel casters or wheels. Each wheel is under the load-carrying surface’s corner. There are square, rectangular, or triangular slats or a solid deck as a load-carrying surface; the surface is approximately 6 inches above the floor surface. There may be a tow bar or rope hole in the deck’s end. The platform truck has a large carton quantity-carrying capacity, is easier to push and steer, requires less physical effort to transfer cartons onto the load-carrying surface, requires additional floor storage space, and has a higher cost. It requires a smooth and even floor surface. The platform truck is used in a single-order operation. To load onto a customer delivery truck, double-carton handling must be used. The dolly has a three-to-four-carton carrying capacity, is difficult to push and steer, requires increased physical effort to transfer cartons, requires minimal floor storage space, has a lower cost, and requires a very smooth and even floor surface with no debris on the pick aisle. To load onto a customer delivery truck, doublecarton handling must be used. The dolly is used in a single-order operation. Four-Wheeled Cart Method The next employee-to-stock method is the four-wheeled cart method. The fourwheeled cart method has an employee physically push or pull a four-wheeled cart with picked cartons from the pick position to the customer-order staging area. The four-wheeled cart method requires a smooth and even floor surface with no debris in the travel path. For additional four-wheeled cart information, we refer the reader to the fourwheeled cart section of Chapter 3. Manual Pallet-Truck or Jack Method The next employee-to-stock method is the manual pallet-truck method. The employee-powered pallet truck is referred as a walkie truck. The method has an employee to physically push or pull a manual pallet truck with a pallet load through the pick aisle. The employee transfers the picked cartons from the pick position onto the pallet board. The completed customer-order or full pallet is pulled to the required customer-order staging area. The manual pallet-truck method requires a smooth and even floor surface with no debris in the pick aisle. The manual pallet truck is designed with an operator handle that activates the hydraulic elevating mechanism, a hand- or foot-operated hydraulic pressure-release lever, one or two steering wheels, and two load-carrying wheels to carry a 3000pound pallet. Each wheel is under a hardened and coated metal fork. With lightweight pallets, the fork length can handle two pallets. To prevent cartons from falling from a pallet, a backrest is attached to the vehicle, and there are pallet entry wheels on the metal fork tips. For best results, the manual pallet-truck method requires a smooth and even floor surface with no debris in the pick aisle, and a pallet with chamfered bottom deck boards, which minimizes fork entry problems. A pallet with chamfered bottom deck boards has each bottom deck board’s top edges angle-cut. When an employee pushes a manual pallet truck into a standard pallet opening, there is good possibility for the fork tip or front wheel to hang up on the bottom deck board. This hang-up



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situation causes the pallet to be pushed across the floor surface, which creates low employee productivity and possible equipment, building, or product damage. If a two-pallet truck is used in an order-fulfillment operation, turning from one pick aisle to another adjacent pick aisle requires a wider turning aisle. To order-pick cartons, the manual pallet-truck method requires an order picker to pick up an empty pallet, set the hydraulic lever in the elevate position, and elevate the pallet. The order picker pulls or pushes the manual pallet truck through the facility’s pick aisles and, per the customer-order, transfers cartons from the pick positions and assembles the cartons onto the pallet. The pallet is stacked to a predetermined (or “computer-cubed”) height or until all picks are completed for a customer-order. With the order-pick activity completed, the pallet is pushed or pulled to the customer-order staging area. To deposit the pallet, the employee sets the hydraulic lever to the lower position. The hand-operated pallet truck is best used in a single customer-pick operation. The truck features a large carrying capacity, is easy to push or pull and steer, and requires less physical effort. When not being used, the truck requires minimal floor storage space. Its cost is low. It requires a smooth and even floor surface, is used in a single-order operation, requires an empty pallet, and is used in the receiving and shipping dock areas. Electric Battery-Powered Walkie Pallet-Truck Method The next employee-to-stock method is the electric battery-powered walkie pallettruck method. The electric battery-powered walkie pallet-truck method is very similar to the manual or electric walkie or rider pallet-truck method. For additional information, we refer the reader to the manual pallet-truck section and the electric battery-powered pallet-truck section in the employee-rides-to-the-pick-position section in this chapter. Electric Battery-Powered “Walkie“ Tugger or Tractor Method The next employee-to-stock method uses an electric battery-powered walkie tugger or tractor with a cart train. The method is very similar to the electric walkie/rider tugger or tractor with a cart train method. For additional information, we refer the reader to the relevant section in the employee-rides-to-the-pick-position section in this chapter. Employee Rides to the Pick Position The second employee-to-stock group has the employee ride on a powered and employee-controlled vehicle to the pick position or to the stock. This group has an employee control and ride on a powered three- or four-wheeled load-carrying vehicle through the pick aisles to the pick positions. At the appropriate pick position, an employee, per the customer-order pick instruction, transfers the carton quantity from the pick position onto the vehicle load-carrying surface. After completion of the customer-order (or all required customer-order picks), the powered vehicle transports the customer-ordered and picked cartons to the customer-order staging area.


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When this group is compared to the group where an employee walks to the pick position, the employee-rides-to-the-pick-position group transports a carton quantity and order picker over a greater travel distance. There is less employee fatigue, and it takes less time to travel the required distance. The order picker transfers the customer-ordered and picked cartons onto the customer delivery device, which is a pallet or a cart. This feature reduces double-handling of the customer-ordered and picked cartons. Vehicles require a battery-charging area and a wider aisle or a guided-pick aisle. Some vehicles permit the order picker to pick from elevated pick positions. The method is used in a single-order operation. There is a maintenance cost. The method requires a smooth and even finished-floor surface with no debris in the pick aisle. There is improved employee productivity and a low cost per carton. The employee-rides-to-the-pick-position methods include the burden-carrier, the electric cart with a towed cart, the electric pallet truck (single pallet, double pallet, remote controlled, elevating employee, and elevating employee and pallet), the electric or manual tractor or tugger with a cart train (manual or remote controlled, with various cart types, the powered forklift truck with attachment, and the HROS or man-up VNA vehicle. Burden-Carrier Method The first method is the manually controlled, powered burden-carrier method. The burden-carrier method has a power source (liquid propane [LP] gas, gasoline, or electric battery). For an indoor carton order-fulfillment operation, the preferred burden-carrier power source is the electric rechargeable battery with a charging device. An electric motor is connected to a drive wheel or wheels. There are three or four wheels, with at least one wheel as a steering wheel and two as power wheels. There is an operator’s position with forward and reverse movement and stop/start controls, and a solid deck that has a load-carrying capacity of 500 pounds, or a 6to 12-carton quantity. While an order picker rides on the burden carrier through the order-fulfillment aisles, the order picker stops the vehicle at the SKU pick position per the customerorder pick instruction, walks to the pick position, and transfers the appropriate carton quantity from the pick position onto the burden carrier’s load-carrying surface. After completion of the customer-order or all required picks, the order picker steers and drives the vehicle to the customer-order staging area. The features are limited weight and carton carrying capacity, carton doublehandling, and pick positions that are one or two pick levels high. The powered burden-carrier method is only to be considered for a very smallvolume carton order-fulfillment operation. Electric Cart with a Towed Cart Method The next method is the manually controlled electric cart with a towed cart. The method includes an operator platform with forward and reverse movement, stop/start controls, and a steering mechanism that is connected to a steering wheel; an electric rechargeable battery; an electric drive motor that is connected to a drive wheel or wheels; and a four-wheeled cart with tow hitch or hook or a roller frame.



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The electric cart with a towed cart handles less weight and carton quantity, can work in a narrow pick aisle, has a shorter end-of-aisle turning requirement, has a smaller electric rechargeable battery, pulls one cart, and requires a lower investment. Electric Pallet Truck Method The next method is the manually controlled electric pallet truck. The manually controlled electric pallet truck is referred to as a low-lift powered pallet truck. The vehicle is used in other operational activities, requires minimal employee training, and is easy to operate. The manually controlled electric pallet truck group includes the walkie pallet truck; the walkie/end-rider pallet truck; the mid-control rider pallet truck; the remotecontrolled pallet truck; the elevate-the-operator-and-pallet-load pallet truck; and the operator-steps-on-the-truck pallet truck. To improve operator safety and employee productivity, most manually controlled electric pallet trucks are available as double pallet-length pallet trucks and as side-rider pallet trucks. Chamfered Pallet For efficient order-picker empty-pallet pickup and full-pallet deposit, a pallet with chamfered bottom deck boards is preferred. The chamfered pallet minimizes pallettruck fork entry and exit problems or hang-ups. Each bottom deck board’s top edges are angle-cut. The angled or chamfered edge minimizes pallet-truck wheel hang-ups. When an employee pushes a pallet truck into a standard square-cut pallet opening, there is a good possibility of the fork tip and front wheel hanging up on the bottom deck board. This pushes the pallet across the floor surface. This feature causes low employee productivity and possible equipment, building, or product damage. Entry Wheels The next pallet-truck option is fork entry wheels. Each fork entry wheel is a hardened-plastic wheel set that has an axle and bearing and is located directly under each load-carrying fork tip. The fork entry wheel is almost 2 inches above the floor. This pallet-truck wheel elevation matches the pallet top-surface exterior deck-board elevation above the floor. As an employee pushes the pallet-truck forks with fork entry wheels into the pallet fork opening, the fork entry wheels come in contact with the pallet bottom-exterior deck board and easily roll over them. Without the fork entry wheels, the fork load wheels ride on the floor and become jammed against the pallet bottom-exterior deck board, which pushes the pallet over the floor. With this situation, the pallet-truck load-carrying wheels push the pallet forward without entering the fork opening, resulting in low employee productivity and potential building and equipment damage. Backrest The next pallet-truck option is the pallet-truck backrest. The backrest is a welded and coated metal structural member that is attached to the load-carrying fork base. The standard pallet-truck backrest is made from 5/16-inch thick steel members. The members cover the two forks’ overall span and are available at 48 and 60 inches high.


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With the backrest, as your employee pushes or pulls a pallet truck with a pallet across the travel path, the high backrest reduces potential carton damage by minimizing the likelihood of cartons falling from the pallet load. Fork Tips The next pallet-truck consideration is the type of fork tip. Options are standard fork tips and extended fork tips. For additional fork information, we refer the reader to the powered-fork section in this chapter. Walkie Single or Double Pallet Truck The first manually controlled electric pallet-truck method is the electric walkie single or double pallet truck. This truck is available as a pallet truck with a set of forks that have the length to handle one or two pallets. The powered walkie pallet-truck control and steering handle in the typical position is in the vertical position. The T-shaped control handlebar is at a 48 inches above the floor surface. The control and steering handle is pulled forward and down to the pallet truck’s front end. The pallet truck’s handle has the pallet-truck forklift and lower controls, the forward and reverse movement controls, the speed controls, and the horn and emergency stop features. In the upright position, the pallet-truck handle functions as a “dead man” brake. To order-pick cartons for a single customer-order, an employee lowers the pallettruck forks and moves the pallet truck forward. The pallet-truck forks move into a pallet-fork opening. With the pallet-truck forks full-length in the pallet opening, the employee raises the pallet-truck fork to raise the pallet above the floor surface. With the pallet in the raised position, the employee lowers the pallet-truck handle and turns the required movement-control device in the desired pallet-truck direction of travel. Your order-pick employee walks with the pallet truck from the dispatch location in the pick aisle to the first customer-ordered SKU pick position. At the appropriate pick position, the order picker stops the pallet truck’s forward movement and transfers the required carton quantity from the pick position to the pallet. After the pallet reaches a predetermined height or the order-picker has completed the customer-order portion, the order picker travels to the staging area and deposits the pallet in the area. The electric walkie pallet truck’s components are a T-shaped vehicle control and steering handle; no operator platform; the shortest overall length, which is the distance from the fork-tip end to the rear of the chassis; the shortest wheel base, which is the distance from the front drive wheel to the fork load-carrying wheels; and a short right-angle turn requirement. The disadvantages include slow travel speed and the fact that the order picker must walk. The method is used for short travel distances and brings with it an increased possibility of employee injury. The advantages are low cost, low maintenance, the shortest area for a right-angle turn, and a narrow travel path. It is easy to train employees with this method. Walkie/End-Rider Single or Double Pallet Truck The second employee-controlled and electric battery-powered pallet truck is the employee-controlled and electric-powered walkie/end-rider single or double pallet



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truck. This pallet truck is available with the fork length that handles a 3000-pound pallet or two pallets with a combined total weight of 5000 pounds. A pallet truck with longer forks requires a wider turning radius and greater aisle-end turning space. The electric battery-powered walkie/end-rider pallet truck has several features. It can be used as a walkie or a rider pallet truck, and it has a handlebar with the fork raise-and-lower controls and a horn device. Most manufacturers have stabilizing casters under each front rider platform, and the truck is capable of faster travel speeds. The employee-riding platform on each pallet truck’s T-shaped handle side is the most distinguishing characteristic and operational feature. When your employee travels through the pick aisles, the employee stands and rides on the rider platform. The end-ride platform dimensions permit a normal-sized order picker to stand on a nonskid platform surface within the pallet-truck frame, or on a platform that extends outward from the end of the chassis. The nonskid end’s ride-platform surface, the metal-frame chassis, and the handlebar reduce the potential for employee injury. With the pallet-truck control and steering handle in the electric end-rider pallet truck’s center and the rider platforms on both sides or on the front, a right- or lefthanded employee can operate the vehicle. The second electric end-rider pallet truck feature is that the handlebar has the fork raise-and-lower controls, the horn device, and the E-stop device. This control handlebar serves to improve operator safety and employee productivity. The control bar provides a handgrip for your order picker. This handgrip improves your order picker’s ability to stand and maintain balance on the end-rider pallet-truck platform. This feature improves order-picker safety. During the pallet board pickup or deposit transaction, as your order picker is standing on the end-rider platform, the pallet-truck handlebar fork is activated by pushing a button. The button permits your order picker to raise or lower the pallettruck forks without releasing the grip on the steering handle. This feature improves employee productivity. The third important end-rider pallet truck features are the stabilizing casters that are under each corner or at both ends of the rider platform. Each stabilizing caster is a swivel-type caster with a 4-inch diameter hardened-plastic wheel on an axle. When your order picker is riding on the end-rider platform and the travel path requires a left- or right-hand turn, as the pallet truck makes the turn these stabilizing casters ensure that the pallet truck’s end-rider platform remains balanced in relation to the floor surface. This feature reduces accidents, improves operator safety, and minimizes damage to the pallet truck or floor surface. To operate an electric battery-powered end-rider pallet truck as an order-pick vehicle, the order-picker activities are similar to the activities with an electric walkie pallet truck, except for two activities. These activities are (1) during empty-pallet pickup or full-pallet deposit, the order picker remains on the vehicle, and (2) during pick-aisle travel between two customer-ordered SKU pick positions, the order picker walks in the aisle or rides on the vehicle platform. The disadvantages are increased cost, increased weight, employee training, and a wider right-angle turning aisle. The advantages are improved operator productivity


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and safety, faster travel speeds, and greater travel distance; the truck can be used as a walkie or a rider truck, and can operate in a narrow aisle. Mid-Control Rider Single or Double Pallet Truck The next employee-controlled and electric battery-powered pallet truck is the employee-controlled and electric battery-powered mid-control rider pallet truck. The employee-controlled and electric battery-powered mid-control rider pallet truck is available as a single pallet truck or a double pallet truck. The mid-control rider pallet truck’s unique features are an operator platform in the middle of the pallet-truck chassis, between the drive motor and forks; a standard full-height pallet load backrest; and a fixed T-shaped upright pallet-truck control and steering handle. The first mid-control rider-platform pallet-truck feature is the operator platform in the pallet truck’s middle. The operator platform is located between the pallet load backrest with forks and the battery compartment. This open space is approximately 15 to 16 inches wide and is equal in width to the full pallet-truck chassis. From the operator platform, an order picker has direct access to the pallet-truck steering and control handle, and has a nonskid floor surface and protective bumpers on the backrest side. The mid-control pallet truck requires a wider right-angle or pickup/deposit transaction aisle, and wider intersecting aisles. The intersecting aisle permits the pallet truck to travel from one pick aisle to an adjacent pick aisle. The second mid-control rider pallet truck feature is the standard full-height pallet backrest. The full-height pallet backrest is located between the forks and the operator platform. The pallet backrest runs the full width and height of your pallet, has welded and coated hardened-metal members, and has operator-platform metal members. During pallet-truck transport from the pick area to the customer-order staging area, when the pallet truck is traveling in a quick-stop manner in the pick aisle, the pallet backrest restricts cartons from moving forward into the operator platform. This feature improves employee safety and reduces carton damage. The third electric battery-powered mid-control rider-platform pallet-truck component is the T-shaped steering and control handle. The T-shaped steering and control handle extends upward from the drive-motor chassis and is angled toward the operator platform. At the pallet-truck steering handle are fork raise-and-lower controls, complete pallet truck forward and reverse movement controls, and a horn. The electric battery-powered mid-control rider-platform pallet truck has the greatest overall length and the longest wheel base dimension. These two features require that the electric battery-powered mid-control rider-platform pallet truck have the longest right-angle empty-pallet pickup or full-pallet deposit turning radius, and the longest intersecting aisle width. When operating the mid-control pallet truck as an order-pick vehicle, the orderpicker activities are similar to those activities with an electric walkie pallet truck. The exceptions are that during empty-pallet pickup or full-pallet deposit, the order picker remains on the vehicle, and during pick-aisle travel between two customerordered SKU pick positions, the order picker rides on the vehicle platform. The disadvantages are cost, increased weight, and additional employee training. To pick up an empty pallet, the truck is driven in reverse; the truck requires the



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widest right-angle turning and intersecting aisle, and there is lower productivity due to walking from the operator platform and pick position. The advantages are operator productivity and safety, faster travel speeds, and greater travel distance; if travel is quickly stopped in the aisle, the truck minimizes carton damage caused by cartons falling from the pallet to the floor. Remote-Controlled Single or Double Pallet Truck The next powered pallet truck is the remote-controlled single or double pallet truck. The remote-controlled single or double electric-powered pallet truck is a sophisticated vehicle that has controls similar to those of the mid-control pallet truck, except that the vehicle’s forward and turning movements are controlled by an order picker from the pick aisle. A transmitter sends these control signals to a receiver on the vehicle. By controlling the remote-controlled single or double pallet truck’s forward movement and steering, this communication network and device allows the order picker to walk in the pick aisle between the pallet truck and pick positions. For additional information, we refer the reader to the remote-controlled tractor or tugger truck section in this chapter. Elevated Operator and Pallet Load Single Pallet Truck The next electric pallet truck is an employee mid-control electric battery-powered mid-rider pallet truck with an elevating operator platform and/or a pallet-carrying set of forks. The vehicle’s design and operating characteristics are the same as for the mid-control pallet truck with two possible exceptions: one model has the operator platform elevate an employee to reach an elevated pick position, and another model has the employee platform and the pallet-carrying set of forks elevate. The ability to elevate approximately 30 to 48 inches above the floor reduces an order-picker’s need to reach for a case from the rear of the second-level pick position. During pick-aisle travel on a manual mid-control electric battery-powered pallet truck with an elevating operator platform and a pallet-carrying set of forks, the order picker stops the pallet truck at the required pick position. A pick instruction is received for a carton from an elevated pick position, and, to reduce the reach height, the order picker has the ability to elevate the operator platform and pallet. For additional information, we refer the reader to the mid-control electric batterypowered mid-rider pallet truck section in this chapter. Operator Step Platform on a Double Pallet Truck The next electric double pallet truck is a manual mid-control electric batterypowered mid-rider pallet truck with a step platform. The vehicle’s design and operating characteristics are the same as those of the mid-control double pallet truck with one exception. The exception is a step platform that allows the order picker to step onto an elevated step to reach a case from the rear of the secondlevel pick position. During pick-aisle travel on a mid-control electric battery-powered mid-rider pallet truck with a step platform, the order picker stops the pallet truck at the required pick position. If the pick instruction is to pick a carton from an elevated pick position, to reduce the reach height the order picker has the ability to step onto the platform.


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For additional information, we refer the reader to the mid-control electric batterypowered mid-rider pallet truck section in this chapter. Side-Rider Single or Double Pallet Truck The next human-controlled and electric battery-powered pallet truck is the side-rider employee-controlled and electric battery-powered pallet truck. This pallet truck is available with fork lengths that can handle one pallet or two pallets. The employee-controlled and electric battery-powered side-rider pallet truck’s features are a protected operator platform that is set to one side of the pallet truck, behind the battery compartment; a swivel steering handle that extends upward and is angled toward the operator platform; and a separate pallet-truck control device that extends upward and is angled toward the operator platform. The pallet truck’s operator platform has sufficient space to allow the operator to sit or stand. In the operator platform area, the pallet-truck floor has a nonskid surface, and there is padding on the protective wraparound side. These features improve operator safety. The second characteristic for the employee-controlled and electric battery-powered side-rider pallet truck is the separate pallet-truck control handle device. The pallet-truck control handle extends upward and is angled toward the operator platform area. In this position, the operator has easy access to all pallet-truck movement controls, fork elevating and lowering controls, and the horn. This feature ensures that the operator has control of the pallet truck. The third employee-controlled and electric battery-powered side-rider pallet truck feature is the swivel steering device or stick. In the operator platform area, the pallet truck travels in the same direction that the stick points. The electric battery-powered side-rider pallet truck has an overall length of 88 inches, with a 36-inch-wide chassis and a 51-inch-long wheel base. The human-controlled and electric battery-powered side-rider pallet truck, when used as an order-pick vehicle, has the same operational characteristics as the midcontrol electric-powered pallet truck. The disadvantages are that the truck requires an employee’s acceptance, and has pallet-truck controls that are separate from the vehicle steering stick or device. The advantages are that there is a protective operator platform area and that the operator sits or stands. Employee-Controlled and Electric Battery-Powered Pallet Trucks: Key Components There are several key components of an employee-controlled and electric batterypowered pallet truck as a carton order-picker vehicle. An electric rechargeable battery is the power source; this requires a battery charger. The first battery and batterycharger feature is volts. The battery voltage is a battery’s electric power. A pallet truck with a higher voltage travels at a higher speed and moves up grades and lifts and lowers pallets at a faster speed. A pallet truck with a lower voltage has less electric power, slower pallet-truck travel speed, and slower pallet loading speed. If your order-fulfillment operation has long travel distances between the pick area and the customer staging dock area, a 24-volt battery is the preferred battery for your



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pallet truck. If your order-fulfillment operation has short travel distances between the pick area and the customer staging dock area, the 12-volt battery is the preferred battery for your pallet truck. The second important feature is ampere hours. A battery with a high amperehour rating provides electric power to operate a pallet truck for a longer period of time. A battery with a low ampere-hour rating provides electric power to operate a pallet truck for a shorter period of time. Pallet trucks that operate for 4 to 5 hours in an 8-hour shift and travel a short distance are candidates for a low ampere-hour battery. Pallet trucks that operate for 7 to 7 1/2 hours in an 8-hour shift and travel a short travel distance are candidates for a high ampere-hour battery. The third important feature is connector types. When your electric-powered pallet-truck and forklift-truck fleet has batteries with several different voltages, each battery voltage group (12-, 24-, and 36-volt) should have a different type, shape, and colored battery connector. This different shaped and colored connector arrangement reduces battery-charging errors (a low-voltage battery hooked up to a highvoltage battery) and damage (or cooking) that occurs when a battery is hooked up to a battery charger with a different voltage. The fourth important feature is the battery charger cable length. When your pallet-truck electric-battery charging area is one pallet truck wide, your cable has a medium length. With this arrangement, the pallet truck’s battery compartment is positioned a short distance from the battery charger. When your pallet-truck electric-battery charging procedure involves two pallet trucks with interlocking forks, your battery charger should be long. A length of 10 feet is sufficient to connect the battery charger to the battery in the pallet-truck compartment. In the previously mentioned pallet-truck electric battery charging options, when your cable is not connected to the battery in the pallet truck, your battery charging station should have an open, flat shelf space or hook to hold the unused cable. To minimize risk of battery damage, a common practice is to have the battery chargers elevated and secured on a shelf, stand, or decked pallet rack, or to have one employee assigned the responsibility to connect the battery charger cable to the pallet-truck battery cable. Pallet-Carrying Forks The next components of the electric-powered pallet truck are the pallet truck’s two load-carrying forks. The pallet truck’s two forks extend from the rear of the powered pallet-truck backrest or battery compartment forward to the required length. The fork length handles the pallet depth or stringer length. The electric-powered pallettruck fork designs are the extended fork-tip design with standard width and the overall length with a standard fork tip. The standard-tip forks are the first electric-powered pallet-truck forks. Each standard-tip fork is 9 inches wide. Between the two forks is an open space, which is the internal space between the two forks. The most common internal open-space dimension between the two forks is 4 feet, 9 inches. This internal open space between the two forks allows the pallet truck’s set of forks to enter the pallet-fork opening.


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With each fork on one pallet interior-stringer side, during travel in the pick aisle this feature provides good pallet balance. The distance to the outside of the two forks is a standard 22 to 27 inches. This overall pallet-truck fork dimension allows the pallet-truck forks to enter the pallet. From the pallet-truck fork’s load-carrying wheels, the standard-tip forks’ end extension is 9 to 10 inches. This fork-length dimension allows each pallet truck’s loadcarrying wheel to sit between the two bottom deck boards and to provide loadcarrying support for the pallet. The second powered pallet-truck fork design is the extended-tip fork design. Each pallet-truck fork is 10 inches wide with an open space between the two forks. The open space between the two pallet-truck forks is 4 to 8 inches wide. This open space between the two forks allows the pallet truck’s two forks to enter the fork opening, and provides space for the pallet board’s interior stringer. The distance to the outside of the two forks is 23 to 28 inches. The overall pallettruck fork dimension allows the pallet-truck forks to enter the pallet fork opening between the two exterior stringers, and to support the pallet. The extended-tip forks are used on double pallet trucks. At the fork tip’s end, the extended fork tip is thinner and narrower to provide the extended-tip fork with longer wear and to guide the pallet-truck forks into the pallet fork openings more easily. Fork Length The next powered pallet-truck design consideration is the fork length. This length is determined by the number of pallets carried per trip, the pallet stringer length or pallet depth, and the corresponding spacing for the pallet bottom and top-deck board opening. The two powered pallet-truck fork designs include the standard-tip fork design with six fork lengths: 36, 42, 48, 54, 60, and 69 inches. The 36-, 42-, and 48-inch forks handle one pallet. The 96-inch forks handle two standard 48-inch long pallets. The extended-tip fork design has three fork lengths: 84, 93, and 96 inches. The 96inch forks handle two standard 48-inch pallets. Important Electric Pallet-Truck Operational Features When we look at the electric pallet-truck group, the order-pick operational features are overall vehicle length, wheel base, maximum fork height, right-angle or transaction turning radius, grade clearance, maximum grade, load weight and carrying capacity, and travel direction. Overall Vehicle Length The first electric pallet truck’s feature is the overall vehicle length. The powered pallet truck’s overall length is the distance between the fork tip and the pallet-truck front chassis. The overall length varies by pallet truck. The various electric pallettruck lengths are the walkie pallet truck, with a length ranging from 65 to 89 inches; the walkie/end-rider pallet truck, with a length ranging from 87 to 138 inches; the side-rider pallet truck with standard forks, with a length ranging from 76 to 136 inches; the side-rider pallet truck with extended-tip forks, with a length ranging from 123 to 136 inches; the mid-control rider pallet truck with standard forks, with a



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length ranging from 89 to 149 inches; and the mid-control rider pallet truck with an extended-tip forks, with a length ranging from 137 to 149 inches. Overall length is an important factor in determining the electric battery-powered pallet truck’s turning transaction or right-angle turn radius. A shorter electric batterypowered pallet-truck means a shorter turning radius, which means a narrower rightangle turning aisle and intersecting aisle. A longer electric battery-powered pallettruck means a wider turning radius, which means a wider right-angle turn area and intersecting aisle. Wheel Base The second electric battery-powered pallet-truck feature is the wheel-base length. The electric battery-powered pallet-truck wheel base is the dimension between the steering-wheel center and the fork load-carrying wheel center (with the forks in the elevated position). The electric battery-powered pallet truck’s wheel base is important because it affects the pallet-truck turning radius and the pallet-truck grade clearance. A walkie pallet truck’s wheel base ranges from 45 to 69 inches. A walkie/end-rider pallet truck’s wheel base ranges from 50 to 110 inches for standardtip forks and 82 inches for extended-tip forks. A side-rider pallet truck’s wheel base ranges from 50 to 110 inches for standard-tip forks and 82 to 84 inches for extendedtip forks. A mid-control rider pallet truck’s wheel base ranges from 68 to 128 inches for standard-tip forks and 100 inches for extended-tip forks. The wheel-base length is an important factor that determines the electric batterypowered pallet truck’s right-angle or transaction turning radius. A shorter wheel base has a shorter right-angle turning radius and a longer wheel base has a wider right-angle turning radius. The short turning radius means a narrower right-angle turn requirement, a narrower intersecting-aisle turn requirement, and a pallet truck that handles one pallet. The longer turning radius means a wider right-angle turn requirement, a wider intersecting-aisle requirement, and a pallet truck that more than likely handles two pallets. The electric battery-powered pallet truck with a shorter wheel base has a highergrade clearance. The pallet-truck grade clearance is the steepest grade percentage that the pallet truck can climb without under-clearance problems. Pallet-truck underclearance problems occur at two locations: (1) at a ramp or dock leveler’s top, as a pallet’s bottom deck members become hung up; or (2) at the ramp or dock leveler’s bottom, as the load-carrying forks or pallet bottom deck boards strike the floor surface. The pallet truck under-clearance is the distance between the floor surface and the lowest part of the pallet truck’s undercarriage or the bottom deck boards. The single pallet truck has a short wheel base and travels without hang-ups over standard dock plates and ramps. Most dock levelers or ramps have an angled peak at the top. A double pallet truck with a long wheel base has a greater potential for hang-ups on the ramp or dock leveler travel path caused by the pallet-truck underside or pallet bottom deck boards. Maximum Fork Height The third important electric battery-powered pallet truck feature is the maximum fork height, which includes the lowered-fork elevation above the floor surface and the maximum elevation of the raised forks above the floor surface.


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With most electric battery-powered pallet trucks, the lowered-fork elevation above the floor surface is 3 1/4 inches, and the maximum raised-fork elevation above the floor surface is 9 1/4 inches. The minimum and maximum fork-height elevations, along with the electric battery-powered pallet truck’s wheel base, affect the electric battery-powered pallet truck’s grade clearance. Turning Transaction Radius The fourth important electric battery-powered pallet-truck operation feature is the turning radius. The turning radius is the minimum distance between two racks or workstations that is required to make a turn and complete a pallet pickup or delivery transaction. The turning radius is the distance from the load-carrying wheel ends and the pallet-truck chassis’s turned front end. The electric battery-powered pallet truck’s turning radius, depending on the truck design and fork length, may be as follows. Walkie pallet-truck wheel bases range from 58 to 82 inches, walkie/endrider pallet-truck wheel bases range (for standard-tip forks) from 71 to 130 inches and (for extended-tip forks) to 103 inches, side-rider pallet-truck wheel bases range (for standard-tip forks) from 70 to 130 inches and (for extended-tip forks) from 100 to 104 inches, and mid-control rider pallet-truck wheel bases range (for standardtip forks) from 82 to 142 inches and (for extended-tip forks) to 100 inches. The walkie pallet truck has the shortest turning radius and the mid-control pallet truck has the widest turning radius. This means that the walkie pallet truck operates in the narrowest aisle and that the mid-control pallet truck requires the widest aisle. Maximum Grade The next characteristic is the maximum grade. The electric battery-powered pallet truck’s maximum grade is the steepest-grade ramp or dock-plate slope that an electric battery-powered pallet truck can climb without a deck board or vehicle chassis’s underside becoming hung up. The electric battery-powered pallet truck’s maximum grade depends upon the pallet-truck length: for a walkie pallet truck with a 5000pound pallet, the grade is 5%; for a walkie/end-rider pallet truck with a 4000-pound pallet, the grade is 5%; for a side-rider pallet truck with a 4000-pound pallet, the grade is 10%; and for a mid-control rider pallet truck with a 6000-pound pallet, the grade is 10%. With no pallet the grade is 15%. Pallet-Truck Load Weight The seventh electric battery-powered pallet-truck operational feature is the pallettruck load-carrying capacity. The pallet-truck load weight includes pallet weight, pallet-truck weight, battery weight, and operator weight for a rider truck. The four weight factors are operator weight, which is an employee’s maximum weight; pallet load weight, which is the maximum weight for your heaviest pallet load; battery weight, which is per your battery specifications; and truck weight. The pallet-truck load weight is the weight that the pallet-truck wheels are required to support, and is the weight that is placed onto the floor surface. A pallet truck with a low weight has fewer pounds per square foot, which lowers the required floor strength and construction cost. To ensure that an elevated floor’s surface



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supports your pallet-truck load weights, you provide the building architect with the pallet-truck design data: truck weight, including battery, maximum pallet load, and heaviest operator; wheel face and diameter; and total weight portion that is supported by each pallet-truck wheel. From this information, the architect or structural engineer determines the requirements for ground or elevated-floor surface support members, floor thickness, re-bar thickness and number, and other elevated-floor construction criteria. The electric pallet-truck load weights when handling a stringer pallet or pallets are as follows. For a standard-fork walkie pallet truck, the range is from 1210 to 1286 pounds. For a walkie/end-rider pallet truck, the ranges are from 1326 to 1540 pounds with standard forks (1345 to 1605 pounds when handling two pallets), and from 1323 to 1619 pounds with extended-tip forks (1583 to 1679 pounds when handling two pallets). For a side-rider pallet truck, the ranges are from 1685 to 1899 pounds with standard forks (from 1704 pounds to 1964 pounds when handling two pallets), and 1765 to 1823 pounds with extended-tip forks (from 1825 to 1823 pounds when handling two pallets). For a mid-control rider pallet truck, the ranges are from 1685 to 1899 pounds with standard forks (from 1704 to 1964 pounds when handling two pallets), and 1882 to 1978 pounds with extended-tip forks (from 1942 to 2038 pounds when handling two pallets). Load or Weight-Carrying Capacity The next operational feature is the load or weight-carrying capacity. The weightcarrying capacity is the maximum pallet weight that the hydraulic pump and the system are able to raise and support. The pallet weight carrying capacities are as follows. A walkie pallet truck has a 5000-pound capacity. A walkie/end-rider single pallet truck has a 6000-pound capacity, and a double pallet truck has an 8000-pound capacity. A side-rider single pallet truck has a 6000-pound capacity, and a double pallet truck has an 8000-pound capacity. A mid-control single pallet truck has a 6000-pound capacity, and a double pallet truck has an 8000 pound capacity. Most electric pallet-truck manufacturers have an overload valve in the hydraulic pump system. This overload valve prevents an employee with an electric pallet truck from lifting a pallet or load that exceeds the electric pallet truck’s load weight. This feature minimizes the risk of equipment damage. Direction of Travel The final operational feature of the electric pallet truck is the direction of travel. The two options for direction of travel are (1) the set of fork leads, and (2) the operator or steering wheel leads. When the operator is located in the powered pallet truck’s front, the powered battery compartment trails the order picker. During travel in a pick aisle, the order picker has maximum control for the moving pallet truck, according to many professionals. Maximum vehicle control results from the fact that the powered pallet truck’s steering is similar to the automotive steering method. With the automotive steering method, as the order picker turns right, the powered pallet truck turns right. This driving and vehicle-travel feature results in faster travel speeds; minimal product, equipment, and building damage; and minimal employee injury.


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When the operator trails the powered pallet truck, the powered battery compartment trails the order picker. During travel in a pick aisle, many professionals consider that the order picker has minimal moving pallet-truck control. Minimal vehicle control results from the fact that as the order picker turns the powered pallet truck steering handle to the right, the powered pallet truck turns to the left. This pallet truck steering method in not natural for an order picker and has the potential to result in slower travel speeds and increased product, equipment, and building damage and employee injury. Smooth and Even Finished-Floor Surface For best results, the electric pallet truck requires a smooth and even floor surface with no debris in the pick aisle and no tape or string on the floor. If tape or string is used to secure a pallet and the string or tape is thrown on the travel path, the string or tape gets threaded around the truck wheels and becomes a maintenance problem. Options and Accessories The electric pallet truck’s options and accessories are additional devices or features that are attached to the pallet truck. These devices and features have one or more objectives: to improve employee productivity; to reduce building, equipment, or product damage; to improve operator safety; and to make the electric pallet truck more flexible and capable of performing other functions. The electric pallet truck’s options and accessories are fork entry wheels, a clipboard document holder, a pallet stop, a high-speed control, a quick-pick handle, a fire extinguisher, an audible horn, a skid adapter, stabilizing casters, and a flashing travel light. Fork Entry Wheels. The first electric pallet-truck options are the fork entry wheels. Each fork entry wheel has a hardened metal bracket, an axle and axle bearing, and a wheel with a hardened plastic cover. Each pallet-truck fork has an entry wheel at the tip. With the fork entry wheel located at the fork tip, as the pallet truck forks enter a pallet fork opening, the forks’ entry wheels assist the pallet-truck loadcarrying wheels in traveling over the exterior pallet bottom deck board. This feature permits quick pallet-truck fork entry into the fork openings and prevents the standard pallet-truck load-carrying wheels from pushing against the bottom deck board. When an electric pallet truck pushes against the pallet, the pallet truck pushes the pallet across the floor surface until it strikes an object. This object is an upright post or workstation, which is damaged from the moving pallet’s impact. If nails are protruding from one of the pallet’s bottom deck boards, the pallet’s movement across the floor damages the floor surface. The purposes of fork entry wheels on a pallet truck are to improve employee productivity and to reduce building, equipment, and product damage. Clipboard Document Holder. The second accessory is the clipboard document holder. Clipboards are solid plastic, metal, or wood, with a spring-loaded clip at the top. The clipboard document holder is a clipboard that is attached to the electric pallettruck operator control area. The clipboard is attached in a location that does not interfere with operator control of the electric pallet truck, allows the operator to read



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the order-pick instructions, and permits a view of the electric pallet truck travel path. The clipboard document holder improves operator productivity and enhances safety. Pallet Stop. The third optional item for the electric pallet truck is the pallet stop. The pallet stop is a hardened metal member that is attached to the base of the forks and runs the full width of the battery compartment. During the electric pallet-truck pallet-board pickup activity, the pallet stop ensures that the pallet is square on the forks and within the chassis frame limits. The pallet stop reduces product damage, equipment and building damage, and employee injuries. High-Speed Control Button. The next electric pallet-truck option is the highspeed pallet-truck travel control button. This option is a button on the mid-control rider pallet truck. During long and straight travel paths, the high-speed travel control button allows the operator to engage the control button and to ensure that an electric truck travels at the fastest possible speed over a travel path. The high-speed control button improves your employee productivity. Quick-Pick Handle. The fifth electric pallet-truck option is the quick-pick handle, which is an option for the end-rider pallet truck. When your employee uses the electric pallet truck as a carton order-pick vehicle, the quick-pick handle is an option on the pallet truck. With the quick-pick control handle in the lowered position, as the order picker walks in the aisle between the pallet truck and the pick positions, the quick-pick handle button allows the order picker to control the truck’s travel speed and forward movement from the remote location. During the carton order-pick activity, the quick-pick handle option improves your employee carton order-pick productivity and reduces employee injuries. Dry-Chemical Fire Extinguisher. The next electric pallet-truck option is a small dry-chemical fire extinguisher. The fire extinguisher is an option for mid-control rider and side-rider pallet trucks that have sufficient clear space on the pallet-truck chassis to attach a fire extinguisher. The fire extinguisher is placed in a location that gives the order picker easy access and does not interfere with the operator on the pallet truck. The fire extinguisher option improves the safety of your order-fulfillment operation. Audible Travel Horn. The next electric pallet-truck option is the audible travel horn. The audible travel horn is available on all electric pallet-truck types. When the electric pallet-truck control handle is lowered, or when the electric pallet truck is moving across the floor surface, the audible travel horn becomes activated and makes an audible sound. This audible sound alerts the order picker and other employees in the order-pick area or aisle that the electric pallet truck is ready to move or is moving across the travel path. When considering using the audible travel horn, you must evaluate the work-area noise level and the horn noise level. The audible travel horn reduces employee injury and improves safety in the pick aisle and work area. Stabilizing Casters. The next electric pallet-truck option is stabilizing casters. This option is used on an end-rider pallet truck. The stabilizing casters are placed under each rider platform’s corner. Each stabilizing caster is a swivel-type caster with a 4-inch


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diameter hardened plastic wheel on an axle. When an order picker is riding on the endrider platform and the travel path requires a left- or right-hand turn, as the pallet truck makes the turn, these stabilizing casters ensure that the pallet-truck end-rider platform remains balanced in relation to the floor. This feature reduces the risk of accidents, improves operator safety, and minimizes equipment and floor surface damage. Traveling Flashing Lights. The final electric pallet-truck option is the traveling flashing light. The traveling flashing light is available on the rider pallet-truck types. When the electric pallet-truck control handle is lowered, or when the electric pallet truck is moving in a pick aisle, it activates a flashing light. This flashing light is a signal to the operator and other employees in the pick aisle that the electric pallet truck is ready to move or is moving in the pick aisle. When considering this option, you should evaluate the light conditions in the pick aisle and the mounting location on the electric pallet truck. The flashing light location on the electric pallet truck should not interfere with the operator or become an item that is frequently damaged. The traveling flashing light reduces employee injury and improves safety in the pick aisle and work area. Empty Pallet Stack. In a pallet-truck carton order-fulfillment operation, having an empty pallet stack is an important design consideration. An available pallet stack keeps order pickers from making unproductive trips to search for empty pallets, reduces damage to equipment from picking up an empty pallet, and reduces product damage from an employee removing a partially depleted pallet from the floor. The empty pallet-stack options are a stack of empty pallets or a pallet-dispensing machine. The empty pallet stack that is placed by a forklift truck is very simple to operate and control. The empty pallets are stacked in an assigned area and, as required, the order picker removes a pallet from the stack. The disadvantages of the method are that the order picker lifts a pallet and that high pallet stacks can fall. The advantages are no capital cost and no maintenance expense. The second option is the pallet dispenser-machine method. With this method a forklift truck places empty pallets into the dispensing machine’s top. When the pallet dispenser is full, the safety gate secures the pallet stack in the tower. As the order picker removes a pallet from the floor-level pallet board take-away position, it becomes empty. The pallet dispenser tower has a sensing device that directs a motordriven device to lower an empty pallet onto the floor position automatically. The pallet dispenser machine is one or two pallets deep. The disadvantages are increased investment and additional forklift operator time to travel and deposit the pallet into the tower. The advantages are increased management control, reduction in unproductive order-picker empty-pallet search time, and reduced rack and equipment damage. Description of Pick Activity When your order-pick operation uses the electric pallet truck as a carton order-pick vehicle, the order-pick instruction options are voice direction, printed labels, selfadhesive labels, and an RF device. After your order-pick employee is given customer-



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order picking instructions, the order picker has the pallet truck pick up an empty pallet. With the pallet on the truck’s forks, the order picker drives the pallet truck to the first assigned pick position. Per the pallet-truck design and customer-order pick instruction method, your employee travels through the pick aisle and stops at the appropriate pick positions. At the required pick positions, the order picker transfers the appropriate carton number from the pick positions onto the pallet. During the pick activity, the order picker with mixed-sized cartons builds a pallet to a predetermined height, or completes all customer-order pick instructions. With the full pallet, your order picker on the pallet truck travels from the pick aisle to the outbound shipping area. In the outbound shipping area, your order picker’s options are to identify the pallet with the customer identification and set it down in the outbound staging area, or load the pallet onto the customer-order delivery vehicle.

ORDER-PICKER ROUTING PATTERNS The next employee order-fulfillment factor is the order-picker routing pattern. The order-picker routing pattern guides the order picker through the pick aisle to the required customer-ordered pick positions. Each order-picker routing pattern follows the pick position and aisle layout. There are many order-picker routing patterns for your carton order-fulfillment operation. When your order-picking routing pattern matches the carton characteristics, throughput volume, and pick area layout, the implemented order-picker routing pattern’s advantages are obtained by your order-fulfillment operation. This match of the order-picker routing pattern with these factors provides you with the opportunity to obtain the best order-picker productivity and the most accurate picks, as well as on-schedule activity and on-budget activity. The various order-picker routing patterns for an employee walking to the pick position are: no routing pattern; the sequential routing group, which includes the single-side pattern, the loop pattern, the horseshoe or U-pattern; the Z-pattern; the block pattern; and the stitch pattern.

NO ROUTING PATTERN When there is no routing pattern, the order pickers determine their own pick path through the pick-area aisles. This method is not considered for implementation in a carton order-fulfillment operation because it offers no advantages. The disadvantage is extremely low employee productivity; this can occur because the employee may walk the same path twice, the employee may suffer from fatigue from increased walking movement, and the employee may spend unproductive time trying to locate the SKU pick position in the pick aisle.

SEQUENTIAL ROUTING PATTERNS In the carton order-fulfillment industry, the sequential order-picker routing patterns are the preferred and most commonly used patterns. The sequential order-picker routing pattern’s fundamental characteristic is that there is an arithmetic progression


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to the pick-position numbers through each pick aisle. This means that the lowest carton (or SKU) pick-position number (0 or 1) is at the entrance to the pick aisle, and the highest pick-position number (99 or 100) is at the exit of the pick aisle. In these patterns, the order picker starts at the first required SKU pick position in the pick aisle and, as the order picker travels down the pick aisle to the end, the next required SKU pick position is as close as possible to the previous SKU pick position. In your carton order-fulfillment operation, a sequential order-picker routing pattern provides you with an efficient and productive order-picker routing group. The advantages are reduced employee unproductive time (two or more trips down a pick aisle), reduced employee fatigue, minimized employee confusion, and increased employee productivity. The order-picker routing pattern’s basic elements include the following. Pickposition numbers that end with an even digit are located on the pick aisle’s right side, and pick-position numbers that end with an odd digit are located on the pick aisle’s left side. Arithmetic progression is used throughout the pick aisle. The order picker is kept in the pick aisle as long as possible. There is improved SKU hit concentration and hit density. The order pickers begin in the fast-moving high-cube section. The method divides the pick activity, keeps the pick aisles clear, maintains good housekeeping, and requires a well-illuminated facility. Order-Picker Aisle Travel In an order-fulfillment operation, an order-picker travels through the pick aisle to complete a customer-order pick transaction. The options are traveling straight in and out of each required pick aisle, and traveling in a serpentine fashion through the various picks aisles. Straight in-and-out Method The first method is the straight in-and-out method. With this travel method, per the customer-ordered SKUs, the order picker travels in the pick aisles. During the pickaisle travel, the order picker completes all required pick transactions. After completion of these pick transactions, the order picker turns the pick cart or pallet truck in the pick aisle and walks back through the aisle to the entrance. Leaving the aisle entrance, the order picker walks to the adjacent aisle and enters the pick aisle. During travel in the pick aisle, the order picker completes all pick transactions to complete the customer-order. With the straight in-and-out method, each pick aisle’s lowest pick-position number starts at the main aisle’s end and arithmetically progresses to the highest pick-position number. The disadvantages are order-picker double travel in each pick aisle, low productivity due to walking past pick positions that do not require picks, an aisle width that must permit a cart or pallet truck turn in the aisle, and two order pickers traveling in different travel directions. Serpentine Travel Method The second method is serpentine travel through the various pick aisles that have customer-ordered SKU pick positions. This method has the order picker travel in



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the required pick aisles to complete the customer order. During the first pick-aisle travel, the order picker completes all required pick transactions. After all pick transactions completed, the order picker exits the pick aisle and enters the second pick-aisle entrance. Entering the second pick aisle, which is adjacent to the first pick aisle’s end or highest number, the order picker walks and completes all pick transactions to complete the customer order. With the serpentine method, each pick aisle’s lowest pick position number starts at the aisle entrance and arithmetically progresses to the highest pick-position number at the exit. There are several advantages to this method. An order picker makes one trip through each pick aisle. There is improved productivity due to walking past pick positions that require picks. The aisle width is at a minimum, and there is a low probability of two order pickers in one pick aisle. Single-Side Pattern The first sequential order-picker routing pattern is the single-side order-picker routing pattern. This routing pattern directs the order-picker through the pick aisles. These aisles are between two rack rows with SKU pick positions. These pick positions contain SKUs that appear on a customer-order instruction form. The singleside order-picker routing pattern method’s options are a single side with one order picker and a single side with two order pickers. Single-Side Order-Picker Routing Pattern for One Picker The single-side order-picker routing pattern for one order picker has one order picker travel down the pick aisle and withdraw SKUs from the pick positions on the pick aisle’s right side; the order picker then turns at the pick aisle’s end and travels down the pick aisle on the left side, withdrawing SKUs from the pick-aisle pick positions. Single-Side Order-Picker Routing Pattern for Two Pickers The single-side order-picker routing pattern for two order pickers has the first order picker travel down pick aisle A and withdraw SKUs from the pick positions on pick aisle A’s right side; at the end of pick aisle A, the order picker transfers to pick aisle B. In pick aisle B, the first order picker withdraws SKUs from the pick positions on pick aisle B’s right side. The second order picker travels down pick aisle A and withdraws SKUs from the pick positions on pick aisle A’s left side; at the end of pick aisle A, the picker transfers to pick aisle B. In pick aisle B, the second order picker withdraws SKUs from the pick positions on pick aisle B’s left side. The single-side order-picker routing pattern is used to withdraw SKUs from floor-stack or rack positions that contain pallets or hand-stacked cartons. The pattern is commonly used in a carton order-fulfillment operation that has an employee walk or ride to the pick position. With fast- and slow-moving SKUs randomly located in the pick-aisle pick positions, the single-side order-picker routing pattern’s disadvantage is low orderpicker productivity. This feature is due to a high probability of unproductive travel or walking distance between two pick positions and, to complete a customer-order, an order picker travels twice or two order pickers travel once down the pick aisle to withdraw cartons from both of the pick aisle’s sides.


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The advantages are easy implementation in a new or existing order-fulfillment operation; very little employee training; excellent employee productivity if an order picker withdraws a large carton number from one pick position; reduced unproductive time spent walking across the pick aisle to select and place SKUs onto the cart, if an order picker is picking onto towed carts; and a productivity that is equal to the productivity that is achieved from the other order-picker routing patterns, if the rack and aisle layout dead-ends into a wall. Loop Pattern The next order-picker routing pattern is the loop pattern. In this routing pattern, the order picker travels down a pick aisle to withdraw SKUs from aisle A’s right-side pick positions. At aisle A’s end, the order picker transfers to aisle B; in aisle B, the order picker withdraws SKUs from aisle B’s left-side pick positions. After completing travel in aisle B, the order picker returns to aisle A and withdraws SKUs from aisle A’s left-side pick positions. After completing travel in aisle A, the order picker travels to aisle C and withdraws SKUs from aisle C’s left-side pick positions. This order-picker routing pattern is repeated until all pick transactions are completed for a customer-order, or the order picker completes the customer-order portion. The loop order-picker routing pattern is used to withdraw cartons from pick positions that are floor-stacked or in rack bays. It is best used in a carton orderfulfillment operation that has numerous different SKUs that are located in numerous aisles. The pattern is best used in the walking or riding (pallet truck or tugger with a cart train) method. If you locate fast- and slow-moving SKUs randomly in a pick aisle’s pick positions, the loop order-picker routing pattern’s disadvantages are low order-picker productivity, which is due to unproductive travel or walking distance between two pick positions, and double travel of an order picker in the same pick aisle to withdraw SKUs from both of an aisle’s sides, which has a picker pass the previously selected pick positions; and extensive employee training. If you have a high-volume carton order-fulfillment operation, good order-picker productivity is achieved by locating the fast-moving SKUs on the pick aisle’s right side and the slow-moving SKUs on the left side. With the towed cart method, the loop order-picker routing pattern reduces the unproductive time spent walking across the pick aisle to select and transfer picked cartons to the carts. Horseshoe or U-Pattern The next order-picker routing pattern is the horseshoe or U-pattern. This routing pattern has an order picker travel down the pick aisle and, at a predetermined pick location, halt in the pick aisle’s middle. At each pick-aisle halt location, the order picker has the opportunity to withdraw SKUs from the four pick positions on the pick aisle’s right and left sides. This feature provides the order picker with the opportunity to pick from eight pick positions. Until the customer-order or cube portion is completed, or the vehicle carton-carrying surface reaches a predetermined height, the pattern is followed through each pick aisle. At pick aisle A’s end, the order picker transfers to pick aisle B.



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The routing pattern is best used to withdraw cartons from floor-stacked or rack pick positions and in an order-fulfillment operation that handles customer orders and has numerous SKUs in various pick aisles. The U pattern is best for a system where an employee walks or rides to the pick position. The disadvantages and advantages are similar to the loop order-picker routing pattern. An additional disadvantage is low employee productivity resulting from the order picker stopping at predetermined pick-aisle halt locations and passing pick positions that are not required on your order-picker customer-order instruction. Z-Pattern The next routing pattern is the Z-pattern. In this routing pattern, the order picker travels once down the pick aisle between an aisle’s pick positions. The pattern directs the order picker to withdraw SKUs from the first four pick-aisle pick positions on pick aisle A’s left side, withdraw SKUs from the next eight pick-aisle pick positions on aisle A’s right side, and withdraw SKUs from the next eight pick-aisle pick positions on aisle A’s left side. Until the customer-order is completed or the pallet or cart reaches a predetermined height, this pattern is followed through the orderpick aisles. The routing pattern is used in a carton order-fulfillment operation that has an employee walk or ride to the pick position. One disadvantage of the Z-pattern is that it requires additional employee training. However, with an excellent SKU locator system, there is improved order-picker productivity because it only takes one pick-aisle trip to withdraw SKUs from pick positions on both sides of the pick aisle. With an arithmetic progression through the pick aisle, there is a reduction in unproductive time to locate the SKU pick position. This unproductive walking time is reduced by allocating fast-moving SKUs to a pick aisle’s right-side pick positions and slow-moving SKUs to a pick aisle’s leftside pick positions. Block Pattern The next order-picker routing pattern is the block order-picker routing pattern. This routing pattern has the order pickers travel once down the pick aisle between the aisle’s pick positions. The order picker withdraws SKUs from the first two pick positions on the pick aisle’s right side, and then SKUs from the two pick positions on the pick aisle’s left side. To complete the customer-order or a pallet or cart, the pattern is followed through each pick aisle. The block order-picker routing pattern is used in a carton order-fulfillment operation that uses a walking or riding order-pick method. If a carton order-fulfillment operation has a large slow-moving SKU number, one disadvantage is an increase in unproductive walking trips in the pick aisle to withdraw SKUs from the pick aisle’s right- and left-side pick positions. In this pattern, the travel distance between the halt locations has the potential to increase an order picker’s unproductive starts and stops. The pattern requires additional employee training and a good stock-locator system.


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If your carton order-fulfillment operation handles fast-moving cartons, the block routing pattern has the same advantages as the Z-pattern. Stitch Pattern The last order picker routing pattern is the stitch order-picker routing pattern. In this routing pattern, the order picker travels down the pick aisle between the pick positions. The pattern directs the order picker to withdraw SKUs from one rack bay (or pick position) on the pick aisle’s right side and to withdraw SKUs from the rack bay (or pick position) on the pick aisle’s left side. To complete a customer-order or fill a pallet or cart, this pattern is followed through the pick aisles. The stitch pattern’s disadvantages and advantages are similar to those of the Zpattern.

DISADVANTAGES AND ADVANTAGES OF ELECTRIC PALLET TRUCKS The electric pallet truck has several disadvantages. The truck requires a pallet. Per order-picker trip, one pallet handles 50 to 65 cartons, and a two-pallet truck handles 100 to 130 cartons; that involves travel time. This concept has lower productivity when compared with a conveyor. The truck requires a battery-charging area and has the potential to cause some building, equipment, or product damage and employee injury. The advantages are low investment, minimal operator training, ability to travel over inclines and declines, the ability to be used in other activities, ability to travel over long distances and on an elevated floor surface, and ability to interface with all order-pick instruction methods.

ORDER INSTRUCTION The next carton order-pick component is the order-picker instruction. The orderpick instruction method directs an order picker to the customer-ordered SKU pick position, describes the SKU, and indicates the case quantity to transfer from the pick position to the vehicle load-carrying surface or conveyor surface. With some order instruction forms, the form states the customer’s name and address.

KEEP IT SIMPLE

AND

CLEAR

The basic philosophy of any order-pick instruction method is to keep the orderpicker instructions as simple as possible. This allows the order-picker to read the instructions (or listen in one method) and clearly understand them. With a manual order-fulfillment method, these instructions are on a paper document, a label, a lighted display panel, or some combination of these; they can also be communicated vocally to the order picker. Each individual or series of characters and digits identifies a specific aisle and carton pick position in your order-fulfillment facility.



INFORMATION

ON THE

365

ORDER-PICK INSTRUCTION

The typical order-picker instruction identifies facility area or zone, pick aisle, and pick position. In most applications, the pick instruction has an alphabetic character and numeric digit combination. This combination helps reduce replenishment and order-picker errors, which result from an employee confusing the numbers. Digits are generally easier for order pickers to read and understand because order pickers in their everyday lives deal more frequently in numbers than in alphabetic characters. Numbers or digits are progressive and unlimited in quantity, but alphabetic characters are limited to the 26 letters, and to provide more than 26 pick-position identifiers, you must double or triple letters for the pick-position identification. There is potential confusion between the letter O and the digit 0 (zero) and between the letter I and the digit 1 (one). Pick Position The pick position is the most significant order-picker instruction component because, in a pick aisle, the order-picker frequently refers to the carton pick position. A pickposition printout has the largest and boldest characters or digits. Pick Level If a pick area has a shelf, hand-stacked or pallet pick positions, and a one-way truck traffic-flow pattern, an additional identification component is required in the picker instruction format. This additional component is required to identify the pick-position level. The component is an alphabetic character because there are less than 26 levels in all order-picker routing patterns. In addition, with an alphabetic character between the two numeric digits, an employee is less likely to become confused than with three consecutive numeric components. Order-Fulfillment or Pick Aisle The next most important instruction component is the pick aisle. This character or digit identifies the pick aisle that contains the pick position for a carton that appears on the order-pick instruction or customer-order document. This component is an alphabetic character. Order-Fulfillment Facility Area or Zone The order-picker instruction component that has the lowest significance is the orderfulfillment facility area or zone. If you use an order-picker instruction format for a manual sorting and checking activity, on the instruction document or label the sorting instructions have the same importance as the pick position but with a different character, a different-colored background, and a different location.


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VARIOUS ORDER-PICK INSTRUCTIONS The order-picker instruction method is matched with the proper order-pick method. The order-pick instruction methods are considered for implementation in a new or existing carton order-fulfillment operation. The order-pick instruction methods are manually printed or machine-printed paper; computer-printed paper labels, the paperless method with a pick-to-light display, bar-code scanner, or RF device; and the voice-directed method. Manual- or Machine-Printed Paper or Card Document The first order-picker instruction method is the manual- (typed or preprinted) or computer-printed paper document. This method is the simplest order-picker instruction method. This method is used in a single customer-order pick system, and in an operation with few SKUs, few customers, and a low volume. The manual paper document is a preprinted page (a single sheet with carbons) that lists all available pick positions and SKU descriptions. Each pick position and SKU description has a corresponding empty block for your customer-ordered quantity, and an empty block for the actual order-picked quantity. The manually printed document method requires an office clerk or assembly clerk to enter (write or type) in the appropriate block the number of SKUs that were ordered by your customer. When the order picker is given the document, the order picker reads the first page of pick positions and travels to the location. After an order picker removes the SKU or carton quantity from the pick position, the order picker places a mark in the appropriate empty block. The disadvantages are that the method does not cube, SKU changes are difficult, there are transposition errors and errors in picks, the method requires additional clerks, and one cannot batch-pick. The advantages are no investment, flexible order entry, and little employee training. Machine-Printed Pick Document Method The computer-printed order-pick document has the same format as the manually printed document. The significant additional advantages are easily handled SKU changes, cubing of the order-picker activity, and reduced transposition errors. The disadvantages are capital investment, print time, and standard customer-order entry time. Computer-Printed Paper Labels The next order-pick instruction method uses a computer-printed label. The computerprinted label is used in a single or batched customer-order handling method. The label order-picker instruction method has the SKU or carton pick position, SKU description, customer name and address, SKU quantity, and other required company information on the label’s front. The computer software and printer make labels in a sequence that routes the order picker through the pick aisles. These labels have pressure-sensitive self-



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adhesive backs for easy attachment to a carton exterior. After removing a carton from the pick position, the order picker removes the label from the backing, places the label onto the carton, and places the labeled carton onto the take-away device. The backing paper is discarded into a strategically located trash container. The trash container is an apron worn by the employee, or a container on the pick position or vehicle. The disadvantages include a higher capital investment and, unless a label holder is used by the order-picker, a label stack that is difficult to handle. The advantages are the ability to be used in a single or batch-pick system, clear and accurate instructions, quick and easy SKU changes, cubing of the order-pick activity, ability to be used in a high-volume operation with a large SKU number, and retail price information that appears on the label. Order-Pick and Sorting Instructions on the Label The order-picker instructions and sorting instructions (characters and digits) are the most important items on the label. If the characters or digits are small and the orderpick and sorting instructions are difficult to read, this reduces the employee productivity and increases errors. The preferred method is to give order-pick and sorting instructions equal emphasis with a different style of characters or digits, with a different-colored background, or in a different location.

PAPERLESS ORDER-PICKING METHODS The next order-picker instruction method is the paperless picking method. The paperless picking method options are manually controlled paperless picking, computer-controlled paperless picking, and voice-directed paperless picking. Manually Controlled Pick to Light The manually controlled paperless picking method is the digital-display method. The paperless picking method has a pick-to-light digital display at the pick position. When there is an illuminated light, it serves as the order-picker instruction. The pick-to-light method has the customer orders sequenced by microcomputer for the pick line. With this method, your pick employee starts at the entrance to the pick aisle or at the lowest number. Per the customer-order identification, the microcomputer activates the appropriate pick lights within each pick zone or aisle. Walking in the pick aisle to the first lit pick position, the order picker removes a carton from the pick position and presses the order-pick button that registers a pick. The pick-to-light microcomputer reduces the customer-ordered quantity on the digital display by one. If another pick is required at the same pick position, the order picker repeats the activity until the digital display indicates zero. The cartons are placed with or without a label onto the vehicle load-carrying surface or onto a powered-conveyor travel path. The pick employee walks in the pick zone to the next pick position. After all picks are completed in the pick zone, the order picker presses the pick-zone light, which activates the pick-zone pick lights for the next customer order.


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RF Device Paperless Pick The RF device paperless pick method has a computer download a series of pick instructions to a handheld or finger scanner device. As the order picker walks in the pick aisle, the RF pick-device digital display indicates the pick position. Arriving at the pick position, the order-picker directs the bar-code scanner to the pick-position bar code. With a good read, the RF device’s digital display indicates that the SKU is on the customer order, and indicates the required carton pick quantity. The order picker transfers the appropriate carton quantity from the pick position to a vehicle load-carrying surface or onto a powered-conveyor travel path. Computer-Controlled Paperless Pick The computer-controlled paperless picking method is an automated order-pick system that has a computer-controlled pick device or pick-release device. The computer transmits an order-pick impulse to the carton pick-position device to pick one carton from the pick position onto a take-away conveyor travel path. In some computercontrolled systems the order-picker device is a moving flipper. Voice-Directed Paperless Pick The last paperless pick method is the voice-directed pick instruction method, which includes a computer system and an order-picker microphone or headset. The method makes use of voice recognition and speech synthesis. With this voice-directed pick method, the order picker has an online communication with the computer. In this paperless pick method, each order picker talks to the computer through a microphone and receives verbal pick instructions from the computer through the headset. The order-picker instruction is achieved by a radio transmission, which directs the order picker to the required pick position. Arriving at a pick position, an order picker receives a customer-ordered carton quantity. The order picker transfers the carton quantity from a pick position to a vehicle load-carrying surface or onto a poweredconveyor travel path. The disadvantages are capital investment, additional employee training, and possible delays in customer orders and replenishments. With some methods, another system is required to handle nonconveyable cartons, while other methods require a bar code on the pick position. Advantages include reduced pick-instruction expense.

PICK-POSITION IDENTIFICATION In a carton order-fulfillment operation, the method used to identify the order and replenishment pick positions have a direct impact on order-picker productivity and accuracy. The order and replenishment positions are discrete identifications that appear on a carton pick-position structural-support member. An employee or a scanner’s light beam must be able easily and clearly to see the identification. The first step is to determine the information that will appear at the pick and replenishment position. The position-identification methods are to use alphabetic



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characters and numeric digits, or to use alphabetic characters and numeric digits with a bar-code label. The first option uses alphabetic characters and numeric digits to identify a pick or replenishment position; this is considered the basic method. A pick or replenishment transaction is verified by a paper document, or is a delayed entry to the inventory file. The disadvantages are that it is difficult to detect replenishment errors and that there is no check system. The advantages are that there is little expense involved in having an employee attach the identification to the position, and that it can be used with any pick method. The second option uses alphabetic characters, numeric digits, SKU description, and a bar-code label to identify the pick and replenishment positions. This method is used in a fixed pick-position facility and is considered the most sophisticated method. With the bar-code label application and a handheld scanner, the pick or replenishment transaction provides accurate online or delayed information transfer. The disadvantages are label expense, a wider or larger label, and an investment in scanning equipment and a computer program. The advantages are the detecting of transaction errors, accurate online data transfer, and a minimized employee reading requirement. The various pick or replenishment position identification methods are no method, manual printing on a carton, manually printed label placed on the pick position, preprinted self-adhesive label on a carton, human- and machine-readable cardboard or paper label in a holder, placard hung from the ceiling or embedded in the floor, digital display on the pick position or structure, and digital display on an RF device.

NO METHOD When there is no identification method, there is no marking on the pick or replenishment structural member or on the floor to identify the pick position. With this method, you rely upon your employee to match the replenishment and pick transaction instruction to a carton’s exterior markings. The disadvantages are that the SKU description or pick-order instruction document must match the vendor carton’s exterior markings, there is low employee productivity, pick errors increase, and that an employee is required to read. The advantage is no expense.

MANUAL PRINTING

ON THE

CARTON

The next pick and replenishment position identification method has an employee use paint, crayon, or chalk to write the pick-position identification numbers or alphabetic characters directly on a pick-position structure’s flat surface. This location is above, below, or to the side of the carton pick position. The disadvantages are that handwriting may be unclear or confusing, it is not easy to transfer, it is not easy to recognize, and uniform characters and digits are difficult to ensure. The advantage is that this is a low-cost method.


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MANUALLY PRINTED LABEL

ON THE

CARTON

OR

PICK POSITION

With the manually printed label on the carton method, an employee places a label or tape on a flat surface of the pick-position structure that is above, below, or to the side of the pick position. The employee writes the pick-position numbers or characters with paint, crayon, or chalk onto the label or tape. The disadvantages are unclear or confusing handwriting and identification labor expense. The advantages are improved employee productivity, low cost, easy transfer, uniform label location, and noticeability.

PREPRINTED SELF-ADHESIVE LABEL The next pick or replenishment identification method is machine-printed digits or characters on a self-adhesive label. The label is preprinted and placed by an employee in the appropriate location on the carton pick-position structure or onto the carton, pallet, or stacking frame. This pick identification is commonly used in a floor-stack pick position and is placed onto the pallet stringer or block or onto the carton that is on the bottom layer, on the left or right end. This carton is the last carton removed from a pallet or stacking frame. The self-adhesive pick-position identification group offers two options. The first uses an individual preprinted label for each digit or alphabetic character. The label sizes vary from 1/2 to 3 inches in height or width; to complete a pick-position identification, the labels are placed on the pick-position rack structure. The disadvantages are label and labor expense, uneven label placement on the structure, and the need for extra labels. The advantages are that it is easy to replace damaged labels and change the identification. With the second method, the entire pick-position identification is printed onto a label face, and the label is placed onto the pick-position structure. The disadvantages are print cost and damaged labels that are costly to replace. The advantages are there is a low label application expense, no label waste, and consistent label placement.

HUMAN-

AND

MACHINE-READABLE CARDBOARD

OR

PAPER LABEL

IN A

HOLDER

The next pick identification method is a human- and machine-readable cardboard or paper label that is inserted into a plastic label holder, which is attached to the pick-position structure. An employee secures a plastic holder to the appropriate location onto the pick-position structure. After the holder is secured by adhesive tape or a magnet on the pick-position structure, an employee inserts a preprinted label into the plastic holder. The disadvantages are label and holder expense, blurring of the pick position identification caused by some holders, and damage to a holder. The advantages are uniform label placement, uniform label printing, and reading of labels by a scanner device.

PLACARD HUNG

FROM THE

CEILING

OR

EMBEDDED

IN THE

FLOOR

The next pick-position identification method is the placard hung from the ceiling or embedded in the floor surface. The disadvantage is that, as a forklift truck completes a floor-stack transaction, there is potential damage to the identification.



DIGITAL DISPLAY

ON THE

PICK POSITION

OR

371

STRUCTURE

The digital display pick-position identification method is the most sophisticated method with an indicator light on the pick-position structure. A customer-order requires a carton from a pick position and, per the customer-order identification, the microcomputer illuminates a light that directs an order picker to remove a carton from the pick position. The disadvantages are the method’s use on a rack or shelf-pick position, capital investment, and difficulty of relocating. The advantages are clear and understandable instructions and no label or labor expense.

DIGITAL DISPLAY

ON THE

RF DEVICE

The digital display on the RF device is the next pick-position identification method. A microcomputer transfers the customer-order to the RF device. An employee with an RF scanner reads a customer-order bar code, and the RF device’s digital display shows an employee the carton pick position and the customer-ordered quantity. The disadvantages are that it is used on a rack or shelf-pick position, and that there is a high capital investment. The advantages are clear and understandable instructions and no labor or label expense.

ELECTRIC TRACTOR OR TUGGER METHOD The next carton order-pick method with a riding employee is the electric batterypowered tugger or tractor with a cart train. This is a manually controlled variablepath carton pick method. The electric battery-powered tugger with a cart train is used in a carton orderfulfillment operation that has the customer-ordered and picked cartons delivered to the customer-order delivery address on carts. The components of the electric batterypowered tugger with a cart train are a battery-powered tugger with a draw, tow bar, or hitch; a nontilt four-wheeled cart train, wherein each cart has a coupler and a hitch; and customer-order pick instructions. The tractor may have an electric rechargeable battery-powered motor. The drive train, steering, and other characteristics are similar to the electric battery-powered pallet truck. The tractor is preferred for indoor order-fulfillment operations. The tractor may also have a combustion engine that uses LP gas, gasoline, or diesel fuel. These fuelburning engines produce fumes and are best for an outdoor order-fulfillment operation. Both powered tow tractors have a coated metal or hard plastic chassis that encloses the power source and cart-coupling device at the rear, with three or four wheels to support the chassis. Most powered tow tractors have an operator platform that has the vehicle’s forward and reverse, stop, and speed controls. The tow tractor’s electric battery or internal combustion engine has the power to move, and the brake system has the power to stop, a full cart train.

VARIOUS TOW TRACTORS

OR

TUGGERS

The electric tow tractor types are walkie, walkie/rider, mid-control rider, and remote controlled.


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Walkie Tow Tractor The first electric tow tractor is the electric battery-powered walkie tow tractor. The electric battery-powered walkie tow tractor is a vehicle that does not have an operator platform. As an order picker travels through a pick aisle, by walking in the front of the vehicle, the operator steers and maintains tow tractor control. To walk with an electric battery-powered walkie tow tractor, the tow tractor’s control and steer handle are pulled downward and in front of the vehicle. A characteristic of this two tractor is that its maximum travel speed is the slowest of all the types. This slow travel speed is caused by the order picker’s walking pace; this pace sets the tow tractor’s travel speed through the pick aisle. The disadvantages are slow travel speed or employee walking pace, the need for a battery charging and changing area, and the increased possibility of employee injury. The advantages are a variable travel path, the handling of a cart train, a narrow turning area, the ability to travel up a grade, and low cost. Walkie/Rider Tow Tractor The second electric battery-powered walkie tow tractor is the walkie/rider electric battery-powered walkie tow tractor. The walkie/rider tow tractor’s characteristics are a movable control and steer handle, which is similar to that of the walkie tow tractor, and an operator’s compartment, which permits an operator to stand in a protective area. These features permit your order picker to control and walk or ride. The disadvantages are a wide turning aisle, a battery charging and changing area, and low grade clearance. The advantages are faster travel speed, a variable travel path, a greater pull-bar capacity for handling a cart train, improved employee safety, and less order-picker physical effort. Mid-Control Rider Tow Tractor The third electric battery-powered tow tractor is the electric battery-powered midcontrol rider tow tractor, which has an order-picker platform that is used to control and steer the vehicle. The operator area designs are stand-up and sit-down. The disadvantages are similar to the walkie/rider model’s, except that the midcontrol rider tow tractor requires the order picker to walk from the vehicle to the pick position. Some models are of a sit-down type, which usually has an internal combustion engine, while other models have steering similar to an automotive steering method. There is a greater pull-bar capacity for handling a cart train and improved employee safety. Less order-picker physical effort is required. Remote-Controlled Tow Tractor The next electric battery-powered tow tractor is the electric battery-powered remotecontrolled tow tractor with a cart train. This method is the most sophisticated, and provides the best carton order-picker productivity.



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A remote-controlled tow tractor is a radio-controlled tow tractor with the forward and directional movements controlled by an employee with a transmitter. The transmitter sends a signal that is received by the tow tractor’s receiver and causes the vehicle to respond. While controlling the tow tractor’s forward movement and steering, this communication network and device allows the order picker to walk in the aisle between the cart and pick position. The vehicle operation is as follows. An order picker stops the remote-controlled tow tractor at the required pick position; per the customer-order pick instruction, the order picker transfers the appropriate carton quantity from the pick position to the cart load-carrying surface. The order picker then walks to the next pick position and simultaneously has the tow tractor move to the next required pick position. The disadvantages are capital investment, with a large vehicle number requiring an additional cost for the remote control system; additional maintenance; and an approved RF wave frequency that must be tested prior to selection. The advantage is higher order-picker productivity. Tow Tractor: Key Components The electric battery-powered rider tow tractor’s key components include a coatedmetal or hardened-plastic chassis that is a protective shell for the drive motor and drive train; three to four wheels with at least one wheel as the rubber drive and steering wheel and, on each corner, two rear-support wheels; an operator control area; and a coupler and hitch. The coupler is attached to the electric battery-powered tow tractor or cart tail. The hitch is attached to the tow cart’s lead end and is secured to the coupler. The coupler and hitch devices are used to tow carts behind an electric battery-powered tow tractor. The coupler methods are manual hook-up (hook and eye, spring-loaded pin or clevis, pin and clevis, and pintle hitch) and automatic methods (the spring-loaded jaw and spring-loaded ball method and the spring-loaded jaw and counterweighted ball method). Other key components include from one to five tow carts, consisting of a deck or load-carrying surface and wheels, and controls and a steering device or T-shaped handle. There is also a pull bar with the following important factors: acceleration resistance; the coefficient of friction, resistance, or drag; rolling or pulling capacity; grade or incline or decline travel path; gross weight of a tow cart or train of tow carts; and rolling resistance. Tow-cart steering methods include caster steering, two-wheel steering, knuckle steering (two-wheel or four-wheel), four-wheel steering, and fifth-wheel steering (single or double). Turning aisles include the straight aisle, the 90º travel-path turn into an intersecting aisle, and the 180º travel-path turn in a straight aisle. Options are the same as for the electric pallet truck. The disadvantages are that the system is used only to pull carts and that it requires a wider intersecting aisle. The advantages are that a customer delivery system is a cart system, and that the tow tractor provides the best order-picker productivity.


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POWERED FORKLIFT-TRUCK METHOD The next method in which an employee rides to the pick position is the powered forklift-truck carton order-fulfillment method. The powered forklift-truck types are WA trucks, NA trucks, and VNA trucks. If the carton order-fulfillment operation handles large high-cube cartons (household appliances and rugs), the counterbalanced powered forklift truck is equipped with an attachment to handle these items. Some of these attachments are the single or double basiload and the appliance handler.

ORDER-PICKER TRUCKS OR HROS The next method in which an employee rides to the pick position is the carton orderpicker trucks or high-rise order-pick system. The carton order-picker truck is a manually controlled order-picker truck or man-up VNA vehicle that has the ability to travel vertically and horizontally through a guided aisle. To ensure maximum employee productivity, fast travel speed, and minimal equipment damage, the guided aisle is between two pick-position rows. These vehicles have an electric rechargeable battery; an operator platform with all the vehicle steering, forward and reverse, and fork elevating controls; and an operator tethering line. The vehicles also have loadcarrying forks and a securing device, three or four wheels with one wheel as the drive and steering wheel, an electric drive motor and drive train, a chassis, an elevating mast, an aisle guidance system, and options and accessories. The order-picker truck components that are similar to the electric rechargeablebattery pallet truck include an electric rechargeable battery, drive and steer and load-carrying wheels, an electric drive motor and drive train, a chassis, and options and accessories. The first unique feature is the operator platform with the entire vehicle’s steering, forward and reverse, and fork elevating controls and an operator tethering line. The operator platform has a rubber mat surface with a wire mesh or plastic barrier between the operator and the elevating masts, safety gates and a rail that surround the operator platform, and an overhead guard. The safety gates and rail devices are engaged to move with the order-picker truck or platform. The controls are a steering device, an operator and load-carrying device elevating control handle, and a forward and reverse control handle. To ensure employee safety, a tethering line is used to connect the operator to the overhead guard section. The order-picker truck has a set of forks and a claw that grabs the pallet stringer and secures the pallet to the platform (or a chain secures a cart to the operator platform). The elevating masts are located in front of the operator platform; per the operator control, the mast, operator platform, and load-carrying device raise or lower above the floor. To have high order-picker productivity, fast travel speed, and minimal equipment damage, most order-picker applications travel in a guided aisle. The aisle guidance methods are rail or mechanical, wire, tape, paint, and laser beam or electric. The mechanical guidance systems are used with some modifications on existing vehicles or in an existing or new facility. If a guidance system is considered for an existing or new facility, prior to the purchase and implementation of the system, careful



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attention is given to the floor (surface, levelness, loading, location of metal objects, and rebar). This is true for a wire guidance system.

RAIL GUIDANCE The basic rail order-picker aisle guidance system has one or two angled iron rails or a rack manufacturer’s guide rails. The angled iron rail is 4 by 3 inches or 4 by 4 inches; the manufacturer’s rail has a 3-inch base extension, which is 1 or 2 inches less. These bases are anchored to the floor along the full length of both vehicle-aisle sides. In one rail guidance system, the guide rail is on the right aisle side as the vehicle travels through the pick aisle. The guide rail is matched to the vehicle guide rollers, which are attached to the side of the vehicle, or a roller device is attached to the right side of the vehicle. The vehicle roller rides against the rail, or the rails provide vehicle travel guidance down the aisle. To assist the vehicle operator with aisle entry, and to reduce rack and vehicle damage, the end-of-aisle angled entry guides are installed on both openings of the aisle entrance. The end-of-aisle angled entry guides extend into the main traffic aisle.

AISLE ENTRY GUIDES At the main traffic aisle, the angled entry guides have a wider opening (at 7º to 10º from the aisle) and become narrower as an entry guide meets the aisle guide rail. The aisle entry guides are rounded, spring loaded, curved, or straight. In an entry, the extension outward from the rack creates a 27-inch open space. When this area is covered with a deck, it provides a good location for trash containers or a document control table. This improves safety and housekeeping.

RAIL INSTALLATION PARAMETERS In most guide-rail applications, each 4-inch angled iron side extends upward and comes in contact with the vehicle guidance rollers. To secure the guide rail to the floor, in a typical installation the rail is anchored on 8-to-9-inch centers for the entry guides and for the first 12 inches into the aisle. After the first 12 inches into the guide aisle, the anchors do not receive as much pressure because of the order-picker truck alignment. This permits the anchors to be placed on 24-inch centers. To provide smooth travel in the aisle and reduce guide-roller wear, at the locations where two angled iron sections are joined together, the angled iron is ground smooth and painted with a safety-approved colored coating. The rail-guidance systems include double-rail guidance systems (elevated and floor-mounted rails and rack-mounted rails) and single-rail guidance systems (mounted and rack mounted). Double-Rail Guidance System A double-rail guidance system has a 4-foot, 6-inch to 4-foot, 8-inch clear space between the two rails. The required clear space between the rails is the vehicle roller’s outside-to-outside width, the pallet or cart dimensions, and the elevation for


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the highest pick level. The order-picker truck manufacturer for each application calculates specific dimensions. Elevated Double-Rail System The elevated-rail aisle guidance system has two rack rows on an elevated floor section. Each elevated floor section aisle’s side has a full-length angled iron face. The vehicle’s two sides have mounted guide rollers that ride against the two metal sides. This method is used for carton-pick systems that handle pallets or hand-stacked cartons. The elevated double-rail system requires the replenishment vehicle to operate within the same aisle. To perform the required transaction at an elevated carton pick position above the floor, an order-picker truck operator hand-stacks the cartons onto a pick position or, from a separate aisle, a forklift truck completes the transaction. The disadvantages are the difficulty of relocating and of reusing the facility floor area, increased capital investment, and potential employee tripping hazard. The advantages are that the first pick position is elevated above the floor, which reduces housekeeping problems, and that the system does not require floor anchors. Double-Rail Floor-Anchored System In the double-rail floor-anchored system, two guide rails are anchored full-length on both aisle sides. In this method the first storage level is on two load beams that are elevated above the guide rails. Replenishments are made with the order-picker truck from the same aisle or with a forklift truck from a separate aisle. From a separate aisle the pallets are set on the floor. The method has the same operational requirements as the previously mentioned elevated rack system. The vehicle guide rollers are side mounted, or there is a guide roller device on the vehicle sides. The disadvantages are that additional investment is required for a separate replenishment aisle with one method, and that entry guides create a housekeeping and employee tripping hazard. The advantages are ease of relocating and ease of reuse for another activity. Double Rail Anchored to the Racks In this method, the guide rails are attached to the two rack structures for the aisle’s full length. This system provides a 6-inch open space between the floor and the guide rail’s bottom. In a carton-pick system, the vehicle has a guide roller device on both sides of the truck, or the two side guide rollers are set at the proper height to come in contact with the guide rails. Pallet or hand-stacked carton replenishment is made from the order-pick aisle with a straddle forklift truck or the order-picker truck, or with a forklift truck to the pick position’s rear from an aisle. The disadvantages are additional load-beam and rail costs, and a separate replenishment to a complete a pallet transaction (in most applications). The advantages are minimized housekeeping problems, easy relocation, and good air circulation on the bottom level. Single-Rail Guidance System Single Rail Anchored to the Floor With the single-rail guidance system, a single rail is attached to the floor for the full aisle length, and the rail is used to guide the order-picker truck. The rail is on the



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floor’s right side and requires the vehicle to have a guide-roller device on the right side. With this rail and guide-roller arrangement, replenishment is a hand-stacked carton activity and is performed by a VNA vehicle that extends the pallet into the pick position, or the replenishment is made from a separate aisle. Disadvantages are housekeeping problems, the requirement for a vehicle with a guide-roller device, and the need for a separate vehicle-replenishment aisle (with most applications). The advantages are a lower rail cost and lower load-beam costs. Single Rail Anchored to the Racks The single rail anchored to the rack is the next guidance method. This method is used specifically to guide an order-picker truck. The guide rail is attached along the aisle’s full length on the right rack side at the first load-beam level’s height. All pallets are replenished with the up-and-over rack method and performed with a stand-up rider straddle forklift truck. There is a 6-inch clear open space between the floor and the bottom of the guide rail, and the aisle is wide enough to complete right-angle stack transactions. This method is used in a carton order-pick operation with SKUs that are handstacked into the pick position or from pallets. The disadvantages are that it entails an additional load-beam cost, the vehicle has a guide roller device, the rail is attached to the rack, and a straddle forklift truck with a low fork elevation of 14 to 18 feet is required. The advantages are that it requires less facility floor space, that it reduces housekeeping problems, and that it permits good air circulation on the first pallet level.

ELECTRONIC GUIDANCE GROUP The next order-picker vehicle aisle-guidance method is the electronic aisle-guidance method, which may make use of wire, magnetic tape, magnetic paint, or laser beams. These order-picker trucks require an aisle-guidance wire, tape, or paint that extends into the intersecting aisle. This feature provides the necessary aisle for an order-picker truck to pick up the guidance signal. Entry guides are optional for orderpicker trucks that are guided by an electronic system. Wire Guidance The next order-picker truck aisle-guidance method is the wire aisle-guidance method. This method has a wire that is buried 3/8 to 5/8 inch in a saw-cut path in the pick aisle’s center. After the wire is embedded in the floor, the saw-cut path is filled in with an approved substance. The wire runs the pick aisle’s full length and is a closed loop for an approximate length of 4000 to 5000 feet. The loop starts and ends at a line driver (or electric impulse creator). At the floor joints, and especially at the expansion joints, the wire is looped to compensate for movement. These electric impulses are sent from the line driver through the wire, and are picked up by the sensing device on the order-picker truck’s undercarriage. This sensing device is the wire guidance system’s second component and is on the undercarriage or under the truck’s operator platform. On the order-picker truck, to prevent equipment damage


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and for safety, most wire guidance systems have a short-duration UPS capability and an off-wire stop feature. After the order-picker truck is on the wire-guide path and the system is activated, if the order-picker truck leaves the path by a margin of 1 to 2 inches, the orderpicker truck travel is stopped in the pick aisle. There are specific standards for floor levelness, metal object location, content of metal hardener, and guide wire to rebar (or wire mesh) depth, to ensure good operation. For completing the loop of the path, there are two design options. First, place cuts that intersect with the existing cuts that are in the main aisle. This method saves on wire installation cost and wire material. Second, the loop can have its own wire path that is parallel to the existing cuts. This method requires a separate floor cut and installation cost. This separate guide wire serves as a vehicle test travel path. If your path cannot exist in a pick aisle, the guide wire’s path to the main aisle is under one of the adjacent pick-position rows. When the floor is cut, it creates a slurry which requires disposal. Other disadvantages include specific floor tolerances, increased vehicle investment, the difficulty of adding length, a length capacity of 4000-to-5000-feet per line driver, and the need for a UPS system. The advantages are reduced housekeeping problems, reduced tripping problems, use of floor positions, and the ability to be used by the orderpicker and storage vehicles. This system is best for a multiple-vehicle and multipleaisle system. Tape Guidance The next method is the magnetic tape strip. The magnetic tape strip is applied to the floor surface for the entire pick-aisle length. With the tape aisle-guidance method, a sensing device located on the orderpicker truck’s undercarriage directs a light beam downward onto the floor and onto the magnetic tape. The light beam is reflected back from the reflective tape to the sensing device, which ensures that the order-picker truck is on the tape guide path. The disadvantages are similar to those of the wire aisle-guidance method. Additional issues include low durability because the tape tears easily and wears with cross-vehicle traffic. This feature becomes a problem in the main aisle at the orderpicker aisle entrance. The method requires a separate replenishment aisle or a vehicle that extends the pallet into the pick position, or the cartons are hand-stacked into the pick positions. The advantages are that it is easy to add length and that the method is less expensive. Magnetic Paint Guidance The magnetic paint order-picker truck aisle-guidance system has similar design and operational features to the tape guidance system. Laser Beam Guidance The next electronic vehicle aisle-guidance system is the laser beam aisle-guidance system. The laser beam order-picker truck aisle-guidance system is considered a



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new technology. The method has a light beam source that is sent from the orderpicker truck to reflective targets. These reflective targets are strategically located in the pick aisle to reflect the light beam from the truck back to a receiver on the orderpicker truck. If the truck does not receive the light beam, the order-picker truck’s travel in the aisle is stopped. The disadvantages are capital investment, the requirement that the order-picker truck have a clear line of sight, and the requirement that an in-aisle replenishment vehicle have the same guidance method (or else a separate replenishment aisle must be used).

WHEN

TO

USE RAIL

OR

WIRE GUIDANCE

If the building floor conditions match an aisle-guidance system’s requirements, the consideration is choosing the appropriate vehicle aisle-guidance system for implementation in your order-fulfillment operation. For the wire aisle-guidance method, the downtime and investment are factors that influence your decision. If your operation is in a remote area and the factory-qualified wire guidance and vehicle service center is not close to the facility, this could create an unacceptable downtime; should you select rail guidance? If the operation is close to a factory-qualified wire guidance and vehicle service center, should you select wire guidance? With a mobile order-picker system (one truck per two or more aisles), wire guidance represents the lowest investment. If the order-picker truck is a captive vehicle or a mobile vehicle between two aisles, rail guidance has a good return on investment.

END-OF-AISLE VEHICLE SLOWDOWN DEVICES Most newly constructed order-fulfillment operations have tall racks with very narrow pick aisles. These tall rack structures require order-picker trucks that permit an employee to complete pick transactions at elevated positions and operate within these very narrow pick aisles. These vehicles have minimum clearances between the two rack rows or pick positions, similar to travel in a tunnel. To achieve the anticipated savings, return on investment, and order-picker productivity, these orderpicker trucks travel at a maximum travel speed and give the operator access to all pick positions. In many operations, to meet these objectives, an order-picker truck transfers between pick aisles and, while in a pick aisle, these order-picker trucks require a guidance system. Per the pick-area design, an order-picker truck performs in a pick area which has two turning aisles, prior to an aisle transfer the order-picker truck obtains a very slow travel speed. This feature reduces potential accidents, and the order-picker truck completes an aisle-end pick transaction at an aisle pick-position end. In a pick area with dead-end aisles (or one turning aisle), prior to aisle transfer or when performing an end-of-aisle pick transaction, the order-picker truck stops or slows down. This feature reduces potential accidents and permits a pick transaction at an aisle-end pick position; in a dead-end aisle the truck stops to avoid hitting the building wall. The aisle-end order-picker truck’s stopping or slowing down provides the operator with a signal. It also stops the order-picker truck to prevent uncontrolled


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travelling into a wall at the end of a dead-end aisle or exiting from the pick aisle at a high travel speed with potential to hit another order-picker truck or employee.

VEHICLE SLOWDOWN METHODS The order-picker truck slowdown or stop methods include the rail and rack or mechanical methods and the electromagnetic or automatic method. These orderpicker truck slowdown or stop methods are used with some modifications on an existing vehicle or in a new facility. If the electromagnetic slowdown method is considered for an existing facility, prior to the purchase and implementation, careful attention is given to the floor (surface, loading, metal object depth, and rebar location or wire-mesh location). The slowdown or stop methods are operator controlled, operator controlled with aisle-end rack bays painted a different color, rail and bumper stop, and electromagnetic stop. An order-picker truck should have a vehicle aisle-guidance system. This system reduces the effort required to steer the vehicle at maximum travel speeds in a very narrow aisle between two rack rows; the operator platform is elevated above a specific elevation that the vehicle’s travel speed is not maximum but is at a lower travel speed. Manually Controlled Slowdown Method In the manually controlled slowdown method, the operator controls the order-picker truck’s travel speed and determines the vehicle’s arrival at the end of the aisle. At the aisle end, the operator proceeds very slowly from the pick aisle (very narrow aisle) to the main traffic aisle, or stops at the dead-end aisle’s end. The disadvantages are employee training, low employee productivity, potential equipment damage, potential vehicle accidents, potential employee injuries, and no method for controlling the vehicle. The advantages are no equipment expense and the ability to implement in an existing building. Rack Bays Painted a Different Color Method The next slowdown method involves painting the rack bays a different color. In this operator-control method, aisle-end rack bays and load beams are painted a different color from the other rack bays. An operator controls the vehicle travel speed and, with a rack color, an operator ensures the vehicle’s arrival at the aisle end. Prior to the aisle end, the last two or four rack-bay upright posts and load beams are painted a different color from the pick aisle’s other rack bays. These different colors are a signal to the operator that the vehicle has reached the aisle’s end. With these signals at these aisle locations, the operator is trained to stop travel at the deadend aisle or to slow the vehicle for entry into the main aisle. The three colors are green for high travel speed in an aisle’s middle, yellow for slow-to-medium travel speed prior to an aisle’s end, and red for very slow travel or stop at an aisle’s end.



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The disadvantages are additional operator training, no method to control the vehicle, and lower employee productivity. The advantages are low cost, the ability to be used in an existing facility, and the ability to be used in combination with other systems. Rail Bumper Method The third order-picker truck stop or slowdown method is a mechanical rail and bumper method. The rail is a 4-by-4-inch or a 4-by-5-inch angled iron that is secured with the leg up on 8-to-9-inch centers to the order-picker aisle floor. With some vehicles in a dead-end aisle method, the bumper is secured to the aisle floor at the aisle end. When the vehicle strikes this angled iron or bumper at slow travel speeds, vehicle travel is stopped. The rail and bumper is painted with a safety-approved color. This method is used in pick aisles that have dead-end aisles. The rail or bumper method is used in conjunction with the colored rack method. This combination provides the advantages of both methods and reduces equipment and floor maintenance problems. The disadvantages are equipment and floor maintenance problems, an employee tripping hazard, and the ability to be used on dead-end aisles. The advantages are low cost, ensured vehicle stops, and ability to be installed in an existing building. Electromagnetic Guidance and Stop Method The next vehicle slowdown or stop method is an electromagnetic guidance and stop method. An electromagnetic guidance and stop method has a sensor attached to the order-picker truck’s undercarriage and several magnets that are set in the floor on both aisle sides at a specific distance from the aisle end. As the order-picker vehicle travels over the magnets, the sensing-device network automatically slows the vehicle travel and warns the operator of the approaching end of an aisle. With this slow travel speed, the vehicle leaves the storage aisle and enters the main aisle. The method is best used in an aisle that has two turning aisles and a vehicle wire guidance system. The disadvantages are that investment and operator training are required. The advantages are that the system is not operator controlled, it reduces potential equipment damage and accidents, and it ensures vehicle slowdown.

CARTON HIGH-RISE ORDER-PICKER TRUCKS The next high-rise order-picker method component is the carton order-picker truck. The order-picker truck is a manually controlled rider (high-rise or multilevel) truck that has the ability to have guided vertical or horizontal travel in an aisle to the assigned pick position. Arriving at the appropriate pick position, the employee transfers the customer-ordered carton quantity from the pick position onto a pallet or cart. After a pick transaction, the truck travels forward or in reverse to another pick position, exits the pick aisle to travel to an adjacent aisle for the next picks, or deposits the customer-ordered and picked cartons into an assigned area.


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The carton order-picker trucks include order-picker trucks with a load-carrying surface that only handles cartons, order-picker trucks with the ability to handle a pallet or cart (counterbalanced trucks, straddle trucks, and platform trucks), and order-picker trucks that handle pallets as storage vehicles and permit the operator to pick cartons.

ORDER-PICKER TRUCK

WITH A

CARTON LOAD-CARRYING SURFACE

The first high-rise order-picker truck is an order-picker truck with a carton loadcarrying surface. The electric battery-powered truck has an operator platform and a carton-carrying device that elevates to a pick position. For detailed information, we refer the reader to the high-rise order-picker truck section in Chapter 3.

COUNTERBALANCED TRUCK The next high-rise order-picker truck is the counterbalanced order-picker truck, which has a set of pallet-carrying forks. The unique counterbalanced-truck feature is that the set of forks extends beyond the two short straddles. The vehicle motor and battery weight is forward or ahead of the operator platform and offsets the pallet weight. This allows a counterbalanced truck to handle a 48-inch long pallet or cart with a 3000-pound weight to a 20-foot height above the floor.

STRADDLE TRUCK The third high-rise order-picker truck is the straddle order-picker truck. This truck is similar to the counterbalanced truck. The straddle truck’s unique feature is that two straddles extend beyond the set of forks. The operator platform is between the drive motor and set of forks. With an elevated pallet or cart, the drive motor and battery and the two straddles stabilize a 48-inch long pallet that has a 3000-pound weight up to 20 to 30 feet above the floor.

PLATFORM TRUCK The next high-rise order-picker truck is the platform truck. The platform truck’s operational characteristics are similar to the counterbalanced truck. A platform truck is designed to elevate the operator platform and cart up to 20 feet above the floor and to handle a carton quantity that weighs less than 500 pounds.

VNA TRUCK The next high-rise order-picker truck is the VNA truck. The VNA truck is very similar to the straddle high-rise order-picker truck. The VNA order-picker truck is designed to travel horizontally or vertically in the pick aisle and to elevate the operator platform up to a 30-to-40-foot height above the floor. The VNA truck is designed to handle a pallet or cart. The VNA truck lets the driver perform carton or pallet storage transactions.



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ORDER-PICK DEVICES The next high-rise order-picker truck features are the customer-ordered and picked carton-carrying devices. The carton-carrying devices permit an order-picker to transfer the required carton quantity from the pick positions onto the truck and to provide support for the picked cartons as the high-rise order-picker truck travels in the pick aisle. The first carrying device is the load-carrying surface. The surface is a solid sheetmetal deck that has the structural strength to support the picked carton quantity. Most load-carrying surfaces are welded or nut-and-bolt connected to the order-picker truck frame. The second device is the pallet. The pallet dimensions determine the order-picker truck’s fork length and the pick-aisle width. A claw device is located at the operator platform’s base to grab the pallet stringer and secure it to the order-picker truck. If an employee steps onto the pallet, the claw secures the pallet to the truck. The third device is the cart. The cart is secured by a chain and lock to the highrise order-picker vehicle member. The fourth device is the picking cage. A high-rise picking cage is used with a high-rise vehicle that has an employee pick cartons onto a pallet. The high-rise picking cage helps reduce an order picker’s high-level fear and product damage. The picking cage has two sides, a rear wall, and a bottom. The material is wood, metal, or plastic; the structure has a bottom support device with a middle stringer. The picking-cage cavity holds a pallet with the pallet stringer facing toward the open side. The picking cage’s open side is designed to permit an order picker, per a customer-order, to transfer cartons from a pick position onto a pallet; and, after a completed customer-order or after the pallet has reach a predetermined height, to permit a forklift truck to remove the pallet easily from the picking cage. The picking cage’s side elevations are predetermined by the order-pick computer’s cube program. The picking cage’s middle stringer is clamped by the vehicle claws. During elevated vehicle travel in the pick aisle, as the elevated vehicle starts and stops in the aisle, the pick cage’s sides and rear wall prevent cartons from falling to the floor, and the clamp securely holds the pallet.

HIGH-RISE TRUCK ROUTING METHODS An important high-rise order-picker truck factor is the order-picker truck routing pattern. The multilevel order-picker routing patterns are specialized routing patterns that are used in a machine-ride multilevel (high-rise) carton order-picker method. The multilevel order-picker routing pattern directs the order picker, who rides onboard a vehicle, to the required pick position. The vehicle travels in a vertical or horizontal direction between two pick-position rows. If the vehicle travels from the first pick position to the last position in the aisle, or from the last pick position to the first pick position, this vehicle travel is one trip down the aisle. To obtain maximum order-picker efficiency with low carton or equipment damage, an orderpicker truck travels in a rail- or wire-guided aisle.


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The HROS routing patterns include one-way truck travel through an aisle and two-way or forward-and-reverse travel in an aisle.

ONE-WAY HIGH-RISE ORDER-PICKER TRUCK ROUTING PATTERN The one-way high-rise order-picker traffic or routing pattern through a pick aisle directs the order-picker to make one trip through the pick aisle. With this routing pattern, as the order-picker and truck enter the pick aisle, the first pick position or lowest number is at the first rack bay’s bottom bay, and the last pick position or highest number is at the last rack bay’s top. This routing pattern guides the order-picker to enter the aisle at one end and to exit at the opposite end. Each next-bay bottom rack position has the lowest bay number. At the bay’s bottom, the pick-position number sequence runs in the vertical direction. With this pattern, the bottom pick position is numbered 0010, the next pick position is numbered 0011 within the same rack bay on the second level, and so on. In the rack bay, after the pick positions reach the rack positions’ maximum number, the next arithmetic pick position is in the opposite rack’s bottom-bay pick position. With the first bottom-bay pick-position number being 0010, the next number is 0020. With this order-picker routing pattern, an order picker picks from both pick positions in an aisle and transfers to another aisle to complete a customer-order. The one-way high-rise order-picker routing pattern is implemented in a carton order-fulfillment operation. The disadvantages are lower productivity due to increased up-and-down vehicle movement, double travel with a complete order, a requirement for turning aisles at each pick-aisle end, and increased product damage from cartons falling from a pallet at high vehicle-travel elevations. The advantages are that the system is easy to implement and that all trips are in one direction through the pick aisle.

TWO-WAY HIGH-RISE ORDER-PICKER TRUCK ROUTING PATTERN The two-way high-rise order-picker truck routing pattern directs the order picker and truck to start at the highest-level pick position and, at the pick aisle’s end, the operator lowers to the same pick-aisle bottom-level pick position. This is a second trip back to the aisle entrance. Therefore, the two-way routing pattern has an aisle with one entrance and exit for the order picker and truck. The first basic order-picker routing pattern has four levels of pick positions. In a four vertical-rack-bay pick-position aisle with a 36-inch maximum height per opening, the order picker in his or her trip down the aisle elevates and withdraws cartons from the rack’s third and fourth (or highest) pick levels. At the pick aisle’s end, the operator lowers the order-picker truck to the floor and travels (in reverse direction) down the aisle to the pick-aisle entrance. During this aisle trip, the order picker withdraws cartons from the first and second rack-level pick positions. The second pattern has six levels of pick positions. If a vertical rack structure has six rack-bay levels, to complete the down-aisle trip, one vehicle trip is made down the aisle in the elevated position, permitting the order picker and truck to



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withdraw cartons from the fourth-, fifth-, and sixth-rack pick positions. At the pick aisle’s end, the order-picker truck lowers to the floor and makes the reverse downaisle trip that permits the order picker to withdraw cartons from the first-, second-, and third-rack pick positions. The third pattern is the 8-to-10 vertical-rack pick-position method. With a 30inch high maximum opening, the order picker travels down the aisle and elevates and withdraws cartons from the rack bay’s highest 4 or 5 levels. In one aisle trip, the order picker picks from levels 10, 9, and 8, and in the second trip from levels 7 and 8. The third pick-aisle trip permits the order picker to withdraw cartons from the levels 5, 4, and 3. In a final pick-aisle trip, an order-picker withdraws cartons at levels 2 and 1 (or the lowest-rack pick positions).

HROS CONSIDERATIONS The HROS system is a carton order-fulfillment method that has the ability to transport one pallet or cart for the carton order-selection activity. In most applications, the carton pick and transport quantity is based on the carton cube. For normal-sized cartons (12 inches long, 10 inches wide, and 12 inches high) the carton number per trip is 55 to 65 cartons. For small-cube cartons (12 inches long, 10 inches wide, and 5 inches high) the carton number per trip is 75 to 85 cartons. The HROS method consolidates the SKU hit concentration and hit density, and the HROS truck has minimal carton-carrying capacity. The high-rise order-picker truck method is considered for an operation with small-cube and slow-moving cartons. The important HROS design considerations include having sufficient ceiling height, having sufficient aisle width to permit pallet or hand-stacked carton replenishment to the pick position, having a sufficient in-feed and out-feed staging area in the front area, and having sufficient aisle length to minimize vehicle transfer between two aisles. The disadvantages include investment in equipment, a rail- or wire-guided aisle, and the ability to handle only one pallet or cart per trip. The operator is required to wear a safety harness, and carton replenishment is made from the same aisle or from a separate replenishment aisle. There is a 20-to-25-foot clear ceiling height above the floor; the method requires a good order-picker routing pattern. The advantages include improved cube utilization, high order-picker productivity with a good orderpicker routing pattern for slow-moving SKUs, high SKU hit concentration and hit density per aisle, a rail or wire-guide path that reduces equipment and building damage and permits high vehicle travel speed, minimization of the required building area; and ability to handle a pallet or cart.

METHODS IN WHICH AN EMPLOYEE WALKS TO PICK POSITIONS AND PICKED CARTONS ARE TRANSPORTED AWAY The next employee order-fulfillment method group is that in which the employee walks to the pick positions and the customer-ordered, picked, and labeled cartons


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are transported from the pick area to the shipping area. Many professionals refer to this method as the mechanized-carton employee-walking pick method. The method in which the employee walks to the pick positions and the customer-ordered and picked cartons are transported is the method in which an employee picks batched customer-ordered cartons and transfers them to a conveyor. The powered-conveyor travel path transports the picked and labeled cartons from the pick area to a sorting area and onto the appropriate customer staging area or delivery vehicle. This employee-carton-pick method has batched or grouped customer orders; pick faces or positions; an employee walkway and, as required, stairs; an order-picker routing pattern; a powered-conveyor travel path; pick labels; a sorting method; a directloading method; and a pallet-replenishment vehicle and aisle.

BATCHED

OR

GROUPED CUSTOMER ORDERS

This method has the customer orders batched or grouped together. The batched or grouped customer orders are the key to an efficient and cost-effective operation. The computer batches or groups your daily customer orders into random customerorder groups, or waves. It is possible for your carton order-fulfillment operation to have several batches or waves each day. The wave number and the number of customer orders per wave are determined by the customer-ordered carton volume, the loading-dock or direct-loading locations and productivity, and your order-picker number and productivity. For each batch or wave, the host computer directs a microcomputer-controlled printer to print an individual label for each customer-ordered carton. With these batch or wave pick labels, an order picker makes a trip in the pick aisle and stops at each pick position. Per the pick label, the order picker transfers a customer-ordered carton quantity from the pick position and applies a label to each carton. Each customer-ordered, picked, and labeled carton is transferred onto the powered-conveyor travel path. The powered-conveyor travel path transports the customer-ordered, picked, and labeled cartons through a sorting area onto the customer-assigned shipping area or directly onto the customer delivery vehicle. The disadvantages are the difficulty of maintaining on-time customer orders and the time it takes for a computer to review and process, the necessity of a sorting activity and area, investment into a computer program, and the need for a humanand machine-readable label with pick and sorting instructions. The advantages are improved order-picker productivity due to increased SKU hit concentration and hit density, the ability to handle a large SKU number and the ability to handle a large customer number and carton volume.

BATCH CONTROL METHODS The batched customer-order pick method requires highly disciplined pick-area control and picker activity in order to transfer customer-ordered, picked, and labeled cartons onto the conveyor travel path. You must ensure that all the order pickers in each pick zone complete each customer batch (or wave) of pick transactions accurately and on time. If your batch or wave of customer-ordered, picked, and labeled



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carton transactions is not released on time or accurately, tremendous confusion and errors result when sorting or direct-loading onto a customer delivery truck. The batch control method is a technique that is used to instruct the order pickers as to the time they are to pick, label, and transfer cartons onto the powered-conveyor travel path. This feature is very critical because several batches (or waves) are picked, sorted, and loaded within a day. The method ensures that the order-picker activity is coordinated with the sorting and direct-load activities; this requires communication between the sorting and direct-load activities and the pick zones. The sorting and direct-load area notifies the pick area regarding the last-labeled batch carton receipt. This notification means that the order pickers are allowed to start the order-fulfillment activity for the next batch or wave. You control batch or wave overlap by ensuring that the total pick-area productivity is equal to your sorting and direct-load productivity. If your pick-area activity is ahead of the sorting and direct-load activities, the sorting area communicates to the pick area to stop the pick activity. To help minimize pick-area activity shutdown, some applications utilize conveyor queue lanes or a recirculation conveyor travel path. In the sorting and direct-load area, you must ensure that there are sufficient lanes to handle complete batches and sufficient dock doors and shipping stations to handle batch changes. You must also ensure that there is an empty customer delivery truck spot at the appropriate dock location, or that there is a sufficient set-down area for problem situations. In addition, all the components, such as labelers, scanners, the conveyor travel path, divert devices, and employees, must be functioning accurately and on time.

BATCH RELEASE METHODS The basic batch release methods include using a control desk and clerk, printing on the pick/sort label and having a clock in each pick zone or area, and having a scoreboard in each pick zone or area. Batch Control Desk with a Clerk With this method, in the pick area a clerk sits at a control desk and issues pick labels to the order pickers. The control clerk issues batch-one pick labels to all order pickers. After issuing all batch-one pick labels, when the order picker returns to the control desk and with proper notification from the sorting and direct-load area, the clerk issues batch-two pick labels. To ensure proper control, the clerk should list the name of all order pickers who receive the pick labels and their anticipated return time. Batch Control Printed on the Pick Label and Clock in the Pick Area With this method, the computer has a printer print each pick zone’s release time on each pick label. This release time indicates to the order picker the expected time that each batch’s cartons are scheduled for transfer onto the powered-conveyor travel path. Each pick zone has a clock and a different release time, because carton-


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conveyor travel time from each pick zone or area to the sorting and direct-load area is different for each pick zone. Batch Control Scoreboard With this method, each pick zone or area has a scoreboard or signal light that has a symbol for each batch. In the pick zone, it indicates to the order pickers the appropriate batch that is scheduled for pick and transfer onto the powered-conveyor travel path.

HOW

TO

DETERMINE

THE

CARTON QUANTITY

PER

BATCH

With a batched customer-order handling method, the entire order-pick and sortingand-direct-load carton transportation methods are designed according to the carton quantity that is handled at each activity location. The methods to determine the carton quantity per batch are order-picker driven and sorting-and-direct-load driven. Order-Picker-Driven Method With an order-picker-driven method, the batched carton quantity is determined by your order pickers’ productivity. This method relies on a computer program to distribute a customer-ordered carton quantity by a predetermined pick productivity rate; the carton quantity is distributed to the sorting and direct-load locations. The design information for the order-picker-driven method includes carton number per customer orders, customer-order number, anticipated order-picker rate, work hours per day, and sorting and direct-load productivity rate. Sorting and Direct- or Fluid-Load Method With the sorting and direct-load driven method, the batched carton quantity is determined by the carton number that is handled by each activity location. Per the order-fulfillment operation, the activity location is a sorting, shipping, or direct-load station. With this method, your computer program ensures that the batched carton quantity has sufficient carton quantity to keep each sorting and direct-load station active. It calculates the carton number to ensure a clean cutoff for the sorting and direct-load activity for your customer-ordered, picked, labeled, and sorted cartons onto a cart, pallet, or customer delivery-truck floor. The sorting and direct-load driven method is preferred for a carton orderfulfillment operation because it ensures a constant carton quantity for all orderfulfillment activities. The design information for this method includes the sorting and direct-load activity station, truck dock, or loader number, which is based on an anticipated productivity or load-conveyor travel speed; the average daily carton quantity; the time required to set up a sorting or direct-load station; the time required to load a nonconveyable product; the average number of pieces per customer-order and per delivery cart, pallet, or truck; and the time required to move a full truck and drop an empty truck at a dock.



PICK FACES

OR

389

POSITIONS

The first components of the method in which an employee walks and picks to a conveyor are the carton pick faces or pick positions. Each pick position contains a carton quantity that is available to the order picker for a customer order. The pickposition type is determined by SKU movement; SKU size or cube, which includes pallet board length, width, and height; SKU number and associated one-year movement; available facility space (length, width, and clear ceiling height); replenishment vehicles; code or local-authority standards; and economics.

PALLET ORIENTATION The options for pallet orientation in the pick position include the stringer facing the pick aisle and the fork opening facing the pick aisle. Pallet’s Long Dimension Faces the Pick Aisle With this method, the pallet’s long dimension faces the pick aisle. As a result, less order-picker reaching is required to reach all the cartons on the pallet. This short employee reach improves order-picker productivity. This pallet-board orientation in the pick position requires the forklift truck to handle the pallet from the stringer side. This feature requires a four-way pallet or a partial four-way pallet. This palletboard orientation requires a wider pallet-rack pick. This feature for a standard 150foot long pick aisle results in fewer pick positions. With this pallet orientation, the pick module (forklift truck aisle, rack row, pick aisle, and pick conveyor) requires a wider dimension. With the option in which the fork opening faces the pick aisle, the short pallet dimension faces the pick aisle. As a result, the order picker must stretch a greater distance to reach all the cartons on the pallet. This long reach slightly lowers the order-picker productivity. This pallet orientation in the pick position requires the forklift truck to handle a pallet from the fork-opening side. This feature permits any pallet to be used in the operation. The pallet-board orientation requires a short pallet position. This feature for a standard 150-foot long pick aisle has the greatest pickposition number. With this pallet orientation, the pick module (forklift truck aisle, rack row, pick aisle, and pick conveyor) requires a shorter dimension.

PALLET HEIGHT The pallet height options are a tall pallet and a short pallet. Tall Pallet Height The mechanized employee-walk pick-to-conveyor method has one or two tall-pallet pick positions per rack bay. The pallet height permits an order picker to have an easy reach for the top carton on the pallet. The tall-pallet pick position provides your operation with fewer replenishments to the pick position. With a high-pallet rack-bay opening, the concerns include the floor-pallet position — an employee


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must walk from the pick aisle into the forklift replenishment aisle — and the elevated rack-bay opening, which must have an underside consisting of a solid deck or netting as an employee safety feature. This feature means a standard 150-foot long pick aisle has fewer pick positions. The tall pallet handles cartons with wide cube characteristics, or fast-moving SKUs. Short Pallet Height The short pallet height has two or four pallet pick positions per rack bay. The short pallet height gives an employee easy access to all cartons on the pallet. To obtain four pick positions, this feature requires a second pair of load beams. To ensure lower second or elevated pick positions, the lower pick-position load-beam tops are at the floor surface. With a second pick level, this feature minimizes the potential that an employee will walk from the pick aisle into the rack bay or into the forklift truck’s replenishment aisle. The short pallet height increases the number of forklift pallet-replenishment transactions. The standard 150-foot long pick aisle has a great pick-position number. A short pallet is used for cartons with a medium cube, or medium- to slow-moving SKUs.

VARIOUS EMPLOYEE PICK-TO-POWERED CONVEYOR METHODS The employee pick-to-powered conveyor pick-position designs include the standard pallet rack, which is parallel or perpendicular to the conveyor travel path; the carton flow rack or decked pallet rack; and the pallet flow rack, which is parallel or perpendicular to the conveyor travel path.

STANDARD PALLET RACK, PARALLEL

TO THE

PICK CONVEYOR

The first conveyor design is the standard pallet rack that is parallel to the pick conveyor. The first component is a standard pallet-rack row that is parallel to the pick conveyor. This feature has the pallet-rack pick positions face the pick conveyor. Per rack bay, these pick positions are one- or two-pallet-high pick positions. The second component is the distance between the pick position and the pick conveyor travel path, a 3-foot-wide dimension which is an employee walkway between the pick face and the powered-conveyor travel path. The third component is the poweredconveyor travel path with light fixtures above the conveyor travel path. The fourth component ensures pallet replenishment to the pick position: the pick area design has a separate forklift replenishment aisle and, at predetermined locations along the employee walkway in the pallet-rack row, there are empty-pallet rack openings. The fifth component is that, per local code, the pick positions have underside solid or netting guards. Order Selection and Pick-Position Replenishment Activities After the order picker receives the batch or wave pick labels, the order picker walks in the pick aisle to the appropriate pick position. At the pick position, the employee



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removes a pick label from its self-adhesive backing and places the label in the appropriate location on the carton. The labeled carton is transferred from the pick position onto the powered-conveyor travel path. Per the customer-order for a specific SKU, the order-pick activity is repeated at the pick position or the order picker walks to another pick position and repeats the pick activity. The label’s self-adhesive backing is placed into a trash bag. After an employee depletes the cartons from the pick position, the order picker removes the empty pallet from the pick position and pushes the empty pallet to an empty-pallet holding position. From a separate forklift replenishment aisle, the forklift truck completes a pick-position replenishment transaction and picks up an empty pallet from the empty-pallet position. The advantages are minimal order-picker walking distance between the pick position and conveyor travel path, which minimizes employee fatigue; a medium pick-position number per linear foot for all pallet types, and per the pallet orientation in the pick position and the load-beam length (this feature requires a large building); a greater number of forklift truck replenishment aisles; the ability to handle all conveyable SKU types (fast- or slow-moving SKUs large- or small-cube SKUs); and minimal walkways and deck material. This walkway structural-member strength and deck material are required to support the combined employee, carton, and emptypallet weight. Standard pallet-rack components permit an equipment-supported elevated pick floor. Per code, each pick level requires lighting, fire sprinklers, and stairs, and each pallet pick position has solid or netting underside protection and pickposition identification. The system provides on-time and accurate forklift truck replenishment.

STANDARD PALLET RACK, PERPENDICULAR

TO THE

PICK CONVEYOR

The second design for a system in which an employee picks to a powered conveyor is the standard pallet rack that is perpendicular to the pick conveyor. The standard pallet-rack row that is perpendicular to the pick conveyor includes pallet-rack uprights and load beams that create pallet-rack rows. The pallet-rack rows are arranged in two long rack bays that are single-rack rows or back-to-back rack rows. These rack rows and bays face an employee-powered pallet-truck aisle. There are four pick positions per rack row, which means that there are eight pick positions per aisle. In the pick-conveyor travel path, there are decked, perpendicular employee walkways or aisles between the pick positions and the pick-conveyor travel path, and between the pallet replenishment location and the pick positions. The aisle serves as the replenishment aisle and the order-pick aisle. As a replenishment aisle, the aisle gives an employee-powered pallet truck access to the forklift pallet-transfer position and to the appropriate rack bay. To complete the pallet replenishment transaction, the rack bay has a solid floor that supports the pallet truck and pallet weight. As an order-picker aisle, the aisle gives the order picker access to each pick position and to the powered-conveyor travel path. Between each rack row and the powered-conveyor travel path there is an employee aisle that permits an employee to walk between the various perpendicular aisles.


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The design also includes a pick-conveyor travel path; appropriate light fixtures in the aisles; and, per local code, a safety gate at the forklift pallet-transfer positions. Order Selection and Pick-Position Replenishment Activities After an order-picker receives the batch or wave pick labels, the order picker walks in the aisle between the rack rows and the end of the pick-conveyor travel path to the appropriate pick aisle. At the appropriate pick aisle, the order-picker walks into the pick aisle to the appropriate pick position. At the pick position, the employee removes a pick label from its self-adhesive backing and places the label in the appropriate location on the carton. The labeled carton is transferred from the pick position, and the employee walks with the labeled carton to the powered-conveyor travel path and transfers the labeled carton onto the powered-conveyor travel path. Per the batch or wave and for a specific SKU, the order-pick activity is repeated at the pick position. If the next label indicates another pick position, the order picker walks from the pick aisle to the appropriate pick aisle and to the appropriate pick position and repeats the pick activity. The label’s self-adhesive backing is placed into a trash bag. After an employee depletes the cartons from the pick position, the order picker removes the empty pallet from a pick position and transports the empty pallet to an empty-pallet holding position. From a separate forklift replenishment aisle, the forklift truck completes a pick-position replenishment transaction by placing a full pallet though the transfer safety gate onto the deck, and completes an empty-pallet pickup from the empty-pallet position. The features include additional order-picker walking distance between the pick position and the pick-conveyor travel path, which increases employee fatigue. The method handles all pallet types; per the pallet orientation in the pick position and load-beam length, there is a greater pick-position number per linear foot. The method requires fewer forklift replenishment aisles, and handles all types of SKUs or cartons, such as fast- or slow-moving SKUs and large- or small-sized or cube SKUs. The method requires the maximum length for decked walkways. The walkway structural-member strength and deck material are required to support the combined employee, employee-powered pallet truck, and pallet weight. Standard pallet-rack components permit an equipment-supported elevated pick floor. The system also includes a pick-conveyor travel path; appropriate light fixtures in the aisles; per local code, a safety gate at the forklift truck pallet-transfer position; per pick aisle; and, per code, fire sprinklers. The system also requires on-time and accurate forklift truck replenishment.

CARTON FLOW RACK

OR

DECKED PALLET RACK

The next design is the carton flow rack or decked pallet rack, standard pallet racks that are arranged in one of the previous (parallel or perpendicular) methods. The carton flow or decked pallet rack is used for small- to medium-cube and slow-moving SKUs. The order-selection activity has the same procedures as for the other pick methods. Per the operation’s replenishment activity, the pick-position replenishment is



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made from a carton mix on a pallet. After the replenishment the empty pallet is moved to the empty-pallet position. The advantages of this method are the greatest pick-position number per square foot, some carton double-handling, and the ability to handle small- to medium-cube and slow-moving SKUs. If the flow rack is not a push-back method, the flow rack requires a separate carton-replenishment aisle. The aisle’s structural-member strength supports a fully loaded employee-powered pallet truck and an employee.

PALLET FLOW RACK, PARALLEL

TO THE

PICK CONVEYOR

The next design is a pallet flow rack that is parallel to the pick conveyor. The components are a standard pallet flow-rack row that has the discharge ends parallel to the pick conveyor. This feature has the pallet-rack pick positions face the pick conveyor. These pick positions are one pallet high and two to three pallets deep. The pallet-flow slope from the charge (or forklift truck) end to the discharge (or order-picker) end is determined by the manufacturer and is based on your product weight and height and the pallet’s bottom deck board quality. To ensure that an empty pallet is removed from a pallet flow lane, the pallet flow lane’s slope does not create line pressure. The discharge end permits an employee easily to remove the empty pallet from the flow lane’s discharge end. There is a 3-foot employee walkway between the pick face and the poweredconveyor travel path. There are light fixtures above the conveyor travel path. To ensure pallet replenishment to the pick position, the pick area design has a separate forklift truck replenishment aisle and, at predetermined locations along the employee walkway in the pallet flow-rack row, there are empty-pallet flow-rack openings. These pallet-rack openings are considered empty-pallet positions, and each emptypallet flow-rack conveyor lane permits an employee to form a pallet stack. When the pallet stack reaches a predetermined height, the employee pushes the pallet stack on the conveyor to the forklift pickup position. Per local code, the pick positions have an underside solid or netting guard to permit an employee to walk into a pallet flow lane and pull a pallet forward to the pick position and, in an empty pallet lane, to permit an employee to walk and push a pallet forward to the forklift pallet-transfer location. Order Selection and Pick-Position Replenishment Activities After the order picker receives the batch or wave pick labels, he or she walks in the pick aisle to the appropriate pick position. At the pick position, the employee removes a pick label from its self-adhesive backing and places the label in the appropriate location on the carton. The labeled carton is transferred from the pick position onto the powered-conveyor travel path. Per the batch or wave, for the specific SKU the order-pick activity is repeated at the pick position. If the next pick label indicates another pick position, the order picker walks to the pick position and repeats the pick activity. The label backing is placed into a trash bag. After an employee depletes the cartons from a pick position, an order picker removes the empty pallet from the pick position and transports the empty pallet to


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an empty-pallet holding position. From a separate forklift replenishment aisle, the forklift truck completes a pick-position replenishment transaction and picks up an empty pallet from the empty-pallet position. The advantages include minimal order-picker walking distance between the pick position and the pick-conveyor travel path, which minimizes employee fatigue. The system handles all pallet types and, per the pallet orientation in the pick position and with conveyor flow lanes and upright support members, there is a minimum number of pick positions per linear foot. (This feature requires a large building.) The system requires forklift replenishment aisles, handles all cartons types (fastor slow-moving SKUs and a wide range of SKU sizes), and requires a decked walkway of minimal length. The walkway structural-member strength and deck material are required to support the combined employee and empty pallet weight. Standard pallet flow-rack components permit an equipment-supported elevated pick section. Per code, each pick level requires lighting, fire sprinklers, solid or netting underside protection, and pick-position identification. The system provides on-time and accurate forklift truck replenishment. Pallet Flow-Lane Considerations The most important pallet flow-lane component is the pallet flow conveyor. The pallet flow conveyor has rollers or skate wheels that revolve as the pallet is moved over the conveyor travel path. The first conveyor travel-path option is standard short rollers. The standard short rollers are hardened-metal, 2-inch diameter rollers that are specified to support the maximum pallet weight; each roller is approximately 6 inches wide. The rollers are located along the full length of the flow lane on very close centers. The close centers ensure a smooth pallet flow and minimal pallet hang-up. The width between the two conveyor roller-lane center lines is equal to the pallet width. The second option is short rollers with exterior flanges, which are similar to the standard roller design except that each roller’s exterior edge is designed with a flange. The upward extension is approximately 1/8 to 1/4 inch and serves a pallet travel-path guide rail. The roller width between two conveyor-roller flanges is equal to the pallet width plus 2 inches. This feature ensures easy placement of a pallet onto the roller conveyor surfaces. The third option is a single strand of skate wheels. The skate-wheel conveyor travel-path method is very similar to the standard-roller conveyor method, except that the pallet travel path has skate wheels. When a pallet is placed onto the skatewheel travel path, the span between the two skate-wheel travel paths is 2 inches less than the pallet width. The fourth option is meshed skate-wheels. The meshed skate-wheel pallet-flow method has two skate-wheel strands side by side for each conveyor travel path. The first skate-wheel strand’s center is slightly forward of the second skate-wheel strand. This provides an even top to the skate wheels. To ensure proper pallet flow through the flow lane and easy employee emptypallet removal, the design considerations are to use pallets with good-quality bottom deck boards, and at the charge end, to have pallet entry guides on both flow lane sides. The entry guides serve as guides that assist with forklift pallet transfer onto



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a flow lane’s charge end. At the discharge end, there should be a roller stop. The roller stop helps an employee to remove an empty pallet from the flow lane. At the discharge end, there should be metal runners in the open space between the two conveyor lanes. At a predetermined interval, runners between the two conveyor lanes maintain rigidity and, during empty pallet removal from the flow lane, ensure that the pallet does not fall through the opening.

PALLET FLOW RACK, PERPENDICULAR

TO THE

PICK CONVEYOR

The next design is the pallet flow rack that is perpendicular to the pick conveyor. With this method, each pallet flow-rack lane extends from the forklift truck aisle to the employee walkway. The pallet flow lane is a single flow lane or back-to-back flow lanes. There are three to four pallet positions per pallet flow lane. With an aisle between two pallet flow lanes, there are eight pick positions per aisle. In the pick-conveyor travel path, there are perpendicular decked walkways or aisles between the pallet flow-lane pick positions and the pick-conveyor travel path, and between the pallet flow-lane end and the carton-conveyor travel path. The aisle serves as the order-pick aisle that gives the order picker access to each pallet on the flow lane, and access to the powered-conveyor travel path. Between the end of each rack row and the powered-conveyor travel path, there is an employee aisle that permits the employee to walk between the various perpendicular aisles. Other elements of the system include the pick-conveyor travel path; appropriate light fixtures in the various aisles; and, as required by local code, a safety gate at the forklift truck pallet-transfer position. Order Selection and Pick Position Replenishment Activities After the order picker receives batch or wave pick labels, he or she walks in the aisle between the pallet flow-lane ends and the pick-conveyor travel path to the appropriate pick aisle. At the appropriate pick aisle, the order picker walks to the appropriate pick position. At the pick position, the employee removes a pick label from its self-adhesive backing and places the label in the appropriate location on the carton. The labeled carton is transferred from the pick position, and the employee walks with the labeled carton to the powered-conveyor travel path and transfers the labeled carton onto the powered-conveyor travel path. Per the batch or wave, for a specific SKU the order-pick activity is repeated at the pick position. If the next label indicates another pick position, the order picker walks from the pick aisle to the appropriate pick aisle and to the appropriate pick position and repeats the pick activity. The label backing is placed into a trash bag. After an employee depletes the cartons from the pallet flow lane, the order picker removes the empty pallet from the pallet flow lane and transports the empty pallet to an empty-pallet holding position. From a separate forklift replenishment aisle, the forklift truck completes a pick-position replenishment transaction and an emptypallet pickup from the empty-pallet position. The features include additional order-picker walking distance between the pallet flow-lane pick position and the pick-conveyor travel path, which increases employee


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fatigue. The system handles all pallet types and, per the pallet orientation in the pick position and the pallet flow-lane length, there is a greater pick-position number per linear foot. This feature requires a small-to-medium-sized building. The system requires fewer forklift replenishment aisles, handles all SKUs or cartons (fast- or slow-moving SKUs and large- or small-sized or cube SKUs), and requires the maximum decked-walkway length. The walkway structural-member strength and deck material are required to support an employee. The system has standard pallet flow-rack components that permit equipment-supported elevated pick sections. Per local code, each pick level requires lighting, fire sprinklers, and solid or netting underside protection. A pallet identification label is required on the pallet-board stringer or block, on the low layer of cartons, or on a carton exterior surface that faces the pick aisle. Also important is on-time and accurate forklift truck replenishment. Since the pallet flow lane is dynamic and the order-pick transaction is completed from the side aisle, the inventory control system and pick instruction identify the pallet flow lane.

PICK TUNNEL The next method in which an employee picks to a powered-conveyor travel path is the pick tunnel method. Pick tunnel is a term that describes an employee-pick-toconveyor method that has multiple elevated levels. Each level has pick positions, a carton-conveyor travel path, and a floor level. When you look at the pick module from the side, the side view looks like a tunnel with a carton-conveyor travel path in the middle of the floor.

UNDERSIDE DECK OR NETTING The next consideration for an elevated carton-pick area is the method used to protect an employee from walking into an open rack and falling to the floor below. In an elevated or mezzanine carton-pick area layout, the underside deck or netting material under the pallet positions and ready-reserve positions prevents your employees from falling through an open or vacant pick or ready-reserve position. The selected material for this area has the structural strength to support an employee and prevent the employee from falling through the material. The pick or ready-reserve underside is an area that has the entire elevated pick floor or mezzanine covered with a constructed floor. The underside is secured to the first pick position’s deck material and to the pick position’s structural members, and all position openings are decked with solid wood, wire mesh, nylon netting, wire screen, or expanded metal slats.

DETERMINING THE CARTON-CONVEYOR TRAVEL PATH When you design a carton-pick-to-conveyor travel path, the carton-conveyor travel path transports the customer-ordered, picked, and labeled cartons from the pick area, through the sorting area, and onto the carton shipping area. The carton-conveyor travel path ensures on-time and continuous carton travel from the pick area.



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The powered carton-conveyor travel path design considerations include the following carton characteristics: the least frequent, most frequent, and average carton length, width, and height, plus the weight and bottom conveying surface. It is also important to determine the operating environment. What is the temperature (in a freezer or otherwise)? How dusty is the operating area? When the frame or roller is touched by an employee or carton surface, a galvanized coating reduces dirt transfer and reduces dust. In some large systems, coating the frame with a colored coating is standard practice. To ensure a smooth and continuous carton flow, there are at least three rollers under the shortest carton. The roller capacity is the maximum weight that a roller supports as the carton is moved across the conveyor travel path. If your carton weight exceeds the roller capacity, increase the roller number under the shortest carton or remove the shortest cartons from the pick-to-conveyor system. The conveyor frame is the maximum weight that a roller-conveyor frame section that is supported between two upright stands. A curved section routes the carton conveyor travel path travel around obstacles. The roller curves may be single straight rollers. With a single straight roller curve, a square or rectangular carton does not travel on the single straight roller curve, but the carton travel tends to slow at the curve exit. The roller curve may also be a double-roller curve. With a double-roller or differential curve, the double-roller design reduces carton twisting but skews the carton at the curve exit. The third option is tapered rollers. With a tapered-roller curve, the rollers at the interior curve are smaller or narrower than the wider or larger roller parts at the curve’s outside. This roller design keeps the cartons in the same position during travel around the curve. Since most conveyor manufacturers have calculated curve charts, you can determine the curve width with the basic carton information (length, width, and desired clearances). The conveyor straight-travel path is determined by the carton width, the clearance between the carton and guard rails, and the decision to use guard rails. If the carton is conveyed without guard rails, the conveyor frame width is designed for the widest carton and for the desired clearance between the carton and conveyor frame. The incline or decline conveyor travel path determines the slope for the conveyor elevation change between the elevated end and the lower end. Most manufacturers have charts that show the plan-view length for the conveyor’s straight run, including the powered tail and nose-over. These slopes range from 5/8 to 1/4 inch per foot, and depend upon the carton and conveying surface. A decline travel path alternative is a gravity-powered slide or chute. A system must have sufficient E-stop buttons or pull cords along the conveyor travel path and for the incline or decline travel path, as well as sufficient protection for the underside of the conveyor belt. A 6-to-12-inch clearance must be allowed for between a carton and building.

HOW TO CROSS THE CARTON-CONVEYOR TRAVEL PATH In most carton-pick-to-conveyor methods, how to cross the carton-pick conveyor travel path by an order-picker is a design requirement. Having an order picker cross


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the carton-pick conveyor travel path permits one order picker to pick cartons from pick positions that are on both sides of the carton-conveyor travel path, and allows for part of the emergency travel path. The methods for crossing the carton-pick conveyor travel path include safety gate, stairs and platform, stile, and ships ladder.

SAFETY GATE The safety gate permits an order picker to pass through the conveyor travel path via the lift gate in the conveyor travel path. A lift-gate section is a 3-foot-long gravity skate-wheel conveyor section that is spring-counterbalanced with handles on both sides of the conveyor frame. In the open position, the lift gate gives an employee access to the other pick aisle. In the closed position, to ensure continued carton flow across the lift gate, the conveyor travel path design has the following features. Prior to the lift gate is a 4foot-long powered-belt conveyor travel-path section, and the lift gate has a switch that controls the electric power to the belt conveyor section. The powered-belt conveyor section feeds cartons onto the lift gate. If the lift gate is in the open position, the switch turns off the powered-belt conveyor section. Without the electric power to the drive motor, the powered-belt conveyor section does not move and cartons do not travel onto the lift gate. In the closed position, the lift gate permits the electric motor to drive the belt conveyor section, which allows the cartons to travel across the lift gate. When the lift gate is in the up or open position, there is a 36-inch clear space for an employee aisle. The drive motor is not on. The lift gate is low in cost and is a path for an order picker to cross a conveyor travel path.

STAIRS

AND

PLATFORM

With this method, the employee walks up and over the carton-conveyor travel path. The components are stairs and handrails that lead to or decline from an elevated platform, and a platform with handrails and kick plates that is above the conveyor travel path. The stairs and platform are welded structural members with coated exterior metal that meets local codes. The stairs and platform, connected together, form a bridge for an employee to cross a carton-conveyor travel path. The stairs and platform method has a higher cost.

STILE The next method by which an employee crosses the carton-conveyor travel path is the stile. The stile is similar to the stair and platform method except that the stile is a preformed, coated metal structure, and the stairs elevate to a short elevated platform. The short platform bridges the carton-conveyor travel path. The advantages are low investment and the ability to relocate the stile along a conveyor travel path.

SHIPS LADDER

WITH

SLATS

BETWEEN

CONVEYOR ROLLERS

The next cross-the-conveyor travel path method is the ship ladder with handrails and slats between the rollers on a conveyor travel path. Between the two handrails and



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conveyor frames is a slat between two rollers. The slat elevation is slightly below the roller top. As an employee walks across the conveyor travel path, these slats are where the employee places his or her feet. The preferred conveyor travel path has low- or zero-pressure conveyors. Before crossing the conveyer travel path, the order picker makes sure that there are no cartons on the conveyor travel path or approaching the crossover path. If there are no cartons on the conveyor travel path, the employee crosses the conveyor travel path. If there are cartons on a conveyor travel path, the employee waits for the cartons to pass or stops the cartons on the conveyor travel path. The advantages are low investment and ease of relocating.

CARTON TRAVEL ON A CONVEYOR TRAVEL PATH At a location on a conveyor travel path, a roller carton-conveyor travel path is designed to direct cartons to one side of a carton-conveyor travel path to have the cartons interface with a divert device, bar-code scanner, or label device. The methods are skewed rollers, sleeve-wrapped or taped rollers, and an angled deflector.

SKEWED ROLLERS The first method to control carton travel on a roller-conveyor travel path is to skew or angle several rollers on the conveyor travel-path section. The skewed rollers create an angled carton travel path on the conveyor surface. As the carton moves forward, it travels across the skewed rollers. The rollers revolve on the travel path, the carton is directed toward the side with the carton conveyor travel path, and travel proceeds along the side with the required conveyor travel path. The skewed-roller method can affect the belt tracking on a belt-driven rollerconveyor method, but your maintenance employees install the skewed rollers on the conveyor travel path and reduce the tracking problems.

SLEEVE-WRAPPED

OR

TAPED ROLLERS

The sleeved-wrapped or taped-roller method is used on any type of roller-conveyor method. Prior to the location where the travel path is required to have the cartons travel on the side with a carton-conveyor travel path, a specific roller number is wrapped or taped in a spiral manner with girt-covered tape. The pattern of the tape on the roller runs from a conveyor travel path’s far side to a conveyor travel path’s near side. With each progressive roller on the conveyor travel path, the spiral tape’s location moves to a conveyor travel path’s near side. With the girt-tape surface, as the carton travels across the tape the carton’s bottom surface comes in contact with the girt tape and directs the carton travel from a conveyor travel path’s far side to the near side. The advantage is low cost. The disadvantages are that the system requires periodic application and that it is used on a roller-conveyor travel path.

ANGLED DEFLECTOR The angled deflector has a solid metal plate, skate wheel, or channel guardrail. The deflector is located on a conveyor travel path’s far side and projects at an angle


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outward toward a conveyor travel path’s near side. As the carton travels on the conveyor travel path and comes in contact with the angled deflector, the carton travel speed, movement, and deflector angle move the carton from a conveyor travel path’s far side to a conveyor travel path’s near side. The advantages are low cost and use on any roller-conveyor travel path.

EMPTY-PALLET RETURN A very important transaction activity and station in a carton-pick-to-conveyor method is the empty-pallet removal and return activity. The empty-pallet removal transaction has an employee remove an empty pallet from the pick position, transport the empty pallet to an empty-pallet queue position, deposit the empty pallet in the position, and leave the queued empty pallets for forklift pickup. The various empty-pallet removal and transport methods are first, to have an order picker physically remove an empty pallet from a pick position and push or pull the empty pallet across the walkway to the empty-pallet queue position; second, to use an empty-pallet nonpowered mechanical method to lower the pallet to a conveyor travel path. This conveyor travel path moves the pallet to a forklift pickup location. The third method uses a manual overhead powered mechanical hoist with a set of hooks and an overhead travel path in an aisle.

ORDER-PICKER REMOVAL

OF THE

EMPTY PALLET

The most common empty-pallet removal and transport method has an order picker remove and push or pull the empty pallet across the walkway to the empty-pallet queue position. The method’s considerations are the empty pallet in the pick position and the floor surface. With a standard pallet-rack position, an empty-pallet removal transaction has the employee bend and pick up an empty pallet. When a pallet flow rack has the pick position at the flow rack’s end, employee empty-pallet removal effort is minimized by a roller end stop and metal runners in the cavity between the two conveyor travel-path frames, which assist in the empty-pallet removal activity. If the pallet flow-rack method has a pick position on the flow rack’s side, employee empty-pallet removal effort is minimized by sufficient conveyor length, which minimizes pick-position pallet-line pressure, and metal runners in the cavity between the two conveyor travel-path frames, which assist in the empty-pallet removal activity. After removal from a pick position, an empty pallet is placed on its end and is pushed or pulled across the floor from the pick position to an empty-pallet queue position. The empty pallet is transferred into the empty-pallet position.

EMPTY-PALLET GUIDE PATH As employee pushes or pulls an empty pallet across the floor, there are potential pallet hang-ups on the floor. To minimize these potential pallet hang-ups, many pick aisles have a 6-to-8-inch-wide hardened metal surface. This metal surface has a continuous and smooth surface (joints are smoothed or overlap like roof shingles), and serves as a pallet travel path that lets the wood pallet travel easily over the metal



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travel path. If the overlapping metal surface is used as the empty-pallet travel path, the empty-pallet travel direction is a one-way travel path with the pallet riding over the overlap. To minimize pallet hang-ups and an employee’s push-and-pull effort, an angled iron or a piece of preformed sheet metal can serve as the metal guide path. The 8-by-8-inch angled iron or preformed sheet metal piece has the leg-up, and the leg-up is against the pick-position member or the conveyor travel-path leg member. The features are employee physical effort, small investment, and employee injury.

POWERED MECHANICAL PALLET-FLOW METHOD The next method for removing an empty pallet from a pick position is the nonpowered mechanical pallet-flow conveyor method. This method has a speciallydesigned pallet pick position with a mechanical device that is activated by an order picker. With an empty pallet in the pick position, an order picker pushes a lever that causes a mechanical device to lower the empty pallet to a pallet-conveyor travel path. The pallet-conveyor travel path runs the entire length under the pick position and is sloped to have an empty pallet flow from the charge location to the discharge (forklift pickup) location. The empty-pallet conveyor travel path has sufficient length for one to three empty pallets. A forklift truck driver removes an empty pallet from the discharge location. The features are less employee physical effort, minimized potential for employee injury, elevation requirement, and additional investment.

MANUALLY CONTROLLED OVERHEAD POWERED MECHANICAL HOIST WITH A SET OF HOOKS The next empty-pallet removal and transport method makes use of a manually controlled overhead powered mechanical hoist with a set of hooks. This method includes a manually controlled overhead mechanical hoist that has the capacity to lift an empty pallet; the hoist is mobile on an overhead structural-support travel path. This travel path is along the employee walkway between the rack’s structural members and the conveyor travel path. Another component is a set of hooks at the hoist chain’s end. The set of hooks is designed to enter an opening between two pallet deck boards and secure the pallet to the hooks. After an empty pallet is secured to a pallet deck opening, the employee activates the hoist device to raise an empty pallet from the pick position. With the raised pallet, the employee walks in the walkway and moves the hoist over the travel path to the empty-pallet queue position. At the empty-pallet queue position, the employee lowers the empty pallet onto an empty-pallet stack. The method requires minimal employee physical effort, though an employee must move and engage the hoist. An investment in the hoists and travel path is required.

EMPTY-PALLET POSITION The next carton-pick-to-conveyor component is the empty-pallet queue position. In a carton-pick-to-conveyor method, the empty-pallet queue position is a very impor-


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tant component. The empty-pallet queue position is a pallet pick position that is allocated to collect empty pallets. These pallets are queued to a predetermined height. When the pallet stack reaches that height, a forklift truck transfers the empty pallet from the position to the receiving dock or other assigned location. For best employee productivity, the empty-pallet position is located every eight to ten pick positions along the pick line. With the standard pallet-rack pick position method, the empty-pallet position is one pallet wide. With the pallet flow-rack method, the empty-pallet position is one pallet wide and the conveyor travel path is flat (with no slope or pitch) from the charge end to the discharge end, or to the forklift pickup side. The empty-pallet conveyor travel path’s underside has a structural surface that permits an employee to push a pallet stack forward to the forklift pickup side.

ELEVATED EMPLOYEE WALKWAY The employee walkway is the next elevated pick-area design factor. The elevated employee walkway paths permit an employee to walk to the required pick positions and complete the various pick transactions. With an elevated employee walkway, the walkway’s structural components and path members have the structural strength to support an employee with a carton. When you consider an aisle for the elevated walkway, the next consideration is to decide between using a closed deck and an open deck on the walkway. The following situations provide some insights.

SOLID-DECK WALKWAY The solid deck is preferred in the following circumstances: • • • • •

• •

When carts and other mobile or wheeled equipment are used on the elevated finished floor When the carton or carton contents could fall through an open deck’s members When the equipment layout on the elevated finished floor is different from that of the lower finished floor When the activity on the elevated floor has a high traffic requirement When the elevated finished floor area is large and you desire to have future flexibility to locate different equipment or activities on the elevated finished floor When women in dresses are working on the elevated finished floor When the local authorities require smoke detectors and fire sprinklers

OPEN-DECK

OR

GRATED-DECK WALKWAY

The open-deck walkway is considered for the following situations:



• • • • •

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When a short span is required for the walkway or aisle When there is a rack- or equipment-supported elevated finished floor When the function on the elevated finished floor is the same as on the lower finished floor When only a few employees are working on the elevated finished floor When heating and ventilation conditions are the same for the two finished floors

STAIRS Stairs are the next consideration for an elevated pick area. The stairs provide an employee with the means to walk between the various elevated finished floors to complete pick transactions and, during an emergency, to exit the facility. In most applications the stairs are hardened metal structures that are located at both ends of the pick aisle and have a number of steps that conforms to the local building code. Other stairway components are handrails, intermediate safety rails, and platforms.

ORDER-PICKER ROUTING PATTERN The next important carton-pick-to-conveyor method is the order-picker routing pattern. The order-picker routing pattern directs the order picker along the pick aisle to the required pick position. The unique feature of the pick-to-conveyor method is that the order-picker pick aisle is on one side of the carton-conveyor travel path. The carton-conveyor travel path prevents the order picker from walking in the pick aisle on the other side of the conveyor travel path. The two order-picker routing pattern options are one order picker per pick aisle and two order pickers per pick aisle. For additional review of these order-picker routing patterns, we refer the reader to the employee-walking section in this chapter.

ORDER-PICKER INSTRUCTION METHOD The next important carton-pick-to-conveyor method is the order-picker instruction method. The order-picker instruction method directs the order picker along the pick aisle to the required pick position. At the pick position, the pick instruction method directs the order-picker to remove a specific carton quantity from the pick position. The carton-pick-to-conveyor method is a batched group of customer-ordered cartons; the most frequently used order-picker instruction form is the self-adhesive label. For additional information, we refer the reader to the previous section in this chapter.

SORTING METHOD A carton sorting method is a basic requirement for a batched or grouped customerordered and picked carton order-pick method. The carton sorting method ensures that a group of your mixed customer-ordered, picked, and labeled cartons are sep-


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arated into the appropriate temporary holding lane or loaded directly onto a customer delivery vehicle.

SORTING

TO

TEMPORARY STORAGE

AND

SHIPPING AREA

In a batched carton order-pick method, sorted cartons are sent to temporary storage or shipping. Temporary-Storage Sorting Method In a temporary-storage sorting method, the sorted cartons are placed into a temporary holding area for later transfer to your customer delivery vehicle. This method is designed to hold your customer-ordered, picked, labeled, and sorted cartons, which are staged prior to being loaded onto a customer delivery vehicle. When your carton order-fulfillment operation handles a large carton orderpick volume in advance of your customer delivery truck’s scheduled arrival, or when the delivery truck is off-schedule, a temporary-storage sorting method is a viable method. It is similar to the normal pick-to-conveyor method, except that cartons are removed from a carton-conveyor travel path and placed into a standard pallet-rack or pallet flow-rack storage position. In the temporary-storage sorting method, the customer-ordered, picked, labeled, and sorted cartons are conveyed and sorted to a customer assigned aisle. In this aisle, an employee transfers the cartons from the conveyor travel path to the appropriate temporary rack position. The rack position is a standard rack or palletflow rack. After the temporary storage pallet attains a predetermined height, the full pallet is allowed to flow on the pallet flow rail, or your employee hand-stacks cartons into another standard rack bay. With the methods, additional cartons on a customer-order are placed in other pallet positions or queued on pallets in the flow rack. When your customer-order is required at the shipping dock, per your delivery truck loading schedule an employee removes the labeled cartons from the pallets in the temporary holding area. These pallets are at the exit end of the pallet flow rack or in standard pallet-rack positions. The employee transfers these cartons onto the conveyor travel path for transport from the temporary holding area to the shippingsorting area, for transfer onto a customer delivery vehicle. The disadvantages are building and material-handling equipment investment, carton double-handling, and errors. The advantages are the handling of a large customer-order number; a reduction in on-hand inventory; increased inventory turns; and the removal of peaks from the picking, sorting, and shipping activities. Shipping-Sorting Method In the shipping-sorting method, your customer-ordered, picked, and labeled cartons are sorted for placement onto your customer delivery device (a cart or pallet), or loaded directly onto your customer delivery vehicle. During this method, when your batch-picked customer cartons are sorted for placement onto the appropriate customer delivery cart or pallet, the order picker



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labels each batch-picked carton. As the labeled carton leaves the picking area, the carton travels to the induction station. At the induction station, the carton-label sorting code is entered into the microcomputer. This information activates the appropriate divert device at the required time to divert the carton from the sorting conveyor travel path to the assigned shipping lane. On the shipping lane or conveyor, the carton travels to the off-loading station. At the off-loading station, the alternative carton-handling methods are direct-loading a customer delivery vehicle or transferring customer cartons onto a cart or pallet. The cart or pallet is staged in a shipping dock area and, at the appropriate time, the carts or pallets are loaded onto a customer delivery vehicle.

DIRECT-LOADING METHOD In the direct-loading method, your sorted cartons travel on a gravity-powered conveyor travel path from the sorting conveyor travel path to an extendible conveyor travel path and onto your customer delivery truck. In a delivery truck, the cartons are manually removed from the extendible conveyor travel path and stacked onto a truck floor. The extendible conveyor travel paths are powered belt, powered roller, nesting nonpowered or powered skate-wheel conveyor, nesting nonpowered or powered roller conveyor, or nonpowered roller or skate-wheel sections on a series of tripods. For additional information on the various conveyor-loading methods, we refer the reader to Chapter 7. The disadvantages of this method are conveyor investment, management control, and the need for delivery trucks at the loading docks. The advantages are less dock or holding area, no carton double-handling, and reduced errors.

SHIPPING CARTONS

ON

CARTS

OR

PALLETS

In this method, cartons travel on a queuing conveyor travel path from the sorting conveyor travel path to a station where cartons are placed on carts or pallets. After each shipping device is placed on a cart or pallet, the completed cart or pallet is transferred to a staging area or is placed onto a customer delivery truck. The disadvantages are the need for activity-station and dock-staging areas, the need for a recirculation conveyor, and the need for carton double-handling. The advantages include easily loaded trucks and protective wrap on a cart or pallet; the method is preferred for a customer with a cart delivery, and the delivery truck is not required at the dock.

VARIOUS SORTING TYPES The common batched-pick carton-sorting design features include a customer identification label that is human-readable or human- and machine-readable; a conveyor travel-path method with the ability to queue cartons prior to the induction and cartloading stations; and the capacity to handle a carton number, customer number, and batch or wave carton customer-order volume.


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SORTING IS

THE

HEART

OF THE

BATCHED ORDER-PICK METHOD

If your carton order-fulfillment pick-to-conveyor method handles a large carton volume for a large customer number, to handle the carton volume and customers the operation uses the batched-pick-to-conveyor method. The carton-sorting method is the heart of a batched order-pick method. Prior to a carton-sorting method’s design and implementation, you determine the following: • • • • • • • • • • •

Carton size (minimum, maximum, and average length; maximum width; and minimum and maximum height) Carton weight (minimum, maximum, and average) Carton exterior top, sides, and bottom Average and peak carton number per day or week Hours per work day Label and bar-code type and size Bar-code encoding and how to read the label Required gap space between two cartons Carton crushability and fragility Ensuring that all cartons are sealed Providing necessary conveyor travel-path space for queue and activity stations

A conveyor-sorting method without a sufficient carton queue creates an out-ofbalance situation between the pick area and the sorting area, which does not permit the order pickers and loading employees to achieve budgeted productivity rates. After these design parameters have been determined for a carton-sorting method, you design a building to house the carton-sorting method, or design a carton-sorting method to fit within an existing building. After your batched cartons are labeled and transferred to the conveyor travel path, the carton-sorting methods include manual sorting and mechanical sorting; the latter includes active, passive, and a hybrid of both. Manual-Sorting Conveyor Methods The manual-sorting conveyor method is a basic and simple sorting method; it requires a human-readable label. The label is placed on the carton in a location (front, side, or top) that is easy to read by the sorting employee. In this manner, the batch-picked cartons are transported to a manual-sorting area that is located in the shipping area. The sorting employee reads a carton’s human-readable label and matches the label identification number to a customer-shipping station number. When there is a match, the carton is transferred from the sorting conveyor travel path onto the appropriate customer-shipping device. Few and large characters and digits mean better sorting productivity and accuracy. With this method, the sorting employee handles 10 to 15 cartons per minute with little damage or impact on the carton’s contents. The maximum carton weight



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is 40 to 50 pounds, and the average weight is 20 to 30 pounds. To ensure efficient carton handling, you maintain a 3-to-6-inch gap between two cartons, and the carton queue conveyor has low or zero pressure. The manual sorting designs are one conveyor, double-stacked conveyors, recirculation loop, and apron. One-Conveyor Method In this manual carton-sorting conveyor design, the sorting queue-conveyor travel path is along your customer shipping stations. The zero- or low-pressure queueconveyor travel path has a 1-inch high guard rail (on the far side from the shipping station) and an end stop. This feature allows the sorting employee to move an unsorted carton in a reverse direction over the conveyor travel path to the appropriate sorting location; when an employee stops a carton on the conveyor travel path, there is minimal forward pressure on the carton. The disadvantages are sorting errors, the need for a large and clear label, low carton volume or few customers, employee effort to return unsorted cartons, a large employee number, and the potential for employee injury. The advantages are there is low impact on the carton, low investment, simple operation and control, sorting to both sides or bilateral sorting, and no high near-side guard rail (or only a minimal one). Double-Stacked Conveyors Method In a double-stacked low- or zero-pressure carton-queue conveyor travel path, each conveyor travel-path level has a 1-inch high far-side guard rail and a fixed end stop. The lower conveyor travel path is for sorting, the elevated conveyor travel path is for the unsorted cartons, and the two conveyor travel paths move cartons in opposite travel directions. If the sorting employee at the first sort station did not sort all the cartons, the employee at the next sort station removes the unsorted cartons from the lower conveyor travel path and places the cartons on the elevated conveyor travel path. The elevated conveyor travel path returns the cartons from sorting station two to sorting station one. The disadvantages are a great employee number, possible sorting errors, handling of few customers and a low carton volume, the need for a human-readable label, and the need for an employee to lift a carton. The advantages are low impact on a carton, medium investment, simple operation and control, and less effort required to handle unsorted cartons. Recirculation-Loop Method In a recirculation loop conveyor method, all cartons travel past all sorting stations, and the unsorted cartons re-enter the sorting-conveyor travel path prior to the first sorting station. A recirculation conveyor’s options are the powered 180º curve and two straight conveyors with end stops and a gap plate. Powered 180º Curve. In the powered 180º-curve method, there are two powered 180º curves and a merge conveyor to recirculate the unsorted cartons automatically. The entire conveyor method has one far-side guardrail and, at the merge junction, a photo eye to control the stopping and starting of conveyors. These devices control the carton flow from the pick area to the sorting area and carton flow on the unsorted


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recirculation loop to the sorting conveyor. The in-feed conveyor transports cartons from the pick conveyor and is located between two straight conveyor sections. Disadvantages are the same as for the double-stacked conveyor design. Additional advantages include the fact that an employee does not lift the unsorted cartons, higher capital investment, and the ability to handle a higher carton volume. Two Straight Conveyors with End Stops and Gap Plate. This design has two straight conveyor travel paths that are side-by-side conveyor travel paths with end stops, and each conveyor travel path moves cartons in opposite travel directions. Between the two conveyor travel paths is a gap plate that is slightly higher in the middle than the conveyor rollers. The gap plate is a solid hardened-metal or plastic piece with a bowed middle. It serves as a far-side guard rail, provides a bridge between the two conveyor travel paths, and permits easy carton transfer between the two conveyor travel paths. If an unsorted carton appears, the employee at the next sorting station gently pushes the carton across the gap plate onto the other conveyor travel path. The second conveyor travel path moves the carton to the first sorting station. At this location, the sorting employee at the second sorting-conveyor travel path stops the carton in-flow from the pick area and pushes the unsorted carton across the gap plate, which reintroduces the carton to the first sorting station. The two sideby-side conveyor travel paths require an investment and handle a medium volume. Apron Method The final manual-sorting conveyor method is the circular apron conveyor. The circular conveyor with a photo-eye stop and start control network allows pick-area cartons and unsorted cartons to pass automatically and recirculate to the first sorting station. The method has the same disadvantages and advantages as the recirculation loop conveyor method, except that there is an additional investment. Mechanical-Sorting Conveyor Methods The mechanical-sorting conveyor method has the capacity to handle a large customer number and a large carton volume per work day. With this method, the customerordered, picked, and labeled cartons are sent from the pick area to the sorting induction station. At the sorting induction station, a scanner device reads the label and encodes the carton onto the sorting-conveyor travel path. At the assigned divert location, a divert device is microcomputer-activated to transfer the appropriate carton from the sorting-conveyor travel path onto a shipping or direct-load lane. At this activity station, an employee transfers the carton from the conveyor travel path onto a cart, pallet, or delivery truck floor. The mechanical sorting method features are a large volume, a greater customer number, fewer employees, minimal sorting errors, the creation of a manifest, equipment and computer investment, a human-readable or human- and machine-readable label with a bar code, and a smaller building. When you consider a carton-sorting conveyor method, you must ensure that there is adequate electrical power in the required location and a drain for an air compressor.



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The carton conveyors that are used in a carton-sorting method design include, first, a nonpowered roller or skate-wheel conveyor with partial and full-line control devices that are used as a carton travel path from the sorting conveyor to a shipping station or direct-load conveyor. The second item is a nonpowered gravity slide or chute with a concave or flat carton-travel surface and with partial and full-line control devices, which is used as a carton travel path from the sorting conveyor to a shipping station or direct-load conveyor. Third, a powered-belt conveyor travel path whose sections control carton movement over an incline or decline travel path is used; these sections can also create a cap at merge locations, at a travel path to a shipping station or direct-load station, or prior to a scan/weigh station. Lastly, powered-roller and skate-wheel conveyors are used for a queue section, a sorting travel path, transportation travel paths, and pick-area conveyor travel paths. Per your design parameters, the powered-roller and skate-wheel conveyor types are the belt-driven roller, the chain-driven roller, the padded chain-driven roller, the line-shaft-driven roller, the drag chain, the belt-driven skate wheel, and the cabledriven roller. Various Sections of the Mechanical-Sorting Method A mechanical carton-sorting conveyor method’s components are the order-pick area; the transport system; the induction or in-feed station with a brake, a meter, and induction conveyors; the no-read spur; the sorting conveyor travel path with divert devices; the shipping conveyors; and the clean-out or recirculation system. Order-Pick Area Conveyor The order-pick area conveyor is the conveyor travel path that travels through the pick aisle. During the pick activity, order pickers transfer picked and labeled cartons onto the pick-area conveyor travel path. The pick-area conveyor travel path transports the cartons from the pick area to merge with the transport conveyor. To ensure proper carton merging, the pick-conveyor travel path’s discharge end has a pop-up stop device or a brake belt conveyor section. In most carton-pick-to-conveyor applications, the pick-area conveyor travel path is a roller conveyor. Transport Conveyor The transport-conveyor travel path ensures that there is a sufficient carton queue prior to the key stations, and that the cartons travel from the pick-area conveyor and recirculation conveyor over the transport conveyor travel path to the inductionstation area. On this travel path, all cartons are individuated and, prior to the induction station, a gap is created between two cartons by a brake and meteringbelt conveyor sections, or by a speed change at the take-away conveyor. This gap ensures that your induction employee or scanner device reads the carton label and that the divert device has sufficient space to complete the divert transaction. Induction or In-Feed Conveyor The induction-conveyor travel path is the location where your customer-carton identification number is entered into the sorting-conveyor microcomputer. The induc-


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tion-area design has a conveyor queue that can provide a constant carton flow to the induction station. The induction methods are manual or keypad, semiautomated or handheld scanner, and automated or fixed-position scanner device. Manual or Keypad At a manual induction station, a carton with a large human-readable code on a label is on the carton’s top or side surface. The label location permits your employee to read the code easily. As the labeled carton passes the induction station, an employee manually encodes the label identification on a keypad. The encoding device transmits the address code to the microcomputer and tracking device. At the appropriate location, a divert device is programmed to transfer the carton from the sorting travel path onto the appropriate shipping lane. Most keypads have 10 numbered buttons (0 to 9) and a repeat button, a scan on/off button, an error signal, a cancel key, a five-digit light-emitting diode (LED) display, an E-stop button, and a send key. To achieve manual induction productivity, the address code has large numbers and contains the minimum number of digits. The disadvantages are employee training, low volume, potential induction errors, a need for the greatest employee number, and the need for all labels to face in one direction. The advantages are low investment and the ability to serve as a backup for the other induction methods. Semiautomated or Handheld Scanner In the semiautomatic induction method, the carton has a human- and machinereadable code on each carton’s top or side. As the carton arrives at the induction station, open space is created between two cartons. At the induction station, an employee takes a handheld scanner device and scans the carton bar-code label. After scanning the label, the carton passes the induction photo eye. The carton is released onto the sorting-conveyor travel path with a constant travel speed, under the control of the microcomputer and tracking device. At the appropriate divert location, a divert device is triggered to complete the sorting activity. The carton’s label information is sent to the manifest system. The disadvantages are additional investment and employee training. The advantages are reduced induction errors, the handling of a medium to high volume, and a requirement for fewer employees. Automated or Fixed-Position Scanner In the automated induction method, a bar-code label is on each carton’s front, side, top, or bottom surface. After the carton achieves proper spacing on the cartonconveyor travel path, it travels to the scanning station. The carton label is read by a fixed-position, fixed-beam scanning device, or a fixed-position, moving-beam scanning device. As the carton passes the induction photo eye, the carton is transferred onto the sorting carton-conveyor travel path. The label information is transmitted to the sorting-method microcomputer, and with a tracking device, conveyor constant travel speed and manifesting system ensure an accurate and complete



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sorting activity and manifesting documentation. The automated induction method is used with all sorting methods. The disadvantages are investment and the need for a human- and machinereadable label. The advantages are reduced induction errors, few employees, and high volume. No-Read Conveyor In all carton-sorting methods, and especially in an automated induction-scanning method, an important activity is the no-read carton’s reintroduction to the inductionconveyor travel path. After the automated label-scanning device station, a no-read conveyor travel-path spur is located on the sorting-conveyor travel path. The no-read spur is 12 to 15 feet from the bar-code scanner and is the first divert location past the scanning station. It is designed to receive all labeled or unlabeled cartons that were not read by a bar-code scanner device. The no-read conveyor travel path returns cartons to the induction station. At the induction station, a carton label is read a second time or manually or semiautomatically inducted onto the sorting-conveyor travel path. After the reinduction process, the carton follows the same sequence as a carton inducted for the first time. Sorting Conveyor with Divert Devices Any carton-sorting method has a carton-sorting conveyor travel path. The cartonsorting conveyor travel path ensures that an inducted carton travels at a constant travel speed across the sorting conveyor from the induction station to the appropriate divert location, and at the appropriate divert location activates a divert device to transfer the carton from the sorting-conveyor travel path onto the assigned divert location. Sorting-Conveyor Travel-Path Designs. The sorting-conveyor travel-path design is the conveyor travel-path layout that directs the inducted carton flow from the induction station to each carton’s assigned divert location. The sorting-conveyor travel path is a surface that moves a carton, and the designs include a single straightline sorting conveyor travel path with no carton-recirculation conveyor travel-path section, and an endless-loop sorting-conveyor travel path with a carton-recirculation conveyor travel-path section. Various Sorting-Conveyor Travel Paths and Divert Devices. The carton-conveyor travel paths or surfaces are roller, smooth top belt, slat tray, tilt tray, SBIR or moving belt, Nova™ sort, and gull wing. The divert devices are a solid metal deflector, a pusher diverter (side-mounted pusher or puller or overhead-mounted pusher or paddle), a powered-belt diverter, a plow diverter, an SBIR or moving belt, a tilt tray, a Nova sort, a tilt slat, a gull wing, a sliding shoe (single side or dual side), a pop-up diverter (pop-up wheel and popup chain), and a rotating paddle. The various sorting-conveyor travel-path and divert devices are the same as those that are reviewed in Chapter 7. For additional sorting-conveyor travel-path and divertdevice information, we refer the reader to Chapter 7.


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Shipping Conveyors or Lanes The shipping conveyor or lane is a gravity-roller, skate-wheel, slide or chute, or powered-belt or roller-conveyor travel path that directs carton flow from the sortingconveyor travel path to the shipping station or direct-loading conveyor. The shipping conveyor-lane options are to have the sorting travel path on the far wall from the shipping doors and to have a diverted carton travel from the divert location to the shipping station or loading conveyor, or to have the sorting travel path on the near wall above the shipping doors and to have a diverted carton travel from the divert location over a U-loop conveyor travel path to a shipping station or loading conveyor. The sorting-conveyor travel-path designs are the same as those that are reviewed in Chapter 7. For additional sorting-conveyor travel-path information, we refer the reader to Chapter 7. Clean-Out or Recirculation Conveyor The clean-out or recirculation-conveyor travel path directs the unsorted cartons from the sorting-conveyor travel path’s end back to the induction station. With some sorting methods, if a carton did not sort, or after a predetermined scan number with no sorting, a clean-out divert device is activated to divert the carton. For additional clean-out and recirculation-conveyor travel-path information, we refer the reader to Chapter 7. The disadvantages are a human-readable or human- and machine-readable code on a label; a requirement for more exact carton volume, SKU quantity, and SKU characteristics design data; and the difficulty of providing on-time customer orders and increased management control. In addition, some SKUs are nonconveyable and require another pick method; the system also requires a capital investment. The advantages are batched or grouped customer orders, the ability to add order pickers to one pick aisle, a high picking rate, accurate and automated sorting and shipping manifesting, fewer employees, a small building area with multiple pick levels, less pallet handling (with a flow rack), and possible family-group picks.

EMPLOYEE RIDES TO PICK POSITIONS AND PICKED CARTONS ARE TRANSPORTED AWAY The next major group of employee order-fulfillment methods is the one in which the employee rides to the pick positions and the customer-ordered, picked, and labeled cartons are transported from the pick area to the shipping area. This group has the batched, customer-ordered, picked, and labeled cartons transferred onto a conveyor travel path. The powered-conveyor travel path transports the picked and labeled cartons from the pick area to a sorting area and onto the appropriate customer staging area or delivery vehicle. This employee carton-pick method has batched or grouped customer orders, pick positions, a vehicle travel path, order-picker instruction and pick position identification, a powered-conveyor travel path, pick labels, a sorting method, a shipping or direct-loading method, and a pallet-replenishment vehicle and aisle. The methods in this group are pick car and Decombe.



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PICK CAR The pick-car method has a pick-car vehicle and a carton take-away conveyor travel path. The pick car travels horizontally and vertically in the pick aisle and has an empty-pallet carrying surface. The pick aisle is between two standard or pallet flowrack pick position rows, and has a floor powered-conveyor travel path. A separate forklift replenishment aisle permits pallet replenishment to the pick position. The pick-car method’s rack layout is designed with a 150-to-200-foot pick aisle and rack-row pick positions that are 1, 2, or 3 pallets high. The self-propelled pick car requires floor rails a pick aisle width of approximately 4 feet, 10 inches and an overhead clearance to elevate and lower the order-picker to the required pick position. The order-picker car is furnished with manual controls, a platform, and an empty-pallet storage magazine. Automatic controls, video display, heater, and picklabel printer are options. The pick car has a pivoting carton take-away belt conveyor that travels through the pick car and declines to the floor-level powered-conveyor travel path. The pick-car order picker has human- and machine-readable labels. After the order picker is onboard the pick car, the controls are set for a trip to the first label pick-position number. At the pick position, the order picker removes a carton from the pick position, places the pick label onto the carton’s exterior surface, and transfers the labeled carton onto the belt take-away conveyor travel path. The carton label faces the front, top, or side, as required by the scanning device. New technology permits semiautomated or fully automated controls and mechanical devices to provide pick-position identification, label printing, and label application on a carton. The labeled cartons flow on the pick-car decline-belt conveyor travel path onto the floor-level powered-conveyor travel path. The travel path transports the cartons from the pick area to the sorting area. The order picker removes all depleted pallets from the depleted pick positions and places an empty pallet onto the pick car empty pallet position. The empty pallet stack is transferred to an assigned empty pallet position. From a separate replenishment aisle, a forklift truck removes the empty pallet stack. Sufficient aisle run-outs are allowed at the pick aisle front and rear ends. These run-outs compensate for the pick car runners and structural members and permit the maximum pick positions per aisle.

DECOMBE TRUCK The next method is the decombe method. The spiral-chute or decombe truck is a high-rise order-picker truck that has guided aisle travel. The decombe truck has an operator platform with an elevating control and steering mechanism that elevates the operator to 20 feet. The spiral-chute truck does not have a load-carrying surface. Ahead of the operator platform is a gravity-powered spiral chute that extends the entire rack pick-position height. The chute and the moveable operator platform allows the order-picker to place the picked and labeled cartons onto the chute. Once the carton is in the chute, gravity and side guards direct the carton flow to the floor-


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level take-away conveyor travel path. This feature allows an order picker to pick cartons from one aisle side. There are several disadvantages to using the pick-car and decombe methods. There is a human- and machine-readable label. The pick car is restricted to one pick aisle and the decombe has access to one side of a pick aisle. Other disadvantages include limited pick-position height, investment, difficulty in handling volume fluctuations, and employee training. Finally, some SKUs are nonconveyable. These methods also have advantages. The order picker has access to all pick levels. There is no walking time or distance. Order-picker errors and equipment and building damage are reduced. Other advantages include accurate carton sorting and automatic carton manifesting; a heated cab for freezer applications; and, as required, family-group picks.

STOCK-TO-EMPLOYEE PICK METHODS The next major employee order-fulfillment method group is the group in which SKUs or pick positions travel to the order-picker at a pick station and the customerordered, picked, and labeled cartons are transported from the pick area to the shipping method. At the pick station, the employee stops the moving pick position and removes a carton from a pick position. With a single customer-order handling method, the order-picker uses a paper pick-instruction form and transfers the picked cartons onto a pallet or cart. The full pallet or cart is transferred to the customerorder staging area. With a batched customer-order handling method with label pick instructions, the customer-ordered and picked cartons are transferred to a poweredconveyor transport method. The powered conveyor transports picked and labeled cartons from a pick area to a sorting area and onto an assigned customer staging area or delivery vehicle. The pick-position-to-employee method involves single or batched customer orders; mobile pick positions; an order-pick station with stations for placing cartons on carts or pallets, or a powered-conveyor take-away travel path; order-picker instruction and pick-position identification; a powered-conveyor travel path; pick labels; a sorting method; a shipping or direct-loading method; and a pallet-replenishment vehicle and aisle. The pick-position-to-employee order-pick station methods are carton carousel, cart carousel, mini-stacker or mini-load, and S.I. Cartrac®.

CARTON CAROUSEL The first pick-position-to-employee method is the carton-carousel method. The carton-carousel method has several baskets or bins that are attached to an endless-loop chain. The carousel’s forward or reverse movement is controlled by a control panel that receives its instructions from an employee who makes a key entry or by a microcomputer. These instructions command the carousel to rotate until the required pick position is halted at the order-pick station. The order picker removes the carton from the pick position and places the picked carton onto the customer cart or pallet,



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or the carton is labeled and placed onto a powered-conveyor travel path. After completion of the pick, the carousel is programmed to advance the next required pick position. The horizontal carousel has an endless chain that is attached to the top or bottom of the drive unit. With mezzanines and available building space, the horizontal carousel method is one or two carousel units high. With sufficient floor space, the carousel layout has multiple horizontal carousels. When two carousels are designed side by side, an order picker station has access to both carousels. When four carousels are designed to service one order-pick station, the order-picker productivity improves because there is less waiting time and an increased SKU number.

CART CAROUSEL The second pick-position-to-employee method is the cart-carousel method. The cart-carousel method has several four-wheeled swivel-caster carts and several platforms that each support a cart and are attached to an endless-loop chain. The carousel cart’s forward or reverse movement is controlled by a control panel that receives its instructions from an employee who makes a key entry or by a microcomputer. These instructions command the carousel to rotate until the required cart with the pick position is halted at the order-pick station. The order-picker removes the carton from the pick position and places the picked carton onto the customer cart or pallet, or the carton is labeled and placed onto a conveyor travel path. After the picks are completed, the carousel cart is programmed to advance the next required pick position. The cart and carousel disadvantages are limited pick positions, the need for a replenishment cycle, and investment. The method is considered best for slow-moving and small-cube cartons. The advantages are that most methods do not require a sorting area, there is a reduced pick-aisle number, there is less employee walking and physical effort, and the method can handle batched customer orders.

S.I. CARTRAC The next pick-position-to-employee method is the S.I. Cartrac method. The carton S.I. Cartrac method has several carts with pallet or hand-stacked carrying surfaces. Each load-carrying surface travels over a fixed travel path and has four wheels. Each load-carrying surface rides on a revolving rail that propels the load-carrying surface forward. The S.I. Cartrac travel path has straight runs, 90º curves, and 180º curves. By pressing a load-carrying surface foot pedal at the pick position, an employee stops the cart and completes the order-pick transactions. After a pick transaction, a cart is released and moved to the next pick location and another cart is moved forward to the vacant order-pick position. The S.I. Cartrac method is designed to move the carts through the pick area and through the pallet replenishment area. A forklift truck operator stops the cart, removes the empty pallet, and transfers a full pallet onto the cart. The features are high pick productivity — at 85 cartons per hour — and high economics.


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SORT LINK The next pick-position-to-employee method is the sort-link method. The sort-link method involves several self-powered four-wheeled carts; vertical incline and decline sort-link cart travel paths; horizontal sort-link cart travel paths on each storage level; several sort-link cart-storage lanes, several carts deep, on each storage level; and computer controls. In the pick area, the sort-link cart travel path runs past the cartonpick stations and take-away conveyor. For additional information on sort-link design features and operational characteristics, which are similar to the pallet sort-link design features and operation, we refer the reader to the pallet-load sort-link section in Chapter 6. After the sort-link microcomputer receives the customer-ordered SKUs for each pick station, the sort-link carts are released from the sort-link cart storage area onto the main travel path from the storage area to the pick area. The pick positions along the sort-link cart travel path are the locations where an order-picker employee transfers the customer-ordered cartons from a pallet to a take-away conveyor or transport device. The customer-order pick method is a single customer-order pick method or a batched customer-order pick method with selfadhesive labels. The pick-position design options are to have the computer-controlled sort-link cart stop on the main sort-link cart travel path at each pick position, and to divert from the main sort-link cart travel path onto a spur sort-link cart travel path for travel to a pick position. When the computer-controlled sort-link cart stops on the main travel path at the pick position, per the customer order-pick instruction the order picker transfers the appropriate carton quantity from the sort-link cart onto the carton take-away conveyor or onto an in-house transport device. The features are minimal sort-link cart travel-path investment; possible sort-link cart queues and potential order pickers waiting for additional carts, with multiple pick stations along the sort-link cart travel path; and the smallest square-foot building area. When the computer-controlled sort-link cart diverts from the main sort-link cart travel path onto a spur sort-link cart travel path for travel to the pick position, per the customer-order-pick instruction the order-picker transfers the appropriate carton quantity from the sort-link cart onto the carton take-away conveyor or onto an inhouse transport device. The features are investment; minimal sort-link cart queues and increased picker productivity, with multiple sort-link cart spurs from a sort-link cart main travel path; and a large building area.

STORAGE AREA

OR

ASRS FRONT-END

The next pick-position-to-employee method is the storage area or ASRS with a dynamic front-end method. The storage or ASRS carton-pick method is located in the front of the pallet-storage or ASRS method. With this carton-pick method, the WMS-controlled storage forklift truck or computer-controlled ASRS pallet method transfers the required pallet from the storage area, over a pallet-conveyor travel path, and to the pick area. Each pallet has a discrete identification.



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The storage or ASRS front-end carton-pick method has an electric aisle-guided stacker crane with in-feed lanes with pickup and delivery (P/D) stations and outfeed lanes with P/D stations, or a forklift truck travel path to a conveyor. The system also contains a pallet main travel path, several carton-pick stations with pallet infeed lanes and pallet take-away lanes (and each pick station has a pick instruction format), a carton take-away conveyor travel path, and computer controls. The storage or ASRS carton-pick method components are ASRS computercontrolled cranes with induction and profile stations, a powered main travel path with in-feed lanes, divert devices, bar-code scanners, photo eyes, P/D stations, and out-feed lanes with P/D stations. The option is a WMS-controlled forklift truck. For additional information on the ASRS pallet design features and operational characteristics, we refer the reader to the pallet-load ASRS section in Chapter 6. The second ASRS carton-pick method component is the carton-pick module. To have a cost-effective and efficient system, the carton-pick method has a three-tofour-pallet conveyor pick module. A carton-pick module has a pallet in-feed lane and a pallet take-away lane. Each pick station has a pick instruction format and a divert device that diverts a pallet from the pallet-conveyor travel path to an active carton pick position. The first carton-pick module component is the carton pick-position section that has a pallet queue-conveyor travel path with an end stop. The pallet queue-conveyor travel path provides pallet queuing prior to the carton-pick station. The end stop halts pallet travel at the carton-pick station and ensures the pallet position is in the proper orientation for the bar-code scanner to have a line of sight to the bar-code label. With a line of sight to the label, a bar-code reader reads the label and transfers the SKU data to the microcomputer-controlled paper or paperless pick-instruction device. The pick-instruction device indicates to the carton order picker the appropriate carton number to pick from the pallet. Per your carton-pick operation, for batched customer orders with labeled cartons, an order picker transfers a carton onto a conveyor travel path. For batched customer orders with unlabeled cartons, a microcomputer-controlled printer prints labels that are applied to each carton that is transferred onto a conveyor travel path. For a single customer-order system, a carton is transferred onto a customer-order pallet, a cart, or a non-powered or powered mobile vehicle. As an option to assist the pick employee in transferring the picked carton from the pallet onto the powered take-away conveyor travel path is to provide a transfer table or platform. The transfer table or platform is a four-wheeled, guided, mobile, flat surface that has the same elevation as the carton-conveyor travel path surface, and that interfaces with the pallet pick position and take-away conveyor travel path. A pick-position design option is to run a pick aisle full-length between the palletconveyor pick positions and the powered carton-conveyor travel path. This feature permits the pick-area manager to allocate one picker per pick station, or to have one employee walk in the aisle and pick cartons from all pick positions. When an employee has completed all required picks, the employee activates the pick-position conveyor to move the pallet from the pick position over the vacant empty pallet lane onto a pallet take-away conveyor for return to the storage area.


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The third carton-pick module pallet lane is the take-away pallet lane. The pallet take-away conveyor travel path permits an empty pallet or a partially full pallet to be transferred from the pick module to the main pallet-conveyor travel path. The main pallet-conveyor travel path transports the pallet from the carton-pick area to the ASRS storage area, or an empty pallet is transferred onto the main conveyor travel path for transport to the empty-pallet station. After the ASRS microcomputer receives the customer-ordered SKUs for each pick station, the ASRS pallets are released from the ASRS pallet-storage area onto the main travel path, from the storage area to the pick area. When the computer-controlled pallet travel stops on the main conveyor travel path at the pick position, per the customer-order-pick instruction the order picker transfers the appropriate carton quantity from the pallet onto the carton take-away conveyor or onto a transport device. The features are minimal pallet-conveyor travelpath investment; possible pallet queues and potential order pickers waiting for additional pallets, with multiple pick stations along the pallet-conveyor travel path; and the smallest square-foot building area. With computer-controlled pallet travel, to divert the appropriate pallet from the main pallet-conveyor travel path onto a pallet-conveyor travel path for travel to a pick position, per the customer-order-pick instruction the order picker transfers the appropriate carton quantity from the pallet onto the carton take-away conveyor or onto an in-house transport device. The features are additional pallet-conveyor travel path investment; minimal pallet queues and increased order-picker productivity, with multiple pallet-conveyor spur travel paths along the main pallet carton travel path; and the largest square-foot building area. For maximum carton order-picker productivity, the WMS and material-handling equipment methods are coordinated so that the pallets that require picks are transferred from the ASRS through to the pick area and, after the pick activity, returned to the ASRS. When we consider the ASRS or storage forklift carton-pick method, the ASRS pallet transactions per crane are 22 to 25 pallets; a normal VNA lift truck completes 18 to 22 transactions per hour. To ensure pick pallets at the pick module, each pickmodule pallet pick lane has at least a 3-to-4-pallet queue space. The disadvantages are increased capital investment; a discrete identification for each pallet, and WMS and microcomputer-controlled devices; additional space required in front of the ASRS; a 3-to-4-pallet lane pick module; and the ability to handle a SKU number that is based on the number of ASRS or VNA forklift truck transactions per hour. The advantages are handling of conveyable and nonconveyable SKUs, minimized employee carton-handling effort, reduced pallet-handling number, minimized carton-pick required area, optimized medium-to-fast-moving SKUs, and the ability to provide carton replenishment to other pick areas.

MINI-LOAD The next pick-position-to-employee method is the mini-stacker or mini-load method. Via a captive computer-controlled aisle vehicle, the required cartons are transported between end-of-aisle P/D stations. The aisle is between two carton storage-position



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rows. The P/D station has an inbound carton-conveyor travel path to a crane pickup station and an outbound carton-conveyor travel path to an order-pick station. At an order-pick station, an order picker transfers a carton from the carton-conveyor travel path to a customer shipping cart or pallet, or the carton is labeled and transferred onto a powered-conveyor travel path. The mini-stacker method options are captive-aisle cranes and cranes that service any aisle. If a mini-stacker method has few cranes for several aisles, a T-car is used to move a stacker crane from one aisle to another aisle. This feature minimizes the stacker crane investment. The order-pick method can interface with a paper, paperless, or label order-pick instruction method. The mini-stacker carton order-pick method has limited applications in a dynamic order-fulfillment operation due to the investment and small inventory capacity.

AUTOMATIC ORDER-PICK METHODS The next major carton order-fulfillment method group is the automatic order-pick method group. In these order-pick methods, the customer-ordered cartons are automatically (by computer control) withdrawn or released from a pick position and transported by a powered carton-conveyor travel path from the pick area to the customer shipping station or directly loaded onto the customer delivery vehicle. The automatic carton-pick methods are the S.I. Ordermatic® method with a single, dual, triple, or quadruple quadrant model; and the Vertique™ method.

S.I. ORDERMATIC The first automatic carton order-pick method is the S.I. Ordermatic method. The method is designed as a one-, two-, three-, or four-quad (or quadrant) method. The one-quad Ordermatic design has a pallet reserve area, a station for removing cartons from pallets, a replenishment system, five-carton-high order-selection flow lanes with a pick impulse path, a picked carton take-away conveyor travel path, an outbound shipping or direct-load station, and a computer-control office. The two-, three-, and four-quad Ordermatic systems are similar to the one-quad Ordermatic system. The two-quad method is designed as a stacked Ordermatic with vertical or horizontal Ordermatic quads. The three-quad Ordermatic method is a very rare design but has a double-stacked Ordermatic and a standalone single quad. The four-quad Ordermatic method has two double-stacked Ordermatics. The typical 5-carton-high carton flow lane is 100 inches wide and represents one bay. One bay for an average carton provides 20 pick positions. For a 2-shift operation, a 4-quad Ordermatic method with 4,800 lanes and 4,400 SKUs handles a 64,000-carton throughput volume. The 80,000-carton throughput volume is reduced by a 15 to 20% utilization factor. An average 4-quad Ordermatic with a manual replenishment module is 77 feet, 6 inches, plus separate forklift truck replenishment aisles. An Ordermatic with a mechanized replenishment lane-loader module is 87 feet, 6 inches wide. The Ordermatic order-fulfillment operation requires that your customer orders are entered on schedule into the order-processing computer. Each customer-ordered


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carton is sent to each quadrant microcomputer. The microcomputer controls the quadrant carton flow-lane level. The microcomputer starts an order-pick impulse at the quadrant’s shipping side and travels to the quadrant’s opposite end. During the order-pick impulse, the Ordermatic releases your customer-ordered single carton from each flow lane. Each impulse is considered a single pick; a multiple-order carton has multiple impulses. The appropriate single carton slides from each pick-level lane onto the level carton-conveyor travel path. The carton travels on the appropriate level conveyor travel path to merge with the Ordermatic’s other pick-level conveyor travel paths. This carton travel path transports cartons from the pick area to the customerorder shipping station or directly onto a customer delivery vehicle. The carton replenishment in the Ordermatic method requires that a depleted carton flow lane has a replenishment prior to a stock-out occurrence. This situation requires that the reserve pallet be transferred on schedule from the reserve area to the station where cartons are removed from pallets. At this station, the required cartons are removed from the pallet and placed into the appropriate carton flow lane’s replenishment side. The partially depleted pallet is returned via forklift truck to an assigned pallet position, and a forklift truck transfers another required SKU pallet to the station. Because the Ordermatic entails a “pick or no pick” situation, the SKU replenishment method is computer-controlled and is on schedule. A failure in the replenishment activity means that stock-outs occur at the picking lane. The replenishment methods are as follows: the pallet position is directly behind the Ordermatic, cartons are transferred from pallets to a powered-conveyor travel path, or there is a mechanical lane loader. Pallet Position Directly behind the Ordermatic (Manual Method) The manual-replenishment method has replenishment rack-row pallet positions that are located directly behind the Ordermatic flow lanes. An employee walkway is between the Ordermatic flow lanes and the rack-row positions. A replenishment employee in the walkway manually transfers the required cartons from the pallet in the SKU flow lane. After the required cartons are transferred to the flow lane, a forklift truck returns the partially depleted pallet to the storage-rack area. Pallet Unloading Station and Conveyor System (Mechanized Method) The mechanized-replenishment method has a replenishment floor-level pallet unloading station. At this station, an employee transfers the required cartons from a replenishment pallet onto the replenishment-conveyor travel path. The cartons travel on the replenishment-conveyor travel path to the assigned SKU replenishment lane. At the SKU lane, an employee or mechanical device (a lane loader) transfers the cartons into the SKU lane. After the replenishment activity, a forklift truck returns the partially depleted pallet to the storage area.



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Lane-Loader or Mechanical Method The lane loader is a floor-level mechanical device that removes a carton layer from a replenishment pallet and transfers the carton layer onto a moveable in-feed carton station. At this station, employees feed the cartons onto the replenishment cartonconveyor travel path. The disadvantages are that the method only works with conveyable cartons, that very fast- and slow-moving conveyable cartons are handled off-system, some SKUs have multiple flow lanes, there is a fixed carton throughput volume, downtime is difficult to compensate for, on-time and accurate replenishments are difficult, queueconveyor travel path sections are required, stock-outs are possible, and a high capital investment is required. The advantages are accurate order picks, few employees, and family-group picks.

VERTIQUE The next computer-controlled or automatic-pick method is the Vertique order-pick method. The Vertique method has replenishment and carton pick-towers, a shipping conveyor travel path, and computer controls. The Vertique method involves an automatic single or batched carton order-picking method. During a pick the replenishment-conveyor travel path replenishes a carton to the pick tower. This method has SKU pallets delivered to a pallet unloading station. At the pallet unloading station, the cartons are manually or mechanically transferred from a pallet to the replenishment-conveyor travel path. The carton identification number is entered into a computer-controlled tracking device that diverts the carton onto the assigned pick-tower charge end or highest elevation. The pick tower has several flippers or pivoting trays that raise and lower to accept and discharge cartons. As a carton enters the pick tower’s charge end, the carton is received in an angled position and is stored in the flat position. In the flat position, the tray levels are ready-reserve positions. As the computer-controlled pick impulse releases a carton from the pick tower’s bottom level, the next pick-tower carton tray pivots, allowing cartons to index (move downward) from the ready-reserve level to the next-lower ready-reserve level or to the pick position. A second computer impulse releases another carton from the same pick tower or travels to the next required SKU pick tower on a customer-order. These cartons travel on the shipping-conveyor travel path from the pick area to the sorting area or to the shipping area. The pick towers are designed to be 10 to 80 feet high. The flippers or pivot devices handle cartons that weigh 10 to 100 pounds, and the pick lane is 12 inches wider than the carton width. The disadvantages are high capital investment, computer and software, and a fixed volume; some cartons are non-conveyable; delivery trucks are required at the dock; and queue-conveyor travel path sections are required. The advantages are accurate and on-schedule picks, the ability to coordinate the pick activity with the


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shipping activity, FIFO product rotation, a small building, picks by family group, and few employees.

NONCONVEYABLE OR VERY-LARGE-SKU ORDER-PICK METHODS In any carton order-fulfillment operation, the carton mix consists of a conveyable and nonconveyable carton combination. In most carton order-fulfillment operations, the conveyable cartons account for 90 to 95% of the annual carton volume. The nonconveyable annual carton volume accounts for 5 to 10% of the annual carton volume. A nonconveyable carton’s length, width, height, weight, size, and shape may not permit mechanization or automation. A manual order-pick method is required; to complete a customer-order, the nonconveyable cartons are loaded onto a customer delivery truck along with the conveyable cartons.

VARIOUS NONCONVEYABLE CARTON PICK METHODS The nonconveyable carton pick methods have the same major components as the conveyable carton pick methods except for some pick vehicles or methods, picked carton flow, and pick-position or customer-order location design.

NONCONVEYABLE CARTON PICK VEHICLES The manual nonconveyable pick methods are floor-stacked pallet positions, stacking frames or pallet cages, or pallets in standard or flow-rack positions. These cartons are picked onto a nonpowered or powered mobile vehicle. The vehicles are two-wheeled or four-wheeled cart or platform cart, pallet on a powered or nonpowered roller conveyor travel path, inverted power and free conveyor, S.I. Cartrac, powered cart carousel, nonpowered or powered pallet truck, and powered tugger with a cart train. Two-Wheeled Truck, Four-Wheeled Cart, or Platform Cart Method The first methods use a two-wheeled truck, four-wheeled cart, or platform cart. These methods require an employee to move or steer the vehicle through a pick aisle. The pick aisle has pick positions on each aisle side. Per the pick instruction, an employee completes a pick by removing a carton from the pick position onto the vehicle loadcarrying surface. For additional information on wheeled cart, or platform truck pick methods, we refer the reader to the carton two-wheeled truck, four-wheeled cart, or platform pick method in this chapter. The disadvantages are employee physical effort, potential of carton damage, and low employee productivity (30 to 45 units per hour); the method can also require double-handling to transfer the carton from the nonpowered vehicle onto a customer delivery-vehicle floor. The advantages are that economics are low on a per-vehicle basis and that there is very flexible operation.



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Pallet on a Powered or Nonpowered Roller-Conveyor Travel-Path Method The powered or nonpowered roller-conveyor travel path is another nonconveyable carton order-pick method. This method has a conveyor travel path with two strands or a single-strand conveyor that is between two rows or along a single pick-position row. After a pallet is placed onto the conveyor travel path, a powered roller conveyor surface or employee moves the pallet over the conveyor travel path. As directed by the customer-order-pick instruction, the pallet is stopped at the appropriate pick position. From the pick position, the employee transfers the required carton quantity from the pick position onto the pallet. After all pick transactions are completed or a pallet is full, the pallet is moved to the discharge location. At the discharge location, a powered forklift truck removes the pallet from the conveyor travel path and travels to the customer dock-staging area or directly onto the customer delivery truck. The disadvantages are conveyor investment and potential carton damage; the method also requires a specific floor area and a powered forklift truck to transfer a full pallet. The advantages are economics and minimal employee physical effort. Inverted-Power and Free-Conveyor Method This method uses a motor-driven endless closed-loop chain that pulls several pallet carrying surfaces over a fixed travel path. The load-carrying surfaces are located on wide centers on the chain and follow a fixed travel path’s past pick positions. The pallet-carrying surface has a set of wheels. These wheels ride on a rail and the loadcarrying surface is employee- or microcomputer-controlled to stop momentarily at each pick-position front. When the inverted power and free carrier is stopped, the order picker, per the customer order, transfers the carton quantity from the pick position onto the load-carrying surface. After all pick transactions are completed or a pallet is full, a forklift truck removes the pallet from the load-carrying surface. The powered forklift truck travels to the customer dock-staging area or directly onto a customer delivery truck. The disadvantages are conveyor investment and potential carton damage; the method also requires a specific floor area and a powered forklift truck to transfer a full pallet. The advantages are that the method is microcomputer-directed and requires minimal employee physical effort. S.I. Cartrac Method The S.I. Cartrac method is a motor-driven method that has four-wheeled carts. Each cart has a load-carrying surface and is propelled over a fixed travel path. The fourwheeled cart travel path is a rotating shaft that revolves and propels the carts forward over the travel path. Per the facility layout, the method is designed with 90º or 180º turns. By pressing a cart foot pedal, the cart stops at the employee pick station. When the S.I. Cartrac is stopped, the order picker, per the customer order, transfers the carton quantity from the pick position onto a customer cart or pallet. After all pick transactions are completed or the pallet is full, a forklift truck removes the


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pallet from the Cartrac load-carrying surface. The powered forklift truck travels to the customer dock staging area or directly onto a customer delivery truck. The disadvantages are conveyor investment and potential carton damage; the method also requires a specific floor area and a powered forklift truck to transfer a full pallet. The advantages are that the method is microcomputer-directed and requires minimal employee physical effort. Powered Cart-Carousel Method The powered cart carousel method is a motor-driven endless closed-loop chain that pulls carts over a fixed travel path. The fixed travel path is past pick positions. Each cart has brackets that permit a cart’s swivel casters or wheels to come in contact with the floor surface. The cart is employee- or microcomputer-controlled to stop momentarily at the appropriate pick position. When the cart is stopped, the order picker, per the customer order, transfers the carton quantity from the pick position onto a customer cart or pallet. After all pick transactions are completed or a pallet is full, a forklift truck removes the pallet from the load-carrying surface. The powered forklift truck travels to the customer dock-staging area or directly onto the customer delivery truck. The disadvantages are conveyor investment and potential carton damage; the method also requires a specific floor area and a powered forklift truck to transfer a full pallet. The advantages are that the method is microcomputer-directed and requires minimal employee physical effort. Nonpowered or Powered Pallet-Truck Method In the electric nonpowered or powered pallet truck nonconveyable carton pick method, the order picker travels with the pallet truck through a pick aisle. The pallet truck carries an empty pallet. Per the order-pick instruction, the employee stops the pallet truck at the appropriate pick position and transfers the required cartons from the pick position onto the pallet-truck pallet. With all customer picks completed or when a pallet is full, the order picker pulls or drives the pallet truck to the customerorder staging area or directly onto the customer delivery truck. The pallet trucks are a manual-powered pallet truck, a single-powered walkie or rider pallet truck, a walkie or rider double-pallet truck, a walkie or rider remotecontrolled pallet truck, and a powered pallet truck with a step or a set of moveable forks and an operator’s platform. For additional information for nonconveyable carton pallet-truck pick methods, we refer the reader to the pallet-truck pick method in this chapter. There is a medium cost per pallet truck. The manual pallet truck requires physical effort and the powered truck requires a battery charging and changing area. Powered Tugger with a Train of Carts Method The electric-powered tugger with a cart train method has an employee travel with an electric-powered tugger and a cart train through a pick aisle. Per order-pick



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instruction, the employee stops the tugger and transfers the appropriate carton quantity from the pick position to the correct cart. After all customer-order-pick transactions are completed, the employee directs the tugger with a cart train to the customer-order dock staging area or directly onto the customer-order delivery truck. For additional information for nonconveyable carton powered-tugger with a cart train pick methods, we refer the reader to the carton powered tugger with a cart train pick method in this chapter. There is a medium cost per tugger. Empty carts require storage space, and the powered tugger requires a battery charging and changing area.

NONCONVEYABLE PICKED-CARTON FLOW The next nonconveyable carton-pick carton component is the picked-carton flow method. The picked-carton flow methods are from a moving pick position to a stationary customer-order cart or pallet, and from a stationary pick position to a moving customer-order cart or pallet. From a Moving Pick Position to a Stationary Customer Location The first method is from a moving pick position to a stationary customer-order cart or pallet. With this pick method, from a storage location a powered forklift truck transfers a pallet or carton quantity onto a powered load-carrying surface. The moving load-carrying surface becomes the SKU’s pick position. The moving pick position with the carton or SKU on its surface travels past the customer-order positions. Per the customer order, the employee or microcomputer stops the pick position at each customer location that requires the SKU quantity. Per the customer order-pick instruction, the order picker transfers the nonconveyable carton quantity from the moving pick position onto the stationary customer position cart or pallet board. When a cart/pallet is full or a customer order is completed, an employee or powered forklift truck transfers the cart/pallet from the pick area to the customerorder staging area or directly onto the customer-order delivery truck. An empty cart or pallet board is placed in the customer position. Onto the empty cart/pallet the pick activity is repeated for the customer order for different SKUs or for another customer order. Per the customer orders, the SKUs are replenished or changed in the pick positions. From a Stationary Pick Position to a Moving Customer Location The second method is from a stationary pick position to a moving customer position. With this pick method, a powered forklift truck transfers a pallet or carton quantity to a fixed or stationary pick position (floor stack, block, rack, stacking frame, or pallet cage). The moving customer-order position is a load-carrying surface, which is a cart or a pallet on a nonpowered or powered-conveyor travel path or vehicle. The customer-order position is identified with the customer discrete identification. The customer-order load-carrying surface travels past all nonconveyable pick positions. Per the customer order, the employee or microcomputer stops the customer-


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order load-carrying surface at each SKU pick position’s front. Per the customer order-pick instruction, the order picker transfers the nonconveyable carton quantity from the stationary pick position onto the moving customer-order position cart or pallet. When the cart/pallet is full or all customer-ordered SKUs are picked, the customer-order moving position is stopped and an employee or powered forklift truck transfers the cart/pallet from the pick area to the customer-order staging area or directly onto the customer-order delivery truck. An empty cart or pallet board is placed in the vacant customer-order position. The pick activity is repeated for the customer-order for different SKUs or for another customer-order. Per the customer orders, the SKUs are replenished or changed in the pick positions.

ARRANGEMENT

OF THE

PICK POSITIONS

The next nonconveyable carton-pick method consideration is the stationary carton or SKU pick positions or customer-order locations. The stationary-component and moving-component design determines the order-picker nonconveyable carton transfer activity. The stationary pick positions or customer-order location designs are (1) parallel to the moving component or (2) perpendicular to moving component. Stationary Positions Parallel to the Moving Component This method has the stationary positions located on each side or one side of the moving component. The stationary parallel position is a standard or flow-rack position. Between the stationary parallel positions and the moving component is an order-pick aisle. The aisle width permits the order picker to complete an order-pick transaction between the stationary position to the moving component. Replenishment to the positions is made from a separate aisle or the stationary position back side. The features are minimum position number per linear foot, a layout that is in a narrow rectangular facility area, and minimal employee walking or physical effort. If the stationary locations are pick positions that are on 4-to-6-foot centers, powered forklift trucks complete replenishment transactions. If the stationary locations are customer-order locations, an employee or powered forklift truck transfers carts or pallets to the customer-order location. Stationary Positions Perpendicular to the Moving Component This method has stationary positions that are located on each side or one side of the moving component. The stationary positions face an aisle that is perpendicular to the moving component. The stationary perpendicular positions are push-back flow rack or standard positions, and the aisle width between the position rows permits SKU position replenishment and order-pick transactions. Between the perpendicular position end is an order-picker aisle that permits an order picker to move between two pick position rows or sections. The features are maximum position number per linear foot and a layout that is in a wide rectangular facility area. In addition, an employee walks a distance between the stationary position to the moving component.



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If these stationary locations are pick positions that are on 4-to-6-foot centers, powered forklift trucks complete replenishment transactions. If these stationary locations are customer-order locations, an employee or powered forklift truck transfers the cart or pallet to the customer-order location.

CARTON OR PALLET REPLENISHMENT The SKU replenishment to a vacated or depleted carton pick position is a requirement for a carton order-fulfillment operation that uses fixed carton pick positions. The SKU replenishment activity ensures that the correct SKU is removed from the assigned storage position on schedule, is in the proper quantity, and is placed into the correct SKU pick position. The SKU replenishment activities include listing the SKU pick positions that require a replenishment onto a paper document or into an RF device, withdrawing the appropriate SKU quantity from the storage position, transferring the SKU replenishment quantity into the pick position, and verifying the replenishment transaction completion. In the various replenishment methods in a carton order-fulfillment operation, a warehouse employee transfers product from a random storage position to a fixed pick position. In an order-fulfillment operation that has a floating slot or pick position method, the SKU cartons or pallets are assigned several discrete pick positions that are entered into the computer. When pick activity depletes product from one pick position, the computer transfers the next pick to another pick position with product.

TYPES OF PICK POSITION In a carton order-fulfillment operation, the SKU pick position is the facility location that contains a carton that is removed by an order picker (manual, mechanized, or automatic machine) to complete a customer-order requirement. Inventory and orderfulfillment professionals recognize that the two types of pick positions are (1) fixed or permanent location or (2) random, floating, or variable location.

FIXED PICK POSITION The fixed position, location, or slot method is a SKU pick-position method designed to have one SKU that is assigned to a permanent pick position. When a depleted fixed SKU position occurs in the pick area or along a pick aisle, SKU replenishment transaction is directed by computer or human to transfer a SKU quantity from the storage area to the depleted fixed SKU pick position. The disadvantages are that the method requires labor to complete the replenishment transaction, increases the SKU handling and potential damage, and can lead to replenishment errors and possible stock-outs. The advantages are good SKU hit density and concentration, family grouping, less floor area for the pick area or pick aisle, and increased replenishment and order-picker productivity.


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FLOATING PICK POSITION The floating, variable, or random pick-position method is a SKU pick location method designed to have a SKU pick position that is randomly located in several pick positions in the pick area aisles or along the pick line. Inbound product replenishment is made by a computer or human allocating a SKU quantity to an assigned pick position. Per SKU quantity, the SKU is transferred to a first pick position and another SKU quantity is transferred to a second pick position. Both pick positions and pick-position quantities are placed into the WMS or inventory management computer. When the order pickers deplete the first pick position, for additional SKUs to complete a customer-order the computer directs the order picker to the second pick position. This computer direction is a replenishment transaction. The disadvantages are a large floor area for the pick area or pick aisle, increased employee walk distance and time, and lower put-away and order-picker productivity. The advantages are no replenishment labor and fewer product handling and associated product damage and errors.

PUT-AWAY AND WITHDRAWAL TRANSACTION-VERIFICATION AND INVENTORY-TRACKING METHODS A very important order-fulfillment operation activity is a product deposit and withdrawal transaction verification. A SKU has a transfer transaction from a receiving dock to a storage location and a replenishment transaction from a storage position transferred at the correct time to the correct pick position. The replenishment transaction verification activity options are manual or visual memory method, manual written method, and automatic method.

HUMAN MEMORY The first replenishment transaction verification method is one in which the employee mentally remembers the storage and pick positions for a SKU replenishment transaction. This method is the basic and simplest replenishment transaction verification method. The employee remembers the storage location and when there is a demand for a SKU replenishment to the pick position, the employee remembers the storage location and completes the replenishment transfer transaction. The disadvantages are low employee productivity, possible errors, low volume and few SKUs, difficulty of controlling over a large area or two shifts, difficulty of handling a FIFO product rotation, and a storage location that is not always the optimum position. The advantages are low cost and low investment.

HANDWRITTEN PAPER DOCUMENT The next replenishment transaction verification method is the manual-handwritten method. In this method, the replenishment employee uses a printed form to record the replenishment transaction. The printed form is a four-column activity sheet that



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has a space for the employee’s name and the date. The four columns are separated into two column groups: two columns under the storage deposit heading are for deposit transactions to a storage location, and two columns under the replenishment heading and are for pick-position replenishment transactions. After the employee completes a transaction, the operator lists the the storage position and SKU identification number for a deposit, or the pick position and SKU identification number that was involved with the transaction for a replenishment. At the shift end, the activity forms are sent to the warehouse office where a clerk performs an inventory control update for SKUs. The disadvantages are low volume, the need for a clerk to make an inventory entry, the addition of another task to the employee work, and possible transposition errors. The advantages are no capital investment, the ability to be used over two shifts, and the ability to be used in a large facility.

MANUAL FILE The next replenishment transaction verification method is the manual-bin file method. This method uses storage position cards. Each card corresponds to a storage position in a facility aisle and the cards are placed in sequential order in a cardholder. In a carton order-fulfillment operation, the cardholders have a slot for each storage position or pick position in a rack bay. The cardholder is attached to a rack’s upright post. The card has the storage position number printed on the top left side and has three columns. The employee who performs a replenishment transaction completes the columns. One column lists a SKU identification number that is involved in a transaction. The other two columns are used to indicate a deposit or withdrawal transaction. After a replenishment transaction completion, the employee obtains the appropriate storage position card from the holder. On the card, the employee lists the SKU identification number and places a mark in the appropriate in or out column that reflects the transaction. The completed card is returned to the cardholder for future reference. The disadvantages are unclear handwritten statements, transposition errors, lost cards, and another employee activity. The advantages are low cost, information in the warehouse area, and easy implementation.

BAR-CODE SCANNING The next replenishment transaction verification method is the bar-code scanning method. The replenishment transaction format is as follows: each carton or pallet has a human- and machine-readable label as part of the SKU identification, there is a bar-code label (human and machine readable) on each SKU position, and a humanheld bar-code scanner holds or transmits the replenishment transaction and quantity to a host computer. In the bar-code scanning replenishment operation, each carton or pallet’s movement or replenishment transaction activity is scanned and the information becomes an online or delayed entry into the WMS for inventory update. To complete a


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replenishment transaction, an employee is directed to a storage position. At the storage position, the employee scans both the SKU and storage position bar codes and travels to the pick area. In the pick area, the employee scans both the SKU and pick-position bar codes. These scanning transactions are online or delayed communications to the WMS. With an on-line replenishment transaction data-entry method, prior to the purchase and implementation you must review the scanning device and transaction numbers, the data transmission distance and clean line, the WMS computer capability to handle online transactions and other activity transactions, the scanner device (finger-, wrist-, or cord-held), and the RF communications to be performed within the building. You must also determine whether the government permits wave use in the facility area. Disadvantages are investment, employee training, management control, and possible requirement for a temporary data-holding capacity to handle all the transactions. The advantages are a high volume, accurate and online information transfer and transaction record, and high employee productivity

VARIOUS REPLENISHMENT METHODS The replenishment activity occurs in a carton order-fulfillment operation and ensures that the correct SKU is in the correct pick position for the order picker to complete the customer-order. The methods to complete a replenishment transaction from the storage position to a fixed pick position are random, slug, sweep, and WMS.

RANDOM REPLENISHMENT The first method makes random pick-position replenishments. The replenishment employee makes replenishment transactions that are based upon an employee’s thoughts. To reduce travel distance and travel time, the order-fulfillment facility aisles are separated into zones. The disadvantages are that replenishment transactions do not complement the order-picker transactions; management control is low; employee productivity is low; and if the pick position is not completely depleted, the extra cartons are not placed in the best location. The advantage is that fast-moving SKUs are handled first.

SLUG REPLENISHMENT The next system is the slug-an-aisle method. Before moving to another aisle, the replenishment employee completes all replenishment transactions within one pick aisle. The additional disadvantages are potential stock-outs and lower employee productivity due to hand-stacking cartons into a pick position. The advantage is decreased employee time and distance between two replenishment positions.

SWEEP REPLENISHMENT In the sweep-replenishment method, the pick area aisles are separated into zones. The replenishment employee starts with one zone and within the zone performs in



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sequential order all replenishment transactions in one order-fulfillment aisle prior to moving to the next aisle. An additional advantage is that the method closely complements the order-pick activity.

WMS REPLENISHMENT The WMS-replenishment method has the WMS program suggest the SKUs and SKU sequence for the replenishment activity. Per the customer-order demand, the WMS transfers the replenishment transactions to an RF device and the employee completes the replenishment transactions in the WMS sequence. The disadvantages are capital investment, a bar code on each SKU storage and pick position, the need for an RF device, and on-line or delayed communication. The advantages are that replenishment transactions complement the order-picker transactions, there is accurate online or delayed information communication, and there is accurate inventory control or tracking.

SKU ALLOCATION TO THE PICK AREA The basic SKU pick-position location principle is to keep the order picker and replenishment employee travel distance as short as possible between two transaction locations. The SKU allocation to the pick position methods are (1) no method, (2) ABC method, and (3) family-group method.

NO METHOD With this method, the SKUs are randomly assigned to the pick positions within the pick area or pick aisle. With this method, a pick position that has the fast-moving SKUs is separated by several slow-moving pick positions; the employee increases the walk or ride time and distance to complete a replenishment or order-pick transaction. The disadvantages are that replenishment and order-picker productivity is low, the method mixes SKUs from different product groups in one area, and it does not maximize space. The advantages are that it is easy to implement and requires minimal management control.

ABC METHOD In the ABC method, the SKU pick positions in the pick aisle or pick area are separated into three major zones: A, B, and C. These zones are subdivided into microzones. Each zone is restricted for particular SKUs that have a specific annual movement The first pick zone is the A zone. The A-zone positions are restricted for fastmoving SKUs. The positions within the B zone are for medium-moving SKUs. The final or C-zone positions are for slow-moving SKUs. Since 80% of the SKU movement (based on Pareto’s law) is from zone A, the ABC method improves the pick aisle SKU hit density and concentration.


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The disadvantages are the need for management control and discipline, mixed family groups in one aisle, and the need for accurate SKU volume projections. The advantages are replenishment and picker productivity and high volume.

FAMILY GROUP In the family group, SKUs with similar characteristics are assigned to pick positions within a pick aisle or zone. The order-fulfillment operation management team determines these characteristics. The disadvantages are the need for management control and discipline, additional positions for new SKUs, the mixing of fast- and slow-moving SKUs in one pick aisle or zone, and low replenishment and order-picker productivity.

VARIOUS REPLENISHMENT QUANTITIES The carton-replenishment activity-handling quantities are pallet, one layer of a pallet, and less than a pallet layer.

PALLET With a pallet-replenishment method, an entire pallet is transferred from the storage area to a carton pick position. To maximize space and labor, this method requires that the pick position is depleted. With this situation, the entire pallet is placed into the pick position. The method replenishes approximately 50 to 75 cartons per transaction, is best used with a WMS, and is used for high-cube or fast- to medium-moving SKUs. The disadvantages are that if cartons remain in the pick position, it lowers employee replenishment productivity; and that sometimes the replenishment activity is not on schedule, which creates a stock-out. The advantages are minimized SKU handling, high replenishment productivity, and ability to be used for medium- and fast-moving SKUs.

REPLENISHMENT

OF

ONE LAYER

OF A

PALLET

The second method is the replenishment by one layer of a pallet. With this method, one or two carton layers from a pallet are removed and transferred from the reserve position to a pick position. This means that the pick position is a hand-stacked rack position, a case-flow rack position, or a shelf position. The method is used for slowmoving to medium-moving SKUs. The one to two carton layer replenishment activity removes the layer or layers and is performed in the storage or pick area. If the layer removal activity is performed in the storage area, the required cartons are removed from a pallet and transferred onto a conveyor system or vehicle loadcarrying surface for transport to the pick aisle. In the pick aisle or in the replenishment aisle, the cartons are transferred into the pick position. The disadvantages are transfer equipment cost and required floor area, doublehandling of the produce, and increased vehicle traffic in the facility aisles. The advantages are minimized pallet moves and reduced potential product and equipment damage, FIFO product rotation, and ability to handle a high volume.



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If the layer removal activity is performed in the pick area, an employee removes the pallet from the storage area and transports the pallet to the pick area. From the pallet, an employee transfers the required carton layer or layers from the pallet load to the pick position. After a replenishment transaction, an employee removes a partially depleted pallet from a pick area and returns the pallet to an assigned storage position. The disadvantages are pallet load double-handling, potential product and equipment damage, and increased forklift truck or pallet truck trips in the aisles. The advantages are that a large carton quantity is transferred to a pick position, and there is minimized employee physical effort to bend and reach for cartons.

REPLENISHMENT

OF

LESS THAN ONE LAYER

OF A

PALLET

This method is used for very slow-moving SKUs. The operational characteristics are that the employee basically order picks the slow-moving cartons from the storage area, transports these cartons from the storage area, and transfers these carton into the appropriate pick position. The disadvantages and advantages are similar to the previous replenishment method except that carton travel is one way from the storage area to the pick area.

VARIOUS TIMING METHODS FOR REPLENISHMENT The SKU or carton fixed pick-position replenishment activity is performed at the moment that the pick position becomes depleted and with the SKU quantity that maximizes the pick position space and employee transaction activity. To achieve this objective, for best results all replenishment transactions and quantities are made by a microcomputer or WMS. Replenishment activity control options are manual and computer control.

MANUAL METHOD The manually controlled replenishment transaction method relies upon an employee to determine the time at which the cartons are moved from the storage position to the pick position. This random method is based on an employee’s experience and is not sequenced with the other order-fulfillment operation activities. On some occasions, the replenishment transaction is made to a partially depleted pick position. This condition requires the replenishment employee to waste time and transfer the cartons. The disadvantages are uncontrolled replenishment employee activity, low employee productivity, poor spatial pick-position utilization, and lack of coordination with the order-pick activity. The advantages are low cost, no capital investment, and no employee training.

COMPUTER METHOD With the computer-controlled replenishment transaction method, the computer or WMS directs an employee to perform a product replenishment transaction from a storage position to a pick position. The replenishment is based on the customerordered SKUs and the inventory quantity in the pick position. There are two methods


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used to direct the employee to complete a replenishment transaction. First, a paper document lists all the replenishment transactions that occur on the employee’s shift. On this form the SKUs are listed by SKU number and description in a sequential order that is based on the anticipated time at which the pick position becomes depleted of SKUs. The first column states the SKU storage position and the second column is for the replenishment employee mark. The mark indicates and verifies that the withdrawal transaction was completed on schedule. The third column states the SKU pick position and the fourth column is for the employee to verify that the replenishment transaction was completed. The second method is bar-code scanning, which has the WMS download to handheld RF devices the required replenishment activities and the sequence for these activities. In addition to the RF devices, a bar code is on each SKU, storage position, and pick position. The scanning device transmits the replenishment information online or in a delayed form to the WMS for inventory-position update. The disadvantages are the need for management control and discipline, capital cost, and employee training. The advantages are accurate and online or delayed transaction records, excellent employee productivity, reduced incidence of lost inventory, improved spatial utilization, and enhanced management control.


6

Pallet Order-Fulfillment Operations INTRODUCTION

When you consider the four order-fulfillment operation types, the pallet operation is the least complex to design, develop a building layout and equipment layout, and manage and control the piece and customer-order flows. The factors that make this a less complex operation include that a pallet operation receives pallets from vendors pallets and sends pallets to the customers, and that there are fewer value-added activities. Other factors include piece and customer-order flows, piece size and handling characteristics, a large pallet number with few to medium stock-keeping units (SKUs), and a large inventory with a store-and-hold requirement. Finally, the SKU storage position is the pick position. This chapter’s objectives are to review the design parameters and operational characteristics; identify and evaluate the pallet storage transaction vehicles, storage devices, and rack and transport methods; discuss methods and technologies to improve employee productivity; and examine storage capacity, position identification, inventory control, and product flow. The awareness and understanding of the design parameters of an order-fulfillment operation are key factors to the design, planning, and operating of a facility. Improvements in these pallet storage and transport activities increase your company’s profit and provide quality service to your customers. The pallet section in a carton or single-item order-fulfillment operation is the main storage section and has the same operational characteristics and design considerations as a pallet order-fulfillment operation. In a pallet operation, the pallet positions are the storage and pick positions.

BASE OPERATIONAL DATA AND AREA INFORMATION The first steps to designing a new or remodeling an existing pallet order-fulfillment operation or facility are to collect, evaluate, review, project, and approve the present and proposed pallet and customer-order volumes, the SKU quantity and characteristics, and other operational parameters for each order-fulfillment activity. The other operational design parameters are:

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• • •

• • • • • •

• •

• • • • •

Average number of customer orders per day, most frequent number of customer orders for a day, and peak number of customer orders for a day Average number of pallets per customer-order, most frequent pallets per customer-order, and peak number of pieces per customer-order Average number of shipping containers per customer-order, most frequent number of containers per customer-order, and peak number of containers per customer-order The best pallet volume to use for your equipment projections Average number of pallets per container and pallet size (most frequent, average, and peak) Pallets by specific inventory classification Present various in-house pallet transport conveyor or vehicle travel speeds Present various customer-order shipping method and delivery vehicle sizes Customer delivery considerations: • Average pallet quantity or container weight • Most frequent pallet quantity or delivery vehicle weight • Peak pallet quantity or delivery vehicle weight Customer-order shipping delivery truck, rail car, or delivery vehicle method Information Management System (IMS) required customer-order processing, IMS download time, and time to communicate directly to the functional area’s microcomputer Types of customer-order priority Customer service time or customer-order and delivery cycle time SKU profile of the pallet storage/pick area Proposed pallet storage/pick area design with vehicle aisle and rack layout and with all required activities and simulations Proposed pallet-flow path with block, plan-view, and detail-view drawings that include all required operational activities

The completion of this data collection and analysis step ensures that the proposed pallet facility with its storage/pick area layout is designed to handle the projected customer-order pallet volume, pallets per customer-order, total daily pallet volume, and customer-order shipping delivery-vehicle volume. These features ensure a costeffective and efficient pallet operation that provides the lowest operational cost and accurate and on-time customer service.

PEAK, AVERAGE, AND MOST FREQUENT PALLET VOLUMES OR CUSTOMER- ORDER VOLUMES When we review the three monthly figures that are used to project a company’s pallet operation, then we shall state that there are two important volumes. The first is the pallet or unit-of-product volumes and lines per order. The unit-of-product volume represents the pallets that are to be handled by the operation. The productivity of your pallet-handling employees or employee-controlled equipment determines the number of vehicles or employees in any functional area. The second important


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volume is the number of customer orders, which represents the number of potential customer pallets that are to flow through your operation from the receiving area, through the pallet storage/pick area, and to the shipping area. If your pallet operation has an increase in the pallets to be handled by the various activities (an increase in the pallets or units of product per customer-order) with no increase in the number of customer orders, this has the potential to mean an equal number of full pallets or a greater number of customer shipping delivery vehicles, and higher employee productivity. If your pallet operation has a decrease in the pallets and the units of product to be handled by the various activities remains constant (a decrease in the pallets per customer-order), with an increase in the number of customer orders, this has the potential to mean an equal number of less than full of customer shipping delivery vehicles and lower employee productivity due to handling fewer pallets per trip. The peak, average, and most frequent monthly unit-of-product or customer-order volumes are used to project your pallet operation’s future pallet or customer-order volume. This future pallet volume or customer-order volume is based on the pallets or customer orders that were handled by your company’s pallet operations for a specific time period. This time period is a day, week, month, or year. This future pallet volume is based on two components. These are the past pallet, unit-of-product, or customer-order volume; and your company’s pallet operation’s anticipated real growth rate. This future pallet or customer-order volumes are the key factors that determine several important future pallet operation design considerations and resulting operational issues. These are as follows: to project or schedule the labor quantity and equipment that is required to handle the pallet or customer-order volume; with a pallet or customer-order volume, to project the annual and other operational expenses for an annual operating budget for your company’s pallet operation; and to project the potential labor quantity, labor costs, labor savings, and other associated operational expenses that justify a capital expenditure request. Peak Pallet or Customer-Order Volume The first pallet-operation pallet or customer-order volume is the peak pallet or customer-order volume. This is the highest pallet or customer-order volume that was handled by an operation for a specific time period. This peak or highest pallet or customer-order volume usually occurs as a result of high receiving or your customer’s pallet purchase increase. On a periodic basis, this customer-order pallet increase does recur and is a result of a customer income-flow increase, customer membership criteria, or another customer motivational factor. Average Pallet or Customer-Order Volume The second pallet-operation pallet or customer-order volume is the average pallet volume or customer-order volume. This is calculated by two methods. The first method is the total time period, which is a day, week, or month of the year’s pallet or customer-order volume divided by the number of days, weeks, or months of the year. The second method is for a specific time period, the total for the highest and lowest pallet or customer-order volume divided by two.


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Most Frequent Pallet or Customer-Order Volume The third pallet-operation pallet or customer-order volume is the most frequent pallet volume or customer-order volume. The most frequent pallet or customer volume for a given time period occurs or repeats most frequently at the pallet operation. In a bell-curve presentation or tracking of the various pallet or customer-order volumes, the most frequent pallet or customer volume typically occurs between the average pallet or customer-order volume and the peak pallet or customer-order volume. Hybrid Pallet Projection Design for an Operation When the task is to project the number of forklift trucks or automated storage and retrieval system (ASRS) vehicles for the design of a pallet operation, then a hybrid pallet-volume projection is the preferred pallet volume to determine the number of forklift trucks or ASRS vehicles. In most operations, a forklift or ASRS vehicle is required to make a storage transaction. When we consider the appropriate volume, most professionals consider that the peak outbound occurs with an average inbound or the average outbound occurs with the peak inbound. The hybrid pallet-volume projection provides a more realistic pallet volume, because the majority of orderfulfillment companies have inbound and outbound peak pallet volumes occurring at different time periods of the year. If we consider the average inbound volume and the average outbound volume, for the peak-volume workday there is potential that the number of forklift trucks or ASRS vehicles would not meet the operational requirement. With this operational feature, the operation would experience overtime and poor customer service. If we consider the peak inbound volume combined with the peak outbound pallet volume, for most work days there is potential that the number of vehicles would exceed the requirement. This situation means that there would be excessive forklift trucks or ASRS vehicles, or that this equipment would be ideal.

FACILITY DESIGN INFORMATION AND CONSIDERATIONS For the best pallet order-fulfillment facility design and operation, the second step is to complete the various building or facility design information and operational department considerations. The size and shape of finished floors of the pallet orderfulfillment building or facility is a result of several factors. These include the size and shape of the land or site location along with the access road; the required square feet or meters that result from the projected storage inventory, the required number of pallet storage/pick positions, and other required operational space requirements; and the soil condition and ability to support the imposed dynamic and static building. Usually the greatest loads are the pallet storage/pick area loads. Other considerations include, per the geographic location, the local building codes and restrictions and seismic, wind, rain, and snow loads; available funds; the number of female and male employees per shift along with employee and vendor and customer delivery-truck parking requirements; the average and peak delivery vendor and customer delivery-



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truck requirement; electrical and other utility requirements; and fire protection and employee emergency-exit requirements. There are other pallet order-fulfillment facility design and operational considerations. These factors include the building shape, expansion capability, and expansion direction, and the local code’s allowable building clear ceiling height and operational acceptance for a single-floor facility and elevated finished-floor sections of the facility for office and administrative areas. Included in the building height and finished-floor square foot area are exits, stairways, and an elevator with appropriate length for run-out and pit. As required by the pallet in-house transportation method, there may be a pit in the finished-floor surface along with personnel protection along the pit perimeter, and a fire wall or elevated wall or finished-floor penetration for the unit-of-product or customer-order in-house transportation method. These features would include fire protection, employee emergency exits, and required walkways to each exit. Also important are lighting fixtures and light levels or lumens at 30 inches above the finished-floor surface, light fixtures turned on and off by a photo eye or activity sensor, and the various lighting levels for each activity workstation or storage/pick aisle or section of the facility. When pits are installed in the finishedfloor surface and are not being used for the in-house transport method, then the pits are covered with hardened metal structural members and plates to support employee or vehicle traffic. Ceiling fans or finished-floor level fans are needed to circulate the air. This feature is a consideration for a geographic area that has high humidity. The moving fan blades improve the mobile vehicle safety and minimize the moisture buildup on the finished-floor surface and employee working environment. This feature reduces a potential employee injury. An uninterruptible power supply (UPS) during a brownout or electrical power failure provides sufficient electric power to prevent a computer crash and to permit the facility to operate for a portion of a shift or the entire shift. The other UPS considerations include the type of system: a battery-powered system that is connected to specific electrical equipment and is designed to operate for a short time period, or a diesel-powered generator that is designed with the capacity to provide for the entire pick line or facility electrical equipment for a long time period. Also important is the method used to activate the UPS, which is either a manual start-up or an online start-up. Since most UPS systems are designed to protect a microcomputer or host computer, most UPS systems are started by an on-line method. The next factor is communication between two microcomputers or between the host computer and a microcomputer-controlled piece of equipment. The various communication factors include the communication method, which is radio frequency (RF) or hard wire, and the communication distance. With RF, the desired frequency is approved by the local government and is tested in a building that has a high metal content. With a hard-wire communication over a long distance, the wire could require short-haul modems or relays to ensure a clear and good communication. In many hard-wire communication applications between two computers, many professionals consider four factors. These are an electric spike protector; a low electrical voltage protector; an electrical power filter to minimize undesired noise


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on the electrical power line; and a dedicated communication line between two computers. To minimize the total investment and ensure the required standards many of these electrical power-supply considerations justify having the electrical power supply sent through the UPS. This feature achieves most or all of these electrical power-supply considerations. Finally, there is the pallet in-house travel path through the facility. The objectives are to have the shortest travel distance and time between two locations; require the fewest handlings with minimal unit-of-product, building, or equipment damage or personnel injury; and ensure that the maximum unit-of-product quantity is delivered accurately, to the correct location, and on-schedule.

SKU LOCATION IN THE STORAGE/PICK AREA The pallet storage-area or pick-area design consideration focuses on the SKU’s physical position in the storage/pick aisle. The location of the SKU along the storage/pick aisle position or sequence of pallet storage/pick positions is a philosophy that has certain guidelines or principles whether the pallet storage/pick activity is a manual forklift truck method or an ASRS method. There are various pallet storage/pick position guidelines and philosophies. These include the SKU’s physical characteristics — height, width, length, and weight. In most pallet storage/pick operations, the heavyweight, short pallets are located at the lowest rack positions or levels or finished-floor levels of the rack structure. The lightweight, tall pallets are located at the highest rack positions or levels of the rack structure. The second guideline is, by the SKU velocity, sales or physical movement for one complete fiscal year. In most pallet storage/pick aisle applications the fast-moving SKUs are located at the start of the aisle, the medium-moving SKUs are located in the middle of the aisle, and the slow-moving SKUs are located at the end of the aisle. The third guideline is the SKU value, a characteristic that determines the pallet position location. In most pallet operations, the high-value SKUs are allocated to a high pallet position that has limited or controlled access. The fourth guideline involves SKUs that require specific environmental storage conditions, such as temperature-sensitive products located at the lowest rack positions. The fifth guideline is SKU hazardous classification. By most local codes, the hazardous SKUs are required to be housed in a pallet position that restricts the SKU’s flight or has a barrier or pit connected to a containment chamber to restrict flammable liquid runoff. The sixth guideline is the pallet board dimensions. When a pallet operation has pallet boards with one or more dimensions, specific pallet storage/pick aisles are allocated to a specific pallet dimension.

PALLET STORAGE-AREA DESIGN The next major step in a pallet order-fulfillment facility design consists of the various steps in the design or layout of the storage/pick positions (rack rows) and forklift truck or ASRS vehicle aisles. Basically, the layout of pallet storage/pick rack rows and forklift truck or ASRS vehicle aisles has two approaches: to fit the rack rows



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and aisles and pallet flow pattern into an existing facility, or to fit the rack rows and aisles and pallet flow pattern into a new facility. Figure 6.1 compares storage capacity for different rack configurations. When we compare the two pallet rack-row design approaches, fitting rack rows and aisles into an existing facility is a more difficult task because the existing building’s columns, column spans, walls, and roof are considered design constraints. The various steps to complete the pallet storage/pick rack row and aisle design are as follows: •

• •

•

• •

• • • • •

To project the annual number of SKUs and associated inventory, pallet and customer-order volume, in-house transportation pallet flow pattern, and customer-order pallet flow pattern To review the various pallet storage/pick methods and select the preferred method To identify the building column clear span, column size, and clear ceiling height; locate the passageways through walls and finished-floor levels; and identify the various utility locations, their quantity, and the light fixture pattern With block layouts and drawings, to develop and refine the rack row and aisle layout, the in-house transportation pallet flow pattern, the customerorder pallet flow pattern, and other building items To develop and finalize the various building drawings and pallet storage/pick area line drawings To complete a simulation that is based on the pallet flow patterns, customer-order flow patterns, pallet pick volumes, and customer-order volumes To review the building layout and rack row and aisle layout drawings for compliance to local codes and company policies and operational acceptance To complete a request for quotes or a bid process and select the preferred small-item order-pick method vendor To develop building construction, remodeling, or pick-line installation plans and schedules To install, test, and debug all building equipment and pallet-handling equipment and complete a building and pallet equipment punch list To start up and turn over the building and pallet equipment to the operational department

PALLET FLOW The next major set of pallet order-fulfillment operation design parameters and considerations focuses on the pallet flow pattern through the facility, as well as the various required operational activities and pallet storage/pick area considerations. The first pallet order-fulfillment consideration is the pallet or unit-of-product flow pattern. The pallet flow pattern runs from the receiving dock, through the qualityassurance (QA) activity, through the storage/pick area, and to the shipping dock.

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FIGURE 6.1 Comparison of storage vs. square feet for different rack configurations. (From Kornylak Corporation, Hamilton, OH. With permission.)





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As the unit or product flows through the pick area, then per the customer-order an order employee withdraws the required mixed units of product. These units of product are collected into a trolley or cart travel path as a completed customer-order. Most pallet flow patterns through a pallet order-fulfillment facility are termed store-and-hold unit-of-product flow methods. The various pallet flow patterns include (1) the horizontal one-way or straight flow pattern and (2) the horizontal two-way pattern with a V- or W-shape.

HORIZONTAL ONE-WAY FLOW PATTERN The horizontal one-way or straight pallet flow pattern through a pallet order-fulfillment facility is also referred to as “in one side and out the other.” In the horizontal one-way or straight pallet flow pattern, the pallets enter the facility from one side and exit the facility from the opposite side of the facility. On one side of the building, the pallet operation receives SKUs and, with mobile or fixed in-house transportation equipment, the pallets are moved through the storage/pick area to the other side of the building. On the other side of the building these customer pallet orders are loaded onto a customer delivery vehicle. This pallet order-flow method requires the pallet (or unit of product) to travel the entire horizontal distance through the facility from the receiving docks, through the storage/pick area, and to the shipping docks. Also, the facility is considered a conventional facility that has a vendor delivery truck yard on one side of the building and a customer delivery truck yard on the other side. Optional facility designs have administrative offices on elevated finished floors to utilize the air space. The additional truck yard does not optimize the site utilization. The one-way or straight pallet flow pattern is not the best for a pallet operation that handles across-the-dock pallet or unit-of-product flows.

HORIZONTAL TWO-WAY FLOW PATTERN In the horizontal two-way pallet (or unit-of-product) flow pattern through a pallet operation, the pallets enter the facility from one side of the building and exit on the same side of the building. The horizontal two-way pallet flow pattern is a good arrangement for a pallet order-fulfillment operation. With the receiving docks and shipping docks on one side of the building, it requires one road, which improves the site utilization. When the horizontal two-way pallet flow pattern is compared to the one-way pallet flow pattern in a facility, the horizontal two-way flow pattern in a facility requires less delivery truck yard and roadway surface. This feature means a reduction in land, a facility designed with elevated finished floors for administrative offices, and other facility investment costs, and increases the possibility of dual cycles in the pallet storage area. This feature means a lower per-unit labor cost. The horizontal two-way pallet flow pattern has two options. These options are the U-flow pattern and the W-flow pattern. U-Flow Pattern The first horizontal two-way pallet flow pattern is the U-flow pattern. In this pattern, the inbound pallets are unloaded or received on one side (the right side) of the


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facility; transported internally through the storage area in the middle of the facility; and, per customer order, loaded or shipped on the same side (the left side) of the facility. Therefore, when you trace the pallet flow pattern through the facility, the pallet movement makes a U-flow pattern through the facility. W-Flow Pattern The second horizontal two-way pallet flow pattern is the W- (or double-U) flow pattern. In this pattern, all inbound pallets are unloaded (received) in the middle of the building and transported through the storage/pick area of the building. On the facility’s same side, per the customer orders, the pallets are loaded (shipped) onto the delivery vehicles. This pallet flow pattern or movement creates a W-flow pattern through the facility.

DRAWINGS To assist with the understanding of any pallet flow pattern and material handling method, many pallet order-fulfillment facility and operational design professionals develop block drawings and detailed plan-view drawings and list the various activities that are performed in the facility.

BLOCK DRAWING A block drawing is a lined presentation that shows several aspects of the pallet flow pattern. Each order-fulfillment operational activity is in the required sequence to ensure a cost-effective and efficient pallet order-fulfillment operation. Lines connect two or more operational activities. These lines permit the design person to trace the pallet flow. The square footage that is required for each activity and for the total facility are shown, as are the various functional areas with required fire walls. The drawing is easy to understand.

PLAN-VIEW DRAWING The second step to understand the pallet flow through the facility is to develop a detailed plan-view drawing of the pallet order-fulfillment facility. The drawing is to scale and shows each order-fulfillment functional or activity area, including the equipment and all building items. From the detailed drawing you understand the interrelationship between the various order-fulfillment activities and the required space.

LIST OF ACTIVITIES The third step is to list and define the various pallet order-fulfillment activities that are performed by the order-fulfillment operation to complete a customer-order. The listing of these activities ensures that the design team and the operations manager have included all the required order-fulfillment activities to provide the required



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customer service at the lowest possible logistics operational cost. The various pallet order-fulfillment activities include: •

• • • • • • • •

• •

• •

Vendor inbound delivery truck or oceangoing container yard control, delivery truck spotting at the receiving docks, and customer delivery-truck spotting at the shipping docks Receiving, unloading, SKU quantity and quality control, pallet or unitof-product identification, and other value-added activities Internal pallet transportation between the pallet order-fulfillment operational activities Pallet storage deposit and withdrawal transactions and inventory control IMS customer-order processing and download of customer orders to the pick area microcomputer Per the customer-order requirements, withdrawal transaction from the storage/pick position As required by the loading activity, pallet customer identification with a discrete customer code Manual or automatic manifesting of the customer discrete identification The customer delivery-vehicle loading activity, wherein the customer pallet is placed in a temporary dock storage area until required at the shipping area, or directly loaded onto a customer delivery vehicle Trash removal includes several activities, such as trash removal from the facility Handling of customer product returns and out-of-season, damaged, or obsolete SKUs, which includes the entire processing, transportation, and storage of the pallets or units of product Customer SKU transfer to ensure that the pallet was received and flowed through the facility Security, risk management, sanitation, and maintenance to ensure that the building equipment and material-handling equipment are able to perform and protect the assets and inventory from damage

PALLET RACK-ROW AND VEHICLE-AISLE DESIGN PARAMETERS When designing a manual forklift truck or ASRS pallet storage/pick area, there are several design considerations or factors. These factors determine the location of the SKU or pallet in the rack row or aisle. These include the ability of the pallet-handling vehicle to complete a transaction; the type of vehicle and travel path used to move the pallets over the in-house transportation method travel path, available electric or air power to move the in-house transportation method’s pallet carrier, and the required travel path window; average and peak number of pallets per customer-order volume and customer delivery pallet capacity; pallet physical characteristics; and how the pallets are loaded onto the customer delivery vehicle.


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The final pallet order-fulfillment method consideration is to determine the pallet volume and customer-order pallet volume and the customer delivery-vehicle and pallet volumes. As previously mentioned, the pallet inbound volumes and customerorder pallet volumes are the average volume, the most frequent volume, and the peak volume. The next pallet consideration consists of the SKU’s physical characteristics. The SKU’s physical characteristics are determined by the pallet’s physical dimensions and the product classification. The first SKU characteristic is the physical dimensions of the pallet. The pallet’s physical dimensions include a short pallet’s quantity, length, width, and height, and a tall pallet’s quantity, length, width, and height. The second pallet or SKU characteristic is the SKU’s product classification. The SKU classifications or characteristics are toxic or nontoxic, tall or short, heavyweight or lightweight, edible or inedible, hazardous or nonhazardous, price or value, and family group or kit component.

PALLET-HANDLING SEQUENCE OF ACTIVITIES To complete the order-fulfillment of a customer’s order, the order-fulfillment pallet storage/pick activities are efficient and cost effective. To have an efficient and costeffective pallet storage/pick activity, each pallet activity or station has a sequential order for the various activities or stations. The completion of these various pallet storage/pick activities ensures the accurate and on-time completion of the pallet transactions. The various pallet transactions are pallet identification and storage/pick position identification, customer-order entry and download of customer pick instructions, and verification of the pick transaction and transfer of a customer’s pallet to an outbound staging area or directly onto the customer delivery vehicle. It is noted that the previous pallet order-fulfillment or pick activities form a complete activity list. The inclusion of these activities is determined by your pallet operation or philosophy.

SCHEDULE AND YARD CONTROL OF VENDOR AND CUSTOMER DELIVERY TRUCKS The first pallet operation activity is the schedule and yard control of the vendor and customer delivery vehicles. The schedule of vendor delivery vehicles includes the schedule of vendor delivery trucks, oceangoing containers, or railcars arriving at your facility on a predetermined day, with trucks or containers at a specific time of the workday. The completion of the schedule activity ensures a smooth receiving dock activity and optimum dock utilization. After the delivery truck arrives at the facility gate, the next step is to assign the vendor delivery truck to a dock door. For maximum unloading, receiving, and inhouse transportation productivity, the vendor truck is assigned to a dock door that permits direct access to the storage area. If the preferred dock door is not available,



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the options are to assign the delivery truck to a temporary holding area, or to assign the delivery truck to a dock door that is adjacent to the preferred dock door.

RECEIVING AND SHIPPING DOCK LOCATIONS The location of a pallet operation’s receiving and shipping docks directly affects the pallet flow and employee productivity. The main objective of the pallet receiving and shipping dock locations is to reduce the in-house transportation distance between the dock area and the storage/pick area. The best dock location is determined by the SKU’s storage/pick position in the storage/pick area. The incremental cost of an additional dock is a small investment when compared to the increase in the additional in-house transportation investment, low employee productivity, and poor pallet flow. The three basic delivery-truck receiving and shipping docks are combination docks, separated receiving docks, and scattered docks.

COMBINATION DOCKS With combination (shipping and receiving) docks, the receiving and shipping activities are performed in one building area, which means that few dock positions are used (Figure 6.2). The receiving and shipping activities use the same building area, equipment, and employees. For best results, the combination method requires a delivery-truck dock schedule in which the inbound pallets are delivered in the morning and the customer pallets (outbound) are loaded in the afternoon. This method is best for a small facility that handles a low pallet volume and a small quantity of SKUs and pallets. With the receiving and shipping docks on the same wall, the pallets flow through the facility in a horseshoe or U-pattern. The disadvantages of the method are that it increases in-house transportation, requires exact scheduling of inbound and outbound delivery trucks, and makes com-

FIGURE 6.2 Dock doors on one side of the building. (From Mulcahy, D.E., Materials Handling Handbook, McGraw-Hill, 1999. With permission.)


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FIGURE 6.3 Dock doors on both sides of the building. (From Mulcahy, D.E., Materials Handling Handbook, McGraw-Hill, 1999. With permission.)

pensating for pallet delivery problems and business fluctuations difficult. The advantages include maximum use of the facility area, flexibility of equipment and employees, increased supervision, ease in assigning delivery trucks, and improved security.

SEPARATED DOCKS The second dock alternative is to have separated dock locations for the receiving and shipping dock activities (Figure 6.3). The receiving activities and shipping activities are performed in separate building areas and with separate equipment and employees and separate supervisions. This method reduces in-house transportation requirements and activities. The separated dock locations method is best for a large operation that handles a high volume, has a large number of SKUs, and has a large SKU mix. With the receiving and shipping docks in separate locations, the dock operations handle any pallet flow patterns. The disadvantages of the method are increased building and dock equipment investment and an increased number of employees. The advantages of the method are flexibility to schedule trucks, increased capacity to handle business fluctuations, improved pallet flow, and reduced in-house transportation costs.

SCATTERED DOCKS The scattered-dock method is a variation on the separated-dock method. The receiving docks are located along one entire building wall. This area is assigned to the inbound side of the building. Each dock is located directly across from the pallet storage/pick area. This dock arrangement permits the pallet to flow directly in a



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straight line (the shortest distance) from the delivery truck dock area to the assigned storage/pick area. The shipping docks are located along the opposite building wall, allowing the pallets to flow from the storage/pick area to the shipping dock area. This method dictates a one-way straight pallet flow pattern. The disadvantages of the method are increased design and planning activity and increased need for management discipline and control of the operation. The advantage is that the method provides a continuous and uninterrupted pallet flow.

TRUCK ACCESS

TO THE

DOCKS

The second important factor for the receiving and shipping functions is the truck access (entrance and exit) to your company facility. This factor determines the receiving and shipping dock locations. In a small facility that is located in an urban area, the inbound and outbound truck access is directly from the city street. This restrictive land area requires the delivery truck to use the city street as its access road to your receiving and shipping docks. With this situation, the time required to position or spot a delivery truck at the dock increases and often a company employee assists the driver. At a large facility located on a site with sufficient land, the inbound or outbound truck access is designed to improve vehicle flow and reduce accidents. In general, a well-planned truck access road allows delivery trucks to be driven forward from the public road onto the truck yard safely, rapidly, and with minimal maneuvering of the delivery truck. Likewise, the exit road permits the delivery truck to be driven forward from the truck yard onto the public road. To permit good delivery truck flow, the access road is at least twice the length of the longest vehicle (or tractor or trailer combination). Most facilities have separate traffic lanes for delivery truck entrance and exit. Between the public road and truck yard, the delivery truck passes through a security gate and a security station or guard-house. The guard ensures that authorized vehicles are allowed on your property and that the truck has arrived at the correct address and contains pallets that are assigned to the facility, verifies that the seal is not broken, and logs the truck’s arrival time. The guard notifies the receiving department of the truck’s arrival. A receiving employee notifies the guard to direct the truck driver to drive the vehicle to an assigned dock location or truck-yard holding spot. Since truck drivers are on the left side of the tractor cab in the U.S., the truck traffic flow around the facility is in a counterclockwise pattern. A counterclockwise pattern provides the driver with a clear visibility while driving through the truck yard or backing the truck up to the dock. When a driver backs up to a dock from a clockwise traffic flow pattern and sits on the left side of the tractor, there is low productivity because of the “blind side” or difficulty in seeing the truck’s side and path. If the facility is in a country where the driver sits on the right-hand side of the tractor cab, the traffic flow pattern around the facility is in a clockwise pattern. This pattern allows clear visibility while driving through the yard or backing the delivery truck to the dock.


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In accordance with the site configuration, local codes, or architectural requirements, normally the truck docks are located in the rear or side of the building; the truck is driven to the rear or to the appropriate side of the building. With a vehicle load of at least 40,000 pounds traveling on the service road, the road has a minimum of 9 inches of crushed gravel and 5 inches of asphalt.

TRUCK TRAFFIC-FLOW PATTERNS The two alternative vehicle traffic-flow patterns in a truck yard or service road are a one-way service road and a two-way service road.

ONE-WAY PATTERN In this pattern, the facility is surrounded by the road, which is at least 13 feet from the building or is of a dimension that allows for the longest parked tractor-trailer combination plus 13 feet and the maneuvering area that extends outward from the truck dock. For an employee walkway adjacent to the truck lane, the width is wider than this combined road and tractor-trailer dimension by at least 4 feet. The disadvantages of the one-way service road are a necessity for increased road construction and additional land investment. The advantages are better vehicle flow and improved yard safety.

TWO-WAY PATTERN The two-way service road allows the delivery truck to travel in both directions between the guard station and truck dock. The method does not require the road to surround the building, but requires at least the length of the longest tractor-trailer combination, a maneuvering area, and a 26-foot-wide truck lane. An employee walkway requires an additional 4 feet, so that the width of the road becomes 30 feet. Disadvantages are decreased yard safety and decreased vehicle control. The advantage is improved vehicle spotting or docking time.

DELIVERY-TRUCK HOLDING AREA The delivery-truck holding (or waiting) area, an important feature, is located in a secured or fenced area. When a delivery truck arrives ahead of its scheduled truck dock time, the delivery truck is allowed to exit the public highway and is assigned to a temporary parking area or buffer zone. In the truck yard, the trailer parking patterns are the block method, the 45˚-angle method, and the back-to-back and side-to-side method.

BLOCK METHOD In the block or square trailer parking pattern, trailers are parked on the perimeter against the security fence, and trailers that are parked on the interior are in a straight row back to back. An option is to place wheel bumpers on the pavement in specific



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locations. These bumpers stop the trailer wheels, preventing the trailer rear from hitting the fence. The block method provides the maximum number of trailer parking positions, but requires the widest truck turning aisle or maneuvering area. Moreover, the trailers with rear doors that face the perimeter are considered a potential security problem. The security rear-door problem is reduced with the interior trailers because they are parked back to back.

45˚-ANGLE METHOD In the 45˚-angle parking pattern, trailers are parked on the perimeter and in the interior at a 45˚ angle to the security fence and to the middle of the yard. When compared to the block pattern, this arrangement provides fewer trailer parking positions but a narrower truck turning or maneuvering area.

BACK-TO-BACK

AND

SIDE-TO-SIDE METHOD

In the back-to-back and side-to-side trailer parking arrangement, all trailers are parked in the yard, arranged in the block or 45˚ pattern on the interior of the truck yard. According to this method, each trailer is backed up to the rear door of another trailer and the trailer side is adjacent to the next trailer. This trailer method does reduce the door security problem because most of the trailer doors are blocked by another trailer.

LANDING GEAR PAD When trailers are parked or dropped in the waiting or parking area without being hooked to a tractor, the trailer landing gear rests on the landing gear pad. This pad is a concrete strip that is 48 inches wide and provides a solid base for the landing gear. If this pad is not provided in the truck yard during hot or warm weather, a fully loaded trailer has the potential to sink below the tractor’s fifth wheel and make it difficult to move the trailer.

OTHER IMPORTANT TRUCK FEATURES The other important truck yard features are the returns building, the maintenance building, the trailer and tractor wash rack, the dispatch station, the fuel island, the forklift truck ramp, engine heaters, and the truck canopy.

TRUCK-YARD SECURITY The next important truck-yard feature is security. The first security feature is a security fence and berm located on the truck yard’s perimeter. This fence-berm combination restricts unauthorized personnel from entering the property, reduces the outside view of the truck yard, and reduces the noise traveling from the truck yard to neighbors in the area. The second security feature is a series of cameras that view the parked trailers and dock locations. The view is transmitted to screens in a


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guardhouse. The third security feature is a guard station and a guard in a mobile vehicle to patrol the truck yard. The guard maintains the company’s truck policies and procedures; stops all unauthorized vehicles or personnel from entering; and notes any damage to the company trucks, building, road surface, lighting, or security fence. The fourth security feature is to provide adequate lighting. Other truck yard factors that render the truck yard more efficient and safe include identification of the dock doors and stripping of truck parking spots, traffic arrows, speed and stop signs, maps and facility identification or signage, and guardrails and bumpers.

TRUCK LOADING AND MANEUVERING AREAS The truck loading and maneuvering yard area is located in front of the docks. The loading area is directly in front of each dock location. During the loading and unloading activity, the delivery trailer is parked in this area. The loading area is designed for the overall length of the longest delivery truck (or tractor-trailer combination). The minimum length is 65 feet from the dock edge. The width is designed for the overall width of the widest delivery truck plus 3 feet on each side of the tractor. This dimension compensates for the two side mirrors on the truck. If the loading area is paved with asphalt and trailers are spotted on their landing gear (without a tractor), then a 4-foot-wide concrete landing gear pad is installed at the required distance in front of and parallel to the docks. The concrete landing gear pad has sufficient strength to prevent the trailer’s landing gear from sinking below the surface. The pad supports a 40,000-pound load on 6-foot centers. The exact landing gear pad location is determined by the trailer length. The normal location for the landing gear on a delivery trailer is 10 feet from the truck’s nose. The maneuvering area is the space that is required to back up the longest overall tractor-trailer combination or delivery truck to the dock. With a counterclockwise vehicle traffic pattern, the maneuvering area is a minimum of 70 feet extending outward from the loading area. For the normal tractor trailer length of 65 feet, the total loading and maneuvering area that extends outward from the dock edge is 135 feet. If shorter delivery trucks are used in the operation, then the area is decreased in size. For a clockwise vehicle traffic pattern, the maneuvering area is doubled in length and the maneuvering length is 140 feet, with a total loading and maneuvering area of 205 feet from the dock edge. The loading area for a delivery truck yard has a slight grade or slope from the maneuvering area to the dock. The degree of slope is a minimum of 3% to a maximum of 10%, with a preferred slope of 6% in geographic areas with snow and ice conditions. To assist with water drainage, the loading area that is adjacent to the dock or building is slightly sloped from the dock edge toward the maneuvering area and to a drain. This outward slope does not extend beyond 3 feet from the dock edge. If the extension is greater, the slope has an effect on the elevation of the delivery truck’s rear doorframe at the dock and the top of the delivery truck at the overhead curtain.



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Since the maneuvering, loading, and dock areas have the sole purpose of facilitating the loading and unloading of delivery trucks, these areas are designed to accommodate the widest range of truck sizes. At some companies, separate docks are designed to handle oversized trucks.

TRUCK DIMENSIONS FOR DOCKS In designing the delivery truck’s dock height, the height of the delivery truck’s bed is the most important dimension. This dimension is determined for both receiving and shipping delivery trucks. If your company owns or leases its shipping and delivery, obtaining the truck information is an easy task. If your company uses a common carrier service, then an employee is assigned to obtain the actual delivery truck dimensions or contact the delivery company or common carrier for these dimensions. During this truck information-collection process, other required dock equipment and delivery information and dimensions include the overall length and overall height of the tractor trailer, with mirrors and wind deflectors; the overall width, height, and length of the trailer; the overall width, height, and length of the tractor, with mirrors and wind deflectors; the landing gear location from the front or nose of the trailer; and the centerline of the rear axle wheels from the end of the trailer. The best dock height provides the smallest variance between the dock edge and the rear of the delivery truck’s bed. To accommodate a wide variety of delivery truck heights, the height differential between the dock edge and the delivery truck’s rear bed is bridged by a loading ramp, dock plate, or dock leveler. As the height differential between the dock edge and truck bed increases, the incline and decline slope of the bridge device increases. If this slope increases to a high degree, then mobile pallet-handling equipment problems occur on the dock plate or dock leveler. This results in decreased employee productivity, increased need for specific equipment and maintenance, and decreased safety. As a general guide, the dock height for most delivery trucks ranges between 46 and 52 inches. If there is a wide variety of bed heights, alternative delivery-truck dock designs include allowing separate docks for specific delivery truck heights, using an extralong dock leveler (up to 12 feet) with an 18-inch up-and-down or vertical travel path from the dock edge, installing a truck leveler in the loading area to raise or lower the entire delivery truck, and installing a dock lift or using portable rear wheel risers to elevate the rear bed of the low delivery trucks.

TRUCK DOCK DESIGN FACTORS The delivery-truck dock type and location that is designed for your order-fulfillment operation is determined by several factors: climate or weather conditions, available land, security, delivery truck traffic flow and control, employee comfort, available investment funds, type of delivery vehicle, and type of load. The various dock methods are flush dock with a slight incline, flush dock with a depressed driveway, open dock, open dock with a canopy, enclosed dock with a side entry, enclosed dock with a straight entry, staggered or saw-toothed dock, side-


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loading or finger dock, dock extension, warehouse yard with a fixed ramp or mobile dock plate, trailer inside the facility, pier dock, free-standing dock or dock house, and forklift truck side-loading from the yard.

FLUSH-DOCK DESIGNS The flush dock with a slight incline’s two designs are cantilever and vestibule. Cantilever Flush Dock The cantilever flush dock is basically a hole in the building wall with a dock door and dock seal along the outside of the door frame. This method provides excellent weather protection and security. For unloading or loading, the delivery truck is backed up to the building wall and is secured against the dock seal. The delivery truck remains outside of the facility and the truck driver enters the building through a personnel entrance. Inside the building, the dock staging area is open to the warehouse storage/pick area. A cantilever flush dock requires a dock leveler with a truck ICC bar restraining device (a dock plate or chock block). It also requires excellent communication between the truck driver and the dock employees to prevent unexpected truck movement during the loading or unloading activity. An alternative communication method is the stop/go dock light system. The building wall is set back to provide at least 8 inches of clearance between the rear of the delivery truck and the building wall at an elevation of 6 feet above the dock and a minimum of 6 inches of clearance between the top of the delivery truck and the building wall. This clearance is achieved by a dock bumper that extends outward from the building wall. The bumper absorbs the delivery truck’s impact from backing up to the dock. The bumper dimensions are determined by the opening size, the loading area slope, the distance between the rear of the truck bed, and the rear wheel center. The bumper is also used with a yard jockey or mule tractor, where the slope of the trailer is increased as the yard tractor lifts the front of the trailer higher than the normal over-the-road tractor. With this angle and height, the tractor-trailer could potentially hit the building. With a flush dock, to prevent the risk of inclement weather (rain or snow) destroying the top of the seal, a small canopy or strut is installed over the seal top. When your facility is on grade level — the ground floor is level to the land — a flush dock with a depressed driveway is designed to provide the dock positions. The driveway (loading area) is depressed to create the proper height between the edge of the dock and the rear of the truck bed. A special consideration is given to the dock bumpers, water and snow removal and drainage, hand railings, and windows in the dock doors. The window in the dock door allows the dock employee to observe the status of the truck yard in front of the dock door without opening the door. Vestibule Flush Dock The vestibule flush-dock design is a variation of the flush-dock type. The difference between the cantilever flush dock and the vestibule dock is inside the building. With



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the vestibule dock, there is an open area between the building’s exterior wall and a second interior wall, which is the storage/pick area wall. This dock design is extremely practical as a staging area and useful in the perishable food and cold storage industry, where storage temperatures are closely controlled to protect the product. Forklift truck and personnel doors in the interior wall or through a tunnel permit access between the storage/pick area and the truck dock area. With two required forklift truck aisles (one for the dock area and one for the storage/pick area), the vestibule dock design requires a large square-foot area.

OPEN-DOCK DESIGN The open-dock design is one of the least expensive dock designs for a warehouse facility. It consists of a concrete platform that extends outward from the exterior building wall. The dock’s distance or depth between the building side of the dock plate and the building wall provides sufficient open space for unloading or loading equipment to travel onto the dock plate (leveler) and for two-way vehicle traffic on the dock. The dock’s width and length provide access to all building areas. Since the open dock is exposed to the weather, safety is a concern in bad weather. When the open dock design is considered for an operation, a canopy extends at least 4 feet beyond the edge of the dock. The canopy prevents rain from making the dock area slippery. A wet dock-area surface is a hazardous condition for operating a pallet truck or forklift truck. An alternative is to install sliding panels or dock curtains on the dock perimeter, reducing the negative impact of rain or snow on the dock operations. Additional open dock safety features are yellow-coated concrete posts and chains on the perimeter. Dock Curtains or Sliding Panels To convert an open dock into a semiclosed dock area, sliding panels or dock curtains are installed on the dock perimeter to create a solid barrier between the dock area and truck well. When required to perform dock activities, these sliding panels or dock curtains are opened at sufficient width to create a passageway for forklift-truck or pallettruck travel between the dock area and the delivery truck. The fixed portion of the dock panels or curtains maintains a solid barrier on the dock edge and the doors of the delivery truck. When not required to perform dock loading or unloading activities, the panels or curtains are closed and create a solid barrier between the dock and truck well. When the external building doors are opened for delivery-truck entry into the truck well, this barrier helps keep cold air from entering the dock area.

ENCLOSED-DOCK DESIGN In this design, the truck loading and unloading area (which is the combined length of a tractor and trailer) is inside the building or sheltered area. At the exterior of the building is a set of doors that control delivery-truck entry to the loading and dock area. The interior enclosed dock area is an open or flush dock design.


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In the enclosed-dock area, adequate ventilation is required to prevent delivery truck engine fumes from accumulating in the area. Other features are adequate water drainage, lighting, a dry or wet sprinkler system that is protected with heat tape or wire, and markings on the floor or dock wall that identify the dock space. These features improve the dock safety and driver truck-stopping efficiency. Side-Entrance Enclosed Dock The first enclosed-dock design is the side-entrance design; construction costs for this design are high. In this design there are two sets of doors (one at each side of the building), and the truck loading and maneuvering areas are inside the building. This feature dictates one-way delivery-truck traffic flow through the building area (in one door on the right-hand side of the building and out the second door on the left-hand side of the building). The side-entrance design accommodates the staggered- or saw-tooth dock design. Straight-In Entrance Enclosed Dock In the straight-in design, there is one exterior door per truck dock position or one extra-large wide exterior door for two truck dock positions. The delivery-truck maneuvering area is outside the building. Since the delivery-truck loading area is inside the building, the delivery truck backs straight into the loading area to the dock edge. The straight-in design provides a shorter delivery-truck loading lane, which permits the trailer to be dropped inside the enclosed dock areas or, with a longer loading lane, to accommodate both tractor and trailer.

SIDE-LOADING

OR

FINGER DOCKS

The side-loading-dock or finger-dock design is used primarily for flatbed trucks and open-sided vans (vans with a side door that opens for loading and unloading). This dock design is a cutout in the building interior floor. The cutout is directed inward from the building exterior wall to the dock staging area. The finger length and width is sufficient in size to permit a flatbed-trailer open-sided van to back into the opening. Concrete platforms on both sides of the cutout permit forklift trucks to unload and load the trailer. To improve dock safety, yellow-coated posts and chains surround the cutout.

DRIVE

THROUGH THE

FACILITY

This drive-through-dock design is used for flatbed trucks or open-sided vans. The flatbed truck or open-sided van drives into the building and forklift trucks unload or load the pallets from or onto the flatbed truck. This dock design requires a oneway flow of vehicles through the facility, or the trucks are backed up into the facility.

STAGGERED

OR

SAW-TOOTH DOCK

When there is limited delivery-truck maneuvering area, the staggered or saw-toothdesign is preferred. This design requires a one-way flow of vehicles in the truck



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yard that matches the approach to the angle of the staggered dock positions. This dock arrangement requires either a counterclockwise or clockwise delivery-truck flow pattern. In addition, the loading area is level at the dock front or the trailer bed will not line up with the edge of the dock. The major disadvantages of the design are that it requires approximately twice the building dock space for fewer docks and increases the building construction requirements and costs.

PIER DOCK If the dock side of the building does not have sufficient wall space for the required number of dock positions or the building interior layout does not permit construction of a dock area, then the pier-dock design has the potential to provide the necessary dock positions. In this design a section of the building extends outward from the building. Dock positions are located on each side of the extension. The width of the extension permits a forklift truck turning aisle for turning onto the dock leveler and a two-way forklift truck on the dock. With this design, there is a tractor trailer maneuvering area on both sides of the pier dock.

FREESTANDING DOCK

OR

DOCK HOUSE

To increase dock positions in a low-volume operation with limited interior space inside a building, a freestanding dock or dock house extension is constructed on the building wall. The freestanding dock is a platform with a dock leveler that extends outward from the building and is enclosed with metal or plastic panels. If the dock extension is an open platform, to improve safety, chains and posts are on the dock perimeter.

MOBILE YARD RAMP The mobile-ramp design is used outside the building. This dock operation uses a mobile ramp that permits a forklift truck to unload or load a delivery truck and to have the mobile warehouse equipment transport the pallet into the facility. If the facility is not at the ground level, then a ramp is required for the forklift truck’s entrance into the facility.

OTHER DOCK DESIGN FEATURES The other dock design features improve employee productivity and dock area safety. Dock-Door Designs Dock-door heights and widths are determined by the delivery truck’s rear dimensions, seal or shelter type, and internal environmental conditions with the facility. It is a general rule of thumb that the dock doors are an energy-loss and security problem; therefore, the number of dock doors is kept as small as possible. For average pallet warehouse operations, door widths range from 8 to 9 feet to agree with the corresponding rear delivery truck dimensions of 8 to 8 1/2 feet. When


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a delivery truck is backed up to the dock door, this arrangement permits the delivery truck to have a slight variation from an exact center. With the trend in delivery truck design of 102-inch-wide trucks, permitting an increase in the pallet load-carrying capacity, the 8 1/2- or 9-foot-wide door is preferred for trailer dock doors on new buildings. For regular delivery-truck loading and unloading activity with a 4-foot high dock, the dock door’s clear height range is from 8 to 10 feet high. The 8-foot high door permits a 7-to-7 1/2-foot-high pallet load to travel across-the-dock plate or leveler. A 9-foot high door with 3 inches of top clearance permits an 8 3/4-foot pallet load height to be handled across-the-dock plate or leveler. The 10-foot high dock door handles a high cube trailer. One important dock-door height principle is that at least one dock door have a 13 1/2-to-14-foot clear height to accommodate the height of the tallest warehouse material-handling equipment with a collapsed mast. A 14-foot high door accommodates most warehouse equipment deliveries. How to Bridge the Gap between the Dock Edge and Trailer Bed At the edge of the dock, the dock plate or leveler bridges the gap between the building dock edge and the rear of the delivery truck bed. The dock plate or leveler is the factor that ensures high employee productivity and safety. The height variation between the dock edge and the rear of the delivery truck bed is the major factor determining the type of mobile pallet-handling equipment that is used in the dock function. The other dock plate or leveler selection factors include frequency of deliveries, pallet-handling equipment, type of dock method, and available capital. Dock equipment needed to bridge the gap includes a portable dock plate, a portable dock board, a mobile yard ramp, a hydraulic recessed dock leveler, a mechanical recessed dock leveler, a vertically stored dock leveler, an edge-of-dock leveler, lift and bridge devices, an in-floor hydraulic lift, a scissors lift, a bascule bridge dock, a tailgate delivery truck, a wheel lift, and a dock leveler lift. Portable Dock Plate The portable dock plate with an equalizing bend is an aluminum plate with a length of 2 to 5 feet and a width of 5 to 6 feet that handles a height differential of 3 to 10 inches. At the truck dock, a short plate handles a low height differential and a long plate handles a high height differential. To reduce mobile warehouse pallet-handling equipment skids, the dock plate’s travel-path surface has a diamond-pattern surface. To secure the plate position in the gap, the plate has a locking leg (or T-bar) that is attached to the underside and fits into the gap. This lightweight and low-cost dock plate with handles on both sides is easily moved by an employee to the required dock position. Safety yellow side strips along both sides of the dock plate’s surface minimize pallet truck runoff. The dock plate has sufficient structural strength and width to handle a pallet truck. When a high height differential exists between the delivery truck and dock edge, the rear two pallet loads of the delivery truck are removed by a forklift truck. Disadvantages of the dock plate are as follows: it limits the use of a forklift truck, some situations require a forklift truck to handle the rear



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two loads, pallet trucks can slide from the travel path surface, and there is potential damage to the delivery truck door’s sides. The advantages are low cost, mobility between dock positions, and capacity to handle a low volume. Portable Dock Board The portable dock board with an equalizing bend is an aluminum device that permits an electric-powered pallet truck or a rider forklift truck to unload or load delivery trucks. To reduce mobile equipment skids on the dock board’s surface, the dock board travel-path surface has a diamond-pattern surface, and to secure the dock board in the gap, locking legs (T-bars) are attached to the underside and are inserted into the gap. Yellow-painted safety curbs help eliminate mobile equipment runoffs. The dock-board weight requires a powered truck to move and position the dock board in the required dock positions. When forklift trucks are used in the dock area, some dock plates have fold-down loops or lifting chains to assist in relocation and positioning of the dock board. When compared to the portable dock plate, the portable dock board has the same disadvantages, except that it is moved to the required dock position by a forklift truck. The advantages are the same, except that it permits a forklift truck to load or unload the delivery vehicle. Mobile Yard Ramp For facilities at grade or ground level, a mobile yard ramp, ranging from 30 to 36 feet in length, permits a forklift truck to unload or load a delivery vehicle. The ramp has an aluminum or steel-grating platform and a usable width that ranges from 4 feet, 5 inches to 7 feet, 4 inches. Side guards on both sides reduce powered equipment runoffs. Dual wheels are located under the center and a tow bar permits a forklift truck to tow and position the ramp. At the required location, some mobile ramp models have a hydraulic system for easy ramp positioning onto the delivery truck bed and a level-off top for forklift truck maneuvering and removing pallets that are at the rear of the delivery truck. Recessed Dock Leveler For facilities that have a truck dock edge at a 4-foot height, the recessed dock leveler is most commonly used to bridge the gap. Each dock leveler is installed in a pit or in a cutout of the warehouse floor. It has a diamond-pattern travel-path surface with a lip. As required, the dock leveler’s surface is raised up with a lip that extends outward and lowers to rest on the rear of the truck bed. The structural strength of the dock leveler permits powered mobile warehouse equipment to travel between the delivery truck and the dock. With an electric-powered pallet truck, the dock leveler is 6 feet long and handles a 7-to-8-inch height differential. A 12-foot-long dock leveler handles a 15-to-16-inch height differential. If a gas-powered forklift truck travels over a 12-foot-long dock leveler, the dock leveler compensates with a 17- to 18-inch height differential. If a pallet jack travels over a 12-foot-long dock leveler, the dock leveler compensates with a 13-to-14-inch height differential. The most common recessed dock leveler length is 8 feet, which handles a height differential of 10 inches.


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The width of the recessed dock leveler has a range from 6 to 7 feet. The 7-footwide leveler is best used for an 8-foot-wide delivery truck and has a tapered lip on each side to compensate for a delivery truck that is spotted (positioned) off center, or for a narrow delivery truck. When a tapered dock leveler is used at the dock position, it creates a material handling equipment drop-off zone as a result of the space that is created by the tapered ends. When a 12-foot-long dock leveler is required at the dock area, the dock leveler extends further into the dock area. This feature compensates for the extreme height differential, but increases the building area requirements and cost or reduces the dock staging area. The standard recessed dock leveler’s lip is 16 inches long, permitting a 12-inch extension into the rear of the delivery truck. Another important lip feature is that the lip or edge permits the lip to stay in firm contact with the delivery truck bed. To reduce pallet jack wheel hang-up in the floor recess or drain of refrigerated delivery trucks, the lip projection length is a very critical factor. When compared to the other dock equipment that bridges the dock edge and delivery truck gap, disadvantages of the recessed dock leveler are higher capital investment and the fact that each dock position requires a dock leveler. The advantages are compensation for a wide differential, the ability to handle forklift trucks, the ability to service a wide range of trucks, the capacity to handle a heavy load, long life, high employee productivity, enhanced dock safety, and the ability to handle a wide range of dock equipment. The recessed dock leveler options that improve dock area safety, energy conservation, and sanitation include full-range toe guards on both sides of the leveler, ICC bar trailer restraints to prevent delivery truck roll-away, a dock restraint lip to prevent forklift trucks from running off an open dock, weather seals between the dock leveler and curb channel to improve sanitation and control the air change, and dock occupancy lights. The recessed dock leveler types are the hydraulic type and the mechanical type. Hydraulic Recessed Dock Leveler. The hydraulic recessed dock leveler has a hydraulic pump and motor in the pit that moves the dock plate to the desired elevation. The dock leveler’s controls are push buttons. The buttons are located on the interior of the building wall that is adjacent to the dock position. After the delivery truck is positioned at the dock, an employee presses the button that causes the dock leveler to rise and lower automatically to a flat, level position with the lip inside the delivery truck bed. With few mechanical parts and structural members in the pit, the hydraulic recessed dock leveler is very reliable, requires little maintenance, and permits cleaning of the pit. This last feature is very important in the industries that require high cleanliness standards. However, the hydraulic recessed dock leveler requires a higher capital investment. Mechanical Recessed Dock Leveler. The mechanical recessed dock leveler has a diamond-pattern travel-path surface and an upwardly biased ramp with a spring mechanism that is held down by a releasable ratchet device. To operate, an employee



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walks onto the ramp and pulls on the release chain that is connected to the ratchet mechanism. This pulling of the ratchet releases the ramp and the ramp rises to its uppermost position. During the upward movement, the ramp lip is automatically extended forward. The employee walks forward onto the extended ramp, which is forced down onto the delivery truck bed, and the dock leveler is ready for the loading and unloading activity. The main advantage of the mechanical recessed dock leveler is that it costs less than the hydraulic model. With a greater number of components in the pit, however, there is increased expense on labor to clean the pit and for maintenance. Vertically Stored Dock Leveler The vertically stored dock leveler consists of a ramp that is withdrawn in the vertical position inside the building. The standard vertical storing ramp is available in a 5foot length with a 6-to-7-foot-wide plate. The 6-foot-wide leveler is best for a delivery truck that is less than 96 inches wide. The lip projection and bend have a standard lip length of 16 to 18 inches and a grade break of 12.5%. This feature allows the vertically storing dock leveler to handle a dock edge and truck bed height differential of 6 inches. The vertically stored ramp pivots on hinges that are installed on the interior side of the building wall in a step-down. The step-down is a continuous pit that runs on a steel channel along the entire wall face that parallels the dock doors. Since the vertically stored dock leveler does not have a pit, it reduces the sanitation problem and loss of controlled air. Other energy control features are a tighter seal on a flush dock and a tighter dock seal on the delivery truck that is backed up to the dock. The vertically stored dock leveler is available in hydraulic (automatic) or mechanical (manual) models. With the hydraulic dock leveler, the dock employee controls the lip and ramp with push buttons from a control panel that is located on the interior of the building wall. After use of the dock leveler, the vertically stored dock-leveler ramp is locked in the vertical position. At this point, the leveler is pushed by the employee to another dock position. The mechanical vertically stored dock leveler is manually moved between dock positions. Generally, the lip is in the extended position; however, if required the lip is manually retracted. At the required dock position, the dock employee manually lowers the ramp onto the delivery truck bed. Counterbalanced springs assist in the lowering effort. When not in use the ramp is returned to the vertical position. When compared to the recessed dock leveler’s design, the vertically stored dock leveler’s design requires a higher initial capital investment per each dock leveler, and the step-down section collects debris. Advantages are lower maintenance costs, energy control improvements, and lower total dock-leveler investment. Edge-of-Dock Leveler The edge-of-dock (EOD) leveler is a short ramp with a lip that is mounted to a steel channel that is embedded in the front of the dock. The EOD leveler is available in ramp lengths of 27 and 30 inches and widths of 66 to 72 inches. The EOD leveler has a standard 15-inch lip with an 11 1/2-inch lip projection. For EODs with a 17-


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inch lip, there is a 13 1/2-inch lip projection into the delivery truck. EOD leveler devices are available in both standard-profile and low-profile types. The low-profile type is best used for dock operations that use a forklift truck or a pallet truck with a low clearance. A generally accepted rule of thumb is that the EOD leveler is not used for high-speed mobile dock equipment. In-Floor Hydraulic Lift The in-floor hydraulic or ram lift is an outdoor device that has an elevating platform. The elevating platform is pit-installed in the delivery-truck loading yard area and is driven by a hydraulic pump that permits the lift to travel in a vertical direction. The in-floor hydraulic lift controls are located on an interior wall of the building or on the platform. The 7-by-10-foot platform has a diamond-pattern surface, and two sides have kick plates and handrails. One open end of the platform faces the warehouse door and the second open end with a lip faces the rear of the delivery truck. As required, the ramp lift permits an employee to move a pallet and pallet truck between the delivery truck and warehouse. The rear of the delivery truck and dock edge differential does not impact the lift to provide a bridge between the delivery truck and warehouse. When the lift is not in use, then the platform side guards (kick plates and handrails) are removed and the surface is at grade level. The hydraulic pump is electrically operated and in cold environments attention is given to keeping the hydraulic fluid warm. To operate the lift, an employee plugs in the controls and raises or lowers the platform to the desired transaction level. At the desired level, the employee performs the transaction and then raises or lowers the platform to the next required level. To improve the safety of the operation, a protective shroud surrounds the three or four sides of the lift. The expanded length of the shroud is from the ground level to the maximum platform elevation. This feature reduces the risk of injury to people and animals who might become trapped under the lift. Scissors Lift. The scissors lift is an outdoor bridge device that is an elevating or declining platform. The scissors lift has a diamond-pattern surface that has the ability to move up and down. The surface area has two sides with kick plates and handrails. Removable gates are located on the two open sides. One open side faces the warehouse door and the second open side faces the delivery truck. The delivery truck’s end has a lip to ensure a smooth transition of the pallet load-handling equipment between the delivery truck and the scissors lift. The scissors lift has a normal lift-height differential of 48 inches from a lowered minimum height of 10 inches above the grade level. Some heavy-duty models have a lowered elevation of 20 inches. With these lowered elevations above the grade, the lift is installed in a pit, which has a lip projection or a slight ramp to compensate for the minimal height differential. The 6-by-8-foot or 8-by-10-foot diamondpattern surface platform size handles a manual pallet truck, a standard pallet load, and two employees. The scissors lift consists of a dual set of legs (the scissors) that are moved by an electrically controlled hydraulic pump. As required, the pump pressure moves the legs upward. The top of the legs have rollers that move on the underside of the



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platform. The legs moving upward and the rollers moving horizontally cause the platform to lower. The electric controls are attached to the lift or to the interior of the building wall. During operation of a scissors lift, a skirt or shroud around the platform improves the safety of the area. The scissors lift is available in three designs. The first is the lift that is installed on the grade level. This design has a base frame that rests on the ground and has the platform lowered to a height that is above the ground. The second design is the pit scissors lift that has the base frame resting in a pit. This method does permit the platform to remain level with the finished floor or ground. The third scissors lift design is the portable lift that handles a 3000-pound load on a 6-by-6-foot platform. The mobile lift with lockable wheels is easily located by an employee at the required location to perform the dock activity. To operate the scissors lift, an employee adjusts or aligns the platform elevation to the rear of the delivery truck and transfers a manually operated pallet truck with a pallet load from the delivery truck onto the platform. Next the platform is lowered to a level that corresponds with the warehouse dock. At this elevation, the pallet load and pallet truck are moved into the warehouse. Bascule Bridge Dock The bascule bridge dock is another outdoor bridge device. The bridge has a diamondpattern surface platform that is attached to the side of the building in front of the dock door. All controls are located on an interior wall of the building. When not in operation, the bridge is in the raised position against the truck door. As required the electronically controlled hydraulic powered unit lowers the bridge in a 90˚ outward arch from the building. In the lowered extended position, legs on each corner support the bridge. In the lowered position, the 6-by-20-foot or 8-by-20-foot platform has a dock lip that sits on the rear of the delivery truck; along the two sides the safety rails, chains, and kick plates are inserted into the platform holes. For safety, when lowering the bridge a second employee outside in the yard ensures that there is no person, animal, or equipment in the bridge lowering path. Tailgate Truck The next bridge device is the tailgate delivery truck. When the delivery truck is on the highway, the tailgate is stored under the delivery truck. At the unloading or loading location, the truck’s electronically controlled hydraulic system unfolds the two sections of the unloading tailgate onto the ground. The tailgate has an 8-by-8foot diamond-pattern surface with a safety plate across the entire width. The hydraulic pump, as required, uses the truck’s electrically powered system or uses the building’s electrical outlet. To operate, the tailgate is raised to the rear of the delivery truck and the pallet is placed on the tailgate. After an employee lowers the tailgate to the ground or dock, the pallet load is transferred to the warehouse.


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Wheel Lift The next outdoor device to raise a delivery truck bed is the wheel lift. The two basic types are the manually and hydraulically operated wheel lifts. Both wheel lifts are outdoor devices that are located next to the building and extend outward in the loading area. The manual wheel lift (two per truck) consists of wood or hardened metal structures that have the width and length to support the delivery truck’s rear wheels. These devices are placed against the building wall under the dock edge and are located in the path of the delivery truck’s two rear wheels. As the truck backs up to the dock, it backs up on the wheel lifts. With the rear wheels on the two wheel lifts, the rear bed section of the delivery truck is raised to a height differential that is handled by a dock board or dock leveler. The hydraulic rear-wheel lift or leveler has a diamond-pattern surface that is pit installed in the loading area against the building wall under the dock edge. The surface is 10 feet wide by 14 feet long. A 5-inch-high wheel locator is an elevated middle portion of the platform. When a delivery truck is backed up to the dock, the wheel locator is between the truck’s rear wheels. The hydraulic device has controls on the inside of the building wall and has the ability to raise or lower the rear truck bed to the required height for a dock board or dock leveler. When using the wheel lift devices, attention is given to the delivery truck’s new slope and the height of the delivery truck and dock. With the new slope the delivery truck bed is higher at the dock edge and lower at the truck nose. To unload or load a delivery truck, this new slope creates an upgrade pull for an employee with a pallet truck. To reduce truck or product damage, the loading employee is required to be extremely careful because of the decline slope that is created inside the delivery truck. Dock Leveler Lift The dock leveler lift is an indoor device that compensates for the elevation change between the ground level and the dock edge. This device is a lift plate with a diamond-pattern surface that travels the distance between the ground level and the edge of the dock. The capacity is to hold a normal counterbalanced forklift truck with an operator and pallet load. The dock lift is equipped with a protective shroud or skirt. When the dock lift is not in use, a sensing device automatically ensures that the lift returns to the warehouse floor level. This feature and yellow-coated chains and posts around the perimeter improve safety. When compared to the ramp design, two disadvantages of the lift design are that it handles only one vehicle per trip and requires greater maintenance; however, it requires only a small area. Options to Improve Dock Safety and Efficiency Your design for an efficient and safe dock operation requires additional devices other than the dock type or bridge device to reduce the height differential between the dock edge and truck bed. These devices and areas are in front of and behind the



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dock doors and include wheel chocks, exterior guard posts, dock bumpers, interior dock guard posts, dock leveler lip, truck canopy, dock ladders, fifth-wheel lock jack, guide lines, and dock identification. Dock-Door Design Features The dock door is a building device that permits passage through a wall, provides security, and ensures energy conservation. The three most common door types are vertical lift, vertical and horizontal, and roll-up. A small window installed in the door is a design advantage as it reduces an employee’s need to open the dock door to verify that a delivery truck is at the dock position. A second feature is that each dock door is designed with a device to lock it from the interior of the building with an industrial paddle lock. This feature as well as the dock door’s window improve security of the facility. The third feature in cold and windy climates is weather stripping along the door, frame, and bottom to reduce energy loss. The fourth feature in the warm climates is a folding gate that covers the entire passageway. During warm and sunny days, the gate is in a closed and locked position, preventing personnel from passing through the door. This arrangement maintains good security and does permit a cool breeze to enter the building. Another door feature in a warm climate with a flush dock to reduce energy loss is a short dock house that extends outward from the exterior of the building at each dock location. This house surrounds the rear of the delivery truck and the feature reduces warm air movement into the building. Dock Seals and Shelters Dock seals and shelters are exterior dock door frames and jam features that extend outward from the building and permit the delivery truck’s rear sides and top to be flush against this extension. These devices ensure that there is no gap on the two sides and top of the delivery truck and the building door frame and jam. Not having a gap improves dock security and energy conservation. The dock seal consists of two pads or an air pad on the two side frames of the dock door and one head curtain along the top of the door jam. Some models have moveable head curtains that are manually adjusted for the delivery truck’s height. Yellow strips or pads with yellow strips are options on the seal’s exterior sides. These yellow strips help the delivery truck driver to locate the delivery truck at the dock position. The pads extend the lift of the seal by reducing wear from the movement of the delivery truck sides, which rise and lower as the delivery truck is loaded or unloaded by the employees. Dock shelters conserve energy and improve dock security. The dock shelter is a fixed frame structure or flexible frame structure with a head curtain that extends outward from the building. The two sides of the frame hang onto the delivery truck sides and roof and conform to the rear doors of the delivery truck. Both types of shelters have steel channel protectors to reduce truck damage as the truck is backed


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up to the dock. Yellow strips on the pads or plain pads serve the same purpose as the yellow seal pads. Dock Lights Dock lights are adjustable and movable devices that provide light in the interior of the delivery truck. The dock light consists of a single lamp that has a flexible arm which reaches to the side and upper portion of the delivery truck’s rear door. Most dock light arms are located between two truck dock doors and service both dock doors. Some dock light arms provide light to a single dock door. Lockable screens protect the lamps from damage and theft. An option is a wire prong that extends into the door path. As an employee opens the door, the wire prong automatically turns the light on as the door is moved into the open position. As the employee closes the door, the wire prong comes in contact with the dock door and turns off the light. ICC Bar or Hook Device The ICC bar lock or hook device is a dock-leveler option that improves forklift safety in the dock area. The lock or hook is a device in the dock leveler pit area and is controlled from the dock to extend forward, upward, and beyond the dock-leveler lip. When a delivery truck is spotted or backed up at the dock, the hook motion and new position are in front of the delivery truck ICC bar. The hook in this position restricts the delivery truck’s forward movement, thus preventing delivery truck rollaway or unexpected delivery-truck departure. Stop and Go Lights Stop and go lights consist of red and green lights on the inside and outside of each dock door location. When a delivery truck is at the dock location, the light is red and signals to both the forklift truck operator and truck driver that the delivery truck is not ready for departure. When there is no delivery truck in the dock position or the delivery truck is ready for departure, the light is green. This green color signals to the forklift truck driver and delivery truck driver that the truck is departing from the dock position and it is not safe to enter the delivery truck.

UNLOADING AND LOADING METHODS When you consider the unloading and loading activity, you are considering the physical movement of the pallets between the delivery truck and dock area. For an effective operation and good productivity, each method is matched with its pallet type and your device to bridge the gap. The various methods are (1) manual method, (2) mechanized method, and (3) automatic method.

MANUAL UNLOADING

AND

LOADING METHODS

The first unloading and loading method group consists of the manual methods. An employee is required to pull or push a pallet between the delivery truck and dock.



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These various manual unloading and loading methods are (1) roller pallet and (2) manual low-lift pallet truck. Roller Pallet The roller pallet is a manual unloading or loading method that consists of a structural metal or wood platform with at least four wheels to roll across the delivery truck floor. The metal pallet rollers have additional center wheels that are rigid. To unload or load a delivery truck, an employee carries, pulls, or pushes the empty roller pallet into the delivery truck. After a pallet board is placed onto a roller pallet and a predetermined number of cartons are placed onto a pallet board, the roller pallet is pushed to the door of the delivery truck. At the door end of the delivery truck, a forklift truck removes the pallet from the roller pallet. It takes 6 to 7 hours to unload or load a delivery truck using this method. Disadvantages of the method include the need for a smooth truck floor, the need to use the greatest number of employees, low employee productivity, and slow turning of the delivery trucks. The advantages are low capital investment and little employee training. Manual Low-Lift Pallet Truck In manual low-lift pallet truck or jack unloading and loading method, an employee pushes and pulls a manual-powered low-lift pallet truck. The pallet truck (Figure 6.4) consists of an operator’s steering handle with steering device, brake lever, and fork hydraulic controls; two rubber or hardened plastic steering wheels; two hardened metal load-carrying forks with one or two hardened plastic load-carrying wheels under each fork and a hydraulic system to control the forks’ vertical movement. The two forks extend forward from the vehicle’s base. Manual pallet truck options are a hardened metal load backrest, tip forks, and a hardened plastic pallet entry wheel on each fork tip. To lift a pallet load, an employee pushes the set of forks into the pallet board opening and operates the hydraulic system, which lifts the pallet load above the finished floor and pushes or pulls the pallet across the travel path. To lower the pallet load, the employee stops the pallet movement and activates the lever to release hydraulic pressure. This causes the pallet board to lower onto the finished floor. To unload a delivery truck, an employee pushes or pulls the pallet truck into the delivery truck, picks up the pallet, and pushes or pulls the pallet to the dock staging area for deposit. With a manual pallet truck, the unloading of a delivery truck takes 2 hours. In some low-volume or foreign country operations that do not have docks, to unload or load a delivery truck the delivery truck has the rear pallets removed by a forklift truck and then a manual pallet truck is placed into the delivery truck. In the delivery truck the pallets are moved to the delivery truck’s rear for forklift truck removal. Disadvantages of the method include handling of a medium volume and difficulty of traveling upgrades. Options improve employee productivity and minimize product damage. The advantages are reduced employee injury and physical effort, fewer


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FIGURE 6.4 Palletjack or pallet truck. (From Crown Images © 2002 Crown Equipment Corporation. With permission.)



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dock positions, an improved vehicle turning time and unloading time, and the ability to be used in other warehouse activities.

MECHANICAL UNLOADING

AND

LOADING METHODS

The second unloading and loading method group consists of the mechanical unloading and loading methods. In these methods, a manually controlled and electric battery or internal combustion engine powered vehicle is used to move pallet loads between the dock area and a delivery truck. The various mechanical unloading and loading methods are electric-powered pallet truck, electric-powered pallet truck with a slip-sheet device, electric or fuel powered forklift truck, forklift truck with a slip-sheet device, and pallet claw. Electric-Powered Pallet Truck The first mechanical unloading and loading device is the electric battery-powered pallet truck or jack. The powered pallet truck is a three-wheeled vehicle that consists of one rubber-covered drive and steering wheel, a steering handle with all vehicle and fork controls plus a “dead man” brake feature, and two hardened metal loadcarrying forks with one or two hardened plastic load-carrying wheels under each fork and a hydraulic system to control the forks’ vertical movement. The two forks extend forward from the vehicle’s base. Other components are an electric battery compartment and, with the rider models, a rider grip bar with controls. The powered pallet truck is available in three models: walkie, walkie/rider, and rider. The powered pallet truck options are as follows: for some models, a hardened metal load backrest; tip forks; an extended fork for long loads; and a hardened plastic pallet entry wheel on each fork tip. To unload a delivery truck, an employee drives the pallet truck into the delivery truck, picks up a pallet load and secures the pallet, and drives with the pallet from the delivery truck onto the dock staging area. A full delivery truck is unloaded in 1 to 2 hours. The disadvantages are a need for greater employee training, a battery-charging area, and additional investment. The advantages are that the method handles a high volume, reduces employee injuries, requires fewer employees and dock positions, easily travels up grades, and can be used in other warehouse activities. Electric-Powered Pallet Truck with a Slip-Sheet Device The second mechanical unloading and loading device is the electric battery-powered pallet truck with a slip-sheet attachment. In this method, a powered pallet truck with a special platen and lip clamp device handles a slip-sheet load that has been separated into units. Disadvantages of the method are a need for greater employee training, a batterycharging area, additional cost, and difficulty of stacking pallets. The advantages are that the method handles a high volume, handles slip-sheets, travels up a grade, requires few employees, and uses a slip-sheet transport vehicle.


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Forklift Truck The electric or fuel-powered forklift truck is the next mechanical unloading and loading device. Most dock-area forklift trucks are the counterbalanced type, and if there is a flat travel path to the device that bridges the gap between the dock edge and the delivery truck, a straddle truck can be used in the operation. The forklift truck is an electric battery-powered or gas, liquid propane (LP) gas, or diesel powered vehicle that is a sit-down or stand-up model. These models have three or four wheels, a set of forks that extend forward from the mast and move up or down along the mast, and an operator’s area that has direct access to all vehicle and mast controls. With a free-lift option, the set of forks elevates without moving the mast. This freelift feature permits the forklift truck to operate inside delivery trucks. The mast height, overhead guard, vehicle under-clearance, and wheel span permit the forklift to enter and exit delivery trucks. For maximum employee productivity and reduced product damage, fork side-shift and tilt and spotlights on the mast are options for consideration. To operate, an employee drives the forklift truck into a delivery truck, picks up a pallet load, and drives with the pallet from the delivery truck to the dock staging area. With this method, a delivery truck is unloaded in one to two hours. When compared to the electric pallet truck method, the forklift truck method’s additional disadvantages are increased operator training and higher cost. The additional advantages are that the method handles stacked pallets and is used in many other warehouse activities. Forklift Truck with a Slip-Sheet Device The next mechanical unloading and loading device is the counterbalanced forklift truck with a slip-sheet attachment. The slip-sheet attachment replaces the set of forks and is attached to the front of the forklift truck. The slip-sheet attachment permits a forklift truck to handle slip-sheet loads between the delivery truck and dock area. When compared to the electric-powered low-lift or pallet truck with a slip-sheet method, the counterbalanced forklift truck method’s additional disadvantages are higher cost and additional operator training. The additional advantage is that the method handles a slip-sheet in a stack. Pallet Claw The next method is the pallet gripper or claw method. The pallet claw method consists of a set of clamps, a chain, and a forklift truck. The pallet claw has tooth edges that are designed to clamp securely onto a pallet board’s middle stringer or block. The other end of the chain is attached to the forklift truck. To operate the pallet claw clamp, an employee sets the claws onto the pallet board’s middle stringer or block and attaches the chain’s loop to the forklift truck. As the forklift truck travels from the delivery truck, the claw grip tightens on the pallet board’s stringer or block and moves the pallet board over the delivery truck floor to the rear of the delivery truck. The forklift truck without the claw removes the pallet from the delivery truck.



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The pallet claw method is designed for an operation that does not have a dock. The disadvantages of the method are that it could be considered dangerous and that it handles a low volume.

AUTOMATIC UNLOADING

AND

LOADING METHODS

The final pallet receiving and shipping method group consists of the automatic pallet unloading and loading methods. The various designs in this group utilize electricpowered conveyors, set-of-forks methods, hydraulic platforms, or specially designed trailers. With very minimal labor, these methods move pallets between the dock area and delivery truck. Pallet-Handling Device The pallet-handling device (PHD) consists of a stationary or mobile and fully automatic device that is used to load and unload pallet between a delivery truck and the dock staging area. With the base of the PHD on the dock and a live roller pallet conveyor on the top of the base, the PHD design provides the pallet staging area for the operation. In the loading process and with a delivery truck at the dock position, the PHD with its sensor devices determines the delivery truck’s length and is ready to receive pallets. The PHD forks are raised and pick up a pallet from the live roller conveyor. With the pallet on the set of forks, the PHD rotates and lowers the pallet for entry into the delivery truck. After entry (by cantilevered extension of the set of forks) into the delivery truck, the PHD device deposits the pallet in the proper position on the delivery truck’s floor. The PHD microcomputer program determines the other pallet drop locations on the truck floor. In the unloading process, in the delivery truck the PHD device uses the set of fork sensors to determine the fork openings of the pallets in the delivery truck. After the PHD set of forks is inserted into a pallet board’s opening, the pallet is raised on the set of forks and the PHD device returns to the dock position and raises the pallet for transfer and placement onto the liver roller conveyor that is on the top of the base. The PHD with a single set of forks handles a delivery truck of 18 pallets in 30 minutes to one hour. If delivery truck spotting time is required, then 15 to 30 minutes is added to the time. A double set of forks PHD handles two pallets with a combined weight of 3500 pounds. With two sets of forks, the delivery truck’s unloading time is 20 to 40 minutes. When used with the fork sensors, the PHD handles a pinwheel pallet-loading pattern, or a four-way pallet permits the PHD to stack pallets in the delivery truck. Safety stoplights along the dock door area provide safety as the PHD device unloads or loads a delivery truck. The disadvantages of the method are capital investment, lack of adequate dock area, and difficulty in handling all loads in a fluid manner. The advantages are very low labor expense, very low dock-leveler investment, reduced product and equipment damage, and minimal dock positions. Strad-O-Lift The automatic Strad-O-Lift® device picks up, transports, and deposits a load of pallets onto a warehouse floor or into the truck-yard loading area. The device consists


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of a specially designed trailer that has a set of lifting shoes. These shoes run the full length of the truck and hydraulic mechanisms clamp the shoes together, lifting all of the pallet loads. After the pallets are in the raised position, the trailer travels to the new facility. At the new facility, the delivery-trailer pallet load is lowered onto the finished floor or onto the truck yard. To facilitate pallet loading and unloading, the pallets are set on full-length stands. The disadvantages of the method as follows: there is low clearance, both the shipping and receiving location must use the method, and all pallets required a secure method. The advantages are that a short time is required to handle the pallet load, that forklift trucks move the pallets, and that few employees and a flat set-down area are required. Pallet Flow Device The pallet-flow device method is an automatic pallet-handling device that moves pallets between the delivery truck and the dock staging area. This method consists of air pressure, a powered chain, and conveyors that move pallet loads between a delivery truck and a dock staging area. The method requires delivery trucks that have a specially designed floor and a dock staging area that has a specially designed floor. These specially designed floors have a push-pull device and a conveyor that move the pallets. To operate, after the delivery truck is located at the dock position, an employee activates the dock area section to push the pallets forward from the dock area onto the delivery truck’s floor. The entire pallet load is pushed onto the delivery truck. After the driver ensures that the load is secured on the delivery truck, the building’s power cable is disconnected from the delivery truck and the driver closes the door. When the delivery truck arrives at the assigned facility, the power cable is hooked to the truck and the powered chains and mechanical devices move the pallets from the delivery truck onto the dock staging area. The disadvantages of the method are capital investment in a delivery truck and dock area, increased maintenance, and the fact that both facilities require the method. The advantages are that the method requires less dock time, fewer dock locations, fewer dock positions, and less dock-area equipment.

RAILCAR UNLOADING AND LOADING METHODS The second major pallet operation receiving and shipping area is the railroad car dock area. Since the delivery-truck method normally has easy access to the highways, the method handles the majority of the pallet deliveries to the operation. In some industries, a rail car transportation method handles nonperishable, high-cube, and low-weight SKUs. To provide railcar access to the order-fulfillment facility without interruption to the delivery truck flow, a rail spur or rail tracks are located parallel to the building on the opposite side of the building from the delivery truck-dock area. When you consider a railcar dock area, the most critical design factor is to determine the state and local codes for the centerline rail clearances at your facility. The second important design factors are railcar overall length, railcar door length, pallet capacity, and number of each type of railcar that is handled by your operation.



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This includes the average and peak number of cars. This information is obtained from the railcar company that services your operation, your company’s railcar receiving records, and the company growth rate. With this information, your railcar dock is designed for you pallet order-fulfillment operation. The rail track section is between the railroad’s main traffic line and your operation’s facility dock area or your rail spur line. The rail spur permits the railroad company to transfer your rail cars from the main line to your dock area. Usually, the maintenance of your rail spur is your company’s responsibility.

VARIOUS RAILCAR DOCK DESIGNS The four main railcar dock area designs are flush dock, rail platform, inside rail dock, and portable dock.

FLUSH DOCK The first railcar dock design is the flush dock design. With this design, the railroad car spur runs along the side of your facility. The distance between the centerline of the rail spur and the farthest extension of the distribution facility or dock is 8 1/2 to 9 1/2 feet. This clearance permits unobstructed railcar travel on the rail spur or track. The flush dock design minimizes the building construction costs, maximizes the building utilization of the site, and maximizes the square foot utilization of the building. With this design, the dock doors have at least the same width as the widest railcar door. To facilitate railcar spotting and possible wider railcar doors, these dock doors are as wide as possible. To improve safety and employee productivity during bad weather, a canopy is extended outward from the side of the building to a distance at least to the center of the track or spur and at least 23 feet above the tracks. Lighting under the canopy improves dock safety. This canopy protects the dock area from becoming wet. A second consideration is an energy conservation design that has, inside the building, a shelter or vestibule. To provide maximum energy conservation and employee safety, a dock shelter is added to the dock door frame. The dock shelter is a fabric-covered frameconstructed device. After a railcar is secured at its dock position, the shelter is extended outward from the building side to cover the railcar opening and dock plate. This extension forms a protected tunnel for the powered or nonpowered vehicle pallet movement between the rail dock and rail car. The disadvantages are that the method requires exact railcar spotting, unloading could require additional in-house transportation distance, and the number of doors determines the number of railcars per day. The advantages are minimum building construction costs, maximum energy conservation, improved dock area safety and security, and maximum site and facility utilization.

RAIL PLATFORM DOCK The second railcar dock design is the rail platform dock. The rail platform dock extends outward from the building side toward the center of the rail spur or track.


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The concrete platform is constructed along the exterior building wall that parallels the rail spur or tracks. This feature permits railcar dock activity at any spot along the platform. The platform has sufficient width that pallets can be stacked along the building exterior wall and pallet unloading and loading equipment can make rightangle turns between the rail dock and rail car. This dimension is approximately 14 to 20 feet between the building wall and dock edge, but is finalized by your material handling equipment selection. The method’s wide platform adds to the building land utilization and construction costs. To facilitate dock activity in bad weather, a canopy extends outward from the building wall to the centerline of the rail spur and at least 23 feet above the tracks. Lighting under the canopy improves dock area safety. The disadvantages of the method are increased construction costs, potential hazardous conditions in rainy weather, and some reduction in dock-area safety and security. The advantages of the method are that it provides a maximum number of dock positions and that it reduces in-house transportation travel distances.

INSIDE RAIL DOCK The third dock design is the inside rail dock design. A railcar inside the building has weather protection and permits day and night dock activity. It also permits railcars to unload at any dock position along the track. With the track between the building rear wall and the dock edge, the design adds to the building construction costs and the building utilization of the site, and requires a door for railcar entry to and exit from the building. With the tracks inside the building and portable dock boards, the distance between the edge of the dock and the centerline of the track is approximately 8 feet. Disadvantages of the method include potential infestation (if there are rodents in the car), increased building and construction costs, and increased rail spur costs. The advantages include activity in any weather, improved security and safety, and reduced in-house transportation costs.

MOBILE

OR

REMOTE DOCK RAMP

The next design is the mobile dock ramp. When your building and site size cannot have a rail spur adjacent to the building and the rail car volume is very low, then the railcar siding is located far away from the building. The remote rail spur is serviced by a dock ramp. Disadvantages are that the method cannot be used in bad weather and that it requires setup time. The advantages are low cost and maximum site utilization.

SINGLE RAILCAR UNLOADING The previously described railcar dock designs are parallel to the rear or to the side of the building. Whenever possible, the railcar track is a single track because this permits railcars to be spotted at any location for easy access to the storage location. When the land or building shape and spur do not permit sufficient space for a single track to handle the daily railcar requirement, there are two alternative strategies.



CONTROLLED

OR

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SELECTIVE RAILCAR UNLOADING

The first strategy is to sequence the railcar spotting on a daily basis by first unloading the oldest railcars or the railcars that contain priority product. This strategy potentially incurs detention charges and inventory flow problems.

DOUBLE RAILCAR UNLOADING The second strategy is a railcar dock-area design in which two rail tracks are parallel to the dock edge. This design increases the number of railcars that are handled by the receiving operation. This design requires a bridge dock board that bridges the gap between two railcars. To unload or load the railcars, a specially designed railcar dock plate bridges the gap between the two railcars, and a normal dock plate bridges the gap between the railcar and dock edge. The railcar to car dock plate bridges the gap between two railcars and supports a fully loaded forklift as it travels across-the-dock plate. Side guards on the dock plate improve the safety of the railcar loading or unloading activity.

VARIOUS RAILCAR DOCK BOARD DESIGNS TO BRIDGE THE GAP When you consider the various dock plates that bridge the gap between the railcar and the dock edge or the gap between two railcars, the options are (1) portable dock board, (2) vertically stored dock board, and (3) railcar to railcar dock board.

PORTABLE DOCK BOARD The first type of railcar dock board is the portable dock board. The portable dock board is designed with a top diamond pattern travel surface with structurally reinforced members on the underside. These members serve a second purpose in reducing the dock board movement. Lips on both ends of the dock board provide a smooth transition from the dock board to the railcar or dock. Two forklift truck handles or loops provide the openings for a forklift truck’s forks to lift and move the board. Securing pins on the railcar dock board ends secure the dock board to the railcar, reducing the dock board movement. Side curbs reduce pallet transport equipment runoffs. The disadvantage is that it requires a forklift truck to move the dock plate. The advantages are lower maintenance costs and improved employee productivity.

VERTICALLY STORED DOCK BOARD The second portable railcar dock board is the vertically stored dock board. The vertically stored dock board has the same design and operational characteristics as the delivery truck vertically stored dock board. The railcar vertically stored dock board is available in both manual and hydraulic types. Both types are attached to a channel that is mounted to the side of the railcar dock platform or building and requires exact measurement from the dock edge to the centerline of the rail spur. The dock boards are best installed after construction of the railcar dock and rail spur.


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PORTABLE RAILCAR

Order-Fulfillment Concepts, Design, and Operations TO

RAILCAR DOCK BOARD

The bridge between two railcars is the next portable railcar dock board method. As described in the previous section on double railcar unloading, this dock board bridges the gap between two railcars. After the inside railcar (adjacent to the dock) is unloaded, a forklift truck places the railcar to railcar dock board in the door of each railcar and thus the dock board bridges the gap between two railcars. The two railcar dock board bridge has two lips. One lip or end rests on the outside railcar door opening and the other end or lip rests on the inside railcar door opening. The travel path has a diamond-pattern surface and the underside has support members that prevent movement of the dock board. Each lip end has securing pins to secure the bridge dock plate to the railcars and prevent movement. With a bridge between the two railcars, pallets from the railcar on the outside are unloaded through the railcar on the inside rail track and onto the dock area. If your building or site size and configuration prevents a single track railcar operation, this design should be considered for your operation.

BASCULE BRIDGE As a result of building expansion or railcar company spur design requirements, the rail spur is designed inside the building with dock space or with storage zones on both sides of the rail spur. This rail spur design separates the building into two zones. To have mobile pallet-handling equipment travel through the entire facility or between two zones, a bascule bridge or drawbridge spans the rail spur track and permits forklift truck travel between the two zones. The bascule bridge is an electrically, mechanically, or hydraulically powered device that consists of a diamond-pattern travel-path surface with underside structural support members, safety sidings, and the ability to raise and lower one end. The bascule bridge device is attached to one side of the dock edge and the other side is in the raised or lowered position. In the raised position, it permits railcar traffic over the rail spur. When the bridge is in the lowered position, the bridge spans the gap between the two dock edges and mobile pallet-handling equipment travels between the two zones.

RAILCAR DOCK-AREA OPTIONS Railcars are assigned or spotted to a railcar position on the rail spur that has the most direct forklift travel path to the storage aisle or in-feed station. For additional information on vendor delivery truck-yard design considerations, we refer the reader to Chapter 7.

PALLET UNLOADING ACTIVITY The next pallet operation activity is pallet unloading from your vendor’s delivery truck, oceangoing container, or railcar. Each of these vendor delivery vehicles is



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unique and has a different unloading location at a facility, but each is unloaded with any of the methods. One of the main receiving and shipping objectives is to transfer pallets or unit loads between the delivery vehicle and the dock area. The method to support or handle the product in the delivery vehicle has a direct influence on your dock employee’s productivity. In the pallet industry, your operation has the potential to receive product on a vendor delivery vehicle in the following forms: (1) on a standard pallet, (2) on a nonstandard pallet, (3) on a slip-sheet, (4) floor-stacked in the delivery vehicle or in a container.

FLOOR-STACKED METHOD In the floor-stacked method, the product is set directly onto the delivery vehicle’s floor. To receive or ship the product, your employees are required to lift and transfer the product onto a pallet board or onto another material-handling device. The disadvantages of this method are increased risk of employee injury, low employee productivity, a requirement for the greatest number of employees, and a requirement for the greatest number of dock positions. The advantages are excellent cube utilization of the delivery vehicle and no extra weight on the delivery vehicle.

PALLET-BOARD METHOD The second method is to put your cartons on a pallet board. The pallet board is a carton-support device with top and bottom deck boards. The forks of a mobile forklift truck or pallet truck are inserted into the pallet board’s fork openings and lift the pallet board. This feature permits the mobile truck to transport the pallet between the dock and the delivery vehicle. The normal delivery vehicle has the capacity for 18 to 20 pallets and it takes 1 to 2 hours to load or unload the delivery truck. To minimize product damage and ensure high employee productivity, the cartons are secured onto the pallet board. The disadvantages of the method are as follows: it requires a storage area for empty pallets, pallets are an additional expense, it adds weight to the delivery vehicle, there is a loss of some cube on the delivery vehicle, and it requires a pallet truck or forklift truck. The advantages are high employee productivity, an operation that requires fewer employees and fewer dock positions due to quicker turns of the delivery vehicles, and reduced risk of employee injury.

SLIP-SHEET METHOD The next method is the slip-sheet method (Figure 6.5). The cartons are packed onto a corrugated, plastic, or other material sheet that has a lip. The lip extends forward from the unit load and permits a mobile vehicle with a slip-sheet attachment to clamp onto the lip and lift the unit load. After the unit load is secured onto the mobile vehicle’s slip-sheet attachment, the unit load is transferred from the delivery vehicle to the dock staging area. To handle a delivery truck with 18 to 20 slip-sheets, the slip-sheet method requires 2 to 2 1/2 hours. When you use a slip-sheet in a truck you need a single lip


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FIGURE 6.5 Slip-sheet equipment. (Long Beach Corporation and Cascade Corporation, Boise, ID. With permission.)

or tab on the slip-sheet; when you use a slip-sheet in a railcar or oceangoing container, you need a multiple lip or tab slip-sheet. The additional disadvantages of the slip-sheet method are increased capital investment for a slip-sheet attachment and requirement for a slip-sheet device. The additional advantages are less weight and lower cube loss.

CONTAINER METHOD The next loading and unloading method is the container method. The container method is a device that has a product support surface, two fork openings, four sides, and legs that sit on a pallet board or on the floor. To transfer a container between the delivery vehicle and dock, the employee uses a forklift truck or pallet truck. The disadvantages of the method are the need for a forklift truck or pallet truck and additional container cost. The advantages are that it handles small cartons and that it is used in the storage and pick area. Since these delivery vehicle methods are similar to the across-the-dock unloading methods, for additional information we refer the reader to Chapter 7. In the delivery-vehicle unloading activity the pallets are moved from the delivery vehicle to the receiving dock. When a pallet order-fulfillment operation unloads pallets, there are several receiving and unloading options as follows. Pallets can be unloaded from the vendor delivery vehicle. This requires a manual or powered pallet fork truck, a powered forklift truck, and an automatic unloading device. To unload a floor-stacked delivery vehicle, your employee must unload or stack products onto a pallet and a mobile vehicle or powered conveyor moves the products to a dock for stacking onto a pallet.



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To unload slip-sheets, your employee must unload or stack products onto a pallet and a mobile vehicle with a slip-sheet handling device or powered conveyor moves the products to a dock for stacking onto a pallet. Since these delivery vehicle methods and dock board and leveler equipment are similar to the across-the-dock unloading methods, for additional information we refer the reader to Chapter 7.

PALLET RECEIVING ACTIVITY After unloading the delivery vehicle pallets onto the receiving dock, the next pallet operation activity is the pallet receiving activity. The pallet receiving activities are: • • • • •

To ensure that there is no product damage and verify that the delivery quantity matches the purchase order quantity To verify that the pallets are quality pallets To take a product sample for quality inspection (QA) To complete discrete identification of each pallet As required, to wrap or secure the product to the pallet

NEED FOR SUFFICIENT, CLEAR FINISHED-FLOOR SPACE AND AISLES To have your pallet warehouse activities performed on schedule with as little product or equipment and building damage as possible, in the warehouse it is required to have sufficient clear finished floor space and adequate aisle dimensions between two pallets. In addition, all warehouse activities are performed by trained employees who control the vehicle that moves a pallet. This feature exists for vehicles that perform transfer transactions between an ASRS in-feed system and the in-house transportation vehicle. In the unloading or receiving dock and the loading or shipping dock areas, the dock area has an aisle between the dock leveler or dock plate and the unit load staging area. To ensure an efficient and safe dock operation, most dock aisles are a minimum of 6 feet or 2 meters wide. The unit load staging area is immediately behind the dock door and has sufficient space to stage the entire pallet quantity of a delivery vehicle. The dock staging space is designed to handle a vendor delivery truck, oceangoing container, or railroad car pallet quantity. In this dock staging area, there is sufficient space for an employee to identify and stabilize a pallet load. A second aisle exists between the receiving or shipping dock staging area and the storage area. This aisle width is designed to ensure efficient vehicle transactions to the storage area. This aisle width is set by your transfer transaction-vehicle aisle width, which is stated by the vehicle’s manufacturer. The aisle permits efficient inhouse transportation of pallets from the staging area to the storage area, and uninterrupted vehicle travel between aisles. In the storage area, the clear aisle width between pallet storage positions (product to product) is sufficient for the forklift truck to make a right-angle turn, or for a guided vehicle to perform a storage transaction.


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HOW TO PROJECT THE REQUIRED NUMBER OF DOCKS The number of vendor or shipping delivery trucks or railcars required at your facility is determined by one of the three following methods: (1) manual calculation, (2) manual simulation, or (3) computer simulation.

MANUAL CALCULATION The number of docks is determined by several factors that are easily obtained or calculated by your logistics department. These factors are as follows: tabulating for one week the number of daily truck or railcar deliveries (peak and average), plus growth; determining the time of day and frequency of delivery truck or railcar arrivals; determining the delivery percentage for floor stacks, slip sheets, and pallet loads; determining the time required to unload or load and stage pallets on the dock area, per the type of delivery; determining the number of mobile material-handling vehicles or vehicles with attachments or conveyors that are used in the dock area; including 30 to 45 minutes for employee coffee or lunch breaks; determining truck maneuvering time, document signing time, and railcar door opening time; and determining a reasonable safety factor such as 20 to 25%. A general rule of thumb is that there should be a sufficient number of dock positions to unload and load the maximum number of delivery trucks or railcars that arrive or are scheduled for unloading or loading at your facility. A simple formula for determining the number of dock positions is the number of trucks or railcars per year multiplied by the hours it takes to load or unload a truck or railcar, and divided by the work hours in a year. When designing the number of docks, add at least one dock space for each of the following: ramp or dock lift for forklift truck travel from the dock to the ground level, maintenance dock with a high door, dock or docks for trash and paper bales, one dock for office supplies and other items, and one dock for express package delivery.

MANUAL SIMULATION A second method to determine the number of dock doors that is required at your facility is the manual dock-simulation method. This method projects the number of docks that are required for the various types of trucks or rail cars that deliver or ship pallets from your facility. Data required for a manual truck or railcar dock simulation consist of the following: for an average day, the number of trucks or rails cars that arrive at your facility; the type of load (floor-stacked or separated into units) and rear truck or side truck or rail car height; the number of hours for each truck or rail car at the dock position (including spot and departure times); and the number of standard or special docks.

COMPUTER SIMULATION When you use a computer to design your truck and railcar dock operations, then you provide the same truck and rail delivery and shipping activities, inbound and



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outbound volume, productivity and dock door and other design information that was mentioned in the section on manual dock calculations. After the data are entered into the computer, the computer program projects each dock door utilization, the required number of doors, and other dock-area design information.

HOW TO DETERMINE THE DOCK-AREA SIZE There are several factors that influence the dock-area size. These factors are (1) mobile forklift truck paths and (2) pallet staging areas.

MOBILE TRUCK PATHS The first dock staging areas in a pallet operation are the mobile forklift-truck travel paths. To have an efficient and cost-effective dock operation, forklift trucks or pallet trucks require unobstructed travel paths from the pallet staging area to the delivery truck, between the dock leveler and the pallet staging area, from the pallet staging area to the main traffic aisle, and between the pallet staging area and the main traffic aisle. In most applications with a powered pallet truck, these aisle widths are 6 to 8 feet. If the powered forklift truck is used in the operation, the aisle widths are 10 to 13 feet.

PALLET STAGING AREA The second dock staging area is a pallet staging area to hold pallets that are staged for the receiving activity or are staged for the shipping operation. If the pallet orderfulfillment operation requires a pallet staging area, then the alternatives are floor stacks, standard pallet racks, two-deep pallet racks, drive-in or drive-through racks (Figure 6.6), flow racks (Figure 6.7), push-back racks (Figure 6.8), and portable racks or stacking frames (Figure 6.9). For additional information on these various pallet storage methods, we refer the reader to the pallet position section of this chapter.

FIGURE 6.6 Drive-through pallet rack. (From Kingway Material Handling, Acworth, GA. With permission.)


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FIGURE 6.7 Pallet flow rack. (From Kornylak Corporation, Hamilton, OH. With permission.)


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FIGURE 6.8 Push-back pallet rack. (From Kornylak Corporation, Hamilton, OH. With permission.)



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FIGURE 6.9 Moveable pallet rack storage comparison. (From Kornylak Corporation, Hamilton, OH. With permission.)

FOUR IMPORTANT RACK AND FACILITY DIMENSIONS When you design a pallet order-fulfillment operation, the four important dimensions are (1) the space between two building columns, (2) the space between the finishedfloor surface and the bottom of the lowest ceiling obstruction, (3) the complete dimensions of the pallet and bottom support device, and (4) clearances or open space between two pallets and between a pallet and a rack structural member. In a facility with pallet racks, the clearance is between a pallet and the rack’s upright post base plate.

CLEAR SPACE

BETWEEN

TWO BUILDING COLUMNS

The clear space between two building columns is the open space between two building columns. This dimension indicates the finished-floor space between the four building walls that is available for your pallet storage/pick area or method. The two important building column dimensions are (1) centerline to centerline, or the dimension between the midpoints of two building columns, and (2) open or clear span between two building column stands or base plates. When you design a pallet storage/pick method inside a building’s four walls, the open (clear) space between two building columns is an important dimension. This dimension determines the number of pallets or rack-bay base plates that fit between two columns.



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During the design process, you verify the clear or open dimensions between all building columns, because some facilities have intermediate columns for an elevated finished-floor support. When it is required to fit the building on a site, some building architects vary the spacing between the two outside columns or dimensions. To fit a facility on a particular site, in some occasions you are required to adjust your building column span. If required to adjust the building column span, most facility designs have two building column spans for the interior building columns and the columns along the exterior wall. Whenever possible, the interior building column span matches the pallet storage/pick equipment design and adjustments are made to the building column span along the exterior wall. Alternately, adjust an interior building column span to match the pallet storage/pick equipment design and maintain the building column span along the exterior wall. With both alternatives building column spans that are different are kept to a minimum.

CLEAR SPACE BETWEEN THE FINISHED-FLOOR SURFACE CEILING OBSTRUCTION

AND THE

LOWEST

The second important dimension is the open or clear space between the finishedfloor surface and the bottom of the lowest ceiling obstruction or the elevated finishedfloor support members. This dimension determines the number of pallets in a floor (or block) stack, the number of load beam levels in a rack section, and the forklift truck or ASRS vehicle pallet-lift requirement to complete a storage/pick transaction. This open or clear space includes the pallet load dimensions, the required forklift truck/ASRS vehicle operational dimension, fire protection or sprinkler space, and storage rack structural members such as load beams or overhead aisle ties. When an exceptional situation occurs in the clear space, such as a heater, the exception is calculated in the pallet storage-area capacity.

PALLET LOAD DIMENSIONS The next important dimensions are the pallet load dimensions. The pallet dimensions have two important parts. First there is the product dimension, which is the length, width, and height of the product’s “ti and hi” on top of the pallet. The ti consists of the number of cartons per layer and the hi is the number of carton layers per pallet. The second part is the pallet or product bottom-support device. If the product ti is within the pallet (or bottom support device) perimeters, there is no product overhang length and width of the pallet and the pallet dimensions are the storage pallet unit load dimensions. If the product ti overhangs the pallet (or bottom support device), the length and width of the overhang become the storage pallet unit load dimensions. The pallet length and width dimensions are important factors that determine the number of floor-stacked pallet positions per area; the depth of the rack frame, bay, or lane; and the number of pallets wide on a rack load beam, on a rack bay, or between two rack upright posts. These two pallet and rack dimensions along with clearances determine the number of floor-stacked pallets, and the number of rack rows and rack bays that fit between two building columns. The pallet height is a key factor that determines the number of pallets in a floor stack or the number of pallets in a rack bay in a vertical stack. The pallet height is


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considered the overall height between the bottom deck board and the top of the highest carton. The pallet load weight consists of the entire pallet. The pallet weight includes the pallet board, securing material, and product weight. The pallet load weight is a key factor that determines the number of pallets per floor stack; the number of pallets or load beam levels per rack bay; the rack posts’ base plate thickness and footprint; the forklift-truck wheel size; and, along with the forklift truck/ASRS vehicle weight, the finished-floor thickness and rebar characteristics.

PALLET LOAD BOTTOM SUPPORT DEVICE The length, width, and fork entry opening of the pallet board (or unit load bottom support device) are important dimensions that determine the location of the rack structural components: the rack load beam length, the rack upright post and load beam depth, and the load arm or rail length. In most forklift truck facilities, the pallet overhangs each load beam or extends into the aisle or flue space by 2 to 3 inches. These key factors and the forklift-truck stacking requirement determine the warehouse aisle width. The pallet load bottom fork-entry opening is the opening between the bottom of the top deck board and the top of the bottom deck board. The opening determines the length and type of a lift truck’s forks or attachments.

OTHER IMPORTANT CLEARANCES OR OPEN SPACES In addition to the previously mentioned clearances, to minimize product, equipment, and building damage; minimize employee injury; and provide good pallet employee storage/pick productivity, there are several other important clearances or open spaces (Figure 6.10). These include the clearance for fire sprinklers; the clearance between a pallet and rack support member; the clearances for a straddle forklift truck; the clearance for a rack-supported elevated floor or a building that requires a wide rack base plate; the flue or open space between back-to-back rack rows or between a rack row and wall; fire baffles and additional fire sprinklers that may be required for a tall-rack facility; for a food facility, a white space along the wall; and open space that may be required for conveyor travel paths adjacent to a building column.

CEILING CLEARANCE FOR FIRE SPRINKLERS When a pallet storage/pick method is designed for a facility, most applications, per local code, company risk-management policy, or insurance-policy underwriter, require fire sprinklers in the facility or rack vertical stack. In a conventional facility, the ceiling fire sprinkler design requires an 18-inch clearance or open space between the top of the highest pallet and the sprinkler head. In a 40-foot- or 13-meter-high facility, the ceiling fire sprinkler design requires a 3-to-5-foot clearance or open space between the top of the highest pallet and the sprinkler head. These clearances or open spaces provide sufficient space for heat accumulation and proper activation of



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FIGURE 6.10 Comparison of building heights, storage, and sprinkler requirements. (From Kornylak Corporation, Hamilton, OH. With permission.)

the sprinkler head, which permits the water spray to cover the area; in addition, they reduce sprinkler damage and accidental discharge of water that damages products.

CLEARANCE

BETWEEN

TWO PALLETS

AND

RACK SUPPORT MEMBERS

Another important clearance is the rack-bay width. For a forklift truck to complete a storage transaction, a rack bay requires horizontal open space between a pallet and the rack upright-post structural support member or base plate. The open space or clearance between two pallets or between the rack upright-post structural support member or base plate and a pallet is 3 to 6 inches. This clearance or open space varies per forklift truck type and ASRS vehicle type. The open space permits a forklift truck to complete a pallet storage/pick transaction with low product and equipment damage and high employee productivity.

CLEARANCES

FOR A

STRADDLE FORKLIFT TRUCK

When a pallet storage/pick operation uses a straddle forklift truck with a pallet on the finished-floor surface as the first pallet position, the clearance between pallets and the rack upright-post structural support member base plate is at least 5 to 6 inches, or the straddle width plus 1 inch. The open space between two pallets or a pallet and a rack upright-post structural support member base plate permits the forklift truck’s straddle to enter the rack bay. This feature permits a straddle forklift truck to complete a pallet storage/pick transaction with low product and equipment damage and high employee productivity.

A RACK-SUPPORTED BUILDING MEANS

A

WIDER RACK BASE PLATE

In a rack-supported or tall-rack building with a very narrow forklift truck, a larger upright-post base plate is required to spread the vertical rack’s stacked load weight. If your vertical pallet rack uses the finished-floor surface as the first pallet position,


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the base plate is considered in the rack’s open clearance. If the base plate is not considered in the rack’s open clearance, the options are to raise the first or bottom pallet level onto a pair of load beams, or to anticipate low forklift-truck driver productivity and potential rack damage.

FLUE

OR

OPEN SPACE

BETWEEN

BACK-TO-BACK RACKS

OR

WALLS

When your pallet storage/pick rack rows are designed in a conventional building with back-to-back rack rows or a single rack row against a wall, there is a 6-to-12inch open space between pallet and pallet or pallet and wall. In a facility with an early-suppression fast-response (ESFR) fire sprinkler method and with back-to-back rack rows or a single rack row against a wall, there is a 4-to-6-inch open space between pallet and pallet or pallet and wall. The open space is defined as the flue space that permits a fire’s heat to flow upward to activate a fire sprinkler head and that permits installation of the fire sprinkler pipes.

FINISHED-FLOOR STACKED PALLET CLEARANCE When your conventional pallet storage/pick operation uses finished-floor stacked (or block storage/pick) pallet positions with a conventional forklift truck, there is an open space that is 2 to 3 inches between two pallet lanes or between two adjacent pallets. If a straddle forklift truck is used in the operation, the open space between two pallet lanes is at least 5 to 6 inches. This open space permits a forklift truck to complete a pallet transaction without product damage and provides good forklifttruck driver productivity. If slip-sheets are used in the pallet floor stack storage/pick, the slip-sheet tab extension (usually 6 inches) is added to the open space between two pallet lanes or two adjacent pallets.

WITH A TALL-RACK FACILITY, ALLOW ADDITIONAL SPRINKERS

FOR

BAFFLE LEVELS

AND

With most tall ASRS facilities, per local code, company risk-management policy, or insurance-policy underwriter, fire baffles or additional fire sprinkler levels could be required in the vertical pallet stack or racks. These components require additional clearances.

WHITE SPACE

ALONG THE

WALL

FOR A

FOOD FACILITY

When the facility is used for a food order-fulfillment operation, most local codes require an 18-inch minimum open space between any wall and pallet in a finishedfloor stack or rack position. This open space is required to ensure proper sanitation and is painted white.

CONVEYORS ADJACENT

TO A

BUILDING COLUMN REQUIRE OPEN SPACE

When an ASRS facility is designed with a conveyor pickup and delivery (P/D) method, or when a conventional facility has conveyor travel paths, all conveyor travel



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paths require a 6-to-12-inch minimum clearance from any building column, building obstacle, or other fixed building or product-handling equipment.

OTHER FACTORS THAT AFFECT EMPLOYEE PRODUCTIVITY The pallet handing components that affect employee productivity, equipment and building damage, and logistics operating costs are as follows: adequate finishedfloor space or conveyor length for pallet accumulation or queuing; the type of pallet storage/pick method; the type of pallet board design; the method used to secure the product onto the pallet; the pallet locator and inventory control system, which includes pallet deposit and withdrawal; the pallet-transaction instruction method; the pallet-position identification method; the pallet-identification method; the pallettransaction verification system; the number of hours per work day; and the pallet inbound and customer-order transaction volumes.

PHYSICAL COMPONENTS OF A PALLET STORAGE/PICK METHOD When we consider a pallet storage/pick method, the important components are the pallet load, which includes pallet type and slip-sheet type; pallet load-handling vehicles (in-house transportation equipment and storage/pick transaction vehicles); pallet load storage/pick positions; and employee instruction.

PALLET LOAD When considering a pallet order-fulfillment operation, the pallet handling method and pallet load support device are two important design factors. The objective of this section is to define the pallet board terms, develop an understanding of the various pallet board designs, and identify the various pallet board materials. Pallet Board The pallet board used in your order-fulfillment operation is a key factor that allows product to flow smoothly through the facility and supports the product. In the pallet order-fulfillment and logistics industry, the pallet board is the common unit-ofproduct support device for corrugated or stackable products. Within the pallet group, the wooden pallet board is the most common device. It is handled by all forklift trucks, fits into virtually every type of storage structure, and is handled in the entire channel of distribution or supply chain. The pallet board’s popularity is due to three reasons: (1) there are common operational characteristics in your facility and through your supply chain; (2) the pallet influences the facility layout, design, and specifications for handling equipment; and (3) pallet board purchases and repairs are a business expense that affects your income statement.


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Pallet boards are available in many sizes and shapes and are manufactured from a variety of materials. The pallet board is a rigid base structure with stringers and blocks and top and bottom deck boards. The pallet board provides support for the material-handling equipment to move the pallet load. A unit or pallet load consists of cartons or cases that are stacked onto the pallet board. The majority of the pallet load order-fulfillment operations use a standard or a specially designed pallet board. Both of these pallet boards support a wide variety of products and are easily handled by material-handling equipment in any of your order-fulfillment activities. Four Basic Pallet Board Types The basic pallet boards used in the pallet order-fulfillment industry include: (1) standard pallet board, (2) throwaway or exchange pallet board, (3) throwaway pallet board, and (4) specially engineered or designed pallet board. The standard pallet board is used in an order-fulfillment operation that has manual or powered forklift trucks. The standard pallet board comes in two types: throwaway pallet board and exchange pallet board. The throwaway pallet is purchased from a product supplier and is delivered with the product to your order-fulfillment operation. After the order-fulfillment operation has made effective use of the throwaway pallet board, the pallet board is thrown in the trash. Given these operational characteristics, the throwaway pallet board is less expensive to manufacture than the exchange pallet board. Usually, the throwaway pallet board has thin top deck boards, narrow stringers, and a few thin bottom deck boards. The exchange pallet is used by your vendors and in your order-fulfillment operation. Both of these operations have the same specifications and standards for pallet boards. Upon receipt of a pallet load from your vendor on an exchange pallet board program, your order-fulfillment operation trades one of your empty pallet boards for each pallet board under your product. The “take it or leave it” pallet board is basically an exchange pallet board that is used by some of your customers and your order-fulfillment operation. It consists of a combination of a slip-sheet unit load on a pallet board that has a specially designed top deck. This unit load combination allows your order-fulfillment operation to handle the unit load as a slip-sheet unit load or as a unit load with a combination of a pallet board and slip-sheet. The customer is given the opportunity to purchase the combination of the slip-sheet and pallet board or to purchase the slip-sheet unit load. If the customer takes the slip-sheet option, then with a push/pull tine device the slip-sheet is pushed and or pulled from the pallet board and the slipsheet unit load is placed onto the customer delivery vehicle. If the customer takes the pallet board and slip-sheet combination option, then a standard forklift truck removes the pallet board from the storage/pick position and the pallet board or slipsheet unit load is placed onto the customer delivery vehicle. In the pallet board and slip-sheet combination option, your pallet order-fulfillment operation and your customers have a pallet-board exchange program. The specially designed or engineered pallet board is considered a slave or captive pallet board. This pallet board is manufactured to your order-fulfillment operation’s



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specifications and standards. Because of your order-fulfillment operation’s policy or material-handling equipment system requirements for a high quality pallet board, these pallet boards are captive or slave to your order-fulfillment operation. A high quality pallet board meets the following criteria: (1) it does not have broken or loose top or bottom deck boards or stringers; (2) nails do not protrude above or below the deck boards; (3) it does not have crooked, cupped, or bowed members; (4) the nails are threaded screw-type flathead; and (5) all wood members are knot-free. Pallet Board Materials Pallet boards are manufactured from a wide variety of materials. The factors that determine the pallet board material for an order-fulfillment operation are as follows: • • • • • • • •

SKU length, width, height, and weight, and total weight, height, depth, and width of the units of product on a pallet board Amount of allowable pallet board deflection or bowing Combined product and pallet weight that is acceptable to the material handling method Storage/pick and safety considerations such as spark-free, noncorrosive, freezer, or high-humidity environments Pallet board investment plan Pallet board exchange program or sending a captive pallet to the facility Pallet material as permitted by local codes Other order-fulfillment operational characteristics

The most common pallet board material is wood with threaded screw-type flathead nails for attachment of the pallet board members. The various pallet board materials are wood (hardwood, medium hardwood, soft hardwood, and softwood), plastic, corrugated, pressboard or fiberboard, rubber, and metal and metal-clad. The hardwood pallet board is a class C wood as defined by the National Wooden Pallet and Container Association (NWPCA). These pallet board components are nailed together; usually the nail holes are predrilled for easy nail entry. By nature a hardwood pallet board ensures that the nail is held, provides the greatest support strength, resists shock or damage or splinters, and is the heaviest. Since the hardwood pallet board is the heaviest of the wood pallets, it is preferred in a captive pallet board order-fulfillment operation. Hardwood types are white ash, white beech, red oak, birch, rock elm, hickory, hard maple, hackberry, and oak. Because of the high cost associated with hardwood, the heavy weight, and the difficulty of drying hardwood pallet boards, they are used less frequently in captive pallet board orderfulfillment operations. The medium density hardwood is a class B wood pallet board. To prevent the wood from splitting, nail holes are predrilled in the wood members. The pallet board has medium strength, dries easily, and has medium weight. These characteristics make medium density wood pallet boards preferred for use in a manual orderfulfillment operation. Some of the medium-density woods include ash (but not white


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ash), soft elm, tupelo, butternut, soft maple, yellow popular, chestnut, sweet gum, sycamore, walnut, and magnolia. The soft hardwood pallet board is a class A wood. The soft hardwood pallet board has medium support weight and a possibility of splitting, and is more lightweight than other hardwoods. Soft wood pallet boards are preferred for a manual order-fulfillment operation. Some soft hardwoods are aspen, basswood, buckeye, cottonwood, and willow. The softwood pallet boards have components that are made of wood that tends to split easily and is very lightweight. The soft wood has low support strength and dries easily. The pallet board components are nailed, stapled, or glued together. Softwood pallet board is lightweight, less costly, and easily handled by employees, so it is preferred in a manual operation or considered a throwaway pallet board. Some of the softwoods are Douglas fir (coast and mountain types), western hemlock, southern pine, and western birch. The disadvantages of softwood pallet board are that loose nails and wood splinters can damage the product, the product easily becomes dirty and infested, and it is difficult to use in a spark-free environment. The advantages are that softwood is repairable and reusable, that it is used in many industries, and that it interfaces with all types of forklift trucks. The plastic board is one piece of preformed molded plastic. The plastic board operational characteristics are similar to those of the wood pallet board. An option during the molding process that increases the plastic pallet board’s support strength is to have metal rods placed in the plastic. The disadvantages of the plastic pallet board are difficulty of repair, possible bowing, and restricted use per some local codes. The advantages are a washable product, long life, minimal infestation problems, minimal splinters, and use in a spark-free environment. The corrugated pallet board is treated heavy-duty corrugated board. The corrugated pallet board is preformed as one piece with its components glued, nailed, or stapled together. Some corrugated pallet boards have plastic cups for support legs. The disadvantages of the corrugated pallet board are that it is not as durable, it is limited to low humidity environments, and some local codes could restrict use. The advantages are its low cost, use in a spark-free environment, light weight, and availability of many shapes and sizes. The pressboard or fiberboard is a pallet board that is manufactured from one preformed piece made of a molded mixture of wood fiber and synthetic resins. The preformed pressboard is made to your operational specifications and size. Some pallets have plastic cups as legs. The disadvantages and advantages are similar to the corrugated pallet. The rubber pallet board is made from one piece of preformed molded polyethylene rubber. The rubber pallet board has the same disadvantages and advantages as the corrugated pallet board. These pallet boards are used in a spark-free environment. An option during the molding process to increase the strength of the rubber pallet board is to have metal rods placed in the rubber. The metal and metal-clad pallet board is the last pallet board material. The fullmetal pallet board has aluminum or steel members and is the heaviest of the pallet board materials. A metal-clad pallet board has aluminum or steel deck boards with wood blocks or stringers. These pallet boards are used in a pallet operation.



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The disadvantages of the pallet board are that it is difficult for employees to handle, adds weight to the unit load, and is more costly. The advantages are that it is fire resistant and has a longer life. Important Pallet Board Dimensions Pallet boards are available in a wide variety of sizes. The factors that determine the pallet board size are (1) the material handling equipment, (2) SKU dimensions and weight, (3) SKU hi and ti or pallet-loading pattern, (4) order-pick requirement, and (5) required SKU storage/pick openings. The pallet board length (into the rack, depth, bearer, or stringer) is stated first. The width or down-aisle or fork opening dimension is stated second. The third dimension is the height. A general rule of thumb is that the pallet board stringer length determines the depth for a forklift truck or the pallet jack fork length. In the U.S. order-fulfillment industry, the most popular pallet board size is the 48-by-40-by-5 1/2-inch flush, nonreversible, partial four-way open-deck pallet board. The height of the pallet board forklift truck opening is determined by the pallet load handling equipment and the storage/pick method requirements. Generally, a counterbalanced chisel forklift truck or a pallet truck’s set of forks requires a 3-to-5-inch-high pallet board opening. Most gravity pallet flow storage/pick methods require a solid slave pallet board that is approximately 1 to 2 inches high. Five Basic Pallet Board Designs The five basic pallet board designs are block; leg or honeycomb; captive, solid, or slave; stringer; and flue. The block pallet board has equally spaced blocks along its length and width. The deck boards are attached to the blocks. In many foreign countries’ logistics industries, the block pallet board is a very common pallet board. The leg or honeycomb pallet board has a solid deck with equally spaced legs along the length and width of the pallet board. These legs are attached to the solid. The base of each leg sits directly on the finished floor and the open space between the top surface and the base is the fork opening. The solid, captive, or slave pallet board has one solid piece of plywood or other material for the top and bottom surface. Because it does not have legs, blocks, or stringers, the slave pallet board sits flat or directly on the finished floor. In many pallet pick or conveyor methods, a solid pallet board is used as a support device for another pallet board. Some solid or slave pallet boards are designed with four holes in the four corners of the deck for easier employee handling of the pallet board. When a forklift truck with a set of forks handles a slave pallet board, the slave pallet board is set on a support device that permits the forklift truck’s set of forks to extend under the slave pallet board. This feature allows the forklift truck to complete the pallet order-fulfillment operation’s transaction. The stringer pallet board has two exterior stringers and one interior stringer for top and bottom deck board attachment. The exterior stringers either are solid or have two notches (openings) in the stringer side. The notches are additional fork-entry


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openings that permit a forklift truck with a set of chisel forks to handle the pallet board from all four sides. In the U.S. logistics industry, the stringer pallet board is the most common type of pallet board. The flue or rippled pallet board is a solid piece pallet or perforated piece of material that has every other ripple sitting directly on the finished floor. The depth and width of the flue space between the ripples are the space or openings for the forklift-truck fork entry. Pallet Board Components The two most popular pallet board types are the wood stringer pallet board and the wood block pallet board. These pallet board types have several similar and different components. These components are top deck boards, bottom deck boards, edge boards and other deck boards, chamfered edge boards, fork-entry openings, notches, stringer boards, stringers or bearers, blocks, and pallet board component connecting devices. The top deck boards are the first pallet board component. These flat wood members are attached to the pallet board’s stringers or to the block pallet board’s stringer board. The top deck boards provide the support for cartons, cases, or units of product. The top deck boards are slats or a solid piece of material. When the top deck board slats are used on a pallet board, the width of the slats or deck boards is from 4 to 8 inches and the open space between slats varies from 1 to 3 inches. The open space is called the deck opening. The deck opening allows air circulation and is very common on pallet boards that are used in a refrigerated or freezer operation. The bottom deck boards are attached to the bottom of the stringers or blocks. These deck boards provide a rigid and flat surface for the board to sit on the finished floor or pallet rack load beams. When a pallet jack with front load wheel is used in the operation, then the space between the bottom edge boards and the next bottom deck board permits the pallet jack wheels to raise or lower the pallet between the finished floor. The top and bottom deck boards at the two normal fork-entry opening ends of the pallet board are the edge boards. These top and bottom boards are 6 inches wide and 1/2 inch high. The width of the remaining top and bottom boards varies from 4 to 8 inches with a 1/2-inch height and the space between the deck openings varies from 1 to 8 inches. In some pallet boards, the two bottom edge deck boards and the bottom deck boards adjacent to the pallet jack wheel open space are chamfered for easy pallet truck fork entry. A chamfered edge on a pallet bottom deck board has the edges cut at a 35˚ angle. The angle cut is 12 inches wide. With the top and bottom deck boards attached to the stringers or blocks, the overall pallet board height is 5 to 6 inches with a 1/2-inch high deck board. This arrangement creates a 4-to-5-inch-high open space that is the fork entry opening for the pallet jack’s or forklift truck’s set of forks. When a solid exterior stringer has two additional openings for a forklift truck’s set-of-forks entry, the stringer openings are called notches. The notch is 1 1/2 inches high and 9 inches long. The notches permit a forklift truck with a set of chisel type forks to handle a pallet board from the stringer side.



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The stringer board is 1 inch thick and is used on a block pallet board for attachment of top deck boards to the docks. The stringer or bearer is the stringer pallet board component that runs the entire depth of the pallet board. Pallet boards with a short face or fork opening have two stringers, and pallet boards with a wide face or fork opening have three stringers. The stringers are 2 to 3 inches wide and serve to attach the top and bottom deck boards, provide space that helps create the fork entry openings, and support the units of product. The blocks are components of the block pallet board. The blocks are square or rectangular parts that are placed under the four corners and in the middle of the pallet board. The blocks serve the same purpose as the stringers of the stringer pallet board. Small pallet boards have six blocks and large pallet boards have nine blocks. These blocks vary from 3 to 4 inches in pallet board length and width. The stringer and block pallet board components are attached to each other by helically threaded (spiral) nails, staples, nut and bolts, or glue. The fastener selected for a pallet board is determined by cost, pallet board material, and your operational requirements. Pallet Board Types The two basic pallet board types are the flush pallet board and the wing pallet board. With the flush type pallet board, the width of the top or bottom deck boards are flush with the pallet board’s stringers or blocks. The flush pallet board type is the most common pallet board type. With the wing pallet board, the width of the top deck boards or sometimes of both the top and bottom deck boards overhangs the exterior stringers or stringer blocks. When a facility rack design calls for a wing pallet board without a slave pallet board, the wing pallet requirement is a design factor for the rack manufacturer. Pallet Board Configurations Both the standard flush and wing pallet boards are designed with one of the following design configurations: open deck, closed or solid deck, two-way entry, four-way entry, partial four-way or notched entry, single wing, double wing, reversible, nonreversible, take it or leave it, nesting, and specially designed or engineered. The open deck pallet board is designed with 1-to-3-inch-wide openings or spaces between two top deck boards or slats. The slats are 4 to 8 inches wide. This open deck pallet board design is very common in the logistics industry. The closed deck or solid deck pallet board is designed with a solid one-piece surface as the top deck. The two-way pallet board is a stringer pallet board that has two external stingers and two normal high fork openings. The four-way pallet board is a block pallet board that is designed with four normal high fork entry openings on all four sides. The fifth pallet board design is a partial, modified, or notched four-way pallet board. This stringer pallet board has the two normal high fork-entry openings at both ends of the pallet board and additional chisel fork entry openings on all stringers. These two additional chisel fork-entry openings are in the exterior stringers and in


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the middle stringer. These notches are 9 inches wide by 1 1/2 inches high and the open space permits a forklift truck with a set of chisel forks to enter these openings. With the single-wing pallet board, the width of the top deck boards extends beyond the two exterior stringers or blocks. In a straddle forklift-truck operation, there is sufficient clearance between the finished floor and the wing’s bottom for the straddles to surround the pallet. With the double-wing pallet board, the width of the top and bottom deck boards extends beyond the top and bottom stringers or blocks. In an operation, the straddle reach forklift truck extends the set of forks outward to handle a pallet. The reversible pallet board has two solid deck boards with no pallet truck wheel space on the top or bottom; the pallet board’s deck side that faces up provides the support surface for the units of product. The other side sits directly on the finished floor. Two fork-entry openings permit a forklift truck to handle the pallet board. The pallet board cannot be handled by a pallet truck. The nonreversible pallet board has top deck boards that provide support for units of product. The bottom deck boards are spaced to permit both pallet jacks and forklift trucks to handle the pallet board. The take it or leave it pallet board is a two-way pallet board that has the normal two pallet fork-entry openings and has a top deck surface with ribs. The ribs run the entire depth or stringer dimension of the pallet board. These ribs elevate a slip-sheet unit load (a slip-sheet and units of product) above the top deck and provide a series of clear space openings. These openings permit a forklift truck with a tine push/pull device to enter under the slip-sheet unit load between the rib spaces. This feature allows the slip-sheet unit load to be removed from the take it or leave it pallet board. This block pallet board has a bottom deck board that spans the width of the pallet board. The open space along the pallet board’s bottom length allows the unused and empty pallet boards to be nested for storage. The specially designed or engineered pallet board is manufactured to handle a specific unit of product or to interface with a specific material handling device. Some example pallets are round pallet, beer keg pallet, and barrel pallet. Slip-Sheet The slip-sheet is a unit load support device that is used primarily in the transportation activity between two facilities. The slip-sheet is designed to minimize a unit load height and weight on a delivery vehicle and to permit a forklift truck with a push device to handle the unit load in the facility. With a pallet board or a forklift truck with a push/pull device under the slip-sheet, the structural or beam strength of the slip-sheet supports the unit load. The most popular slip-sheet is manufactured from solid fiberboard, corrugated materials, or plastic shaped to the same length and width as the pallet board. A 4to-6-inch lip extends beyond one of the slip-sheet sides. Most slip-sheets have a single lip or tab that extends forward and faces upward from the slip-sheet base. Some slip-sheets have two lips, three lips, and four lips. The lip or tab permits a forklift truck’s push/pull device to clamp onto the lip for lifting the slip-sheet unit load from the finished floor or pallet board.



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Compared to other unit load support devices, the slip-sheet reduces the weight and space in a delivery vehicle. However, when a slip-sheet unit load is placed in a storage/pick area, clear space is needed for the slip-sheet tab extension. Slip-Sheet Material The various slip-sheet materials are corrugated, fiberboard or solid Kraft linerboard, plastic (plain surface polypropylene or dimpled surface polyethylene), and bop slip-sheet. The corrugated slip-sheet consists of two kraft linerboard outside surfaces with a corrugated interior that is bonded together. This bond provides the required strength for clamping once or twice by the gripper bar of the forklift truck’s push/pull device. The corrugated slip-sheet is considered a one-way slip-sheet because it is easily torn. Its disadvantages are that it is not durable, it is not moisture resistant, it is difficult to use in high humidity environments, and it is difficult to use in cold storage environments. The fiberboard or solid kraft board slip-sheet has several plies or layers of solid fiberboard that are laminated together. This bonding of several flat sheets (usually three to four) increases the nontear strength. It permits the slip-sheet to be used several times (at least a two-way slip-sheet) and in different temperature environments. Some fiberboard slip-sheets are coated with a plastic cover that improves the slip-sheet use in a storage environment with high moisture or humidity. Disadvantages of the fiberboard slip-sheet are that it has a medium cost and that it is not durable. The advantages of the slip-sheet are that it is at least a two-way slip-sheet and that it can be used in different environments. The plastic slip-sheet is made from a combination of polymerized materials that include polyethylene and polypropylene. This material combination gives the plastic slip-sheet its greatest tear strength, so it can be used for at least 12 items. This feature makes the plastic slip-sheet the most durable slip-sheet and the best for use in a humid or cold environment. The disadvantage is its high cost. The advantages are that it has multiple uses and that it can be used in a humid or cold environment. The plastic slip-sheet is a vacuum-formed polyethylene slip-sheet that has a series of spherical dimples on very close centers. These dimples cover the entire bottom surface of the slip-sheet and provide a cushion for the product as it rides in the delivery vehicle. The dimples extend downward on the underside of the slipsheet. This dimple direction does not damage the product’s exterior packages and does not interfere with the push/pull device or activity. When compared to the plain plastic or fiberboard slip-sheet, the dimpled slip-sheet does not have any additional major disadvantages except that the cost is slightly higher. The additional advantages are longer life and improved cushion for the product. The bop slip-sheet is another slip-sheet design. The bop slip-sheet is designed to be placed on top of a slave take it or leave it pallet board. This slip-sheet consists of two fiberboard full-length sleeves that are attached to the underside of the slipsheet. The sleeve on the fork entry end has an opening with an upper guide lip. The distance between the two sleeves is on 24-inch centers. The openings and spacing permit the regular 4-by-43-inch tapered chisel forks of a forklift truck to be inserted to the full normal fork depth under the slip-sheet. At this depth, the forklift truck


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tilts and lifts the slip-sheet unit load from the slave pallet board. For easy entry and withdrawal, the slave pallet board has four pieces of 2-by-2-inch wood runners. There are two runners placed along each exterior and two runners that are placed 12 inches from each exterior piece. The locations of these runners and their heights permit easy forklift truck entry and withdrawal. The disadvantages are the need for employee training, the need for a specially designed pallet board, and an addition to the overall unit load height. The advantages are that a push/pull device is not required and that the method can be used in many storage/pick environments. Slip-Sheet Design Parameters If you are considering purchasing and implementing a slip-sheet method in your operation, the slip-sheet guidelines are size of load; weight of the load; product description and characteristics of length, width, and height; stabilization method, which includes the unit-of-product ti and hi; and storage method, with or without a pallet board. If a pallet board is proposed for the operation, state the size and type. Other guidelines include the type of push/pull device and gripper; the number of trips and the use or expected life; storage/pick conditions to include humidity, moisture, and temperature; possible requirement for holes; use on trucks, containers, or railcars to include loading pattern; customer use of the slip-sheet in the operation; and number and location of lips or tabs. Slip-Sheet Designs Slip-sheets are available in most common pallet board surface sizes and dimensions. There are five basic designs for the slip-sheet tab: (1) one-tab slip-sheet, (2) twotab slip-sheet on opposite sides, (3) two-tab slip-sheet on adjacent sides, (4) threetab slip-sheet, and (5) four-tab slip-sheet. In the slip-sheeting of delivery trucks, the one-tab design is most common because in the slip-sheet delivery truck loading pattern the tab faces the door of the delivery truck. The delivery-truck loading arrangement of the slip-sheet gives the forklift truck’s push/pull device direct access to the slip-sheet tab, which permits the slip-sheet load to be handled with efficiency and minimal damage. When the multiple-tab slip-sheet is used in an operation, to reduce product damage and unit load space requirements, the tab not being used in the operation is secured to the unit load side or is removed from the slip-sheet unit load. In shipping slip-sheets with railcars or on vehicles that permit variations of the slip-sheet unit load placement onto the delivery vehicle’s floor, the multiple-tab slip-sheet enables the push/pull device to handle the slip-sheet unit load from all four sides. This flexibility permits the slip-sheet unit load in the delivery vehicle to maximize the delivery vehicle’s cube space and permits an efficient unloading and loading activity with minimal product damage. Tips on Slip-Sheet Use When a slip-sheet is used in a pallet order-fulfillment operation, there are several guidelines to increase storage capacity and reduce operational cost.



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Make sure that the edge of cartons, cases, or units of product on the top of the slip-sheet match the slip-sheet edges. If there are open spaces between units of product, then the open spaces are in the middle of the pattern. Secure the unit load with a stabilization method that reduces unit-of-product movement on the slipsheet. When a delivery vehicle is loaded, use dunnage material (empty pallets, corrugated air bags, or preformed corrugated pieces) in the void spaces. Whenever possible, use a pallet board in the facility’s storage/pick area. After the slip-sheet is in its final location, cut the tab or secure the tab to the unit load. Train your forklift-truck operators. Types of Forklift Truck Used to Handle a Slip-Sheet If you are considering using a slip-sheet in your operation, then the forklift truck’s push/pull device is the second important component of an efficient operation. The various components of the push/pull slip-sheet handling equipment are the type of forklift truck, the type of push/pull device or gripper, and the type of pallet board. The forklift-truck or slip-sheet unit load handling equipment that is adapted with a push/pull device includes a sit-down counterbalanced forklift truck that handles the new unit load weight lift requirement or lift capacity and can enter and exit delivery vehicles; it also includes a low lift powered rider pallet truck that has the ability to enter and exit delivery vehicles, travel over the finished floor to the assigned location, and set the slip-sheet load onto the finished floor. Slip-Sheet Attachments The push/pull attachment consists of a pantographic arm that extends forward from the forklift truck’s mast with a backrest and gripper bar. This arm is hydraulically controlled by the operator to extend over a platen, a set of platens, or a series of chisel tines. When the operator activates the gripper, it grips the slip-sheet lip or tab and holds it firm or fast between the backrest bottom and gripper bar. The operator controls the hydraulic system that orders the pantographic device to lift the slipsheet unit load upward. This lifting action raises the side of the slip-sheet. In the raised position, the pantographic device and slip-sheet are pulled over the platens or tines to the mast of the forklift truck. With the slip-sheet on top of the hardened metal surface of the platens or tines, the forklift truck transports the unit load to another facility location, onto a pallet board, or onto a delivery vehicle floor. The slip-sheet deposit activity from a forklift truck is a simple transaction. The forklift-truck operator positions the unit load directly in front of a pallet board. The hydraulic system raises the unit load to an elevation slightly above the pallet board. The pallet board is located on a slip-sheet transfer device. The pallet board far side is placed against a slip-sheet transfer device backstop. The slip-sheet in the elevated position is moved forward until the unit load platens are over the pallet board. In this position, the push/pull device with the unit load is extended forward until the unit load touches the backstop. In this action one far side of the unit load touches the pallet board. When this happens, the operator makes the hydraulic system gripper bar release the lip and the backrest remains firm and extended over the near side of


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the pallet board. As the forklift truck is moved backward, the slip-sheet unit load rests on the pallet board. This completes the transfer transaction. Platen Push/Pull Device The platen type slip-sheet attachment consists of two options: single platen or double platen. The single platen consists of one tapered hardened metal platen. The single platen dimensions are 1 to 2 inches less than the slip-sheet unit load dimensions. The double platen type consists of two 15-to-18-inch-wide platens. A platen resembles a flat shovel. A 4-inch open space between the two platens provides at the minimum a 34-inch-wide surface to support a 40-inch-wide (maximum) slip-sheet unit load. The platens are 48 inches long for a 48-inch-long slip-sheet unit load. Tine Push/Pull Device The tine or chisel slip-sheet attachment consists of a series of full-tapered hardened metal extensions from the base of the forklift truck’s mast. The tine length varies from a minimum of 36 inches long up to a maximum of 48 inches long. Each tine is 4 to 5 inches wide with a 4-to-5-inch open space between two tines. This overall width (tines and open spaces) provides adequate support for a 40-inch-wide slip-sheet load. How to Secure a Pallet Load A very important aspect of a pallet load operation is to ensure that the cartons or cases are retained on the pallet board or slip-sheet. Separating cartons or cases on a pallet board is considered a must to ensure an efficient and cost-effective material handling method with minimal product and equipment damage. The various factors that determine your pallet order-fulfillment operation’s requirement to stabilize a pallet load are the ability to interlock the cartons or cases, the physical characteristics, the height of the pallet load, and good alignment of the carton stack. A good pallet load stabilization method is part of the carton separating and pallet-loading program provides the benefits of less product damage, improved space utilization, improved security, improved forklift-truck productivity, and improved product appearance. Prior to the implementation of a pallet load stabilization program, a review of your existing system includes the expenses associated with product damage and the rework labor to ensure a good return on investment. Prior to implementation of a plastic stretch or shrink wrap stabilization program, the new plastic wrapped pallet loads in the storage position are approved by your company’s insurance underwriter and local fire authorities. Various Pallet Stabilization Methods Pallet load stabilization techniques used in a pallet load operation are: ti and hi, tape, plastic or steel bands, string, stretch wrap, shrink-wrap, netting, glue or adhesive, and industrial rubber bands. Ti and Hi The basic stabilization for a pallet load is the carton stacking arrangement. It ensures that the cartons of a layer (the hi) and each layer (the ti) are interlocked on the pallet



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load. The alignment is straight and there is no overhang beyond the pallet board. The carton separating or pallet-loading pattern for a 48-by-40-inch pallet board with an allowable overhand is 52 by 44 inches. To achieve a good ti and hi pattern, the carton varies from 5 to 21 1/2 inches wide and 6 1/2 to 43 inches long with 1/2-inch increments from the smallest to the largest dimension. The disadvantage is potential shifting of the load. The advantages are its low cost, ease of removing cartons, and ease of seeing the cartons; the method also causes no trash problems. Tape An employee applies tape to the various carton layers of a pallet. In most applications, the tape is on the top and bottom layers. The tape is plastic or fiberglass reinforced, is available in various widths from 1/4 to 2 inches, and is cut with an industrial knife. The disadvantages are that tape creates a trash problem, it is difficult to apply on the lower levels, and it creates a maintenance problem on a vehicle’s wheels. The advantages are its low cost, easy application, and ability to be used at any location. Plastic or Steel Bands Steel or plastic bands are placed horizontally around one or several layers of cartons and over the top and bottom of the pallet. The bandwidth ranges from 1/2 to 3/4 inch and requires a band stretcher and clamp gripper. To protect the pallet from damage, corrugated board material is used at the corners and top edges. Banding of the pallet is done manually or automatically with a machine. The disadvantages are that the method is labor intensive; there is potential carton damage; and when cutting the bands, there is potential employee injury. The advantages are that the method permits circulation, allows good visibility, and stabilizes the top and bottom. String The same application method is used for string as for tape, except that string is tied by an employee around the pallet. The string is taken from a spool or cut to predetermined lengths with a loop or metal S-hook. The disadvantages are that string is difficult to apply at lower carton layers, it creates a trash problem, and it creates a maintenance problem with a vehicle’s wheels. The advantages are its low cost and ability to be applied anywhere in the warehouse. Stretch Wrap Stretch wrap is a pallet-stabilizing method in which a plastic film is wrapped tightly around the four sides of the pallet. The plastic film is applied by a manual or semiautomatic method. Some of the mechanical stretch-wrap methods use prestretched film wrap that provides a more secure pallet. To wrap a pallet, the stretch wrap film is tucked under a carton and then wrapped around the pallet and tied under another carton. The two applications options are the manual method and the automatic method. Manual Application

The manual portable stretch-wrap equipment consists of a handheld device that has a handle grip and a spool for a roll of wrapping material. After the pallet is in


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position, an employee tucks the film under a carton and walks around the pallet the required number of times to secure the pallet. Then the employee cuts the film and tucks it under another carton. The second manual method employs a portable stretch-wrap machine that is constructed of welded steel members and is mounted on a bed with 3-inch-high heavy-duty casters and wheels. It requires a forklift truck to set a pallet next to the machine. The film holder is attached to the machine. After film is tucked under the carton, the employee walks one complete turn around the pallet, activates the brake and continues to walk around the pallet that stretches the film wrap. The manual portable machine handles 10 to 15 pallets per hour. Automatic Application

The automatic wrap machine is a steel machine with a film roll attached to a single post in front of the turntable with a spring-loaded top. After the forklift truck or conveyor places the pallet onto the turn table, the employee tucks the film under the carton and turns on the machine. With completion of the activity, the employee cuts the film and tucks it under the carton. The automatic method handles approximately 25 pallets per hour. A second machine type is a standard model that is similar to the other automatic machine except that it has a brake and handles about 35 pallets per hour. A third automatic machine method uses the automatic multiple-roll machine, which has the same features as the automatic standard machine; the exception is that the multiple-roll machine has two to three film rolls and handles 30 to 40 pallets per hour. The disadvantages are waste or cost due to mistakes, a trash problem, and an increase in the investment. The advantages are that the method handles odd shaped pallets, creates a moisture barrier, and improves security. Shrink Wrap The automatic shrink-wrap method consists of a shrink-wrap tunnel that has an infeed and out-feed conveyor travel path (Figure 6.11). To operate a shrink-wrap process, a pallet is placed onto the in-feed conveyor. Prior to the shrink tunnel, a piece of plastic is draped over the pallet. The pallet is conveyed into the shrink tunnel. In the tunnel, heat is applied to the plastic material that causes the plastic to shrink around the pallet. In this process, the plastic conforms to the pallet. Another shrink-wrap method uses a handheld gun that shrink-wraps plastic onto the pallet. The plastic is draped over the pallet and then the employee uses a handheld heat gun to apply direct heat against the plastic. This heat causes the plastic to conform to the pallet. The disadvantages are equipment cost, the required floor space for the automatic method, and the need for energy for heat. The advantages are protection against moisture, dirt, and dust, and less wrapping waste. Netting A net is placed over the pallet and is pulled tightly around the base and the top of the pallet. The netting material is made from plastic and the application to the pallet is similar to the stretch-wrap method.



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FIGURE 6.11 Shrink-wrap methods. From Battenfeld Gloucester Engineering, Gloucester, MA. With permission.)

The disadvantages of the method are that it permits dust or dirt and that it creates a trash problem. The advantages are that the method permits air circulation, allows good visibility, and stabilizes the top and bottom. Glue or Adhesive Glue and adhesives are used to stabilize pallets. With modern glue or adhesive and new application technologies and equipment, glue is applied to the top of the individual cartons or bags of the pallet. As the cartons or bags with glue are placed on top of each other to form the pallet, the cartons stick to each other, forming an entire pallet that is stabilized with glue. When an employee requires a carton from the pallet, the bond between the cartons is broken with a simple bump or pull on the carton. The disadvantages are no moisture, dirt or dust protection, and possible damage to cartons. The advantages are its low cost and good visibility; it also does not cause a trash problem. Industrial Bands The elastic band method has bands placed around various layers of the pallet. These elastic bands are available in various widths, thicknesses, and lengths. They are manufactured in a circular form to specific lengths. The bands are precut and joined by a metal clip. This type of elastic band secures the pallet top and bottom. The disadvantages are its high cost, difficulty in applying to lower layers, and occasional difficulty in reusing. The advantage is that the bands are reusable.

PALLET LOAD-HANDLING VEHICLE The second major physical component is the pallet load-handling vehicle. The vehicle makes the pallet deposit and withdrawal transactions to and from the pallet storage/pick position. This vehicle is one of the key factors that determines the facility’s aisle width and the number of pallet positions (load beam levels) above


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the finished floor surface. The vehicle’s aisle width and the maximum pallet position (load beam) elevation above the finished-floor surface influence the facility’s storage utilization, required land and building/equipment investment costs, and projected annual logistics facility operating costs. The various pallet load-handling vehicle types are separated into five groups. Each group name is determined by the vehicle’s basic operating characteristics: (1) wide-aisle (WA) group; (2) narrow-aisle (NA) group; (3) very-narrow-aisle (VNA) group, which includes car-in-rack and ASRS vehicles; (4) mobile-aisle (MA) or transfer car (T-car) group; and (5) captive-aisle (CA) group. Wide-Aisle Vehicle Group The first pallet load handling group is the WA vehicle group (Figure 6.12). The WA group gets its name from the fact that the vehicle requires a 10-to-13-foot-wide clear aisle between two pallets. This aisle distance between two pallets allows the manual controlled forklift truck to make a right-angle (stacking) turn and to complete a storage/pick transaction at the pallet position. Also, the distance allows the operator to achieve the desired transaction productivity with minimal product, equipment, and building damage. In most applications, the exact aisle width is based on the stated manufacturer’s standard for your pallet board dimensions plus 6 to 12 inches. These WA vehicles are mobile aisle vehicles. With wide hard rubber tires, most WA vehicles are used to transport pallets between two warehouse locations. These vehicles are powered by an electric rechargeable battery, gasoline, LP gas, or a diesel engine. The diesel and gasoline powered vehicles are preferred for outdoor activities. The long wheel center-to-center distance and a high undercarriage, the vehicle easily travels up or down grades. The WA vehicle is equipped with a set of forks and, as required, a slip-sheet or other attachment to an elevating mast. The forks lift a pallet load to a pallet position that is 20 feet high. Tilt and side shift options improve operator productivity and reduce product and equipment damage. Free lift permits the forks to move upward without the mast moving upward. This feature permits the forklift truck to operate inside a delivery vehicle or under a low ceiling. The various WA vehicles include the walkie/stacker forklift truck, the straddle or counterbalanced-straddle walkie/stacker forklift truck, the straddle or counterbalanced-straddle walkie/stacker forklift truck with a fork reach feature, the sit-down three- or four-wheeled counterbalanced forklift truck, and the stand-up rider counterbalanced forklift truck. Walkie/Stacker Forklift Trucks The walkie/stacker forklift truck is a manual push or electric powered drive wheel vehicle that handles a maximum load of 1500 pounds up to a stacking height of 10 to 12 feet. The second walkie/stacker vehicle is the straddle or counterbalanced-straddle walkie/stacker forklift truck. This truck has two stabilizing straddles that extend forward from the vehicle’s base and a space between the two straddles for a pallet load.



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FIGURE 6.12 Wide-aisle lift truck group. (From Crown Images © 2002 Crown Equipment Corporation, New Bremen, OH. With permission.)

The third walkie/stacker vehicle is the straddle or counterbalanced-straddle walkie/stacker forklift truck with a fork reach feature. This truck has two stabilizing straddles that extend forward from the vehicle’s base, a space between the two straddles for a pallet load, and a set of forks that extends outward. The walkie/stacker forklift truck vehicles have a set of forks on a telescopic mast that elevate and lower pallet loads at 10 to 12 feet, storage/pick positions, two load-carrying wheels, a drive and steer wheel, and an operator’s handle. The operator’s handle contains all vehicle movement controls. The operator who walks behind the vehicle has easy access to the fork movement controls and includes free lift. Free lift allows the set of forks to rise and the mast to remain at the low elevation. This feature permits the vehicle to operate in low ceiling areas or in delivery trucks. The vehicles have slow travel speeds which means low transport employee productivity. It receives its power from a rechargeable electric battery. Most walkie/stacker


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vehicles operate in a 10-to-13-foot-wide aisle. The walkie/stacker forklift truck is considered for a low volume pallet operation. Stand-Up Rider Counterbalanced Forklift Truck The next vehicle is the stand-up rider counterbalanced forklift truck. The stand-up rider counterbalanced forklift truck is considered a WA vehicle. The vehicle has similar design features and operational capabilities to the sit-down rider counterbalanced forklift truck. The major difference between the two forklift trucks is that with the stand-up rider vehicle the operator stands up in the operator’s platform area. This feature permits a shorter wheelbase. With the shorter wheelbase, the vehicle makes right-angle stacking turns in a 9-to-10-foot-wide aisle and places a 2000-to-3000pound pallet load into an 18-foot floor or rack position. The 24- or 36-volt electric rechargeable battery-powered mobile aisle vehicle is very maneuverable and versatile, performs all activities on a normal facility finished floor, and enters and exits most delivery vehicles. Some models, in addition to the tilt and side shift options, have an option of a retractable overhead guard which permits delivery truck entry. Sit-Down Three- or Four-Wheeled Counterbalanced Forklift Truck The next WA vehicle is the sit-down counterbalanced forklift truck. With a low mast and overhead guard, the forklift truck is a very maneuverable and versatile pallet handling vehicle. The truck is used as a dock, transport, and storage/pick area vehicle and it requires a normal facility finished floor surface. Also, it can travel up a 15˚ grade or ramp. The vehicle is designed with a set of load-carrying forks that elevate and lower on a telescopic mast and an operator’s area with a seat. From the seat the operator has access to all horizontal vehicle and vertical fork movement controls. Some models have see-through masts that provide the operator with a complete view of the vehicle’s travel path. The vehicle counterweight is located in the rear chassis and the vehicle has a long wheelbase. These features provide the vehicle with the ability to offset the pallet load weight. The most common indoor truck is powered by a rechargeable electric battery. When the forklift truck is used as an outdoor vehicle, the power source is diesel, LP gas, or gasoline. These alternative power sources are common on the counterbalanced vehicle. The vehicle has three or four wheels, with one wheel as a drive and steer wheel. The wheels are fitted with pneumatic tires for outdoor use and cushions and solid polyurethane or rubber tires for indoor use. These counterbalanced vehicles are available with 1-, 2-, 3-, or 4-stage masts that provide the vehicle with a stacking height of 16 to 18 feet. Counterbalanced forklift trucks are used to deposit, pick, or withdraw a 2000-to-4000-pound pallet load from a floor or rack position. Some forklift trucks have a counterweight and wheel base that can handle a heavier load at a lower position height. Fork side shift and mat tilt devices are options that increase operator productivity and reduce product and equipment damage. An experienced operator can make 20 to 25 pick transactions per hour. All pallet deposits and picks are controlled or eyeballed by the operator. The sit-down rider counterbalanced forklift truck with a low mast and low overhead guard is a very maneuverable and versatile pallet-handling vehicle. The



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vehicle with its wheel base has good grade clearance, which allows the vehicle to load and unload delivery vehicles easily, transport pallet loads through the facility (including towing a train of carts), and perform standard floor and rack pick transactions. With limitations, a standard counterbalanced forklift truck handles a wide variety of pallet loads over a normal finished floor. The four-wheeled counterbalanced forklift truck with its long wheelbase and chassis weight is fitted with various attachments to perform other tasks. However, for a given forklift truck, you must verify with the vehicle manufacturer that the forklift truck will accept the attachment weight and new center of load and will reach the position elevation. Lift Truck Stability When we use the term forklift truckload capacity with stability, it means that when a counterbalanced forklift truck picks up a unit load, then the fulcrum (balance point) for the counterbalance action is the centerline of the front wheels. The unit load weight plus any attachment is counterbalanced by the forklift truck’s counterbalance weight and wheelbase dimension. This weight includes the battery weight and counterbalance weight. Lift Truck Capacity The forklift truck capacity is the amount of weight that it safely lifts. Each forklift truck has a capacity that is stated by the manufacturer. This weight capacity decreases as longer loads are handled. The forklift truck handles shorter loads up to the limit specified by the manufacturer. As the length of the unit load increases from the standard 24-inch center, the forklift truck can handle less weight. If the unit load is heavier than the standard dimensions, then a bigger, heavier, and more expensive forklift truck is needed for the operation. Lift Truck Mast The next important component is the type of forklift truck mast. There are two mast specification parameters: the overall extended or lift height that allows a vehicle to complete transactions from the highest finished floor or rack position, and the lowered or collapsed height of the mast. This height is the clearance for the forklift truck to pass through the facility doorways, enter and exit delivery vehicles, and interface with most storage/pick position methods. In considering these specification parameters for maximum forklift truck height, the vehicle’s height is influenced by the backrest height or unit load height to the lowest ceiling (building) obstruction. The clearance height for a forklift truck is affected by the overhead guard height which may be higher than the mast. In this situation the forklift truck’s ability to pass through a low ceiling area, doorway, rack lanes, and delivery vehicles is restricted. Seven types of forklift truck masts are available for a vehicle: (1) single mast, (2) two-stage mast nontelescopic, (3) standard two-stage mast, (4) two-stage mast with high-free lift, (5) three-stage mast, (6) four-stage mast, and (7) rigid mast.


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The single stage nontelescopic mast lifts a pallet load to a 7-to-8-foot-high floor or pick position. In today’s operations, the single-stage mast has very limited application and is uncommon in most companies’ forklift truck fleets. The two-stage nontelescopic mast has little or no free lift. No free lift means that as the set of forks start to rise, the mast starts to rise. With this mast, the forklift truck completes pallet transactions at 12 to 13 feet high. With the two-stage standard mast with load free lift, the forklift truck completes a transactions at 15 to 20 feet high. This mast feature of low free lift conserves energy and permits the forklift truck to be used as multipurpose vehicle in a low ceiling area. With this two-stage mast with high-free lift, the mast permits the forklift truck to complete a pallet load transaction at an elevation that is equal almost to the half of the mast elevation. This feature permits the forklift truck to operate as a dock vehicle to enter and exit delivery vehicles. Also, the forklift truck completes transactions at positions 20 feet high and operates in low ceiling areas. The three-stage mast with full-free lift allows the forklift truck to complete a transaction at a 20-to-25-foot elevation above the finished floor. The entire full-free lift feature permits the forklift truck to operate in a low ceiling area and to enter and exit most delivery vehicles. The four-stage mast with full-free lift permits a forklift truck to complete a pallet transaction from an elevated rack position that is 30 to 40 feet high above the finished floor. The mast is used on a vehicle that requires aisle guidance. The rigid mast with or without free lift permits the forklift truck to complete a transaction to an elevated rack position that is 40 to 60 feet high above the finished floor. The rigid mast is used on hybrid or high-rise vehicles. Lift Truck Maneuverability The next important forklift truck factor is the forklift truck’s maneuverability or ability to make a right-angle turn or a turn in an intersection aisle. A forklift truck right-angle stacking turn is the distance that is required for the forklift truck to turn and complete a transaction from a storage/pick position. This distance is the aisle width. An easy way to determine the aisle width is to take a conventional pallet load length (stringer) plus the distance from the face of the set of forks to the centerline of the forklift truck’s drive wheel plus the outside turning radius. For excellent operator productivity and reduced product and equipment damage, 6 to 12 inches is added to the above calculation. If there is a pallet load overhang, the overhang dimension is added to the stringer length. In planning a warehouse aisle with the forklift truck manufacturer’s aisle width recommendation, for good operator productivity and low product and equipment damage, the forklift truck’s aisle width is from product to product plus 6 to 12 inches. Lift Truck Wheelbase In theory, the counterbalanced forklift truck wheelbase determines the aisle width. The wheelbase is the distance between the front and rear wheels. A forklift truck



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with a short wheelbase requires a narrow right-angle turning aisle. Therefore, a forklift truck with a short wheelbase makes the truck very maneuverable. A forklift truck with a long wheelbase requires a wide right-angle turning aisle, but has improved ride, steering traction, and stability. Lift Truck Ability to Climb a Grade and Lift Truck Under-Clearance The second maneuverability factor is the forklift truck’s ability to climb a ramp or grade and its under-clearance. The grade-climbing ability of a forklift truck is the steepest percent grade or ramp that a forklift truck can climb with a pallet load. An electric forklift truck’s steepest grade is 15% and the grade for a gasoline, LP gas, or diesel truck is 20 to 25%. The forklift truck under-clearance is the distance between the finished floor and the lowest part of the forklift truck undercarriage. The important under-clearance locations are midway between the wheelbase and the bottom of the mast because of the mechanical operating parts in these areas. In considering a vehicle that will climb ramps, enter and exit delivery vehicles and vehicles for outdoor operations, grade ability and under-clearance are important for avoiding future repair expenses and forklift truck downtime. In theory, a forklift truck with a short wheel base and high clearance is the best for ramp, dock, and outdoor work. The most popular WA forklift truck or vehicle is the three- or four-wheeled counterbalanced forklift truck. On the counterbalanced forklift truck, the operator sits on a seat or stands on a platform in front of the vehicle control panel and steering wheel. The disadvantages of the WA vehicle are that, due to a wide aisle, it requires a larger building; there is limited forklift elevation; and operators sit and can become lazy. The advantages of the WA vehicle are that it is used on the dock to load and unload delivery vehicles; with free lift, it can be used under a mezzanine; it handles a slip-sheet or other attachment; it is easier to operate; it operates on a conventional warehouse finished floor; it requires little employee training; it travels up and down grades; it can be used as a transport vehicle; it has faster travel speeds; and it interfaces with all storage/pick methods except two-deep and ASRS systems. Narrow-Aisle Vehicle Group The second pallet load handling vehicle group is the NA group (Figure 6.13). The NA group forklift trucks operate in an aisle that has a 7-to-10-foot clearance between pallets. Most NA vehicle manufacturers suggest a minimum aisle width plus 6 to 12 inches. The NA vehicle requires a 7-to-10-foot clear aisle width to complete a pallet storage/pick transaction with good operator productivity and minimal product, equipment, and building damage. To ensure good NA forklift truck driver productivity, most applications require 5 to 6 inches between two pallets or between a pallet and upright post. A raised load-beam method on the lowest level of the pallet racks permits the NA vehicle to operate in an aisle that has a narrower dimension of 7 feet, but it


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FIGURE 6.13 Narrow-aisle lift truck group. (From Crown Images © 2002 Crown Equipment Corporation, New Bremen, OH. With permission.)

provides lower employee productivity. With the raised load beam method, the first pallet storage level is raised 12 inches above the finished floor. With a 6-inch-high load beam, the load beam elevation permits the forklift straddle to travel under the load beam and into the rack position. This means that the straddles do not travel between two pallets or between a pallet and upright post. This method permits the forklift truck to complete a pallet storage/pick transaction without striking a pallet. The NA forklift truck group is considered mobile aisle equipment that travels between two storage/pick area aisles. The vehicle is powered by an electric rechargeable battery and has a set of forks that elevate on a mast. The forks raise a pallet load to a storage/pick position that is 25 to 28 feet high above the finished floor. The operator stands on a platform under an overhead guard and has access to all controls and the steering wheel. An option on the NA truck is a safety bar on the rear side of the operator’s platform. The safety bar is attached to the compartment’s metal side and extends upward to the overhead guard. In an aisle and when backing from the completion of a pallet storage/pick transaction, the safety bar minimizes the operator backing into a rack load beam. The various NA fork trucks are as follows: stand-up rider straddle forklift truck with a set of forks that do not extend outward, stand-up rider straddle-reach forklift truck with a set of forks that extend outward 20 inches, stand-up rider two-deep forklift truck with a set of forks that extend outward 48 to 52 inches, and stand-up four-directional forklift truck. The stand-up rider straddle forklift truck is powered by a rechargeable electric battery. If there is no deflection on a dock lever, the forklift truck enters and exits a delivery truck. But if there is dock lever deflection, the forklift cannot enter or exit a delivery truck. The vehicle is designed with two load-carrying wheels and one drive and steering wheel, a set of forks that elevate and lower over a telescopic mast, an overhead guard, two stabilizing outriggers, and an operator’s platform area. The operator’s platform has both horizontal truck and vehicle fork movement controls.



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To elevate, lower, and transport a pallet load, the outriggers assume the majority of the pallet load weight. Since the forklift truck straddles (outrigger surrounds) surround the majority of the pallet load between the two straddles or outriggers, the straddle forklift truck operates in a 7-to-8-foot-wide aisle. On a normal finishedfloor surface, the straddle forklift truck completes a transaction up to a 20-foot-high pallet position and an operator completes 18 to 20 transactions per hour. The second NA forklift truck is the stand-up rider straddle reach forklift truck. The stand-up rider straddle forklift truck has similar design features and operational characteristics to the straddle forklift truck, except that its forks are attached to a pantographic reach device. The device allows the set of forks to extend out beyond or forward of the outriggers to pick up and retract a pallet load. This device permits the reach forklift truck to handle a pallet load that is wider than the interior space between the outriggers. This reach feature increases the right-angle turn or stack requirement, requires an 8-to-10-foot-wide aisle, and allows an operator in a normallength aisle to complete 15 to 18 transactions per hour. The next NA forklift truck is the stand-up rider double-deep forklift truck. The stand-up rider double-deep forklift truck is nicknamed the two-deep or deep-reach forklift truck. Its basic design feature and operational characteristics are the same as those of the straddle reach forklift truck, except that the pantographic device has a greater extension. It extends forward out into the second deep interior pallet position of a two-deep rack method. For best results, this extension or stroke is a fixed number of inches from 43 to 51 inches. This means that all pallet boards have the same dimension. Operators make 13 to 16 transactions per hour in a 9-to-10foot-wide aisle. The fourth NA forklift truck is the four-directional forklift truck. This unique stand-up rider straddle reach truck has similar operational features to the regular reach forklift trucks, but all four forklift truck wheels turn to the direction of travel. One load wheel hydraulically shifts to forward or reverse or lateral for travel sideways. The other load wheel is the free swiveling wheel. This feature gives the forklift truck its name. While traveling in the main aisle with a long load in front and for fork entry into the narrow aisle to perform a transaction, the operator stops and shifts the load wheel direction. This permits the forklift truck to travel sideways into the narrow aisle and complete the transaction. The narrow aisle is 8 feet, 6 inches wide. Very Narrow-Aisle and ASRS Vehicles The third pallet load handling vehicle is the VNA and ASRS vehicle group (Figure 6.14). Within this group there is distinction or separation of the vehicle into two groups. The first is VNA vehicles. These vehicles are battery powered and manually operated vehicles with a fork height of 35 to 37 feet above the finished floor. The second is ASRS vehicles, which are direct current (DC) electric powered and manually or computer controlled to storage positions that have an elevation range up to 110 feet above the finished floor. These VNA and ASRS vehicles operate in an aisle that is 5 feet, 6 inches to 7 feet, 6 inches wide product to product. This feature gives these vehicles their name.


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FIGURE 6.14 Very narrow-aisle lift truck group. (From Crown Images © 2002 Crown Equipment Corporation, New Bremen, OH. With permission.)

The vehicle operates in these aisles to make pallet deposit or withdrawal transactions. The pallet storage/pick transactions are completed by a shuttle carriage or a set of forks directly to the pallet position without the vehicle turning in the aisle. This ability to complete the pallet storage/pick transaction from the vehicle side permits the very narrow-aisle width. The other VNA or ASRS vehicle characteristics are that the vehicle travel is rail or wire guided (Figure 6.15); pallet storage/pick transactions are performed by a set of forks or a platen; in most applications, the lowest pallet position is raised 16 to 34 inches above the finished floor; the operator is located in a protective station and has a tether line; some vehicles handle two pallets per trip and complete pallet transactions to a two-deep pallet location or to pallet flow rack positions; many facilities have the rack structural support members support the walls and roof; and the pallet position height range is from 30 to 110 feet above the finished floor. The various VNA vehicles are as follows: •

Man-controlled and man-down: • Rider side-loading forklift truck



WIRE DEPTH

3/8" TO 5/8" WIRE BURIED IN THE FLOOR

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WIRE GUIDE PATH LINE DRIVER & UPS

WALL

FIGURE 6.15 Forklift guide wire path.

•

•

•

• Stand-up rider double-deep lift truck • Sit-down rider counterbalanced side-loader with a swing mast • Operator-down counterbalanced side-loading forklift truck • Operator-down side-loading turret forklift truck Man-controlled and man-up: • Operator-up side-loading forklift truck • Stand-up outrigger side-loading rising cab forklift truck, a Turn-aLoad™ or Rack Loader • Operator-up side-loading turret forklift truck • Counterbalanced side-loading forklift truck with rising cab and auxiliary mast lift Man-controlled storage retrieval (MSR): • Captive aisle machines • Mobile aisle machines Computer-controlled storage retrieval or ASRS or stacking automated guided vehicles (AGVs); within the ASRS group, the methods include: • Sort link • Mole • Car-in-rack methods and options for the following: • Captive aisle machines • Mobile aisle machines that use a transfer car or bridge car

Figure 6.16 shows pallet labeling for man-up and man-down pallet trucks. Man-Controlled and Man-Down Forklift Truck The first VNA forklift truck group consists of a forklift truck that has the capability to complete pallet transactions to a tall rack pallet position from a very narrow aisle with the forklift truck operator at the finished-floor level. Rider Side-Loading Forklift Truck The rider side-loading forklift truck has a set of load-carrying forks that are attached to a pantographic device that elevates and lowers on a telescopic mast. It has an overhead guard and an operator’s area. The operator’s area has full machine controls


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FIGURE 6.16 Pallet location labeling for man-up vs. man-down pallet truck. (From Kornylak Corporation, Hamilton, OH. With permission.)

and a steering device. The vehicle has two steering wheels and two load-carrying wheels that are under the two decks, outriggers, or straddles. There is sufficient width between the decks for the pallet load which is taken onto the set of forks and into the well. Prior to travel, the pallet load is lowered and rests on the front and rear decks. The two decks become the stabilizing platform for the pallet load. The side-loading vehicle takes the pallet load onto the set of forks with the pallet operator facing the rack position. Since the set of forks face one side of the aisle, all transactions are performed from one side of the aisle; therefore, without a computerized inventory control program, the number of transactions per hour is 17 to 19 storage transactions for a normal aisle length. This feature allows the lift truck to operate in a 5-foot, 6-inch-wide aisle and complete transactions to positions 30 feet above the finished floor. Stand-Up Rider Double-Deep Forklift Truck The stand-up rider double-deep forklift truck has the same design features and operational characteristics as the side-loading forklift truck, except that the pantographic device performs transactions from a two-deep rack position. This vehicle requires a 6-to-7-foot-wide aisle. Due to the double-deep transaction at the high pallet position, the operator performs 15 to 17 transactions per hour. Sit-Down Rider Counterbalanced Side Loader with a Swing Mast Forklift Truck The next vehicle is the sit-down rider counterbalanced side loader with a swing mast forklift truck. The design features and operational characteristics of this forklift truck



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are the same as for the regular counterbalanced forklift truck. However, to make transactions to the position, the telescopic mast swings 90˚ to the right side of the aisle. The mast movement gives the forklift truck its nickname: the swing-mast forklift truck. An electric rechargeable battery is the power source and the truck operates in a 6-to-8-foot-wide wire-guided aisle with a minimum aisle width that is 1 foot wider than the pallet load. The swing-mast truck makes pallet transactions from the finished floor to positions 25 to 30 feet above the finished floor. In an aisle of normal length, the operator’s throughput capacity is 17 to 20 pallet transactions per hour for a dual cycle. When the transactions are not on the same side of the aisle (single cycle), then productivity is 15 to 17 transactions per hour because of the need for two down-aisle trips. The truck requires a dead level finished floor and a 10-to-12-foot intersecting aisle. Compared to the other VNA forklift trucks, the swing-mast forklift truck functions as a transport and dock vehicle. Operator-Down Counterbalanced Side-Loading Forklift Truck The operator-down counterbalanced side-loading forklift truck is the next vehicle. On this electric rechargeable battery powered forklift truck, the set of forks are attached to a telescopic mast. The set of forks moves from the right side to the left side of the aisle. This feature permits the forklift truck to complete pallet transactions at 30-to-40-foot-high rack positions. These forklift trucks have side shifts to assist the pallet transaction. The forklift truck’s nickname is the turret or swing reach forklift truck. Aisles are 20 inches wider than the pallet load or 6 inches wider than the diagonal dimension of the pallet to turn the pallet in the aisle as the forklift travels in the aisle. The operator transaction activities are 20 to 23 transactions per hour in a guided aisle of a normal length. With 40-foot-high transaction capabilities, the mobile aisle forklift truck requires a dead-level finished floor. The intersecting aisle is a minimum of 17 feet wide. For maximum productivity, these vehicles require end of aisle pickup and delivery stations. Operator-Down Side-Loading Turret Forklift Truck With this forklift truck vehicle, the set of forks is attached to the top of the carriage. The carriage is attached to a telescopic mast that permits the set of forks to handle a pallet load transaction from a rack position on either side of the aisle. For best operational results, the forklift truck requires an aisle guidance system, end of aisle pickup and delivery stations, and a dead-level finished floor. The forklift truck travels in an aisle that is 5 feet, 6 inches to 6 feet, 6 inches wide and is 1 foot wider than the pallet load. To change aisles, the forklift truck requires a 17-to-18-foot-wide intersecting aisle. The forklift truck receives its power from an electric rechargeable battery. Man-Controlled and Man-Up Forklift Truck The man-controlled man-up forklift truck is a VNA forklift truck group that has the capability to have the operator rise with the pallet load to the rack and position. In this elevated position, the operator has complete vision of the pallet transaction. Figure 6.17 shows operator positions for man-up and man-down forklifts.


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FIGURE 6.17 Man-up vs. man-down operator position. (From Crown Images © Crown Equipment Corporation, New Bremen, OH. With permission.)

Operator-Up Side-Loading Forklift Truck The operator-up side-loading forklift truck has the same design and operational characteristics as the standard side-loader forklift truck except that the operator elevates and lowers with the pallet load to the position. The vehicle performs one to two additional transactions per hour more than the standard side-loader forklift truck. Operator-Up Side-Loading Forklift Truck The unique feature of this forklift truck is that the pallet load-carrying set of forks is placed on a set of outriggers. This feature permits the vehicle to pick up and deliver a pallet from the truck’s aisle. As the set of forks rise, the operator’s cab rises with the pallet. In one model, at the rack position, the set of forks rotate on a turntable to perform a transaction from either side of the aisle. In a second model, at the pickup station the set of forks is flipped to the proper side to make the transaction at the rack position. This feature gives the trucks their nickname: turna-load or rack loader. These forklift trucks are powered with an electric rechargeable battery. They operate in an aisle that is 10 to 20 inches wider than the pallet load. The bottom pallet rack position is required at an elevation of 14 to 16 inches above the finished floor and the top rack position is 20 to 21 feet high. An operator performs 17 to 18 transactions per hour. Side-Loading Turret Forklift Truck with Operator Up With this forklift truck vehicle, the set of forks is attached to the top of the carriage. The carriage is attached to a telescopic mast that permits the set of forks to handle a pallet load transaction from a rack position on either side of the aisle. For best operational results, the forklift truck requires an aisle guidance system, end of aisle pickup and delivery stations, and a dead level finished floor. The forklift truck travels in an aisle that is 5 feet, 6 inches to 6 feet, 6 inches wide and is 1 foot wider than the pallet load. To change aisles, the forklift truck requires a 17-to-18-foot-wide intersecting aisle. The forklift truck receives its power from an electric rechargeable battery.



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Counterbalanced Side-Loading Forklift Truck with Rising Cab and Auxiliary Mast Lift This multiple mast forklift truck carries a pallet in front of the operator’s cab. The operator’s cab has all vehicle controls for movement and fork travel. As the cab moves up or down, the pallet on an auxiliary mast moves with the cab. The unique feature of this forklift truck is the auxiliary mast that is attached to the front of the cab. This feature provides the forklift truck with free forklift that allows a pallet transaction to a 40-foot-high rack position with minimal damage to the product or equipment because the operator has a complete view of the pallet transaction. Also, in a carton-storage or order-pick operation, the operator hand-stacks carton. The forklift truck requires 16 to 20 inches clearance from the bottom of the ceiling. Compared to other forklift trucks, operator productivity is increased by 1 to 2 pallets per hour. Outrigger Stand-Up or Sit-Down Truck with Rising Cab and Fixed Mast This forklift truck vehicle is considered a hybrid between an ASRS machine and a side-loading forklift truck. These forklift trucks handle a pallet at 60-foot-high rack positions. With some vehicles, the set of forks is attached to the front of the cab and the cab elevates and declines with the pallet on one rigid mast to the pallet rack position. Other trucks have dual masts with shuttles or a set of forks between them. The first storage position is 16 inches above the finished floor. Some vehicles carry the pallet between the two outriggers and are guided by a rail in the middle of the aisle. Still other vehicles have guide wheels mounted on both sides of the vehicle. In the aisle the truck obtains its power from the ceiling DC power system and recharges the rechargeable battery. Normal vehicle aisle transfer time ranges from 1 to 2 minutes and the transfer aisle width ranges from 24 to 27 feet. Due to the electric hookup, top guidance system, and wide transfer aisle, in most facility designs, the lift truck enters from one end of the aisle. With proper electric devices at the top of the dual mast vehicle, forklift truck entry is designed at both ends of an aisle. The storage aisle is 4 to 6 inches wider than the pallet. To perform a transaction at the end of the aisle, an 8-to-10-foot run-out is required at the other end of the aisle. Operators perform 25 to 30 transactions per hour in the normal aisle. When to Consider an Operator-Down or Operator-Up Forklift Truck If your operation’s pallet rack stacking height is three to four pallet loads high and there is a cost difference between operator-down and operator-up vehicles, consider an operator-down vehicle. For stacking heights above three to four pallet loads high, the operator-up vehicle has become more popular in the industry. With the operatorup vehicle with its operator platform and environmental control of the cab, the facility’s utilities are kept at a minimum when compared with conventional warehouse utilities. Man-Controlled Storage Retrieval Forklift Truck In the MSR vehicle, the operator’s cab rises with the cab. For best results, the vehicle requires an end-of-aisle pickup and delivery station.


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Computer-Controlled Storage Retrieval or ASRS Forklift Truck Storage and retrieval vehicles require an aisle that is 3 to 6 inches wider than a pallet. The vehicle is designed with one or two masts and as a manual (from a frontend remote control station) or a completely automated vehicle to complete a pallet transaction at a 40-to-80-foot-high rack position. These vehicles require a dead-level finished floor, middle-rail guidance system, a first storage level 34 inches above the finished floor, and clearance at the ceiling for a mast and ceiling-attached DC system. All storage and retrieval vehicles require a run-out at 15 to 20 feet to perform pallet transactions at the end rack positions. The run-out length is determined by the vehicle’s length. The vehicle operating area requires minimal utilities. Sort Link, Mole, or Car-in-Rack The next pallet storage/pick vehicle consists of the sort link, mole or car-in-rack methods. These methods consists of dense or multiple deep-pallet storage positions and a mobile cart or car. These DC electric powered mobile carts or cars transport pallets over a fixed travel path between the storage area and the pallet pick and delivery station. See sort link, car-in-rack, or mole in the “Rack Method” section of this chapter. AGV or Automatic Stacking Wire Guided Vehicle The last pallet storage/pick vehicle is the AGV or automatic stacking wire-guided vehicle (Figure 6.18). The AGV vehicle is a counterbalanced or straddle vehicle. The power source is several rechargeable electric batteries. The AGV vehicle has three to four wheels (at least one is steering), a fixed mast, a set of load carrying forks, a manual or remote-controlled onboard control device, and a wire guidance system. The vehicle requires a very flat finished floor surface. After the AGV vehicle picks up a pallet load from the receiving area, it travels over the warehouse main traffic aisle to the assigned aisle, enters the assigned aisle, travels in the aisle to the assigned pallet position, and deposits the pallet to the assigned position. To pick a pallet for a customer-order, the computer directs the AGV to the assigned pallet position in an aisle. At the assigned pallet position, the AGV takes the pallet onboard, travels in the aisle, exits the aisle to the main traffic aisle, and travels on the main traffic aisle to the shipping dock area. In the shipping dock area, the pallet is transferred to the customer-assigned staging area. The AGV has the capability to complete a pallet transaction to a rack position that is 180 inches above the finished floor and has a 10 to 12 pallet transaction rate per hour. The pallet transaction aisle width is 10 to 12 feet wide for the counterbalanced truck and for the straddle type truck it is less. Due to instability of the finished floor stacked pallet loads, the majority of the AGV vehicles stack pallets one high on the finished floor. Other Computer-Controlled Vehicle Considerations To have an efficient and cost-effective ASRS pallet storage/pick operation, there are several other computer-controlled vehicle considerations.



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FIGURE 6.18 Cart with switching towline. (From S.I. Handling, Easton, PA. With permission.)

Load-Handling Devices (Set of Forks or Platens) The first consideration is the pallet load handling device. The pallet load-handling device is the ASRS vehicle component that carries the pallet load between the pickup and delivery station and storage/pick position and completes the pallet storage/pick transaction. The ASRS two pallet-handling options are (1) set of forks and (2) platens. The set of forks option permits the ASRS vehicle to complete a pallet transaction to a pallet rack position. This option requires minimal vertical clearance in the pallet position, but it requires exact tolerances.


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When platens are used in the operation, the bottom pallet load requires a slave pallet board and the rack opening consists of two rails, two support arms, and sufficient pallet position clearance to complete the transaction. This option requires additional pallet openings and the tolerances are not as tight. The second ASRS consideration is the pallet handling capacity. The pallet capacity options are (1) single shuttle or (2) dual shuttle. The single shuttle has the capacity to handle one pallet per aisle trip. This feature requires less run-out space, less weight, and lower overall productivity. The dual shuttle has the capacity to handle two pallets per trip into the aisle. The ASRS vehicle is designed with the carriage area to take two pallets on board. This feature requires additional run-out space, additional truck weight, and higher overall productivity of an additional 20 to 25%. The increase considers additional starts and stops and slower travel speeds in the aisle to complete the required pallet transactions. Vehicle Commands The next ASRS consideration is the vehicle commands. The vehicle commands refer to the computer commands that direct the ASRS vehicle to complete a pallet storage/pick transaction. The two ASRS command options are (1) single-command mode or (2) dual-command mode. The first ASRS command mode is the single-command mode. The typical singlecommand mode has the computer direct the vehicle to make one down-aisle trip. During the aisle trip, the vehicle completes one pallet storage/pick transaction. With this mode, the vehicle completes 18 to 24 transactions per hour. This mode does not require a balance of the inbound and outbound transactions. In the dual-command mode, the ASRS vehicle makes an aisle trip. During the aisle trip, the computer directs the vehicle to complete a pallet deposit transaction and on the aisle exit to complete a pallet withdrawal transaction. The represents two pallet transactions per trip and the vehicle completes 22 to 26 dual commands per hour. The dual command mode does not double the single-command productivity rate because of additional aisle travel time and set of fork (platen) activity time. To achieve dual commands, there is a requirement for a balance between the inbound and outbound transactions. Pallet Pickup and Delivery Stations The end-of-aisle P/D station is designed as a static or dynamic pallet operation and is considered a temporary holding position for pallets that are transferred between the VNA or ASRS vehicle and the in-house transportation vehicle. In the pallet load storage/pick industry, recently many companies have increased their warehouse space utilization and vehicle productivity by implementation of VNA or ASRS storage/pick methods. In these storage/pick methods, the forklift trucks perform the storage/pick transactions at the various rack positions, operate within a very narrow aisle, and perform the maximum number of pallet transactions per hour. These forklift trucks remain in the aisle and perform the maximum number of dual or



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single pallet transactions per hour. Since the typical pallet operation inbound activity is skewed to the morning hours and the outbound activity is skewed to the afternoon, an imbalance in the projected forklift truck storage/pick transactions is created in the 8-hour day. To obtain the desired pallet storage/pick transactions and return on investment, these forklift truck methods require pallet load P/D stations at the end of each forklift truck aisle. The pickup and delivery stations are pallet load positions located at the end of each storage/pick aisle. The P/D stations provide temporary pallet accumulation for inbound and outbound pallet loads that are assigned for deposit or withdrawal transactions or transport to another operation’s location. In addition, the P/D station location gives the forklift truck direct and unobstructed access from the aisle to the pallet load for the start or completion of a storage/pick transaction. Also, the P/D station ensures that the pallet board openings are in the correct orientation for pickup or delivery by a forklift truck or transport vehicle. The P/D station improves forklift truck productivity, decreases product damage, decreases rack and forklift truck damage, and reduces transaction errors. Various P/D Station Designs The end of aisle is designed as a static or dynamic method. Static P/D stations are designed as staggered or flush to the main traffic aisle. The various P/D stations are the static type, which includes finished floor, structural stand, or standard pallet rack; the dynamic type, which includes four-wheeled carts and on-board transfer cars; gravity powered conveyor; powered roller conveyor; and powered shuttle car. Static Staggered P/D Stations. The static staggered P/D station is the most common P/D static station. With the staggered P/D station the pallet board fork entry openings face the storage/pick aisle. This staggered or saw-toothed rack layout consists of four rack rows and two storage/pick aisles. In a plan view of the pallet storage/pick area, the rack arrangement has the interior two rack rows shorter by the number of required pallet positions at the P/D stations and the exterior two rack rows extend outward toward the main traffic aisle by an equal number of P/D stations. With these extended rack bays, this rack design provides sufficient aisle width (10 to 15 feet) between the two exterior rack rows. This open space permits most inhouse transport vehicles to complete the transport transaction. The staggered P/D station method is used with a manually operated VNA forklift-truck method and provides pallet accumulation. Static Flush P/D Stations. In the static flush P/D station, the pallet board openings face the main or transfer aisle. The method handles a low volume, provides minimal pallet accumulation, interfaces with a manually operated VNA forklift truck, and is not considered for a dynamic operation. Dynamic P/D Stations. The dynamic P/D station consists of a series of pallet conveyor lanes, onboard transfer cars, shuttle car stops, or four-wheel carts. Most four-wheeled cart P/D stations interface with a manually operated VNA truck method. The pallet conveyor lanes, shuttle car, and on-board transfer car are used with an ASRS method.


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Pallet Delivery and Pickup or Transport Vehicles The next component of the VNA or ASRS method is the pallet delivery or in-house transport vehicle. The in-house transport vehicle completes a pallet transport transaction between the storage/pick area and the receiving/shipping dock area. The objective of the in-house transport vehicle is to ensure a constant pallet flow and to ensure that the pallet is properly oriented as it is transferred to the P/D station. The various in-house pallet transport methods are (1) pallet truck or forklift truck, (2) AGV, (3) powered conveyor, and (4) monorail. The pallet truck or forklift truck method interfaces with a manual VNA forklift truck operation that has staggered or flush P/D stations. The AGV in-house transportation method interfaces with a manual VNA forklift truck operation that has staggered P/D stations. The DC electric powered overhead monorail pallet in-house transportation method has a powered conveyor carrying surface that interfaces with an ASRS operation that has staggered P/D stations. The DC electric powered pallet roller conveyor in-house transportation method interfaces with an ASRS operation that has staggered P/D stations. Captive Aisle Vehicle In a captive aisle forklift truck operation, per the pallet rack and aisle arrangement there are multiple forklift trucks in the pallet operation. With this design one forklift truck is allocated to one warehouse aisle. In this aisle the forklift truck performs all storage/pick transactions. The projected pallet storage/pick transaction activity has each forklift truck vehicle performing at its maximum transaction activity rate. This means that the warehouse computer is required to spread the daily pallet storage/pick transactions as evenly as possible among the various aisles and forklift trucks. Mobile Aisle Vehicle When we consider captive or mobile pallet storage/pick vehicles, the three major vehicle groups are (1) the WA vehicles, which are mobile aisle vehicles; (2) the NA vehicles, which are mobile aisle vehicles; and (3) the VNA vehicles, which are considered captive or mobile aisle vehicles. With the mobile aisle design, from the main traffic aisle the vehicle has access to any storage aisle. In any warehouse aisle, the forklift truck completes the assigned pallet storage/pick transaction. The warehouse computer spreads the pallet storage/pick transactions that are based on an arrangement to maintain the forklift truck productivity standards and service the receiving and shipping area requirements. Typically, the mobile aisle is powered by a rechargeable battery and has three or four wheels. T-Car The travel of most ASRS vehicles is restricted to one pallet area’s aisle. However, with the proper rack arrangement, additional equipment, and sufficient time, a captive



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aisle vehicle is transferred between the various pallet warehouses’ aisles. With the means of a DC electric powered T-car or bridge car in a transfer aisle, the T-car has the mobility and capacity to transfer the ASRS vehicle from one aisle to another aisle. The T-car is computer controlled to physically receive the ASRS vehicle in its cradle or bridge (take on-board) and travel from one aisle on its wheels over the guided travel path and to align the bridge for discharge of the ASRS vehicle into the required aisle. The T-car aisle width is 25 to 40 feet wide according to the storage/retrieval vehicle’s length. In most applications, the T-car aisle is located opposite the pickup/delivery station side of the ASRS facility.

PALLET LOAD STORAGE/PICK POSITION METHODS The pallet load storage/pick position method ensures that there is proper pallet accessibility and that there is maximum space utilization. The pallet storage/pick method is a key factor that determines the pallet load operation’s ability to satisfy the company storage/pick objective of the lowest possible logistics cost and best customer service. The design parameters that influence the preferred pallet storage/pick method include the type of operation, average and peak volumes, pallet load dimensions and weight, type of product rotation, number of pallets per SKU, type of SKU and shape, type of pallet board or bottom support device, type of material-handling equipment, and required storage conditions and building codes. The various methods are floor stack or block, which includes 90˚ angle and 45˚ angle; tier rack or stacking frames; double-deep or two-deep racks; standard pallet racks; bridge the aisle; drive-in racks; drive-through racks; gravity and air flow racks; push-back racks; cantilevered racks; high-rise racks; and mole, car-in, and sort link racks. Floor-Stack or Block Storage/Pick Methods The first pallet storage/pick method is a dense pallet storage/pick method. The first pallet method is the floor stack or block storage/pick method, which has the pallet placed directly onto the finished floor. The floor-stacked method provides a maximum six to ten pallets deep per storage lane. A storage lane is a single lane or backto-back storage lanes. Because of the leaning of pallets and the variance of pallet load placement on the finished floor and on another pallet, deeper storage lanes reduce manually controlled forklift truck ability to complete transactions. To utilize the air space, additional pallet loads are stacked on top of the finished floor pallets to a maximum of three to four pallet loads high. This floor-stacking practice requires that the SKU must be capable of supporting the stacked weight and that the SKU at the aisle position is the same for the entire storage lane. The floor-stacked storage/pick method, when full, offers the highest storage density with the lowest investment cost, but has poor pallet load accessibility. A 60% utilization factor is used to determine the number of storage/pick positions. The 60% utilization factor is used due to honeycombing (vacant pallet positions in the vertical stack) and vacant pallet positions in the storage lane depth. These situations occur from normal forklift truck activity.


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In a floor-stack or block method, to make a pallet load transaction, from aisle A the forklift truck enters the storage lane, travels to the lane pallet load position, performs the required transaction, and backs out from the storage lane to the same aisle A. When a floor-stack storage method is designed, the number of pallet loads deep per storage lane is varied to bury building columns in or between the storage lane. The method has a last-in, first-out (LIFO) product rotation, handles a high throughput volume, and interfaces with WA or NA forklift trucks. 90˚ Angle. The most common floor-stack method is the 90˚ stack method. The method provides the greatest number of SKU openings and storage positions per aisle. 45˚ Angle. The 45˚ floor-stack method allows a minimum right-angle forklift truck turning aisle, but fewer openings per aisle. Tier Racks and Stacking Frames The second storage method involves portable containers, tier racks, or stacking frames (portable racks), and is considered a dense storage method. When the SKU that is placed in a floor or block storage is crushable (is not self-supporting or is not square), the container, tier rack, or stacking frame makes stackable and uniform unit loads that optimize the cube (air) storage space. When you use these storage devices, common practice has one SKU per unit load lane and stack. Local fire protection codes are reviewed for storage height, sprinkler requirements, and depth restrictions. Standard Pallet Racks The next pallet load storage/pick position method is the standard pallet-rack method. One, two, or three pallet loads are placed into the rack opening, which is determined by the pallet board’s width and the load beam’s length. Usually pallet loads in the first vertical opening are placed on the finished floor and pallet loads are placed in the other vertical openings onto load beams. There is 3 to 6 inches of clearance between unit loads and uprights and between unit loads and load beams. If a straddle forklift truck is used in the pallet rack with three unit loads or if the pallet load is placed in the rack opening with its long dimension (48 inches down-aisle), then the bottom rack opening is raised above the finished floor onto a pair of load beams. This feature provides clearance for forklift truck straddles to travel under the load beams. If the straddle truck is used with the unit load on the finished floor in the 40-inch dimension, then at least 5 inches are allowed between the unit loads and rack members. A rack bay consists of two vertical upright frames and two pairs of load beams that are attached to the upright frames. At the minimum, one pair of load beams is at the first level and a second pair of load beams is at the top of the upright frame. This feature provides good stability. Many rack installations are three or four levels high. In a tall building, they are at least four or six levels high. The upright frames are designed by the manufacturer to hold all the rack bay’s pallet load weight plus the rack weight. The pair of load beams is designed to hold



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the rack opening’s pallet load weight. It is common for the upright frame and the load beam connection method to permit 2 to 3 inches adjustability of the rack opening vertical height. In a pallet order-fulfillment facility, the standard pallet-rack method is designed as single rack rows or back-to-back rack rows. The pallet load position utilization factor is 85%. With access to all pallet positions, the pallet load rotation is first-in, first-out (FIFO) and it handles a medium to high volume. Whenever possible, all building columns and fire sprinklers are located in the flue space (8 to 12 inches open space) between back-to-back rack rows or wall. If required the building column is designed in a rack bay to occupy one pallet position in the rack bay but not in the aisle. With an aisle between each rack row, most conventional standard rack layouts have low density but excellent pallet accessibility. Diagonal and Horizontal Bracing Intersection Faces the Aisle During rack installation, the intersection of the upright frame’s bottom diagonal and horizontal support structural members should face the aisle. If there is a forklift truck impact against the frame, then this arrangement allows the bracing to withstand the impact. To meet stability requirements and seismic conditions, the back-to-back upright frames and single rows along a wall are tied to the wall or overhead. With heavy pallets, the upright frame base plates widen to disburse the weight. When a standard pallet rack is installed in your facility, the first front upright frame post is anchored to the finished floor at the start of each row and the next anchor is on the rear of the second upright frame post. This anchor pattern ensures rack stability but is approved by the rack manufacturer. Pallet Bottom Deck Boards Lock the Pallet onto the Load Beam In your pallet order-fulfillment operation, if you are concerned about the pallet becoming dislodged from the rack bay, then one solution is to have front to rear members installed in each pallet storage position. These members space the open space between the two load beams and provide support for the pallet’s bottom exterior deck boards. An alternative to secure the pallet in the rack opening is to use the load beam and the pallet’s bottom exterior deck board to lock the pallet board in the rack bay. To use the open space between the pallet’s exterior bottom deck boards to lock the pallet board in the rack bay, the depth of the upright frames and load beams are equal to the pallet load depth less the depth of the pallet’s two exterior bottom deck boards. After a forklift truck places a pallet into the rack bay, the pallet’s two bottom deck boards are on the outside of the two load beams. This arrangement has two or three stringers of the pallet board rest directly on the two load beams. Since the pallet’s bottom exterior bottom deck boards are at least 1/2 inch high, in the rack bay this reduces the pallet board forward and reverse movement. This arrangement does not interfere with the performance of the forklift truck storage/pick transactions because the pallet board fork openings are maintained at the standard height.


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Upright Frames The upright frame is considered the vertical component of a rack bay. The upright frame consists of two upright posts with a base plate under each post. Each post has a series of holes on specific and constant centers full-length for load beam attachment. There is also a series of horizontal brace members between the upright posts with connection members and a series of diagonal brace members between the upright posts with connection members. The upright frame is designed to structurally support the project pallet weight that is determined by your rack manufacturer from your design parameters. The upright frame design options are straight leg and cant leg. The straight upright post is very common in the logistics industry. With this design, the front or aisle upright post is a straight structural member from the base plate to the frame’s top. The cant leg upright post design has the aisle post from a location interior to the rack position extend on an angle upward and outward toward the aisle and connect with the straight upright frame post. In a WA forklift truck operation, the cant leg design provides additional clearance, which allows the forklift truck driver to make a right-angle turn without hitting the upright frame leg with the pallet load or a counterbalanced forklift truck’s rear chassis. Upright Frame and Post and Load Beam Designs The metal upright rack frame post basic designs are C-channel, round, and H- or structural-shaped. The three hardened and coated metal load beam designs are the step, the structural or H, and the rectangular or box. Each rack manufacturer has a series of holes that are punched into the upright frame post for load beam connection and possible future rack opening height elevation changes. The various manufacturers’ hole designs are unique and make it difficult to mix one manufacturer’s racks with another manufacturer’s racks. Two load beams provide the pallet load support structure. The rack manufacturer from your pallet load weight design parameters designs the load beam’s metal gauge and vertical height to support your design load weights. The three methods to connect the load beams to an upright frame are bolt, washer, and nut; clip-on; and safety lock. Important Rack Dimensions In the design of your pallet storage/pick area, several important rack dimensions ensure that your desired storage/pick design fits into your building and that your forklift truck operators meet the projected transaction productivity. The three pallet dimensions are based on your design parameters and are rack depth, rack height, and rack length. The first important rack dimension is the rack depth — the dimension that holds the pallet load. The rack depth is determined by your pallet board dimension that you plan to have support by a pair of load beams and permit your forklift truck to complete a transaction.



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In a standard one- or two-deep rack design, the rack depth dimension is 4 to 6 inches, less the pallet board dimension. The second important rack dimension is the upright frame height. The rack height is the upright frame height or post height that is sufficient to support the top unit and to permit sufficient horizontal and diagonal brace members and, as required, overhead ties. In most standard pallet rack designs, the upright frame height extends 2 to 6 inches above the top of the top load beam. This additional upright post height serves as a guide for the forklift truck driver to complete a pallet transaction. In a drive-in or drive-through rack method, the front or aisle upright post extends upward and is tied at the top. If the standard rack installation is in a seismic location, then per the local code the upright frames are extended above the top pallet load position to top-tie the rack structure. The rack or load beam length is the last dimension and has two important components: (1) internal dimension (ID) and (2) centerline-to-centerline (C/C) dimension. This dimension is considered the rack bay’s opening that horizontally holds the pallets and permits a forklift truck to complete a transfer transaction. The load beam length or ID dimension is the rack length that handles the combination for the width or fork opening for the storage pallets and the required clearances or open space. Another definition of ID is the open or clear space between two upright frames or posts. The C/C dimension is the rack length that is the combination of the load beam length and one upright frame post’s width. When you calculate the order-fulfillment aisle length, you use the C/C dimension plus the length of one upright post or frame. To determine your facility aisle, you count the number of rack bays or openings and multiply the number of bays by the C/C dimension plus a 3-to-4-inch post width. With a tall-rack rack supported facility or heavy loads, the rack post width is a minimum of 5 inches. If you calculate the warehouse aisle with the load beam length or ID, the actual warehouse aisle is short by the sum of the number of upright post widths in the aisle length. Two-High Unit Loads on the Floor When the standard, drive-in, or drive-through rack design has two high pallet loads, the two-high unit load is set on the finished floor and the rack levels are one pallet load high. This rack feature is required in your rack specifications. With this arrangement, the upright frames and upright posts are manufactured with additional strength for the increased bottom level vertical height. Also, this installation design is approved by the rack manufacturer. Rack post protectors are placed on the aisle side of the upright frame post to reduce forklift truck damage. Double Deep or Two Deep Racks The next pallet load storage/pick method is the two-deep or double-deep rack method which is considered a dense storage/pick method. The two-deep pallet rack compo-


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nents and design characteristics are similar to those for the standard pallet rack method, with a few exceptions. The first exception is that the rack upright frame has two design options, which are determined by the weight of the pallets and the desired flexibility to reuse the upright frames at another location. These options are long frame and two standard upright frames. The long or one-frame method has one long upright frame with four load beams and two load beams. The second frame configuration consists of two standard upright frames with four standard load beams. Two-Deep Characteristics The two-deep rack has a utilization factor of 85% for the interior pallet position and 70% for the exterior pallet position. The double-deep rack row design requires that one rack bay be placed directly behind the other rack bay. The space between the exterior and interior pallet positions varies between 1 to 4 inches. This space is a function of the forklift truck stroke or set of forks extension. The doubledeep rack design allows the rack opening to hold four conventional pallets. The second unique feature is that the two-deep rack method requires a double-deep reach forklift truck that has a stroke or set of forks forward extension of 43 to 51 inches. In the two-deep rack, the first pallet deposit is made to the interior rack position and the second pallet deposit is made to the aisle or exterior pallet position. The first pallet pick is made from the aisle or exterior pallet position, and the second pallet pick is made from the interior pallet position. This feature and the time required to extend the set of forks provides a LIFO product rotation and the ability to handle a medium volume. With four pallets per rack bay, the double-deep rack method provides medium pallet position density and fair pallet accessibility. The two-deep rack method design options are up and over or raised above the floor arrangement, and bottom load sets on the finished floor. Up and Over or Raised above the Floor Arrangement. In the first method, the bottom rack opening is raised above the finished floor. The open space permits the forklift truck straddles to pass under the bottom load beam and to turn in a narrow aisle. Also, this feature allows easy pallet deposit and picks at any rack level because the straddles are not required to straddle the floor-level pallet. This raised bottom pallet level (up and over) method is required for pallets with narrow widths or pallet load widths that exceed the open distance between the straddles. Also, this method requires a narrower rack opening, but increases the rack investment, rack height, and building height. Bottom Load on the Floor Arrangement. In the second arrangement, the bottom pallet is set on the finished floor. This method requires that all pallets in the elevated rack positions are in direct alignment with the bottom pallet. This feature reduces a forklift truck operator’s transaction productivity due to the additional time that is required to line up the forklift truck straddles between the pallets. Also, this method reduces the rack investment, rack height, and building height, but provides a wider rack (load beam length) and fewer pallets per aisle.



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Long Load Beam If your pallet load operation is a tall warehouse (above 30 feet) and you expect not to change the vertical height of the pallet, then in your rack specifications you state that a load beam can span two or three rack bays or openings. This load beam design has the load beam attached to the face or aisle side of the upright post. For stability, the load beams are staggered (the front load beam spans two bays and the rear load beam spans three bays). Compared to standard upright frame depths, the upright frame depths are narrower. In comparison to standard rack installation costs, this arrangement has the potential to reduce rack material and installation costs. With the staggered load beam feature, if the rack opening vertical height is adjusted, then the entire rack row requires adjustment. Tips and Insight on Installing Used Racks When you are considering installing used storage racks in your facility, these guidelines can reduce potential installation problems. Determine What Is Required in Your Facility After you have completed the facility layout drawings, from your drawings you can determine the various quantities of upright frames and load beams that are required for the operation. If you have a mix of new and used racks, then on the layout drawing the appropriate rack bays (frames and load beams) are identified as new or used equipment. Develop Written Specifications for the Rack In addition to the above facility and equipment layout drawings, you develop a complete rack written specification package which is sent to your rack vendors. In addition to the regular rack specification information, you identify who is responsible to take down the existing rack equipment and how the anchor bolts are to be removed and the holes filled in level to the finished-floor surface. This includes the material to fill in the holes. Then you decide who is responsible for bundling the upright frames and load beams and other rack components into bundles that are handled by a conventional forklift truck, and who is responsible for loading and unloading the equipment and transporting the equipment. Communicate with the Rack Vendors Next you develop a rack vendor list that contains both used-equipment and newequipment dealers. Prior to sending a bid package to these vendors, call them assesses their willingness to participate in your used-rack bid. To the vendors who are willing to participate, you send the used rack layout drawings and written specifications. This rack vendor list is obtained from your company’s past vendor list, industry directories, industry newspapers, or the Internet. Review the Equipment After you receive the completed rack bids, you determine which vendor provides the racks that satisfies your specifications and is most economical. Prior to the


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equipment purchase, obtain (if available) a complete set of drawings of the existing rack layout, upright frame and load beam listing, description, pictures, and written history of the equipment. This includes the stated capacity of the upright frames and load beams. If the stated capacity is not available and you know the original rack manufacturer, then you contact the rack manufacturer because most manufacturers have records of this information. If you visit the site or facility, review the upright frames and load beams for damage, accumulated dust or dirt, discoloring, rust, upright frame and load beam colors, base plate and load beam and upright frame connection method, and ability to reuse the components. It is a good practice to take pictures of the racks. Follow Installation Tips To complete your rack, it is possible that you could mix manufacturers’ racks. This situation means that your future rack layout will have mixed colors of racks. If top management accepts this color scheme, that reduces the installation project problems. If top management requires one color scheme, have the uprights and load beam components painted prior to installation in your facility. Also, based on C/C dimensions and if you are required to mix different racks within one rack row, the row length increases by the dimensions of each new manufacturer’s upright post. If the existing rack has accumulated dust or dirt or rust, then the rack components are cleaned by air pressure or water and as required sanded or coated prior to installation in your facility. Bridge Racks or Bridge Across the Aisle The standard pallet-rack method is designed to bridge a pallet operation’s aisles. This is considered a pallet design that takes advantage of the total available space within the facility. This method has the same rack design and operational characteristics as the standard pallet rack. Pairs of load beams with front to rear members span the aisle and are connected to the upright frames of the appropriate rack rows. This arrangement forms a bridge across the aisle. For each rack bay the bridge across the aisle provides one or two additional pallet openings. A very important bridge design consideration is to allow sufficient space for the forklift truck’s mast (collapsed) or clearance between the finished floor and the bottom of the bridge load beam. Drive-In Racks The next rack method is the drive-in rack method, which handles nonself-supporting pallets of product. A drive-in rack consists of pallet rack storage lanes and is a dense pallet storage/pick method. The rack components are required upright frames; upright posts; support arms; guide rails; support rails; and side, top, and back bracing. The drive-in rack bottom lane has the bottom pallets set on the finished floor, and the elevated storage lanes are set on the rack structural members. A drive-in rack lane is two to ten pallets or positions deep and three to four pallets high per storage



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lane. This rack layout provides medium to good storage density and poor pallet accessibility, and the product rotation is LIFO. Drive-in racks are designed with a single row or back-to-back rows. The SKU that is in the storage lane floor level or bottom aisle position is the SKU that is in all pallet positions of the rack storage lane. This feature provides a pallet utilization factor of 66%. In designing drive-in racks, the rack second-level storage lane and the structural members have sufficient strength to permit a forklift truck (guards and overhead) guard and, as required, the forklift straddles to enter and exit the floor level storage lane. For the drive-in rack method, the number of pallets is varied to place building columns within the flue space of the back-to-back drive-in rack rows. The drive-in rack storage lanes are best designed between building columns. This feature means that the building columns are not in the drive-in storage position or lanes. In all drive-in rack down-aisle designs, structural members require fire sprinklers and forklift truck masts and overhead and straddle clearances. Most drive-in rack methods are designed with the pallet board fork opening side facing the aisle. This pallet arrangement has the maximum number of faces per aisle and provides excellent pallet load stability in the rack positions. To complete transactions in a drive-in rack storage method, a forklift truck enters the floor level storage lane from aisle A, completes the deposit or pick transaction and backs out of the storage lanes into the same aisle A. Because of this operational characteristic, a drive-in rack method handles a medium volume and has a LIFO product rotation. Drive-Through Racks The next pallet rack method is the drive-through rack method, which handles nonself-supporting pallets. Drive-through racks have the same rack components, design characteristics, and utilization factor (66%) as the drive-in rack method. However, there is no back bracing, but there is a requirement for top bracing of the rack. With no back bracing, a drive-through rack is designed as a stand-alone rack row with a forklift truck aisle on both sides. This means that it is not designed with back-toback rows. A drive-in rack arrangement handles a medium volume and the product rotation is LIFO or FIFO. With the LIFO product rotation, the forklift truck enters the drive-through rack lane from aisle A, completes the deposit or pick transaction, and backs out of the rack lane into aisle A. With the FIFO product rotation, the forklift truck enters the drive-through rack lane from aisle A, completes the deposit or pick transaction, and drives through the rack lane into aisle B. An alternative procedure in a FIFO product rotation is to exit the storage lane by driving without a pallet through the storage lane and exiting into aisle B. To retrieve a pallet, the forklift truck enters the rack lane from aisle B, retrieves a pallet, and backs out of the storage lane into aisle B. The drive-through rack has medium storage density and poor pallet accessibility. The dimension of the pallet position has the same characteristics as that of drivein racks.


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Mobile or Sliding Racks The next rack method is the mobile or sliding rack method, which is similar to the standard rack method. The exceptions are that it is considered a sense storage method. It requires fewer forklift truck aisles, and the rack rows move to create the forklift truck aisle. Mobile racks are standard single-deep pallet rack rows or backto-back rack rows that are placed onto moveable bases. The end two single-deep rack rows of a module are fixed rack rows. All rack rows are placed in a 90˚ angle to the main traffic aisle. Mobile racks are designed with six sections of back-to-back moveable rows; one forklift truck aisle; and at each end of these moveable sections, single-deep rack sections or rows. The mobile rack method has a ratio of four to five pallets high to one deep. If sprinklers are required in the racks, then the mobile rack manufacturer is notified of the design requirement and the sprinklers are designed for the method. For access to the pallet position, a mobile rack moves to the side and creates a forklift truck transaction aisle between the required rack rows. The forklift truck enters the aisle, performs the required storage/pick transaction, and exits into the main traffic aisle. After the transaction, as required the mobile rack sections are moved to create a new forklift truck aisle between two different rack rows. Sensing devices on the moveable rack base bottom section sense the existence of an object or employee in the mobile rack section travel path, and if there is an object the mobile rack section stops its movement. This feature prevents the moveable rack and equipment from being damaged and prevents employee injuries. With one access aisle, a mobile rack provides high pallet position density and good accessibility. The mobile rack method has a utilization factor of 85% and handles a low-to-medium volume due to slow rack movement to create the forklift truck aisle. With a good inventory control program and batched transactions per row, the forklift truck transaction productivity is improved. Gravity Racks The next rack method is the gravity or flow-through rack. This rack method is designed as a single or stand-alone rack method that has one aisle for pallet in-feed and another aisle for pallet out-feed. The pallet gravity flow rack method consists of upright frames, upright posts, braces, brakes, end stops, and skate wheel or roller conveyors that make individual flow or pallet storage lanes. In a conventional forklift truck operation, the pallet flow lanes are three or four levels high. In a hybrid facility, the pallet lanes are seven to eight pallet lanes high. The weight and height of the pallet determines the slope and pitch to the flow rack lanes. The pallet unit height/length ratio is 3 to 1. If pallets exceed this ratio, there is a potential for uneven flow-through or hang-ups in the storage lane. The gravity flow rack method is designed for 3 to 20 pallet loads per lane. In most pallet flow rack systems, to ensure smooth flow through the storage lane, the pallet is placed onto a captive or slave pallet board. In some flow rack methods, the conveyor rollers have flanged wheels that act as guides for the pallet as it flows through the rack. To prevent rack damage, lane entry guides, upright post



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protectors, forklift truck stops, and sufficient forklift turning aisle widths are recommended at the entry and exit positions. The pallet gravity flow rack method has a forklift truck that permits access to the deposit side of the flow rack. After the forklift truck in aisle A places the pallet onto the conveyor, gravity and the pallet weight on the rollers allow the pallet to flow through the storage flow lane to the exit end of the storage lane. The pallet load is removed by a forklift truck in aisle B from the exit end of the storage lane. This activity permits the next pallet in the lane to flow, move, or index forward to the withdrawal position. In a long method, to reduce line pressure and product damage, pallet load brakes and at the exit position a pallet separator are installed in the flow lane. The pallet gravity flow method indexing movement of the pallet loads from the deposit (entry) position to the withdrawal position and allows each storage flow lane to accommodate one SKU per storage lane. This feature permits gravity flow racks with two aisles to have high storage density and fair pallet load accessibility. Air Flow Racks Another type of pallet flow-through storage method is air flow racks. Air flow racks are very similar to pallet gravity flow racks, except that the pallets are indexed through the storage lane by air that is forced through tiny holes in the pallet rails. This feature requires a higher pitch or slope to the storage lane and an air compressor with its associated piping. Push-Back Racks The next pallet rack method is the push-back rack. The push-back rack is a standalone rack method with one aisle. This method consists of the same rack structural components and design characteristics as the pallet gravity flow rack with some exceptions. A push-back rack method is designed as a single rack row that is installed along a building wall, in a building location that permits one aisle for a forklift truck to perform all transactions or as back-to-back rack rows. The method is designed to be two to six pallets deep and three to four loads high. To complete a pallet transaction, a forklift truck places a pallet against an existing pallet that is in the storage lane’s aisle position. When the existing pallet is sufficiently pushed back into the storage lane, it creates the required new pallet load space. To withdraw a pallet, the forklift truck slowly raises the pallet 2 to 3 inches high above the storage lane conveyor and backs out the pallet from the storage lane. As the pallet is removed from the storage lane, gravity force moves the next pallet into the storage lane exit or aisle position. This feature permits a 66% lane utilization and a LIFO product rotation. The push-back rack provides good storage density and fair accessibility and handles a low-to-medium volume; each lane handles one SKU. The push-back rack method options are standard conveyor push-back rack and telescoping push-back rack.


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In a standard pallet push-back flow rack, the push-back flow rack conveyor does not require brakes but requires end stops on both ends of the flow lanes. In a telescoping carriage push-back rack method, the push-back method consists of pallet carriages that ride on a set of tracks. The carriage design permits the carriage that travels into the interior pallet position when not in use (without a pallet) to nest over the empty carriage adjacent to the aisle Cantilevered Racks The next storage/pick method is a cantilevered rack, which is designed to handle long pallets such as pipe. A cantilevered rack consists of upright posts, support arms, legs, and braces. At several levels, sufficient space is designed between the pallets and metal members for fire sprinklers. With solid or wire-mesh decks on the support arms, a cantilevered rack is designed to handle all types of pallets. The cantilever rack is designed as a single-arm row or double-arm rows. The arms extend outward from the upright post and create pallet positions. The pallet positions are serviced by an NA forklift truck. The cantilevered rack permits a FIFO product rotation, excellent storage density, and excellent product accessibility. The pallet position has a utilization of 85%. High-Rise Racks The final rack method is the high-rise rack facility that uses the vertical air space rather than the horizontal footprint. These methods are designed for conventional buildings or in a rack-supported structure. The rack-supported structure has the racks’ upright frames and posts as the support and attachment members for in-rack sprinklers, the walls or skin, and the roof. All of these systems require a dead-level or F75/F100-level finished floor and a vehicle guidance system. The structure is designed for the snow, seismic, and wind forces; fire protection (including walls, barriers, and sprinklers); and mast clearances at the top of the racks. In an automated high-rise facility, all pallets pass through a size and weigh station to verify that the pallet dimensions and weight conform to the system’s design standards. The high-rise rack facilities are designed with single-deep racks, twodeep racks, and flow racks as part of the structure. High-Rise Pallet Rack Openings The single-deep pallet rack openings’ alternative designs are standard pallet rack openings and four-arm pallet openings. Standard Pallet Rack Openings. The first type of rack opening is the standard pallet rack bay that has two pallets per set or pair of load beams. This rack opening requires that the forklift truck or vehicle has a set of forks. To complete the transaction, the set of forks enter the pallet board fork openings as a normal forklift truck. In the typical high-rise facility, the first pallet sets 30 to 36 inches above the finished floor. Compared to the alternative single-deep rack method, the standard rack method has the advantages of: (1) fewer upright posts per aisle, (2) greater number of facings per aisle, and (3) a shorter building.



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Four-Arm Pallet Openings. The second rack opening has four load arms and two pallet rails that support one pallet per opening. This rack opening requires a captive or slave pallet board and the vehicle to have a set of platens that go under the pallet to complete the transaction. The first rack level is approximately 17 to 24 inches above the finished floor, but at each rack level an additional 3 to 6 inches of clearance is designed for the platens between the top of the pallet and the support arms of the next pallet position level. Car-in-Rack or Mole The next pallet method is the car-in-rack method. The car-in-rack method has the nickname “the mole.“ The rack method consists of upright frames, posts, car rails, pallet support rails, a car-in-rack vehicle, slave pallets, and an aisle travel vehicle. Sufficient space is designed between the pallet and rack members or storage lane for fire sprinklers and a car with elevated pallet load travel in a storage lane. The car-in-rack method is designed to be 3 to 8 pallet levels high and to have 10 to 20 pallet positions per storage lane. Each storage lane has one SKU. A very narrow aisle and guided vehicle carries the car-in-rack vehicle between the rack rows to the required storage lane and performs the pallet transaction. One-Aisle Car-in-Rack In a one-aisle arrangement, the car-in-rack vehicle leaves the host vehicle from aisle A, enters and travels into the storage lane, arrives at the required pallet storage lane position, performs the pallet transaction (deposit or pick), and exits the storage lane to the same aisle A and onto the host vehicle. This arrangement provides a LIFO product rotation and pallet utilization factor of 66% and handles a low to medium volume. The one aisle car-in-rack method provides high pallet density, poor pallet accessibility, and excellent security. Two-Aisle Car-in-Rack The two-aisle car-in-rack method requires two host storage vehicles and two car-inrack vehicles. In this method, from the inbound aisle A, all deposits are made by the aisle A vehicle with its car-in-rack vehicle. From an outbound aisle B, all picks are completed by the aisle B host vehicle with its car-in-rack vehicle. The method provides FIFO product rotation, excellent security, high pallet density, and poor pallet accessibility. If the pallets in the storage lane are indexed forward by a car-in-rack vehicle toward the withdrawal aisle, then the two-aisle car-in-rack method has an 85 to 90% utilization factor and handles a higher volume. Sort Link The next pallet storage/pick method is the sort link method. The sort link method is an automatic or computer-controlled method. The components include captive or slave carrier and travel path, rail-guided horizontal four-wheeled pallet load carrier or cart and travel path, multiple storage level facility, vertical cart carrier, dense cart storage lanes, and computer controls.


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The first sort link component is the captive or slave carrier. The carrier board is manufactured from a hardened and coated steel frame and is designed to handle a pallet. Under each corner of the metal frame is a flanged wheel. The flanged wheel permits the carrier to be moved in two directions. These directions are between the pallet load carrier and the storage lane or discharge lane. To improve the ability to move carriers, the carrier’s lead end has a special coupler and hook device. When one carrier’s hook is engaged in another carrier’s coupler, the motor driven parent device moves one or several carriers between two locations. The carrier is moved over a dual rail-guide path that interfaces with the carrier’s flanged wheels. The path ensures that the carriers are in a straight line. The second component is the rail-guided horizontal four-wheeled pallet load carrier or cart and travel path. On each storage facility level, these are designed to take on board a slave pallet carrier. These four-wheeled devices are motor driven to travel over the rail-guide path and at a pickup location to take on board an inbound carrier, and in the storage area to complete a deposit or pickup transaction. Per the transaction, the hooking device engages or disengages the carrier. The path is a straight travel path that runs the entire length of the storage facility. Per the facility design and storage lane configuration, there are one or several guide paths to serve one facility level. The next sort link component is the storage facility. The storage facility consists of one level for inbound and outbound transactions and the required pallet staging area. The other facility floor levels are designed as storage finished floors that have two purposes. The first purpose is to provide the guided travel path for the required four-wheeled devices to complete the in-house transportation of pallet carriers between the four-wheeled device and storage lane and between the four-wheeled device and the vertical in-house pallet carrier transport method. As required, each finished-floor level is serviced by a vertical in-house pallet carrier device. The second purpose is to provide the pallet carrier with rail-guided storage lanes. The number of faces and depth of the storage lanes is determined by the land and building design parameters. On the proper finished-floor level, a forklift truck performs transfer transactions to in-feed a pallet to the storage facility or to pick a pallet from the storage facility to complete a customer-order. The next sort link component is the vertical cart carrier. The vertical cart carrier is an in-house transportation method that moves the pallet carrier between the computer assigned finished floors. The next sort link components are the dense cart storage lanes. These dense cart storage lanes consist of two flanged wheel rails per storage lane. These storage lanes hold the pallet carriers. As required by the operation the motor-driven guided carrier moves a pallet carrier from one storage lane to another storage lane. This activity is performed to provide access to the assigned pallet or increase the storage space utilization. The final component consists of the computer controls and inventory controls that ensure smooth and constant pallet carrier movement through the facility, assign a pallet to the proper storage area, and track the inventory.



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Pallet Facility Layout Considerations The pallet order-fulfillment facility layout considerations are the factors that determine your order-fulfillment operation’s ability to satisfy your objectives: (1) to control operational cost and earn a profit, and (2) to satisfy and increase your customers. In addition to the pallet flow consideration, the major order-fulfillment facility layout considerations are the layout philosophy and layout principle. Layout Philosophy and Principle Your pallet order-fulfillment layout philosophy and principle are the factors that influence your material-handling equipment arrangement and the locations of your pallet order-fulfillment storage and pick areas and positions. The two most important areas in a pallet order-fulfillment operation are inventory or reserve storage/pick areas and positions. The pallet order-fulfillment activities and positions require the majority of the finished-floor area and have the greatest number of employees. The various philosophies and principles are SKU popularity or Pareto’s law (80/20 rule); ABC theory; unloading and loading ratio; family group; product rotation; rack row and aisle direction; aisle length, adequate aisles, and aisle width; and pallet height (short or tall). SKU Popularity or Pareto’s Law (80/20 Rule) When a pallet order-fulfillment operation has a layout that is based on SKU popularity, it is based on Pareto’s law. This law states that 85% of the wealth is held by 15% of the people. In the order-fulfillment industry, this law indicates that 85% of the volume shipped to your customers is derived from 15% of the SKUs. Many studies have indicated that another 10% of the volume shipped to your customers results from another 30% of SKUs, and an additional 5% of the volume shipped to your customers is attributed to 55% of the SKUs. If you are in the catalog or directmail business, then 90 to 95% of your business is from 5% of your SKUs because two to four catalogs are introduced within a year. Each catalog has a different inventory of SKUs. In recent studies, the results show that 95% of the volume shipped to your customers is obtained from 55% of the SKUs. This is referred to as “Pareto’s law revisited.” ABC Theory When a pallet order-fulfillment professional refers to the three zones of Pareto’s law, their reference is to the ABC theory. The ABC theory simply states that the A pick zone is allocated to the fast-moving SKUs. These SKUs are few in number and have a large inventory quantity per SKU. The B pick zone is allocated to the normallymoving SKUs. These SKUs are medium in number and have a medium inventory quantity per SKU. The C pick zone is allocated to the slow-moving SKUs. These SKUs are large in number and have a small inventory quantity per SKU. If in a pallet order-fulfillment operation layout the receiving and shipping docks are located on the front side of the facility and the SKU’s location is based on the ABC theory, the fast-moving SKUs will be at the front of the facility. If the receiving


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and shipping docks are located on opposite sides of the facility, the fast-moving SKUs are located by the SKU’s unloading and loading ratio. Unloading and Loading Ratio The unloading and loading ratio compares the number of trips that the unloading employees and loading employees require to handle a truck load of pallets. When the number of employee-unloading trips equals the number of employee-loading trips, the SKU pallet loads (positions) are located near the shipping docks or in any location in the rack row. When the employee-unloading trips are more numerous than the employee-loading trips, the SKU pallet loads (positions) are located near the receiving docks. This feature reduces the employee’s total travel distance. Family Group The next order-fulfillment operation layout philosophy is the family-group philosophy. This philosophy is dictated by your company’s requirement that the SKUs are located in a pick aisle with other SKUs that have the same inventory classification. With this philosophy, by a predetermined criterion, the SKUs are assigned to specific locations (areas, aisles, or positions) within your facility. This layout philosophy requires that the facility and material-handling method be designed to accommodate the SKUs that have similar dimensions, weights, and SKU components; are located in the same aisle in the retail store; require normal, refrigerated, or freezer conditions; require high security; are from toxic or nontoxic materials; include edible or inedible substances; include flammable or nonflammable materials; include stackable or nonstackable products; and include crushable and noncrushable packages. Pallet Height The next order-fulfillment operation layout philosophy is the pallet-height philosophy. The pallet height is dictated by your company’s specifications and a vendor’s ability to pallet-load units of product to a predetermined height The philosophy options are (1) tall pallet and (2) short pallet. Tall Pallet. When the pallet order-fulfillment operation receives pallet loads that are considered tall pallets, the order-fulfillment floor stack or rack positions are designed to handle a tall pallet. Each pallet has the greatest number of units of product per pallet. A tall pallet has the maximum number of layers of cartons without crushing the cartons on the bottom layer. When compared to the short-pallet option, the tall-pallet option means fewer number of transactions and trips completed by the storage/pick vehicles. The maximum number of products on a delivery truck means fewer dock positions; less potential product, equipment, and building damage due to fewer handlings; increased requirement and potential to secure the product on the pallet; and, with a tall position opening, maximum position flexibility. Short Pallet. When the pallet order-fulfillment operation receives pallet loads that are considered short pallets, the order-fulfillment floor stack or rack positions are designed to handle a short pallet. With this method, the pallet has the fewest number of units of product per pallet. A short pallet has the maximum number of layers of cartons without crushing the cartons on the bottom layer. When compared to the



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tall-pallet option, the short-pallet option means a greater number of transactions and trips completed by the storage/pick vehicles; increased potential product, equipment, and building damage due to increased handlings; and, with a short position opening, minimum position flexibility and a greater number of load beams, increasing the rack investment and lowering the cube utilization. Product Rotation The next order-fulfillment operation layout philosophy is the product rotation philosophy. The product rotation is dictated by the life cycle of the product and the requirement for specific product to be picked for a customer-order. The two product rotation philosophy options are (1) FIFO rotation and (2) LIFO rotation. FIFO Rotation. In the FIFO product rotation the SKU that is received first in the order-fulfillment operation is shipped out first from the order-fulfillment operation. This indicates that the product has a predetermined life (or time limit) before it spoils. After a specific date, the SKU is not withdrawn from the inventory for customer orders. A pallet order-fulfillment operation layout that is designed to have SKUs with a FIFO product rotation requires access to all pallet positions in the storage/pick area and ensures that the oldest pallet or product is withdrawn first from the storage/pick area or position. LIFO Rotation. In LIFO SKU rotation, the pallet that is last received in the orderfulfillment facility is shipped out first from the facility. This type of product does not have a specific shelf life. The order-fulfillment facility design does not provide access to the oldest pallet or unit of product. This feature allows the order-fulfillment operation layout to use dense storage/pick positions that reduce the building square feet or meters. Rack Row and Aisle Direction The next philosophy is based on the rack row and aisle direction of flow to the shipping docks. The two philosophies are (1) parallel to the shipping docks and (2) straight to the shipping docks. Parallel to the Shipping Docks. The first rack row and aisle direction of flow method has the rack rows and aisle direction of flow parallel to the shipping docks. With the rack row and aisle direction of flow in this arrangement, at least two turning aisles are at the end of the storage/pick aisles and rack rows and a middle traffic aisle is required in the layout. These aisles lead to the shipping docks. This arrangement increases order-picker travel time between the storage/pick area and shipping docks. Straight to the Shipping Docks. In the second layout, the rack row and storage/pick aisle direction of flow is straight from the storage/pick area to the shipping docks. In this design each storage/pick aisle provides access to the shipping dock area and the main traffic aisle serves as a vehicle-turning aisle. The middle cross aisle ensures good employee productivity to perform a transaction in a different pick aisle.


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Aisle Length The next pallet order-fulfillment operation philosophy involves a layout that is based on the storage/pick aisle length. The two philosophies are (1) short storage/pick aisle and (2) long storage/pick aisle. Short Storage/Pick Aisle. The short storage/pick aisle length philosophy specifies that the rack row and storage/pick aisles run in the short facility dimension or short width of a rectangular-shaped facility. This method requires turning aisles at the end of each rack row and storage/pick aisle. When compared to the long storage/pick aisle method and on a SKU per square foot basis, the short storage/pick aisle method provides less density and lower employee productivity because of an increased number of unproductive end-of-aisle turns. Long Storage/Pick Aisle. With the long storage/pick aisle philosophy, the rack rows and storage/pick aisles are arranged to flow in the long direction of the facility or rectangular-shaped building. This long storage/pick aisle method does have a cross or middle aisle in the middle of the rack row or storage/pick aisle to provide easy and quick transfer to another facility storage/pick aisle. The long storage/pick aisle method does provide greater density and fewer unproductive employee turning aisles. Most employee controlled pallet facilities are designed with length of 300 to 400 feet or 75 to 100 pallets. In an automatic ASRS facility, the aisle length is from 100 to 150 pallets or 400 to 450 feet.

PALLET IDENTIFICATION The purpose of the pallet identification is to identify the assigned storage/pick position and to discretely identify the SKU from the other SKUs in inventory. The identification location on the pallet considerations are that it is in a location that minimizes damage and that it is easily recognized by your employees. In a pallet order-fulfillment operation, the identification label is placed in a consistent location, either in the lower right-hand corner of the pallet load or attached to the right-hand stringer or block. Identification Methods The type of pallet identification method is determined by the several factors: the type of pallet load operation, such as manual operated forklift truck or ASRS; the label identification method, such as manual, bar-code scanner, or other reader; and your acceptance of the vendor’s pallet identification. The various identification methods are (1) no method, (2) manual-printed methods, or (3) machine-printed methods. No Method The first pallet identification method is no identification method at all. Your company relies upon your vendor’s exterior carton markings for the pallet identification. This identification method does not require that your company markings are placed on the pallet exterior; the majority of the companies that use this method have only one SKU in an aisle. This storage system is usually a two- or three-pallet-deep floor stack method and there is a large number of pallets for one SKU.



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The disadvantages are that it handles a limited number of SKUs, there are possible errors, and there is low employee productivity. The advantages are no expense or capital investment and less time spent to attach the label. Manual-Printed Methods The first pallet identification method group is the manual-printed identification group. With these methods an employee physically writes the pallet identification onto the pallet load side or onto a label that is placed onto the pallet load side. The various manual printed methods are (1) crayon or chalk marks on the exterior of the pallet, (2) crayon or chalk marks on a label, and (3) crayon or chalk marks on a color-coded label. Crayon or Chalk Marks on the Pallet. In this method, the receiving clerk uses a crayon or chalk to mark the pallet location and identification on the exterior of the pallet. This is considered the basic method. The disadvantages are difficulty of reading, transposition errors, smeared numbers, additional labor time, and difficulty of identifying with other markings on the pallet. The advantages are low cost and no investment. Crayon Marks on a Label. In this method, the receiving clerk uses a crayon or chalk to write the pallet identification and assigned position onto a label. The completed label is placed onto the pallet. The disadvantages and advantages of this method are similar to those of the previous method. An additional advantage is that the identification is easier to identify. Crayon Marks an a Color-Coded Label. With this method, the pallet identification and assigned position is written onto a label that is a color coded label. The color coded label corresponds to a particular month of a year. This color code allows an employee to easily and quickly identify the age of the pallet. The disadvantages and advantages of this method are similar to those of the previous method. An additional advantage is that the identification is easier to identify and that it is easy to determine the age of the pallet. Machine-Printed Methods The second pallet identification method group is the machine-printed identification group. With these methods a machine prints the pallet identification onto the pallet load side or onto a label that is placed onto the pallet load side. The various manual printed methods are (1) machine-printed human-readable label and (2) machineprinted human- and machine-readable label. Machine-Printed Human-Readable Label. In this method, a computer-controlled printer prints the pallet identification and assigned location onto a label. These labels have alphabetic characters or digits that are printed prior to the delivery truck’s arrival at the dock or printed upon demand at the receiving dock. After the employee receives the label, the label is placed onto the pallet’s exterior surface. The disadvantages are additional label costs, investment in the printer and computer, office space, and print time. The advantages are uniform identification, clear identification, medium to low labor requirement, no transposition errors, and the ability to preprint labels.


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Machine Printed Human- and Machine-Readable Label. With the method, the computer prints human-readable characters and digits and a machine-readable bar code on the label. Most logistic professionals refer to the bar code/humanreadable label as the pallet’s license plate. The disadvantages and advantages of the method are similar, but the additional disadvantage is additional print time and the additional advantage is that it permits bar-code scanning. The bar-code/human-readable label options are (1) self-adhesive labels, (2) nonadhesive labels, (3) black print on a white background, and (4) color-coded labels. The self-adhesive label is widely used in the pallet warehouse industry as the pallet identification and assigned position identification method. The self-adhesive label provides a positive method to secure the identification to the pallet. This feature ensures that the identification label remains with the pallet and allows an employee to recognize the label. The nonadhesive label consists of print on the front of a piece of paper or thin cardboard. The label is slipped between the material that secures the pallet or under a carton. With a bar-code scanning operation, this feature can increase the difficulty to obtain a bar-code read. Another important feature of the pallet identification label is the colored label background or ink color. The color types are the plain white backing with black alphabetic characters and digits and black bars. This label is considered a humanand machine-readable label. The color-coded pallet identification label has a unique color for each month of the year. The color code consists of the borders or the ink colors. The colorcoded label provides a quick indication of the month that the pallet was received at the facility. Pallet Transaction Instruction Methods The fundamental of any pallet transaction instruction method is that it directs an employee or computer-controlled vehicle to complete a customer-order transaction or a storage transaction. The basic philosophy of any order-pick or storage transaction method is to keep the transaction instruction as simple as possible. With an employee-based method, the employee has to read the instructions and clearly understand the instructions. These instructions are separated into three groups: (1) to direct an employee, which is paper directed or characters or numeric digits printed on a paper document; (2) paperless directed, which includes an RF device with a visual display screen and voice direction; and computer directed, where a computer directs an ASRS crane. Paper Document The first employee pallet order-fulfillment instruction method is the computer-printed or manual-printed paper document. The paper document method is the simplest of the employee instruction methods. The method is used in any operation that has the employee control a forklift truck to complete the pallet deposit or pick transaction. The paper document is a printed page (single sheet or multiple carbon sheets) that lists all available pallet positions and SKU descriptions that are involved in the



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deposit or pick transactions. Each pallet to be handled has a corresponding column or open block. After completing the transaction, the employee places a mark in the block to verify completion of the transaction. With the completion of all required transactions, the document is given to an office clerk to update the inventory files. The disadvantages of the method are the transposition or entry errors, the need for a clerk, the need for an employee to read, the fact that inventory update is a delayed transaction, and the fact that the paper document can become lost. The advantages are no capital investment, little employee training, the ability to be used in all manually controlled or operated systems, and the ability to be used in a small operation. Paperless The next method is the paperless transaction method. The paperless transaction method means that the employee transaction instruction is provided by a visual display terminal or is provided by a voice direction, and that the computer controls a computer-controlled ASRS vehicle. The transaction directs an employee or a computercontrolled ASRS vehicle to complete a transaction. With a pallet order-fulfillment operation’s requirements the paperless method options are (1) RF with a visual display screen, (2) voice directed, and (3) computer directed with an ASRS crane. RF and Digital Display. The first paperless transaction method is the RF terminal and digit display unit. In this method, the employee obtains the transaction position from the alphabetic characters or digits that are shown on a display screen, and the employee follows several steps: with a bar-code scanner, to read the pallet’s barcode label for a deposit transaction; to have the pallet’s assigned position; to travel through the various aisles to the assigned pallet position; and at the assigned pallet position, to complete the deposit transaction and have a bar-code scanner read the pallet’s identification label and the position’s identification label. For a withdrawal transaction, the employee’s activities are basically reversed from the pallet position to the shipping dock area. These pallet transactions are delayed or transmitted online from the RF device to the host computer. The disadvantages of the method are that it requires additional investment and identification on each pallet or position; for on-line communication, you must verify that the method operates in your facility; and it requires employee training. The advantages are accurate transaction completion and on-line transaction verification; also, fewer employees are needed and there is no need for a clerk. Voice Directed. The voice-directed pallet transaction method consists of a computer system and an employee with a microphone or earphones (headset). With this method (voice recognition and speech synthesis), the employee has online communication with the host computer. Each employee talks to the computer through a microphone and receives of verbal transaction instructions from the computer through the headset. The disadvantages and advantages of the method are similar to the RF paperless method, except the method requires additional training. Computer Directed. The computer-controlled paperless method is used in an automated or ASRS facility. In the automatic computer-controlled method, the host


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computer communicates to each ASRS vehicle’s microcomputer to complete a pallet deposit or withdrawal between an assigned pallet position and a P/D station. To verify the completion of each transaction, a bar-code scanning device along the pallet travel path verifies the transaction’s completion. The disadvantages are high capital investment, difficulty of providing on-time customer orders, the requirement that all pallets and positions have an identification, and the need for a computer program. The advantages are accurate transaction completion, online transaction verification, fewer employees, and the need for a building with a small footprint. Aisle and Position Identification Format Each series of alphabetic characters or numeric digits identifies a specific aisle and a position within an aisle. With an operation with a standard pallet rack method, the information on an instruction format consists of (1) warehouse, (2) warehouse aisle, (3) bay within an aisle, (4) level within a bay, and (5) a pallet position within a level. For some pallet storage/pick methods, the above format is for a standard pallet rack method. With a drive-in, drive-through, and pallet flow rack method, the format consists of (1) warehouse, (2) warehouse aisle, (3) bay within an aisle, and (4) level within a bay. This feature is due to the fact that there is only one pallet per rack bay. Warehouse The warehouse location has the lowest significance to an employee in a pallet orderfulfillment operation. This component or field is used to identify the warehouse from another warehouse in a company’s supply chain logistics strategy. In most logistics strategies this component is an alphabetic character. Warehouse Aisle The most important instruction format component or field is the warehouse aisle. This character or digit identifies your warehouse aisle that contains the pallet or vacant position that appears on the instruction. Most applications have this component as an alphabetic character. Bay in an Aisle The rack bay in a warehouse aisle is used to direct the employee as the employee travels in the aisle. In most applications the rack bay positions are identified with a numeric digit, and these digits have an arithmetic progression from the aisle entrance. Level in a Bay After the employee arrives at the rack bay, the next most important component or field is the load beam or rack level within the rack bay. In most pallet order-fulfillment operations, this component or field is an alphabetic character. There are several reasons why the level in a bay is an alphabetic character. For a manually based pallet order-fulfillment operation and in most ASRS or tall rack operations, 26 characters are sufficient to identify pallet levels in a rack structure. Typically for the components or fields before and after the level in a bay component or field a numeric digit or digits are used to identify the bay in an aisle and the position in a level. With an



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alphabetic character between two numeric digits, an employee is less likely to become confused than with three consecutive numeric or digit components or fields. Pallet Position in a Bay The pallet position in a rack bay is the most significant component or field of the employee-instruction format. After your instruction format has directed your employee to the warehouse aisle and level in a rack bay, the assigned position is where the employee completes the pallet transaction. The pallet position is identified with numeric digits and the print is the easiest to read on a digital display or paper document. Aisle and Position Identification In your pallet order-fulfillment operation, to ensure an accurate and on-time transaction, proper signs clearly identify the aisle and positions and are considered part of the instruction format. A very important step of the aisle and position identification process is to determine how information appears on the position. The first option is to use characters and digits. This method is considered the basic method. The disadvantages are that it is difficult to detect errors and that there is no check system. The second option is to use characters, digits, and a bar-code label. This method is considered a sophisticated method. With the bar-code label scanning method, the information is transferred online and accurately. The disadvantages are label expense, the need for a wider or larger label, investment in scanning equipment, and the need for a communication network. The advantages are detection of errors and on-line, accurate information transfer. Aisle Identification There are three aisle identification options: placard with one-way vision, two-way vision placard against the rack, and four-way aisle placard. The first method is considered a one-way vision method. A placard is placed flat against the end of the aisle upright frame or is hung from the ceiling. In this arrangement, the aisle identification faces outward, which lets an employee entering the aisle identify the aisle. The second method is a rack two-way vision method. With this method, the first option is to use two placards. On each upright frame a placard extends outward from the upright post into the main traffic aisle. At a proper elevation the placard is easily recognized and does not get damaged. The second option is to use three placards, where two placards extend outward into the main traffic aisle and a third placard is placed flat between the two placards. With the two-way options, as the employee is traveling in the main traffic aisle, each aisle number is easily recognized from the main traffic aisle. A four-way aisle identification method is a ceiling hung placard that has four sides. Each side has the aisle identification. With the four-way option, as the employee is traveling in the main traffic aisle, each aisle number is easily recognized from the main traffic aisle.


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Position Identification In a pallet order-fulfillment operation, the method used to identify the pallet position has a direct impact on the employee’s transaction productivity and accuracy. The position identification methods are the floor-stack group, which includes a placard hung from the ceiling and a placard embedded in the finished floor, and the rack group. Floor Stack Identification Methods The first position identification method is the floor-stack identification method. With the various pallet floor or block storage/pick methods, the position identification may have a placard hung from the ceiling with the position identification. When considering the placard method, the clearance between the placard and a forklift truck mast is a consideration. Alternately, the position identification is embedded in the finished floor. When considering this method, the durability of the identification in the finished floor is a consideration. Rack Identification Methods The rack identification is attached to a metal structure of the rack bay. With the rack identification method, the various methods are no method; handwritten on the position; handwritten onto adhesive labels or tape; preprinted adhesive labels, as individual characters or digits or as the entire identification; and paper or cardboard placed into a plastic holder. No Method. The first position identification method is no identification. With this method, there are no markings on the position members. When a company uses no method, it relies upon the pallet’s exterior markings to identify the position. The disadvantages are the difficulty of having a SKU description match the employee’s instruction, low employee productivity, possible errors, and the need for an employee to read. The advantage is there is no expense. Handwritten on the Position. The handwritten position identification is the second method. An employee uses paint, crayon, or chalk to write the position identification numbers or alphabetic characters directly onto a flat surface of the rack structure that is above, below, or to the side of the position. The disadvantages are unclear writing, difficulty in transferring, difficulty in recognizing characters or numbers, and difficulty ensuring uniformity. In addition, identification is not in a uniform location. The advantage is low cost. Handwritten onto an Adhesive Label or Tape. With this method, an employee places a strip of tape or an adhesive label on a flat surface of the position structure that is above, below, or to side of the position. Next, with a crayon, paint, or chalk, the employee marks the proper identification onto the label or tape. The disadvantages are unclear or confused handwriting, additional label expense, and additional labor. The advantages are improved employee productivity, ease of transfer, and a uniform label location. This method is also easy to notice. Preprinted Adhesive Labels. With this method, a computer-controlled or print machine prints the position identification onto an adhesive label. The label is placed



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by an employee in the appropriate location at the position. The disadvantage is additional label expense. The advantages are clear print, uniform label, uniform label location, and ease of transfer. Within the self-adhesive label group is (1) individual characters or digits and (2) entire identification. The first method uses an individual preprinted label for each digit or alphabetic character. These labels vary in size from 1/2 to 3 inches in height or width. As required, to complete the identification, each label is placed on the rack structure at the position. The disadvantages are increased labor expense, possible uneven label placement, and need for extra labels. The advantages are ease of replacing damaged labels and ease of changing or transferring identification. The second method has the entire identification printed onto a label. The label face contains the alphabetic characters, digits, and bar-code label and is placed onto the rack structure. The disadvantages are increased print cost and damaged labels that are costly to replace. The advantages are low label application cost, no label waste, consistent label placement, and the ability to use a bar-code scanner operation. Paper or Cardboard Placed into a Plastic Holder. The plastic-holder method has two components: (1) the position identification printed onto a paper sheet or cardboard and (2) a clear or transparent plastic holder with an adhesive back. With this method, an employee places the plastic holder onto the rack structure and the employee inserts the identification into the plastic holder. The disadvantages are additional label material, application labor expense, and potential holder damage. The advantages are uniform label placement and bar-code scanning (in some operations). Pallet Handling Device Routing Patterns The fundamental rule of a successful pallet pick operation is that the instruction follows a pattern through each aisle. The instruction form directs an employee to the appropriate position for a SKU that appears on a customer-order. With a pallet load operation, the single side with one or two order pickers method is the most popular routing pattern. With the sequential order-picker routing pattern, the forklift truck driver enters the aisle, completes the transaction, and exits from the same aisle. As the order picker travels through the aisle, the lowest position number starts at the entrance from the main aisle and these numbers are progressive to the highest number at the end of the aisle. To ensure maximum employee productivity, the guidelines are as follows: (1) position numbers that end with an even number are located on the right side of the aisle and position numbers that end with an odd number are located on the left side of the aisle; (2) an arithmetic progression is used through the aisle; and (3) the aisles are clear and well illuminated, and good housekeeping is maintained. In most pallet order-fulfillment applications, the transaction is to handle one pallet per trip, and the aisle routing pattern has the employee enter the aisle from the main traffic aisle, complete the transactions, and travel to the main traffic aisle. Pallet Transaction Verification A very important pallet order-fulfillment activity is the employee’s completion of a transaction and the verification of the transaction. The verification of the transaction


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ensures that the correct SKU has been deposited or withdrawn at the correct time, and has been transferred to the assigned station. The three transaction verification methods are (1) manual or memory, (2) manual written document, and (3) automatic or bar-code scanning method. Human Memory Method The first pallet transaction verification technique has the forklift truck operator mentally remember the position for the SKU. This method is the most basic and simplest of the transaction verification methods. The forklift truck operator completes the transaction and when there is a demand for the SKU, the operator remembers the location and completes the transaction. The disadvantages of the method are low productivity, possible errors, a low volume and few SKUs, and difficulty of controlling over two shifts or a large area. The advantages are low cost and no capital investment. Handwritten Paper Document The next transaction verification method is the manual handwritten method. In this method, the forklift truck operator uses a printed document to record each transaction. The printed document is a four-column activity sheet that has a space for the operator’s name and date. The four columns are separated into two groups of two columns each. Two columns under the deposit heading are for the listing of all deposit transactions. Under the withdrawal heading, the two columns are for the listing of all withdrawal transactions. After the operator completes a transaction, he or she lists the position and SKU identification number that was involved in the transaction. At the end of the shift, the activity documents are sent to the office. In the office, a clerk performs an inventory update. The disadvantages of the method are that it handles a low volume, requires a clerk’s effort, adds to the operator’s work, and there are possible transposition errors. The advantages are no capital investment, the ability to be used over two shifts, and the ability to be used in a large facility. Bar Code Scanning The bar-code scanning technique requires a bar-code scanning device and a barcode label as the transaction verification format. Most labels are human- and machine-readable and a discrete label is attached to the pallet load and each position. The bar code scanner has the capability to hold the transaction or to send the transaction on-line to the host computer. In the bar code scanning operation, prior to picking up a pallet the forklift truck operator scans the pallet label and per the instruction format travels to the assigned position. Arriving at the position, the pallet is placed into the assigned position and the position identification is scanned by the operator. This information is sent by a delayed or online transmission to the host computer. The disadvantages of the method are investment, employee training, identification of each position, and management control and discipline. The advantages are accurate information, on-line or delayed information transfer, and high employee productivity.



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IN-HOUSE TRANSPORTATION METHODS In a pallet order-fulfillment operation, the operation has several different activity locations. To complete the receiving activity or shipping activity, pallets are required to be moved or in-house transported between the various activity locations. To move a pallet between two locations, the pallet-handling vehicle travels over a variable travel path or over a fixed travel path. The power source for these in-house transportation vehicles are: employee powered, DC electric motor, electric battery, and fuel engine. The various in-house transportation methods are: human-powered pallet truck, powered pallet truck, forklift truck, powered vehicle with a train of carts, AGV, tow line, and overhead Towveyor®.

HUMAN-POWERED PALLET TRUCK A manual-powered pallet truck is used to transport a pallet over a variable and short travel path. Due to the physical effort that is required from the employee, the manualpowered pallet truck is used in the dock area. For additional information, we refer the reader to the pick vehicle section.

POWERED PALLET TRUCK The second in-house transportation vehicle is an electric battery-powered vehicle. This truck is available in walkie, walkie/rider, and rider models and has the ability to transport a pallet over a long travel distance at a fast travel speed over a variable travel path. The electric battery-powered pallet truck is designed with the capability to carry one or two pallets. For additional information, we refer the reader to the pick vehicle section in this chapter.

FORKLIFT TRUCK The next in-house transportation vehicle is an electric battery- or fuel-engine powered forklift truck. The forklift truck has the travel speed and capacity to transport one or two pallets between two facility locations. The travel path is variable and the forklift truck completes elevation pallet transfer transactions. For additional information, we refer the reader to the pick vehicle section in this chapter.

POWERED VEHICLE

WITH A

TRAIN

OF

CARTS

The next in-house transportation method consists of a powered vehicle with the capability to tow a train of carts. Most powered forklift trucks and AGVs have the draw bar towing capacity to pull a series of carts over a fixed or variable travel path. Each cart has the capacity to handle one or two pallets. With the train of carts method, consideration is given to the intersecting aisle widths, the towing vehicle capacity, and the ability to unload and load pallets at the assigned locations. The various carts that are used in a train of carts method, and the various cart couple and steering methods are very important. For additional cart steering and couple information, we refer the reader to the cart section in Chapter 5.


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AGV The next pallet in-house transportation method is the AGV method. The AGV is an electric battery-powered driverless vehicle that has one pallet carrying surface or the ability to tow a series of carts. The AGV follows a fixed closed-loop travel path between two locations. Stop or address locations and spur (branch) lines are segments from the main traffic line and run parallel to the main traffic travel path. The return line has a separate travel path or runs parallel to the main travel path. The travel path spur and return line design permits a vehicle to unload or load a pallet at a stop while other vehicles are traveling over the travel path. All AGV types are equipped with safety bumpers and have multiple vehicles on one system. You can extend or change the travel path, as required, up to 5000 feet. The unique features are weight and how the AGV moves the pallet as a carrier or tow vehicle, guidance on the travel path, and how the AGV performs tasks. The AGV is considered for a pallet in-house transportation method when the following criteria are met: a transport activity is performed by a forklift truck, pallet truck, or tugger with a train of carts; delivery is between two locations; the delivery path is fixed; deliveries are frequent and on schedule; the pallet is unloaded or loaded automatically or is forklift truck assisted; the pallet is within the design parameters; there is a smooth or level finished floor and grades are gradual; and the delivery travel path is a long distance and is a closed loop. Various AGV Control Methods The AVG is a driverless vehicle. Control of the AGV movement for travel is programmed by three different options: (1) basic controls, (2) advanced controls with a microprocessor, and (3) microprocessor controls that interface with another system. The basic control method is the simplest control method and is implemented in a system that has one or two vehicles, less than four address locations, and a total guide path of less than 5000 feet. The advance control method with microprocessor controls is used for more complex systems that have a guidance path of more than 5000 feet and a vehicle travel path that is more complex or requires blocking. This method is used if the activity requires more than four vehicles and more than four automatic unload and load stations. The microprocessor control method is the most sophisticated control method and it interfaces with another automatic system. The transportation vehicle performs pickups and deliveries of a pallet to and from another automated system. These pickups and deliveries require on-time performance and have at least the same operational design parameters as the advanced control method. Various AGV Dispatch Methods There are two ways to dispatch AGVs: (1) the fundamental human-dispatch method and (2) via remote communications to a host computer or automated system. To manually dispatch an AGV there are three different ways to program the AGV controls: (1) toggle switch, (2) thumbwheel switch, and (3) push-button numeric pad.



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With AGVs there are several basic mechanical and electrical features that improve vehicle efficiency and safety. The first is a safety bumper on the vehicle’s lead end. When the bumper comes in contact with an object or employee, this stops the vehicle. Running lights are illuminated when the vehicle is traveling on the guide path. This is a colored light that is readily noticed by an employee near the travel path. An AGV system has a control pad and a mimic display panel that shows the operational status of each vehicle on the guide path and permits you to start or stop the system. These panels indicate where each AGV is located on the guide path and where the safety stops are located, and they contain other devices and controls for the AGV system. An off-line stop device is an emergency device that reduces damage to the pallet or material handling equipment and the building. When an AGV deviates or strays from the guide path by more than 2 inches, the device is activated and the vehicle is immediately stopped. A UPS provides temporary electric power to the AGV vehicle wire guidance system during a brownout or electric power company failure. It provides power long enough to ensure that all AGVs on the travel path are returned to the main dispatch station. This reduces damage to the pallet, material-handling equipment, and building. AGV Anticollision Methods The most sophisticated AGV systems have vehicle anticollision controls that are considered blocking systems. The blocking system permits several vehicles to travel on one guide path. The anticollision system is onboard the vehicle or built along the guide path. The two options are the optical anticollision method and the zone-blocking methods (point-to-point blocking, continuous blocking, and computer-zone blocking). Optical Anticollision Method The optical controls on each vehicle consist of a light beam (source), receiver, and reflective target. On the front end of each vehicle a light device produces a light beam at a fixed level directed to the front of the AGV. A receiver on the front of each vehicle is at a fixed level to receive the reflected light. A reflective target at the same elevation as the light beam is located on each vehicle’s rear end. On a multiple vehicle transport system, when the second or trailing vehicle light beam is returned (reflected) from the first or lead vehicle’s target, the onboard controls of the second vehicle stop the second vehicle’s travel. This anticollision system is used with a pallet or with towing AGV vehicles that have a structural member on the rear or a cart for the attachment of the light source, light receiver, and reflective target. The system is not preferred on a driverless pallet truck because there is not always a reflective target on the rear of the vehicle. If a reflective target is temporarily attached to the rear of the pallet, then the anticollision system functions as a normal system. Zone-Blocking Method In the zone-blocking method, the guide path is divided into various zones or segments of sufficient length to contain a vehicle or a train of carts plus a margin of safety.


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The anticollision control program permits only one vehicle per zone at a time; therefore, if a vehicle occupies a zone and another vehicle enters the zone, the entering vehicle must wait until the first vehicle exits the zone. The three zone blocking methods are: (1) point to point, (2) continuous, and (3) computer. Point to Point Blocking. The point-to-point zone-blocking method consists of zone-sensing devices that are mounted on a physical object or column adjacent to the guide path. As a vehicle passes from zone A into zone B, the vehicle actuates the devices in the zone B control package to prevent another vehicle from entering zone B and permit another vehicle to enter zone A. Continuous Blocking. The continuous-blocking method consists of an onboard blocking signal transmitter, an onboard receiver, and an auxiliary multiple-loop wire that is buried in the finished floor under the travel path. Each loop wire section becomes a zone. As each vehicle travels on the guide path, it sends a signal into this looped wire that is detected by the second vehicle’s blocking devices. When a vehicle is in one zone loop wire and a second vehicle sends a signal on the loop wire, then the second vehicle’s sensing device picks up the signal and stops (queues) until the first vehicle leaves or clears the zone or travels from the loop wire. Computer Zone Blocking. In the computer zone-blocking system, each vehicle is equipped with an onboard microprocessor and onboard transmitting and receiving antenna, and has the ability to communicate with a host computer or another smart vehicle. The finished-floor area under the travel guide-wire path contains magnets or plates that identify each zone. As the vehicle passes over the magnet or plate, it sends a signal through the guide wire or by RF radio link. This method links the vehicle zone status to a second vehicle and to the host computer. When one vehicle is in a zone, a second vehicle that wants to enter the occupied zone is restricted by its onboard microprocessor or host computer. AGV Design Parameters When you are considering an AGV transportation system in your facility, you are required to define these fundamental design parameters. There must be good traction for the wheels. The finished floor is hard, and the metal is not within 2 inches of the guide wire. The guide wire path avoids expansion joints. If expansion joints are passed, the wire is looped. All grades are 10% or less in slope. There must be a UPS for the system. Determine and identify the number of turns in the travel path that are uncompensated or tangential turns that have a shorter width to turn, are compensated turns which have a wider width to turn, and are mitered or 90˚ rightangle turns. Calculate the vehicle travel requirements. Basic is used for a one- or twodirectional vehicle system with a simple manual dispatch method. Advanced is used for two-directional smart vehicles with a host computer or automated dispatch system. Simulation is used for the sophisticated system with a host computer or automated dispatch method that interfaces with another automated system. Calculate the number of required vehicles on the vehicle loop travel time (travel from a start



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location and return to the start location), with an 80% allowance for equipment utilization and dispatch and online placement time (includes load and unload time). Determine the guidance system, which is inductive. It has a finished-floor embedded wire that carries a low (40-volt) electric current and sensors on the vehicle’s undercarriage. This is the most common guidance method. Chemically treated tape or paint and an ultraviolet light beam from the vehicle stimulates fluorescent particles in the path and transfers the light beam back to the vehicle’s underside sensor. Alternately, the laser beam has red light sent from a light on the mast of the vehicle that is reflected back to the vehicle from strategically placed reflective targets. AGV Types The various pallet AGV types are: (1) towing AGV, (2) driverless pallet truck, and (3) pallet load AGV. AGV Towing Vehicle The first AGV transportation vehicle is the towing AGV. When your pallet operation has frequent deliveries (high volume) over a long travel path or distance (more than 3000 feet) and several carts or pallets are assigned to one facility location, then a towing AGV is considered as an option. Also, another important feature is that one AGV with a train of carts can drop or pick up loads at multiple locations. This feature requires an employee to uncouple or couple the carts and to program the AGV towing vehicle for travel to the next location. If a towing AGV with a train of carts is to make a turn, consideration is given to the train of carts turning requirement. A second consideration is that the loading and unloading spur or siding must be long enough to accommodate the vehicle and train of carts. This design feature permits other towing AGVs on the main travel path to pass the AGV that is on the siding. A third consideration is that the vehicle is manually controlled for cart hookup and unhooking activity. Driverless Pallet Stop and Drop Vehicle The driverless pallet truck carries one of two pallets to one or two drop locations. This vehicle has the name “stop and drop” and is a driverless vehicle that travels in one direction. It can be manually controlled. Manual control is required for the pallet truck to travel in the reverse direction for pickup of the two pallets. After the pallets are on the pallet truck forks, the employee enters the dispatch code or codes in the vehicle pushbutton control panel and dispatches the vehicle. Arriving at the assigned location, the driverless pallet truck travels onto the siding, and stops and drops the pallets at the location. The driverless pallet truck travels on the main travel path to perform if one load was dropped, another drop function, or continues to the dispatch location. The vehicle is battery powered and has an operator control area, safety light, and safety bumper. Pallet Load AGV The pallet AGV is the most common vehicle used to transport pallets between two warehouse locations. The pallet AGV has a battery compartment, three to four wheels


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(one at least for steering), safety bumper, control device, path sensor device, and pallet carrying surface. Three important nonvehicle components are the vehicle guidance system, pickup and delivery stations, and control or mimic panels. Onboard rechargeable batteries power the AGV on a guide path. The most common guide path uses a wire embedded in the finished floor. This is the inductive guidance method in which an electric charge travels through the wire. The sensor devices under the AGV maintain travel control via electric impulses that direct the AGV travel on the guide path. The other guidance systems are (1) the optical method, which uses chemically treated tape or paint on the finished floor, or (2) the laser light-beam method, which uses a light beam sent from the vehicle to reflect from reflective targets. With three or four wheels, the AGV travels in the forward and reverse direction over the travel path. In some newer models, the pallet-carrying surface is designed to handle a wide variety of pallets. The next important pallet AGV feature is the pallet-carrying surface, or how the AGV handles the pallet. The first method is to tow the pallet carrying cart and it was reviewed earlier in this section. The second method is to carry the pallet. Various AGV Pallet-Carrying Surfaces The AGV pallet-carrying surface is equipped with any type of device that is placed on a pallet or forklift truck. Some of the most common pallet load-carrying surfaces are a fixed-position single-pallet carrier that requires a forklift truck or fork device to deposit or lift a pallet from the vehicle’s carrying surface, a lift and lower singlepallet carrying surface for unassisted and assisted loading or unloading transactions, a gravity roller surface for side assisted loading and unloading transactions, a powered roller surface for automatic loading and unloading of pallets, and a set of forks to elevate and lower pallets from the finished floor to an elevated position. The AGV P/D station is an important design criteria and is matched to the AGV pallet load-carrying surface and travel direction capability. Various AGV P/D Stations There are several types of AGV P/D stations: (1) the manual type that has a forklift truck deposit or pick up a pallet, (2) an AGV that automatically loads or unloads onto a structural stand that requires the AGV to turn and back up to the stand, (3) a conveyor stand that has a gravity or powered roller conveyor section to interface with the AGV, (4) a slave-driven stand that has the AGV provide the power to transfer the pallet, and (5) a finished floor or rack position that requires the AGV to have a set of forks. Tow Line The in-floor tow line is a very common method in a large pallet load operation and the tow-line cart travels at 60 to 90 feet per minute. It is used to transport a high volume of pallets on a series of four-wheeled carts between two locations.



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The in-floor tow line is considered a fixed-path system that is designed with multiple automatic divert and in-feed locations (spurs or sidings) and that is installed in a facility with inclines and declines having a slope grade of 10% or less. Also, tow-line carts are transferred from one chain travel path to another chain travel path. Throughout the tow line system, a tow cart is manually removed or placed onto the chain. The in-floor tow line has two major components: (1) a tow-line chain that is enclosed in a hardened metal travel path and is driven by an electric powered motor, and (2) a tow-line cart. There are two types of tow-line methods. The first is conventional heavy duty. The conventional tow-line chain is in a pit 7 inches deep, 6 inches wide at the top, and 3 inches wide at the bottom with clean-out pits that are 4-inch-deep holes. These cleanout pits are periodically checked and cleaned out. Also, along the chain travel path there are automatic oilers at various locations to ensure proper lubrications of the chain. The second method is the low-profile or light-load tow line. The low-profile tow-line chain method is a pit 3 inches deep and 2 1/2 inches wide. The low-profile chain has a lower installation cost and is installed in a thin or average depth finished floor. With a tow line, there should be a good preventive maintenance program, and employees should be prevented from sweeping trash into the slot trench for the chain. Inside of these chain travel paths are a bottom and two wear bars that are strips of hardened metal. These wear bars are the tracks for the tow-line chain. As the chain travels across the wear bar, the wear bar prevents excessive chain wear. The tow-line chain is pulled by an electric motor-driven sprocket that is located on a straight run and is in a pit. In this pit is a take-up device that allows the towline slack chain condition to be taken up. Slack chain results from wear and weather changes. A tight chain ensures good performance from the tow line. Chain Links and Link with a Cavity or Dog The tow line consists of a series of motor driven chain links that travel in a C-channel track, and it is designed to travel over 90˚ or 180˚ turns or to incline or decline over grades of approximately 10˚ to 15˚. It is composed of numerous chain links and every 20 feet there is a link with a cavity or dog. For long lasting wear, these chain components are hardened steel. At every 20 feet or as determined by the tow-line cart length, a dog link is located; this is the tow-line chain component that pulls the tow-line cart. The dog is a specially designed link with a cavity to hold the cart’s tow pin. The motor, sprocket, and take-up device are located in a pit. The motor and sprocket pull the chain forward through the travel path and the tow line is designed to pull the maximum number of carts on a chain. The take-up device provides the means to increase or decrease the chain length, which adjusts the chain tension. The spur is a left or right nonpowered track that intersects the chain travel path at 45˚ angles. It is considered a branch line that permits nonpowered cart travel to a warehouse location. The chain sensor device or pad is in the finished floor prior to the spur. After the spur is activated by the cart’s coded sensor, the spur diverter (finished-floor mounted lever) slides across the chain travel path. The lever being in this position and the chain pulling the cart forward together force the cart’s pin to


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become disengaged from the chain-link dog and to flow into the spur’s open travel path. The spur allows the diverted cart to clear the main travel path, which permits continuation of other cart traffic on the main line. All spurs or branch lines are designed for a specific length and have full-line sensors. When activated by a towline cart, these sensors do not allow the diverter mechanism to divert additional carts onto the spur. Therefore, when you purchase used carts, be sure that the carts match the tow-line system’s specifications. Tow-Line Cart The tow-line cart is a four-wheeled vehicle that has a pallet-carrying surface and a code bar on its front end. The two standard carts are 6 and 10 feet long and 3 to 4 feet wide. The most common load-carrying surface is a flat wooden surface with a hardened metal borders. This feature requires the pallet transfer transaction to be completed by a forklift truck. The three unique features of the tow line cart are the (1) tow pin; (2) selector pin rack, selector pin, or bar-code label and bar-code scanner device; and (3) location and types of wheels under the cart. These features make the tow-line cart different from the other carts. Tow Pin To prevent excessive wear, the tow pin is a hardened steel rod that is set inside a sleeve. The pin sleeve is attached to the lead end and center of the tow cart. As required, it allows the tow pin to be removed from a tow cart pin sleeve. The tow pin has two positions: disengaged and engaged. In the engaged position, the tow pin is in the secured position, which keeps the pin in a raised position above the finished floor. The disengaged position is maintained by a cap or retainer on the end of the tow pin. This prevents the pin from mistakenly being placed in the tow chain. When the cart is not being towed on the system, this is the preferred position to prevent pin damage. The engaged position is in the lowered predetermined position. The exact pin length is a specification that is based on the track and dog depth. The rod retainer or cap permits the tow pin to reach this predetermined depth. When the tow pin is in the engaged position and in the track, as the empty dog arrives at the cart, the pin automatically slides into the dog (open link) and the tow chain pulls the cart forward to the assigned location. Selector Rack, Pins, or Bar-Code Label and Scanner The selector rack and selector pins are at the lead of the cart and in combination these two devices allow an employee to assign a divert address to the cart. The selector racks are on each side of the tow pin at the center of the cart. A series of 12 holes permit the selector pin to hang in a vertical position that is approximately at the finished-floor level. Each position has an alphabetic character in the front. The pin’s hanging arrangement from the specific selector rack hole corresponds to a discrete series of sensors in the spur (finished floor mounted) sensor device. A single selector pin rack handles up to 12 address locations, 2 selector pin racks handle up to 150 locations, and 3 pin racks handle several hundred locations.



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The selector pin or probe is a metal rod with a flexible or spring-loaded magnetized tip and a metal cap or retainer. To prevent pin damage, the pins are attached to the selector pin rack with a string or chain. When not in use, the pins are placed in a tray that is behind the selector pin rack. The metal cap and selector pin rack permit the pin to hang vertically at specific heights and to have the magnetized tip at approximately finished floor level. This is the proper height to activate the finished-floor spur-sensing device, which activates the diverter to transfer the cart from the tow-line travel path. An alternative to the selector pin is the bar-coded label on the lead or front side of the cart. The bar code is read by a scanning device that communicates with a microcomputer. The microcomputer triggers the divert device to direct the cart from the main travel path to the spur or to another travel path. Wheels of a Tow Cart The tow-line cart has four wheels. The cart’s rear two wheels are rigid casters or wheels and are located on the two corners under the rectangular-shaped load-carrying surface. The two front casters or wheels are the swivel type and are located under the two front corners of the rectangular shaped cart. However, compared to the rear wheels, with an underside plan view of the cart, the front-wheel locations are interior. This feature reduces drag as the tow cart is pulled through a curve of the tow-line travel path. During tow-line operations, to prevent injuries to employees and damage to material-handling equipment or to the building, a cart is not pushed or towed by another cart that is being pulled by a tow-line dog. To operate a tow line, an employee-operated forklift truck places the pallet onto the cart’s load-carrying surface and an employee pushes the cart onto the tow-line track. At the track, the selector pin is inserted into the assigned selector rack hole. The employee waits for an open link or dog on the tow line on every 20 feet and pushes the cart over the track. In this position, the tow pin is released and rides on the top of the track and chain and the dog automatically engages the tow pin. When this occurs, the tow-line cart is moved by the tow chain to the new warehouse location that corresponds to the selector pin arrangement or bar-code label. As the tow cart approaches the assigned spur, the magnetized selector pin passes over the finished-floor mounted sensing device (the bar code passes a reader) and activates (trips) a finished-floor mounted divert device (lever) that extends across the cart path. When the tow pin of the cart strikes the lever, the two pins slide from the dog’s mouth or cavity and the cart travels onto the spur away from the main travel path of another cart. At this location, the employee removes the cart from the tow-line travel path and removes the pins from the engaged rack position, and a forklift truck removes the pallet from the cart. Overhead Towveyor The next overhead powered pallet in-house transportation method is the overhead towveyor method. Many in-house transportation professionals refer to the overheadpowered towveyor as the overhead-powered tow conveyor in-house pallet transportation method.


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The method consists of three major components. The first is an overheadpowered or electric motor-powered rivetless chain travel path and a free-trolley travel path. The free-trolley has a pendant or arm that extends downward toward the finished-floor surface. At the end of the pendant is a loop or strap. The second is a four-wheeled tow cart with a rigid tow mast that extends upward and has a T-shaped top or end or a nonpowered pallet truck with a T-shaped handle. The third is a towcart travel path across the finished floor surface. After a forklift truck or mechanical pallet-lifting device transfers a pallet onto the four-wheeled tow-cart load-carrying deck or a nonpowered pallet truck with a T-shaped handle picks up a pallet board, on the dispatch station siding or spur travel path an employee attaches the free-trolley pendant loop or strap onto the fourwheeled tow-cart mast’s T-shaped end or raises and inserts the nonpowered pallet truck’s T-shaped handle into the loop or strap. When the tow cart or pallet truck is attached to the free trolley, the employee enters the pallet’s dispatch, destination, or delivery address (code) onto the trolley code device. With the completion of the free-trolley dispatch code entry, the employee transfers the tow cart or pallet truck by a rail switch device onto the free-trolley main travel path. The path is directly under the rivetless powered-chain travel path. At this travel-path location, the free trolley with the tow cart or pallet truck is queued or waits for a rivetless poweredchain pusher dog to engage the free trolley pusher dog. When the rivetless poweredchain pusher dog engages the free-trolley pusher dog, the four-wheeled tow cart or pallet truck is pulled over the towveyor tow cart’s finished-floor travel path to the assigned location. The overhead-powered towveyor pallet in-house transportation method is used to transport pallet loads over long travel distances to identified delivery destinations. When we compare the overhead and free conveyor pallet carrier to the overheadpowered towveyor method, the overhead towveyor transportation method has many similarities and several unique features. Similar Characteristics of a Towveyor and an Overhead The similar features of the overhead powered and free conveyor to an overhead towveyor method are as follows: tall finished-floor stands or ceiling hung structural support members; rivetless powered-chain with an I-beam or C-shaped enclosed channel travel path; powered-chain drive motor, drive train, and take-up device; and free-trolley travel path. With a multiple free-trolley arrangement, the front or lead trolley has a pusher dog, hold-back dog, operating link, bumper, and a downward extending arm or pendant with a loop or strap, and the rear or trail trolley neck has a cam tail. Other features in common are curves, switches, and transfers; free-trolley dispatch code method or device; and controls and safety devices. Unique Characteristics of the Overhead Towveyor The overhead-powered towveyor in-house pallet transportation method has several unique characteristics: use of only the multiple free-trolley arrangement, lead or front trolley bar with a pendant or arm with a loop or strap that extends downward toward the finished floor, endless closed-loop rivetless powered-chain travel path



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and free-trolley travel path, four-wheeled tow carts with a rigid tow mast that has a T-shaped end or nonpowered pallet truck with a T-shaped handle, nonpowered fourwheeled pallet carrying tow vehicle that travels over the finished-floor surface travel path, tall floor stands or ceiling-hung structural support members, two vehicle pickup and delivery station areas, and controls and safety devices. The first unique feature of the overhead-powered towveyor pallet transportation method is the tow cart’s or pallet truck’s overall length, which requires the towveyor method to use multiple free trolleys to pull one tow cart or pallet truck over the finished-floor travel path. With multiple free trolleys as the overhead towveyor pallet transportation method, the free trolley has several characteristics. The multiple free trolleys are connected by an articulating load bar. The front or lead free trolley’s neck has a pusher dog, hold-back dog, operating link, and bumper. The rear or trail free trolley’s neck has a cam tail. With the multiple free-trolley components and arrangement, as required by the free-trolley travel-path traffic situation, the free-trolley components function on the path as a queued or accumulated or held free-trolley or as a transport trolley. The second unique characteristic of the overhead-powered towveyor transportation method is that the lead or front free-trolley load bar has a pendant, carrier arm, or extension. From the free-trolley load bar, the pendant extends downward toward the finished floor. Attached to the pendant end is a loop or strap that hangs downward toward the finished floor. The pendant loop or strap has several unique characteristics. The diameter of the loop or strap has sufficient open space so an employee can easily place the loop or strap over the tow-cart mast that has a Tshaped end or a pallet truck T-shaped handle. When the strap or loop is not connected to the tow cart mast or pallet truck T-shaped handle end, the strap or loop is considered a straight piece of material. This feature minimizes unintentional cart hook-ups or accidents and requires an employee to connect and fasten the loose end of the strap or loop to the end that is attached to the pendant. A two-cart system with a rigid mast as the towveyor pallet vehicle has a Tshaped end as the pallet-carrying vehicle. With this towveyor vehicle, the free-trolley pendant whose loop or strap extends downward has sufficient depth to meet two objectives: (1) the pendant depth does not strike the tow-cart mast, and (2) an employee can easily transfer or hook the pendant loop or strap over or from the tow cart’s rigid tow mast. For a pallet truck with a T-shaped handle as the pallet-carrying vehicle, the free trolley pendant whose loop or strap extends downward has sufficient depth to ensure that an employee can easily transfer the pendant loop or strap over or from the pallet truck T-shaped handle and hook the strap or loop loose end to the pendant end. The third unique design feature of the overhead-powered towveyor transportation method is the endless closed loop rivetless powered-chain travel path and the freetrolley travel path. The powered overhead towveyor transportation method has two unique operational features: (1) a free trolley with a pendant that extends downward with a strap or loop, and (2) a four-wheeled tow cart or nonpowered pallet truck that must be returned to home base or the dispatch location or towed to another travel path activity location. With these two operational features, most overheadpowered rivetless powered-chain travel path and free-trolley travel paths have several


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design parameters. The outbound and inbound travel paths must be adjacent to each other. After the last free-trolley travel-path delivery station and prior to the freetrolley travel-path dispatch station, these travel paths must complete a closed loop travel path. These two travel paths require a clear travel-path window between the finished-floor surface and the bottom of the free-trolley travel path. The four-wheeled two-cart system with a rigid mast that has a T-shaped end or a nonpowered pallet truck with a T-shaped handle is considered the fourth unique component of the overhead powered towveyor. The four-wheeled tow cart with a rigid mast that has a T-shaped end and a nonpowered pallet truck with a T-shaped handle are considered the pallet-carrying vehicles. These pallet vehicles serve several purposes. The vehicle provides support for the combined tow vehicle and pallet weight. The tow vehicle’s wheels and the finished-floor surface ensure a low coefficient of friction or drag as the tow cart or pallet truck is pulled over the travel path. The tow vehicle’s front wheels are swivel casters or wheels and the rear wheels are rigid casters or wheels to ensure a low coefficient of friction or drag as the tow vehicle travels through the travel tow-cart path curve. The mast that has a T-shaped end or a pallet truck with a T-shaped handle provides the means for connection to the overhead powered towveyor free trolley pendant strap or loop. If the overhead-powered towveyor transportation method has a series of powered chain stops and starts, these two cart or pallet truck towing features do not ensure smooth tow cart or pallet truck stopping, and when starting, the two vehicle’s masts or handles jerk or surge. The next unique design parameters of the method is the four-wheeled palletcarrying vehicle’s finished-floor travel path. Since the pallet-carrying vehicle’s four wheels come in contact with the finished floor and the vehicle is pulled forward over the finished-floor travel path, the path has several design parameters. The palletcarrying vehicle’s four wheels and finished-floor surface have a low coefficient of friction. The travel path must be free and clear of debris, cracks, holes, and joints. The travel path is considered a high traffic aisle and is coated to minimize dust and the floor rebar is designed for the combined weight of the pallet load and cart. This is considered the vehicle’s wheel or wheel-load factor. The closed loop travel path feature requires the tow vehicles to be returned to home base. The return travel path has the same design travel-path window criteria as the outgoing or fully loaded vehicle travel-path window. The next unique design parameter is the design of the tall floor or ceiling-hung structural support members. The combined weight of the pallet and cart is assumed by the tow vehicle’s four wheels and the finished-floor surface travel path. This feature means that the tall floor structural support stands or ceiling hung structural support members have less load weight to support than the typical overhead-powered towveyor transportation method. Another unique design characteristic is the tow cart or pallet truck travel-path P/D station area. Since the method has tow carts or pallet trucks that are towed over a main travel path and a free trolley with the tow cart or pallet truck is diverted onto a delivery station spur, the P/D station spur travel-path design has three features: (1) the divert spur free-trolley travel path and finished floor is sloped to the end of the P/D spur, or the P/D station employee ensures that the diverted tow cart or pallet



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truck has cleared the main travel path and is at the end of the P/D spur; (2) there are full-line controls on the spur travel path to control the P/D station divert mechanism; and (3) the spur travel-path has a rail switch that allows an employee to transfer the free trolley with an empty or full tow cart or pallet truck onto the powered rivetless chain and free trolley main travel path. After the tow cart or pallet truck is on the divert spur, to ensure an efficient inhouse transportation method, the P/D station employee removes the tow cart or pallet truck from the divert spur. At this location, the employee removes the free-trolley pendant strap or loop from the tow vehicle’s T-shaped component and pushes the tow cart or pallet truck to the inbound staging area. As required, the employee transfers an empty or full tow cart or pallet truck to the main travel path’s in-feed line. On this in-feed line, the employee places a free-trolley pendant loop or strap onto the tow vehicle’s T-shaped component, enters the dispatch code onto the free trolley, and moves the free trolley with a tow cart or pallet truck onto the main travel path. On the powered rivetless chain and free-trolley main travel path, the free trolley with a tow cart or pallet truck waits for pickup by a rivetless powered chain pusher dog. With these operational characteristics, a towveyor travel-path P/D station has several design characteristics: (1) sufficient floor space to stage inbound tow carts or pallet trucks, (2) sufficient floor space to stage empty or outbound tow carts or pallet trucks, and (3) adequate floor space for forklift trucks to complete a pallet transfer transaction and travel from the staging area to the activity area. When the overhead-powered towveyor transportation method is compared to the other overhead-powered pallet transportation methods, the conclusions are that the former method has unique design parameters, similar operational procedures, restricted use of the finished-floor area, and the ability to transport pallets over long distances.



7

Single-Item, GOH, Carton, or Pallet Acrossthe-Dock Operations INTRODUCTION

The logistics profession’s evolution began when two skilled logisticians from Napoleon’s army wrote a textbook on logistics called The Practical Art of Moving an Army. Today, the profession is developing new logistics strategies, technologies, and methods. The most recent and dynamic innovative logistics strategy is the acrossthe-dock supply-chain logistics strategy. In the 1980s, logistics strategies were directed to improve piece movement, storage, and handling within the four walls of a distribution facility. Some companies were involved in break-bulk terminal operations that were the initial across-thedock supply-chain logistics strategies. These break-bulk terminal operation or across-the-dock method characteristics were as follows. Vendor delivery trucks or railcars were located along a rectangular-shaped facility’s long side. This facility provided a long wall that had maximum receiving dock doors plus a dock staging area. A forklift truck, in-floor powered tow line, or piece transport method and sorting method was located in the building’s middle. This middle location provided a mechanized sorting method with a sorting induction station, the sorting method travel path, and divert staging lanes, or with a powered in-floor tow line or forklift truck transportation or sorting method, sufficient space to move and stage pallets from the receiving area to the shipping area. There was a customer delivery vehicle and dock staging area along a building’s long wall. The facility’s rectangular shape provided a long wall that allowed the maximum shipping dock doors plus a dock staging area along a rectangle building’s side. The piece flow through the facility was from the receiving vehicle directly to the in-house transport or sorting method and onto the customer delivery vehicle or onto the customer-assigned shipping staging area. In the 1990s, most vendors and some retail store companies developed a global supply-chain logistics strategy. The strategy was developed due to the low labor resource costs in other countries. The low labor cost permitted the companies to maintain a price competitive position in the market. With large piece quantities entering their domestic supply-chain logistics strategy (channel of distribution) from

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various seaports and airports, many companies shifted their company logistics investment and emphasis. This new company logistics investment shift or emphasis was from the traditional piece storage and pick activities to designing and implementing an across-the-dock piece and customer-order supply-chain logistics strategy. The across-the-dock supply chain logistics strategy directed the investments and emphasis on the logistics segment receiving and shipping activities. Other logistics industry terms that are used to describe an across-the-dock method are just-in-time (JIT) replenishment, across-the-docking, cross-docking, fast response, quick response, and flow through. Your company annual logistics costs are increasing at an increasing rate. This creates pressure at an increasing rate for you to introduce an across-the-dock supplychain logistics strategy. For your company to have a cost-effective and efficient strategy, there are several design factors. The first factor is a complete understanding for the various across-the-dock piece or customer-order flow patterns and methods. From these various across-the-dock methods, you select the one that best satisfies your company objectives, handles your piece and customer-order mix and volume, and adapts to your supply-chain logistics strategy. The various logistics operational requirements include your company, vendors, and customers; the impact on your company’s various departments; the various pieces or customer-order material-handling equipment and methods; the various economic and noneconomic justification factors; and the necessary steps to implement an across-the-dock method in your supply-chain logistics strategy. With this new supply-chain logistics method, all your company vendors understand your across-the-dock method and adapt your piece and packaging design to meet your supply-chain logistics strategy requirements. You may be asking yourself why most companies are considering an across-thedock supply-chain logistics strategy. Most companies are shrinking their distribution facility sizes. The customer-order and delivery cycle time or your company customerservice standard is more compressed, such as 12 days from your vendor facility to your company customer, 7 days from your vendor facility through your distribution facility, 3 days from your distribution facility to your customer, and 2 days from the customer store area to the sales floor. It is difficult to find labor quality and quantity for the conventional store, hold, and pick distribution activities. There are high inventory carrying costs. To create sales, 26% of the retail companies’ supply-chain logistics strategies pull the piece for their stores, 40% of the retail companies’ supply-chain logistics strategies push (or allocate) the pieces to their stores or customers, and 26% of retail companies’ supply-chain logistics strategies use a combination push and pull method. There is a 10 to 15% increase in logistics employee productivity; and the method reduces the retail store space investment, which is $35 to $55 per square foot. One chapter section reviews the various piece across-the-dock handling options that are available for implementation in your distribution operation to handle your across-the-dock single item, flat wear, garments on hangers (GOH), master carton, or pallet mix and volume.


Single-Item, GOH, Carton, or Pallet Across-the-Dock Operations

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An across-the-dock operation is a company strategy to establish a new supplychain logistics strategy and to become more dynamic more and competitive. In the past, to handle flow-through pieces many retail companies have used a private trucking company break-bulk terminal, their own company break-bulk terminals, or their own company’s conventionally designed store and hold distribution facilities. These facilities were designed to receive large piece quantities that were separated by each retail store (customer) location and transferred to the appropriate customer shipping dock staging area or directly onto the customer delivery vehicle. If held in the shipping staging dock location, at the assigned time the pieces were loaded onto a customer delivery vehicle for transport to the customer location.

ACROSS-THE-DOCK DEFINITION An across-the-dock operation is considered a supply-chain logistics strategy method that requires minimal piece storage area and customer-order pick or fulfillment activities. The across-the-dock operation moves individual customer pieces along with other customer pieces directly from the receiving dock area, through the facility in-house transport and sorting area, and into the individual customer shipping dock staging area or directly into the individual customer delivery vehicle. In this operation, the preferred piece characteristics are as follows: transport on a powered conveyor method; exterior surface with a human- and machine-readable code that permits a bar-code scanner, radio frequency (RF) scanner, or employee to read the customer address; and sorting travel path with a microcomputer to control divert devices. The divert device sorts the appropriate piece from the sorting method onto the customer-assigned shipping lane for transfer onto the customer delivery vehicle. Per your across-the-dock operation, prior to the sorting method, the pieces flow through a price ticketing activity. The price-ticketing activity has an employee or machine place a retail price ticket onto each retail piece. An across-the-dock operation method is considered for implementation in most retail store distribution operations’ supply-chain logistics strategies or any company channel of distribution that pushes pieces through the company supply-chain logistics strategy or channel of distribution.

OBJECTIVE OF AN ACROSS-THE-DOCK OPERATION When using an across-the-dock operation for a distribution company supply-chain logistics strategy, there are two objectives. The first is to reduce the days that are required for pieces to flow from the vendor, through the company supply chain logistics strategy, and onto the company or customer retail sales floor. The second objective is to reduce the company distribution or logistics operating costs by reducing inventory carrying costs and piece handling costs. If a company uses its conventional store-and-hold distribution method and the company delivery vehicle to handle both the across-the-dock pieces and conventional customer orders, an across-the-dock operation achieves a low logistics operating cost.


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The future for retail-store piece distribution is to organize an across-the-dock supply-chain logistics strategy that handles single item, flat wear, GOH, master cartons, or pallets. In an across-the-dock supply-chain logistics strategy, the vast piece quantity is handled by the standard distribution activities for receiving and quality control, customer sorting, ticketing and packing, transport and sorting, manifesting, loading and shipping, and truck delivery.

WHAT IS REQUIRED To maximize your company’s return on investment and provide the best customer service with an across-the-dock operation, your company develops several segments for an across-the-dock supply-chain logistics strategy. These are to ensure that your company vendors meet your strict piece quality and quantity standards, there is a good information paper or data flow system, there is an excellent piece flow pattern through your facility, there is a good material-handling layout at the receiving and shipping docks, the required customer delivery vehicle is at the shipping docks, and there are accurate and on-time customer orders. When a company develops an across-the-dock operation, in most applications the operation is combined with the conventional (store-and-hold) customer distribution operation. This conventional store-and-hold inventory flow pattern combined with the across-the-dock piece flow method increases the return on investment, provides maximum service to the customers, and requires that your vendors and customers increase their involvement in your supply-chain logistics strategy. The areas of vendor and customer involvement are to have vendors ensure high quality pieces, correct SKUs, and exact quantities; to have a smaller piece quantity per individual customer-order; to have vendors ensure that the piece exterior has the proper customer discrete identification; to ensure that each piece is identified with a code that is used by all segments in your company supply-chain logistics strategy and has the proper price tickets; and to ensure that the pieces are conveyable SKUs.

WHO FROM YOUR COMPANY IS INVOLVED As your company supply-chain logistics strategy or channel of distribution becomes involved in an across-the-dock program, the distribution operation establishes a good communication network and becomes the communications center among the purchasing department, the vendors, the distribution and quality control departments, the transportation department, and the customers. After your distribution company has decided to undertake an across-the-dock operation strategy, the strategy options are to have a pass-through strategy that handles pallets or master cartons, and to handle large small-item, flat wear, or GOH stock-keeping unit (SKU) quantities that at the across-the-dock facility are broken down into single items or master cartons. These individual items are price ticketed and distributed into smaller quantities that complete the customer orders. In a master carton or pallet load across-the-dock method, the purchasing department is required to send the vendor company the total piece quantity that is required



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for the company sales program. If the across-the-dock operation has multiple facilities, the purchase order (PO) is for the entire company sales program, but the PO is separated into required piece quantities or subtotals for each across-the-dock facility. Each regional distribution facility or across-the-dock facility becomes a break-bulk or terminal segment in the company across-the-dock supply-chain logistics strategy. Each regional facility is responsible for receiving, separating, or sorting the pieces by the quantity that accommodates each region’s customer orders.

THE VENDOR RESPONSIBILITY In an across-the-dock supply-chain logistics strategy, your company vendor responsibilities are to provide quality pieces that are per your piece PO, in the exact quantities, and with the customer discrete address on each piece’s exterior surface and appropriate location. This feature requires your company vendors to place the correct code and to have the piece description on each piece’s exterior surface. These factors minimize the piece flow time through your across-the-dock supply-chain logistics strategy and minimize your company distribution expenses, but slightly increase your company’s cost of goods sold. An option has the vendor responsible for providing pieces with a piece description on each piece’s exterior surface and no customer discrete identification. With this option, it requires your company employee at the receiving dock to apply the appropriate code to each piece’s exterior surface. This feature slightly increases the piece flow time through your company supply-chain logistics strategy, and label cost is a distribution expense, not part of the cost of goods.

PIECE OR CUSTOMER IDENTIFICATION The piece or customer identification is a key component to an efficient and costeffective across-the-dock supply-chain logistics strategy at each across-the-dock facility. The piece or customer identification activity has a human-readable, machinereadable, or human- and machine-readable code on each piece’s exterior surface. For an across-the-dock operation to obtain the optimum results from its in-house transport and sorting method, there are several piece identification factors. The first factor is that the identification is placed in each appropriate location on each piece’s exterior surface. The location allows each reader, bar code, or employee in your company supply-chain logistics strategy to read each piece’s discrete identification. The second factor is a discrete number or address for each customer. The third factor is that the identification is readable at each supply-chain logistics strategy or channel of distribution segment, which includes vendors, each company facility, and customer location. In an across-the-dock piece flow strategy, the codes to discretely identify your piece’s exterior surface are (1) human-printed and human-readable and machineprinted and human-readable (Figure 7.1), (2) machine-printed and machine-readable, or (3) machine-printed and human- and machine-readable (Figure 7.2). All code types have human-readable price tags included on the label face.


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FIGURE 7.1 Human-readable labels. (From Mulcahy, D.E., Materials Handling Handbook, McGraw-Hill, 1999. With permission.)

FIGURE 7.2 Human- and machine-readable label. (From Mulcahy, D.E., Materials Handling Handbook, McGraw-Hill, 1999. With permission.)

HUMAN-READABLE IDENTIFICATION The minimum vendor exterior piece or master carton markings are the piece description, which includes size, color, and SKU description, and the customer discrete identification. With only piece description, the company receiving department verifies the piece destination or, as required, marks or applies a printed customer address label on each piece exterior; verifies the piece quantity; and transfers the discretely identified piece onto the in-house transport and sorting method for sorting onto the customer shipping dock staging area or directly onto the customer delivery vehicle. This customer discrete identification is a man- or machine-printed label that is human- or machine-applied to each piece or master carton exterior surface.



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The disadvantages are the increased errors, low employee productivity, need for 1 to 2 days to handle a vendor truck delivery, large receiving and shipping dock areas and additional dock doors, a large employee number, reduced mechanized conveyor transport and sorting method payback, unclear markings, low piece volume, and employee injuries. The advantages are low piece cost savings from vendors not marking each piece, a wide product mix, and no investment.

MACHINE-READABLE IDENTIFICATION The second code is the machine-readable code. In most across-the-dock supplychain logistics strategies, the piece is handled by a human who controls a handheld bar-code scanner or the piece travels past or under a fixed position (fixed beam, waving beam, or moving beam) bar-code scanner. The various codes are bar code, RF tag, prongs, and optical characters. A mechanical device or a bar-code scanner reads these codes. The unique feature is that without the scanning device an employee does not interrupt the code. During a reader failure or electrical power problem, and to avoid an across-the-dock method total shutdown, most companies involved in an across-the-dock supply-chain logistics strategy use a human- and machine-readable code.

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If your across-the-dock operation piece is identified with a machine-printed humanand machine-readable label that includes the customer sorting or discrete identification, your operation is able to use a manual or mechanized encode and sorting method. The encode device, microcomputer, tracking device, and divert device ensure that each customer piece was received, transported, transferred, and manifested to the assigned customer delivery vehicle. The most frequently used human- and machine-readable identification method is a bar-code label. A human- and machine-readable bar-code label’s components are a label face that has black bars on a white background, with white spaces between the black bars; a label face with black or colored human-readable alphabetic characters or numeric digits on a white background; and, when the self-adhesive backing is removed from the label face, a label face that sticks to a piece’s exterior surface. In the manual bar-code scanning system, your employee physically receives, moves, sorts, and manifests each customer piece. With the manual method, an employee uses a handheld bar code scanning device to verify piece quantity receipt and to manifest each piece or discrete identification. The disadvantages are the low employee productivity, need for 1 or 2 days to handle a truck load, large receiving and shipping dock areas and additional dock doors, large employee number, potential employee injuries, and investment in barcode scanners and a computer system. The advantages are a medium piece volume, a wide piece mix, accurate information, human-readable markings, and the ability to be used on a mechanized conveyor method. With a machine-printed human- and machine-readable label as the customer discrete number or address on each piece, as the piece travels over the conveyor travel path, the across-the-dock operation uses a conveyor sorting and transport


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FIGURE 7.3 Bar codes one side. (From Mulcahy, D.E., Materials Handling Handbook, McGraw-Hill, 1999. With permission.)

method. With a piece or master carton on the conveyor travel path and with a human- and machine-readable label in the proper orientation of travel on the conveyor travel path, the piece or master carton is transported past an automatic bar-code scanning device. This device reads the bar-code label and sends through the communication network the piece or master carton discrete information to the microcomputer (Figure 7.3 to Figure 7.5). This information is required for the receiving department recordkeeping and receipt preparation. The conveyor method microcomputer and conveyor (sorting) method tracking device requires the discrete information for the proper carton sorting. As the master carton or piece travels on the conveyor travel path, the microcomputer or tracking device tracks the piece or master carton. When the piece or master carton arrives at the appropriate location, the controls activate the appropriate divert device to transfer the piece or master carton from the sorting conveyor travel path onto the appropriate customer loading conveyor travel path. The automatic bar-code scanning device is a fixed-position fixed beam, fixed-position waving beam, or fixed-position moving beam scanner that reads the bar code label on the piece or master carton exterior surface. With this across-the-dock conveyor method, it is understood that a handheld bar-code scanner and a nonconveyable transport and sorting method handle nonconveyable master cartons. If a check weigh-scale method is part of the automatic bar-code scanning method, each vendor master carton quantity is checked for its weight. With this, as the carton is individuated and travels over the conveyor travel path, a bar-code scanner reads the carton discrete label. The bar-code data are sent to the microcomputer, which looks up the previous or downloaded host computer projected carton weight. With the carton momentarily stopped on the in-line scale, the scale sends the actual carton weight to the microcomputer. The microcomputer compares the carton’s actual weight to the carton’s computer-projected weight. If the carton’s actual weight



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FIGURE 7.4 Multiple bar codes top and side. (From Mulcahy, D.E., Materials Handling Handbook, McGraw-Hill, 1999. With permission.)

matches the downloaded weight or is within a predetermined weight variance, the carton contents are verified as accurate and the carton continues travel on the conveyor travel path. If the carton actual weight does not match the downloaded weight and is out of the allowed variance, the carton is diverted from the conveyor travel path onto a problem conveyor travel path. On the travel path, an employee verifies the carton contents, updates the inventory files, and returns the carton to the conveyor travel path; the carton then continues travel on the conveyor travel path. The disadvantages are the need to use a bar-code scanner on the conveyor transport and sorting method; for nonconveyable SKUs, the need to use a handheld bar-code scanner and manual scale method; capital investment; and, with the check weigh-scale system, the need to develop and refine the system. The advantages are a high piece volume, the need for 1 or less days to move a vendor delivery truck through a facility, a smaller receiving and shipping dock area and fewer doors, the fewest employees, and the ability to handle volume surges and peaks.

ACROSS-THE-DOCK FORMATS AND PIECE FLOW METHODS When you consider an across-the-dock piece flow method for your company supplychain logistics strategy, according an article by J. Eric Peters in the WERC Sheet for


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FIGURE 7.5 Bar-code orientation. (From Mulcahy, D.E., Materials Handling Handbook, McGraw-Hill, 1999. With permission.)

September 1995, there are three across-the-dock piece flow patterns for your piece flow from a vendor facility to your customer delivery address. The three crossdocking patterns are manufacturing, distribution center, and terminal. Within each cross-docking pattern, the piece characteristics are unsorted and unlabeled, unsorted and labeled, and sorted and labeled. Prior to an across-the-dock piece flow pattern selection and implementation for your company supply chain logistics strategy, you answer your design parameters or considerations. These are included in another section in this chapter.

MANUFACTURING CROSS-DOCKING METHOD The first cross-docking piece flow pattern is the manufacturing cross-docking method. Per Peters, the “current manufacturing cross docking” method involves moving finished goods or pieces right off the production line onto a waiting customer delivery truck. Most manufacturing cross-docking methods have the pieces staged for later piece loading and shipping to the customer. Many logistics professionals recognize the manufacturing cross-docking piece flow method’s similarity to a vendor consignment piece distribution method. With a vendor consignment piece flow method, a vendor manufactures and holds your customer pieces at the manufacturing facility until the customer orders the pieces. After customer-order receipt, the vendor releases the customer’s ordered pieces for



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direct delivery to the customer or for delivery to your facility for cross-docking onto a customer delivery truck.

DISTRIBUTION CROSS-DOCKING METHOD The second cross-docking piece flow format is the distribution center cross-docking piece flow method. J. Eric Peters separates distribution center cross-docking methods into three piece flow categories: current and active, current same day, and future. The current and active across-the-dock piece flow method has your across-thedock operation unload the pieces from a vendor delivery truck, verify the receipt, and transfer the pieces onto a customer delivery truck. The current and active across-the-dock piece flow method characteristics are the smallest size building; a minimal piece queue area, which means a lower material-handling equipment investment; from the vendor’s labeled and sorted pieces; the maximum number of customer delivery truck dock door locations; and the greatest potential not to optimize a customer delivery truck utilization that creates a higher transport cost per piece. The second distribution center across-the-dock piece flow pattern is the current and same day piece flow pattern. According to J. Eric Peters, the current and same day across-the-dock piece flow pattern means that pieces are unloaded from a vendor delivery truck; the receipt is verified by your operation; and the pieces are staged or held on a conveyor network or in a floor shipping staging area and, later that same day, released to a customer delivery truck. The current and same day piece across-the-dock flow pattern characteristics include a large facility and a piece queue area or staging area for each daily customer-order. This feature means a higher material-handling equipment investment and building investment. This pattern handles all piece types, including unlabeled and unsorted pieces, labeled and sorted pieces, and a combination of both. It optimizes a customer delivery truck utilization which means a low transport cost per piece. The third distribution center across-the-dock piece flow pattern is the future across-the-dock piece flow pattern. With the future pattern, the various pieces for each customer are unloaded from a vendor delivery truck, the receipt is verified, and the pieces are transferred to a shipping staging area. After these held customer pieces become current and active pieces, they are released from the staging area and transferred onto a customer delivery truck.

TERMINAL CROSS-DOCKING METHOD According J. Eric Peters, the third across-the-dock piece flow format is the terminal cross-docking format. With the terminal across-the-dock format, there are several company distribution facilities that are located close to a vendor facility that manufacturers pieces. At a company facility, these pieces are received and consolidated onto one delivery vehicle and are shipped from the company distribution facility to each company terminal’s across-the-dock facility. At the facility, from the receiving delivery vehicle these mixed pieces and customer orders are unloaded, verified,


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sorted or separated, and combined in a customer staging area, or are loaded directly onto a customer delivery truck.

VARIOUS ACROSS-THE-DOCK PIECE CHARACTERISTICS When a company becomes involved in an across-the-dock operation, your company across-the-dock strategy piece classifications are unsorted and unlabeled, unsorted and labeled, and sorted and labeled. An unsorted piece means that a pallet contains pieces for several customers. A sorted piece means that a pallet contains pieces for one customer. An unlabeled pieces means that each piece’s exterior surface has no customer discrete identification or code. This means that a piece is sent to any customer. A labeled piece means that the piece’s exterior surface has a customer discrete identification code. This means that a piece is assigned to a specific customer.

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The first across-the-dock piece classification is unsorted and unlabeled pieces. Unsorted and unlabeled pieces are considered vendor pieces that have been ordered by several customers. Each piece does not have a customer discrete identification label on the exterior of the carton. With unsorted and unlabeled pieces, these pieces are unloaded from the vendor delivery truck and quantity verified, your company labor and labels are applied to each piece per the customer-order requirement, and the pieces are separated or sorted by customer name and mixed with other customerordered pieces. These pieces are held in an assigned customer holding area or are loaded directly onto the customer delivery truck. The unsorted and unlabeled piece characteristics are a large employee number, material-handling and labeling equipment investment, a large dock area, and the longest time for a piece to flow through a company supply chain logistics strategy or an across-the-dock facility.

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The second across-the-dock piece type is the unsorted and labeled across-the-dock piece. The unsorted and labeled across-the-dock piece characteristics are that a piece group was ordered by several customers and that each piece has a customer discrete address label on its exterior surface. At an across-the-dock facility, these pieces are sorted by customer discrete order number. After sorting, the piece are loaded on pallets with other pieces that are discretely identified with the customer name or loaded on a customer delivery vehicle. The advantages are fewer employees; no labeling equipment investment, but a manual or mechanized conveyor transport and sorting method; a small dock area; a small-sized facility; a shorter time for the pieces to flow through your across-thedock supply-chain logistics strategy or segment; and a slight increase in the cost of goods sold due to the vendor applying labels to the pieces or master cartons.



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The third across-the-dock piece classification is the sorted and labeled across-thedock pieces. These pieces are the preferred pieces for an across-the-dock supplychain logistics strategy. These pieces are sorted by the vendor with a customer discrete identification per the customer-ordered piece quantity. On each piece’s exterior surface is the customer discrete identification. These sorted and labeled pieces are secured onto a pallet or slip-sheet and each pallet is properly identified with the customer discrete name, number, or address. At your facility, from a vendor delivery truck, the pieces are unloaded, verified, and placed onto the assigned customer shipping staging area, or are loaded directly onto a customer delivery truck. This method does require sufficient dock space and adequate and direct piece transport aisles between the receiving and shipping areas, and investment in dock area equipment such as dock lights, levelers, and forklift trucks with the proper set of forks or attachment. The method handles a wide piece mix. An unloading option is to off-load the pieces or master cartons from a vendor delivery truck onto a powered conveyor method for transport from the receiving dock, through a sorting method, and to the assigned customer shipping staging area or directly onto the customer delivery truck. The features are a material-handling equipment investment, a bar-code label for each conveyable SKU, piece accurate accounting and flow tracking through your company supply-chain logistics strategy and each segment, and a method to handle nonconveyable pieces. The advantages are the fewest employees; no label equipment investment and building investment; higher forklift truck and dock area equipment investment; and, with pallets, a small-size-facility due to no required conveyor transport or sorting method investment and building space. A master carton flow requires a transport and sorting method and building space. It takes a short time to flow a vendor delivery truck’s pieces through your company supply-chain logistics strategy and through each across-the-dock facility.

RECEIVING AND SHIPPING DOCK AREAS ARE MOST IMPORTANT When your distribution facility becomes involved in an across-the-dock operation, the receiving and shipping functions and dock areas become more important than storage and pick functions and areas. Included in the receiving and shipping functions and areas is the truck yard and vendor and customer delivery-truck control. This new emphasis on the piece flow through an across-the-dock facility increases the receiving and shipping dock and door number; requires larger receiving and shipping dock staging areas; and requires a sufficient number of well-designed and adequate piece travel paths from the receiving dock area, through a sorting method, to a shipping dock area. These new across-the-dock facility design factors permit a facility to handle a large vendor delivery truck number and customer delivery trucks; to unload, sort,


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stage, and load a greater piece volume through a facility; and to handle an increased customer number at a facility. With the distribution operational emphasis on the piece flow through a facility, a new across-the-dock facility is designed with separate receiving and shipping docks and doors. The other building design features are a rectangular-shaped facility that has a short travel distance from the receiving dock area, through a sorting method and to the shipping dock area; dock area equipment; truck dock guides and dock canopy; painted lines on the dock area floor to identify staging areas; sufficient floor or ceiling strength to support the imposed loads from your across-the-dock master carton transport and sorting method; and a low ceiling height. With the building design and across-the-dock operational or functional activity criteria, the receiving and shipping dock and door options are to be located directly opposite each other on a rectangular-shaped building’s opposite long sides, to be located on the building’s corners on opposing long sides, and to be located at the building’s corners on the same side. The factors that determine the across-the-dock receiving and shipping dock and door location are the site or building physical dimensions; the vendor delivery truck yard space in the building front; per day, the vendor delivery-truck number and the associated unloading times and across-the-dock piece type with its value-added activities; per day, the customer delivery-truck number and associated loading times; and the piece flow through an across-the-dock facility. The across-the-dock piece flow pattern to load pieces onto a customer delivery truck requires the greatest dock number but a smaller building size. This feature is due to less required receiving and shipping dock staging areas. The across-the-dock piece flow pattern to temporarily hold and stage pieces for a customer delivery truck requires the lowest dock number but a large building size. This feature is due to larger required receiving and shipping dock staging areas. In an across-the-dock operation, a material-handling method transports the pieces from the receiving dock area, sorts the pieces onto the correct customer location, and moves the pieces to the appropriate customer staging area or directly onto a customer delivery truck. This piece transport and sorting method is a manual or mechanized transport and sorting method. If the across-the-dock receiving department handles master cartons or pallets, the receiving department’s objective is to unload a vendor delivery vehicle on schedule and to verify that the total delivered piece quantity matches your company total PO quantity. The detail objective of a master carton across-the-dock operation is to verify that the actual customer quantity matches the PO carton quantity. If there is no match, the receiving and purchasing department completes the necessary individual customer piece adjustments to ensure that each individual customer receives a reasonable carton quantity. Per J. Eric Peters, the three across-the-dock piece flow methods of a manufacturing and distribution center and terminal cross-dock method each have unique receiving and shipping dock locations. The manufacturing cross-dock method has the piece flow from the building center or side. This piece flow is from the manu-



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facturing area through a customer outbound staging area into a customer delivery truck, or from the manufacturing area directly onto a customer delivery truck. The distribution center across-the-dock method options are the current and active distribution center cross-dock method, the current and same day distribution center cross-dock method, and the future distribution center cross-dock method. The terminal across-the-dock method has the current and same day across-the-dock method. The three distribution center across-the-dock methods and piece flow methods common characteristics are as follows: the shipping function and receiving function are separated and located on the facility’s same side or are located on opposite facility sides, and the facility has sufficient floor space or has an elevated conveyor travel path for transport, staging, and piece queue. The terminal-dock piece flow method’s receiving dock and shipping dock locations are located and separated on one facility wall or located on opposing facility walls.

RECEIVING AND SHIPPING DOCK PROJECTIONS AND OTHER CONSIDERATIONS The across-the-dock piece method requires vendor delivery trucks spotted at the correct receiving dock and at the appropriate time. The incremental cost for an additional receiving dock is a small investment when compared with the logistics operational costs that are associated with the increased transport and sorting method cost, low employee productivity, poor piece flow, late customer delivery, or inability to unload critical pieces on time. There are several design parameters and operational characteristics to ensure an accurate and on-time vendor and customer delivery-truck movement within the truck yard and to have a cost-effective and efficient vendor delivery-truck unloading activity and customer delivery-truck loading activity. These factors are to project accurately the required vendor and customer delivery truck numbers and associated unloading and loading times; to design the appropriate receiving and shipping dock staging areas; to provide easy vendor delivery-truck access to the truck yard, the best truck traffic-flow pattern within the truck yard, and at each dock location sufficient truck yard space (Figure 7.6); to provide an adequately designed delivery vehicle holding area; and to design and equip the vendor and customer delivery truck docks.

REQUIRED TRUCK DOCK NUMBER The first vendor and customer delivery-truck design factor is to determine the required inbound and outbound delivery-truck dock number that is associated with time to unload a vendor or to load a customer delivery truck. For an across-the-dock operation the methodologies to determine the required receiving and shipping dock number have slightly different factors. The vendor delivery-truck dock number at an across-the-dock facility is determined by (1) manual calculation, (2) manual simulation, or (3) computer simulation.


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FIGURE 7.6 Truck flow patterns: (a) load and unload in the truck yard; (b) finger dock; and (c) in the facility. (From Rite Hite, Milwaukee, WI. With permission.)



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Manual Dock Calculation Method The manual dock-calculation method for the vendor delivery-truck dock number requires several factors that are easily determined or calculated by your receiving department. These factors are to tabulate for a time period, which is a week or month, the daily truck number for a peak and average day plus growth; to calculate the vendor delivery-truck arrival time and frequency; to determine the load type on the delivery truck, which is floor stack, slip-sheet, four-wheeled cart, stacking frame, and pallets; to estimate the time that is required to unload and stage the pieces on a receiving dock or to unload the pieces onto a powered conveyor transport method; to identify and determine the vendor and customer delivery-truck type, such as oceangoing container, back-haul trailer, common carrier, Federal Express, United Parcel Service, or U.S. Postal Service; to estimate the material handling equipment or pieces with attachments or unloading conveyors that are used in the dock area; to include the time for coffee and lunch breaks, truck maneuvering in the truck yard, the truck driver signing documents, and the time to break or attach a seal or lock to a delivery truck; and to determine a reasonable safety factor such as 20 to 25%. Provide a sufficient receiving dock number to unload the maximum number of vendor delivery trucks that arrive or are scheduled for unloading at an across-thedock facility. A formula to determine the receiving truck’s dock number is the vendor delivery-truck number per year multiplied by the hours that it takes to unload a delivery truck divided by the total work hours per year. When designing the receiving number dock, add at least one dock space for each of the following: (1) a ramp or dock lift to permit forklift truck travel between the dock level and the ground level, (2) a maintenance dock with a high door, (3) trash, (4) paper bales, and (5) express mail and regular mail. Manual Dock Simulation A second method to determine your receiving dock number is the manual docksimulation method. This method projects the number of receiving docks that are required for the various vehicle types that deliver pieces to your present facility. The data that are required for a manual delivery-truck dock simulation is as follows. The first item, for an average workday, is the vendor delivery-truck number that arrives at your facility. This includes the load type, which is floor stacked or separated into units, and the vendor delivery truck or container rear bed heights. The second item is the workday time that the vendor delivery truck arrived at your facility, and the third is the hours that each vendor delivery truck was at a facility dock. This time includes truck spot, driver signing the delivery document, and departure time. The fourth item is the standard and special dock positions, and the fifth is your company’s anticipated growth rate and peak activity factor. With these data, you have the necessary information to perform a manual dock simulation for your existing or proposed receiving dock area. The manual dock simulation shows dock utilization per hour, the total available dock (work) hours for one week or day, and the receiving dock number that is required to handle your


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projected vendor delivery-truck activity. This is based on the your company’s previous delivery-truck receiving experience and company receiving policy. This policy is that your company provides a truck dock for every vendor delivery truck as it arrives at your facility or your facility is designed with a fixed dock-position number. With the latter arrangement, if a vendor delivery-truck arrival number exceeds your vendor delivery dock-position number, your across-the-dock operation has a vendor delivery-truck number that is sent to the temporary vendor deliverytruck holding area. A manual vendor delivery-truck dock simulation shows you how to improve your present vendor delivery dock operation or assignment, shows the requirement to develop a vendor delivery-truck arrival schedule for better vendor delivery-truck dock utilization, and shows the vendor delivery-truck dock number that is required for a proposed across-the-dock facility. Manual Delivery-Truck Dock Simulation Steps To perform a manual vendor delivery-truck dock simulation, you require the previously mentioned vendor delivery truck information plus other receiving delivery truck activity data. The other data include a delivery-truck dock simulation form that shows the delivery truck docks along the page top, vendor delivery-truck number that arrived at the facility per time slot or period, the work hours per a day in 15-minute intervals, and the number and time lengths for employee coffee and lunch breaks. The vendor delivery-truck dock simulation steps are as follows. For each vendor delivery truck, the delivery-truck arrival time at the facility is entered under the truck arrival column. For each delivery truck, under the receiving dock column and in the appropriate square, enter the time that the vendor delivery truck was assigned to the receiving dock. Fill in the squares under the appropriate receiving dock that represents the delivery-truck unloading time. Remember that coffee breaks and lunch breaks represent delivery-truck dock occupancy time, but the delivery-truck unloading activity does not actually occur. As other delivery trucks arrive at the facility the other docks become occupied with delivery trucks. If a new delivery truck arrives at the facility and all existing docks are occupied by delivery trucks, the new delivery truck is assigned to the delivery-truck temporary holding area until a dock becomes available. When a dock is available, the oldest delivery truck from the holding area is assigned to the available dock and you follow the previously mentioned steps. Computer Simulation of Dock Operations When you use a computer dock simulation to design your across-the-dock deliverytruck receiving operation, you provide the same receiving delivery-truck activity, vendor delivery-truck volume, employee productivity, dock number, and other dock area design and operational information that was mentioned in the section for the manual dock calculation and manual dock simulation. After these receiving deliverytruck data are entered into the computer, the computer program projects each receiving delivery-truck dock utilization, required or future dock number, and other dockarea design data.



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The advantage of a computer simulation is that it is dynamic. Rather than inputting static average values for all the variables, in a dynamic simulation each variable has an input distribution based on the actual or projected data. The interaction of the high-end values for some variables against the low-end value of another most always will yield a different result than a static simulation. Bottlenecks that otherwise would not be apparent in a static simulation with average values will show up in the design. The more complex the design, the more likely a simulation will prove valuable to the final outcome.

REQUIRED NUMBER

OF

SHIPPING

OR

CUSTOMER DELIVERY-TRUCK DOCKS

When you are required to determine the required customer delivery-truck dock number for an across-the-dock operation, the customer delivery-truck dock number is a key factor that determines the required customer delivery-truck dock number. If your across-the-dock operation has a direct unload and load piece flow method, the customer delivery-truck dock number is equal to the customer delivery-truck dock number for one shift. If your across-the-dock operation has the pieces placed in a customer staging area for later customer delivery vehicle loading, a method determines the customer delivery-truck dock number.

RECEIVING

AND

SHIPPING DOCK STAGING AREA

OR

CONVEYOR NETWORK

The next factor for an across-the-dock receiving and shipping operation is to provide sufficient floor space, dock staging area, or queue conveyor. The dock staging area is based on the piece type and flow method. In most across-the-dock operations, most pieces are transferred directly from the vendor delivery truck, travel over the piece transport and sorting method, and are sent directly to the customer delivery truck. When designing a dock area for an across-the-dock piece method, floor space considerations are (1) nonconveyable piece peak quantity, (2) the potential customer delivery truck no-show, (3) potential conveyor travel-path or bar-code scanner mechanical or electric power failure, and (4) insufficient employees to handle the delivery truck loading volume. If the across-the-dock operation piece flow has the pieces held for a period of time, an across-the-dock operation has a very high requirement for a shipping dock staging area. The shipping dock staging area factors are the anticipated piece quantity; the ability to utilize storage racks, portable stacking racks, or frames; and employee and customer delivery-truck availability.

DELIVERY TRUCK ACCESS

TO THE

TRUCK DOCKS

The next important factor for the receiving function is the vendor and customer delivery-vehicle access (entrance) and exit to your facility’s truck yard. This is a factor that determines the receiving dock locations. At a large across-the-dock facility that is located on a site with sufficient land, the vendor delivery-truck access is designed to improve a delivery truck’s flow through the truck yard and reduce accidents.


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FIGURE 7.7 Truck-yard vehicle patterns. (From Rite Hite, Milwaukee, WI. With permission.)

A well-planned truck access road allows vendor or customer delivery trucks to be driven forward from the public highway into the truck yard safely, rapidly, and with minimal vendor delivery-truck maneuvering. The exit road permits the vendor or customer delivery truck to be driven forward from the truck yard onto the public highway. To permit good vendor or customer delivery-truck flow in the truck yard, the access road is at least twice the longest vehicle (tractor and trailer combination) length. Across-the-dock facilities have separate traffic lanes for a truck yard’s entrance and exit. Between the public road and truck yard, the vendor or customer delivery truck passes through a security gate and past a security station or guardhouse. The security guard ensures that only authorized vehicles are allowed onto the company property, that the delivery truck has arrived at the correct address and contains pieces that are assigned to the company facility, that the seal is not broken, and that the delivery truck’s arrival time is logged. The security guard notifies the receiving department that a vendor delivery truck has arrived at the facility. A receiving employee notifies the security guard to direct the vender delivery-truck driver to drive the vehicle to an assigned receiving dock or vendor or customer delivery truck-yard holding spot. The vendor delivery-truck drivers are on the tractor cab left side, and the vendor or customer delivery-truck traffic flow around the facility is in a counterclockwise pattern (Figure 7.7). A counterclockwise pattern provides the truck driver with clear visibility while driving the truck through the truck yard or backing the truck up to a receiving dock. When a truck driver backs up to a receiving dock from a clockwise traffic-flow pattern and sits on the tractor’s left side, there is low productivity due to the “blind side” or difficulty spotting a truck at a truck dock. In accordance with the site configuration, local codes, or architectural requirements, normally the delivery-truck receiving docks are located in the rectangularshaped building’s rear or side and the vendor delivery truck is driven to the rear or to the appropriate building side. For a delivery vehicle load with a 40,000-pound capacity traveling on the service road and truck yard, the vehicle travel path has 9 inches minimum of crushed gravel,



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5 inches of asphalt, proper lighting, highway lines, and proper location or building door signage.

TRUCK-YARD TRAFFIC-FLOW PATTERNS The delivery-truck flow patterns in a truck yard or service road options are (1) oneway truck yard and service road and (2) a two-way truck yard and service road. In the one-way truck-yard traffic pattern, the across-the-dock facility is surrounded by the service road and truck yard. In this design the service road is at least 13 feet from the building, or a dimension that allows for the longest parked tractortrailer combination plus 13 feet. The maneuvering area extends outward from the delivery-truck dock. For an employee walkway adjacent to the truck traffic lane, the width is wider than this combined service road and tractor-trailer dimension by at least 4 feet. Disadvantages are a necessity for increased service road construction and additional land investment. The advantages are better delivery-truck flow and improved truck-yard safety. The two-way truck-yard traffic pattern allows the vendor delivery trucks to travel in both directions between the guard station (entrance-exit) and the delivery-truck dock. The method does not require the service road to surround the facility, but requires at least the longest tractor-trailer combination length and maneuvering area and a 26-foot-wide truck lane. An employee walkway requires an additional 4 feet of the service road’s width. The disadvantages are decreased delivery-truck yard safety and low vehicle control. The advantage is improved delivery vehicle receiving dock spotting time.

DELIVERY-TRUCK TEMPORARY HOLDING AREA The vendor or customer delivery-truck temporary holding (waiting) area is an important feature of a truck yard. The holding area is located in a secured or fenced area. When a delivery truck arrives ahead of its scheduled dock time, the delivery truck is allowed to exit the public highway and is assigned to a temporary parking area. In the temporary parking area, the three delivery-truck parking patterns are (1) block or square, (2) 45˚ angle, and (3) back-to-back and side-to-side (Figure 7.8). The vendor delivery-truck block or square parking pattern has the delivery trucks parked on the holding area perimeter straight back against the security fence, and delivery trucks that are parked in the holding area interior are in a single row back to back. An option is to place wheel bumpers on the pavement in specific locations. These bumpers stop the truck or trailer wheels, which prevents the delivery truck’s rear from the hitting the fence. This method provides a holding area with the maximum delivery-truck parking position number but requires the widest delivery-truck turning aisle, road, or maneuvering area. The delivery trucks with rear doors that face the holding area perimeter are considered a potential security problem. The delivery trailer’s rear-door security problem is reduced with the interior delivery trailers because the delivery trucks are


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FIGURE 7.8 Truck parking arrangements for truck yard: (a) straight vehicle along perimeter; (b) angle/sawtooth pattern; and (c) straight pattern in the center. (From Rite Hite, Milwaukee, WI. With permission.)

back to back. This truck arrangement has one truck’s rear door against another truck’s rear door. In the 45˚-angle vendor delivery-truck parking pattern, the delivery trucks are parked on the holding area perimeter and in the holding area interior at a 45˚ angle to the security fence and to the truck yard middle. This arrangement provides fewer delivery truck parking positions, but a narrower delivery-truck turning aisle or maneuvering area. In the back-to-back and side-to-side method, all delivery trucks that are parked in the truck holding area are arranged in the block or 45˚ parking pattern on the holding area interior. The delivery trucks are backed up to another delivery truck’s rear door and the delivery truck’s side is adjacent to the next delivery truck. This method does reduce the delivery truck’s rear-door and side-door security problem because most delivery truck’s rear doors are blocked by another delivery truck’s rear door.

LANDING-GEAR PAD At many across-the-dock facilities, when delivery trailers are parked (or dropped) in the temporary holding area or in the truck yard at a receiving dock without being hooked to a tractor, the delivery trailer rests on its landing gear on a landinggear pad. This pad is a reinforced concrete strip that is 48 inches wide. The length is determined by the width for the total delivery-truck number and provides a solid base for the landing gear. If the pad is not provided in the truck yard, during the hot or warm weather a fully loaded vendor delivery trailer has the potential to sink below a delivery trailer’s fifth wheel and make it difficult to move the delivery trailer.



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TRUCK-YARD SECURITY The truck yard’s security features include a security fence and berm that is located on the truck yard’s perimeter. The security fence and berm combination restricts unauthorized personnel from entering the property, reduces a truck-yard view from the outside, and reduces the noise traveling from the truck yard to the neighbors in the area. Cameras view the parked delivery vehicles and docks. The camera view is transmitted to screens in a guardhouse or dispatch station. Adequate lighting must be provided in the truck yard and along the building’s perimeter. There is a guard and dispatch station and a security guard on a mobile vehicle that travels through the truck yard. The guard and dispatch station maintains the company truck-yard policies and procedures, stops all vehicles and personnel as they enter the truck yard to verify that the vehicle or person has arrived at the correct location, and with direction from the receiving department assigns the delivery vehicle to a truck-yard spot. The station also ensures that as the delivery vehicle exits the truck yard there are no unauthorized pieces on the vehicle and that the truck is properly sealed with an appropriate discrete numbered seal. Other truck-yard factors that render the truck yard more efficient and safe area are clear and easy-to-read dock-door identification and stripping truck-yard parking spots, traffic lines and arrows, speed and stop signage, maps and facility identification, truck dock guides, and guardrails and bumpers.

DELIVERY-TRUCK CANOPY An across-the-dock facility focus is to ensure that the delivery truck’s pieces are unloaded in an efficient method with minimal downtime. When a delivery truck is backed up to a receiving dock position, to prevent rain water or melting snow water from falling onto the dock leveler, an across-the-dock facility has a truck canopy. A truck canopy is a solid wood or metal member that is attached to the facility side wall and extends outward from the facility side. The solid member extension is slightly angled downward and extends outward by a 6- or 12-foot dimension. With a truck canopy’s outward extension over the delivery truck rear of 6 or 12 feet, the extension deflects the falling rainwater from falling through a small gap that exists between the delivery truck top and building side. When a powered pallet truck travels over a metal dock leveler with water on the surface, this is a safety concern.

DELIVERY-TRUCK UNLOADING

AND

MANEUVERING AREA

The delivery-truck unloading and maneuvering area is located along the across-thedock facility dock fronts. The unloading area is directly in each receiving dock front. During the truck unloading activity, the delivery truck is parked in this truckyard area. The truck-yard unloading area is designed for the overall length of the longest tractor-trailer combination. The minimum unloading area length is 65 feet from the facility dock edge. The area width is designed for the delivery truck’s overall width plus 3 feet on each tractor side. This overall width dimension compensates for the two side mirrors on the delivery truck. If the unloading area is paved with asphalt and delivery trailers are spotted on their landing gear pads, a 4-


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foot-wide reinforced concrete landing gear pad is installed at the required distance in front and parallel to the facility docks. The landing gear required distance is determined by your various delivery-trailer landing gear pad locations, number per truck, and delivery-trailer length. The normal location for the landing gear on an over the road delivery trailer is 10 feet behind the delivery trailer nose. The reinforced concrete landing-gear pad has sufficient strength to prevent the delivery trailer’s landing gear from sinking below the surface. The pad supports a 40,000pound load on 6-foot centers. The truck-yard maneuvering space is the space that is required to have the longest overall tractor-trailer combination at a receiving dock. With a counterclockwise delivery-truck traffic pattern, the truck-yard maneuvering area is a minimum of 70 feet extending outward from the truck yard loading area. For the normal delivery tractor-trailer 65-foot length, the total truck-yard loading and truck-yard maneuvering area that extends outward from the dock edge is 135 feet. If short delivery tractortrailer combinations are used in your vendor or customer delivery activity, the truckyard maneuvering area is decreased in length. For a clockwise delivery-vehicle traffic pattern, the truck yard maneuvering area is doubled in length and the truck yard maneuvering length is 140 feet with a total truck yard loading and truck yard maneuvering area of 205 feet from the dock edge. In most truck yards, the delivery-truck loading area has a slight grade or slope from the maneuvering area to the dock edge. The degree of slope is a 3% minimum to a 10% maximum. The preferred slope is 6% in geographic areas with snow and ice conditions. Your delivery truck’s length and local building codes and company policy determine the exact slope. To assist with water drainage, the truck-yard loading area that is adjacent to the docks is slightly sloped from the dock edge toward the truck-yard maneuvering area (away from the building) to a drain. This outward slope is not extended beyond 3 feet from the dock edge. If the extension is greater than 3 feet, the slope meets the truck’s rear wheels. This wheel and slope characteristic has an effect on the delivery truck’s rear edge elevation to the dock edge and delivery truck’s top to the facility dock door overhead curtain. The truck-yard maneuvering, unloading, and dock areas have the sole purpose of facilitating the delivery truck’s unloading; these areas are designed to accommodate the widest delivery-truck size range. At some companies, separate receiving docks are designed to handle oversized delivery trucks.

DELIVERY-TRUCK DIMENSIONS

FOR THE

DOCKS

In designing the delivery-truck dock height, the delivery-truck rear-bed height is an important dimension. This truck dimension determines the receiving truck dock edge height or elevation above the ground. If your across-the-dock operation owns or leases its delivery trucks, to obtain this delivery-truck height and other truck dimensional data is an easy task. If your across-the-dock operation uses a common carrier service, an employee is assigned the task to obtain the actual delivery truck’s dimensions or contact the truck company for the dimensions.



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During your delivery truck information collection process, other required dock equipment and delivery truck information requirement includes (1) truck overall length and overall height (including dimension between side mirror and side mirror and additional height for a wind deflector); (2) truck overall width, height, and length; (3) landing-gear location from the delivery truck’s front; and (4) rear axle centerline from the delivery truck’s rear end.

OTHER IMPORTANT DELIVERY-TRUCK YARD FEATURES Other important delivery-truck yard features to improve truck movement through the truck yard and within the truck yard, and to improve safety and employee productivity, are the maintenance building, the truck wash rack, the fuel island, the forklift truck ramp or dock lift, and the truck engine heaters.

DELIVERY TRUCK DOCK DESIGN FACTORS The factors of the delivery truck dock type (Figure 7.9) designed for your acrossthe-dock facility are including climate, weather conditions, and prevailing winds;

FIGURE 7.9 Truck docks. (From Rite Hite, Milwaukee, WI. With permission.)


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available land; security; delivery-truck traffic flows and control; employee comfort; safety; available investment funds; delivery vehicle type; and delivery load type. The delivery-truck dock methods are the flush-dock design, which includes cantilevered flush dock and vestibule flush dock; open-dock design, which includes open dock and open dock with curtains or sliding panels; enclosed-dock design, which includes straight-in entrance enclosed dock; side-loading or finger dock; drive through a facility or in-facility dock; staggered or saw-tooth dock; pier dock; and freestanding dock or dock house dock. Flush-Dock Design The flush-dock design is most common receiving-dock design that is used at an across-the-dock facility. The facility has an unloading conveyor or pallet truck method, a powered pallet truck or conveyor transport and sorting method, and a loading conveyor or pallet truck for direct piece load onto the customer delivery truck method. The flush-dock designs are the cantilevered type and the vestibule type. Cantilevered Flush Dock The cantilevered flush dock is basically a hole in a building wall with a dock door and dock seal along the door frame outside. This method provides excellent weather protection and security. For unloading, the delivery truck is backed up to the building wall and the rear door is secured against the dock seal. The delivery truck remains outside the facility and the truck driver enters the building through a personnel entrance. Inside the building, the dock staging area is open to the storage area. A cantilevered flush dock requires a dock leveler with a truck ICC bar-restricting device dock plate or chock block. It requires excellent communication between the truck driver and dock employees to prevent unexpected delivery-truck yard movements during the unloading activity. An optional communication method is the stop/go light system. With the cantilevered flush-dock design, the building wall is set back to provide at least 8 inches. This distance provides clearance between the delivery truck’s rear and the building wall at a 6-foot elevation above the dock. The building architect approves a 6-inch minimum clearance between the delivery truck’s top and the building wall. Two dock bumpers that extend outward from the building wall achieve this clearance. These solid sections or rubber strip bumpers are attached to the building wall and absorb the impact from the truck backing up to the dock. The bumper dimensions are determined by the opening size, the loading area shape, the distance between the rear of the delivery truck’s bed, and the truck’s rear wheel center. The bumper method is also used with a yard jockey (mule) tractor, where the slope of the truck is increased as the yard tractor lifts the delivery truck front end higher than the normal over the road tractor. Without the bumper and with this delivery-truck angle and height, the tractor-trailer has potential to hit and damage the building wall. With a flush-dock method, to prevent inclement weather conditions (rain or snow) from destroying the dock seal top, a small canopy or strut is installed to extend over the seal top and rear delivery-truck section.



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When your across-the-dock facility ground floor is on grade level (the ground floor is level to the land), a flush dock with a depressed driveway is designed to provide the delivery-truck dock unloading and loading positions. The driveway (loading area) is depressed to create the proper height between the dock edge and the delivery truck’s rear bed. Special consideration is given to the dock bumpers, water or snow removal or drainage, hand railings, and a window in each dock door. The window in a dock door allows the dock employee to observe the truck-yard status in front without opening the dock door. The cantilever dock design is used for an across-the-dock operation that handles single small items, flat wear, GOH, master cartons, or pallets. Vestibule Flush Dock The vestibule delivery-truck design is a flush dock variation. The difference between the cantilevered flush dock and the vestibule dock is inside the building. With the vestibule dock, there is an open area between the building exterior wall and a second interior wall. With this design the characteristics include several mobile equipment or lift truck aisles (the building requires a large land area), and with a master carton or GOH on a powered trolley conveyor unload, transport, sorting, and load method, wall penetrations. With a GOH on a cart or pallet across-the-dock operation, this design is extremely practical as a staging area. Open Dock Design The open dock design is the least expensive delivery-truck dock design for an acrossthe-dock operation. The method uses a concrete platform that extends outward from the exterior building wall. The open-dock surface or distance (depth) between the building side and dock plate and the building wall provides sufficient open space for unloading equipment to travel onto the dock plate and two-way mobile pallet truck travel path on the dock. The open-dock width and length provides access to all building doors. Since this method is exposed to the weather, employee and power vehicle operator safety is a concern in bad weather. When the design is considered for an across-the-dock operation, a canopy is extended at least 6 to 12 feet beyond the truck’s dock edge. The canopy prevents rain and snow from falling onto the opendock surface. Water makes the dock leveler and dock area travel-path surface area slippery. A wet dock leveler surface or travel-path area is considered a hazardous condition for operating powered mobile forklift trucks. An open-dock protection method is to install sliding panels or dock curtains on the open dock’s perimeter. This feature reduces the negative impact from rainy or snowy weather on the open dock operations. Additional open-dock safety features are yellow-coated concrete posts and chains on the dock edge perimeter. Another consideration is security as the pieces are unloaded from the delivery truck. This open feature makes it difficult to ensure security for use at a single-item, flat wear, GOH, or master carton across-the-dock operation. The open dock is preferred for a pallet across-the-dock operation.


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Dock Curtains or Sliding Panels To convert an open dock into a semienclosed across-the-dock facility, sliding panels or dock curtains are installed on the open-dock edge perimeter. This feature creates a solid barrier between the dock area and truck yard. When required to perform unloading dock activities, and after the truck is backed up to the dock, these sliding panels or dock curtains are opened a sufficient width. This width creates a passageway for forklift or pallet truck travel between the dock area and the delivery truck. The dock panels and curtains maintain a solid barrier on a dock edge and a delivery truck door. When not required to perform unloading dock activities, these sliding panels or dock curtains are closed to create a solid barrier between the dock area and the delivery truck. Enclosed-Dock Design With the enclosed-dock design, the truck unloading area (combined length of tractor and trailer) is inside the building or sheltered area. At the building exterior is a set of building doors that control the delivery truck’s entry to the truck unloading area and dock area. The interior enclosed dock area is an open- or flushdock design. With an internal open enclosed-dock design, the facility design has building doors that permit delivery-truck access to the internal open dock. When the external building doors are opened for delivery truck entry into the truck well, this barrier helps kept the cold air or dust in the truck well from entering the building. To improve enclosed-truck dock area safety and the driver’s truck spotting efficiency, the important considerations are an exterior metal truck entry or travel guides; along the truck well floor surface, full-length painted guide lines; on the truck well’s rear wall, two yellow painted strips; adequate lighting on the driver’s side; if located in a cold climate, sprinkler pipe protection from freezing in the cold; adequate ventilation to prevent tractor or truck engine fumes from entering and accumulating in the building area; and adequate water or melting snow drainage. When considering the enclosed-dock design, the design options are side-entrance enclosed dock; straight-in entrance enclosed dock; side-unloading or finger enclosed dock; drive-through the facility or in-facility dock; staggered or saw-tooth encloseddock design; pier-dock design; and freestanding-dock or dock-house design. Side-Entrance Enclosed Dock The first enclosed-dock design is the side-entrance design. With this design, building construction costs are high. In this design, there are two door sets (one on each building side) and the truck unloading and maneuvering areas are inside the building’s four walls. This feature dictates one-way delivery truck traffic flow through the building (in one door on the building’s right side and out the second door on the building’s left side). The side entrance enclosed dock design is best combined with the staggered- (saw-tooth) dock design. When this method is designed for an across-the-dock operation, the operation has a manual or mechanized direct or temporary stage unload, transport, sorting,



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and load method for single items, flat wear, GOH, cartons, or pallets. The sideentrance enclosed dock, with its high cost, is not the preferred dock method. Straight-In Entrance Enclosed-Dock Design With this design, the designs are one exterior building door per truck dock position or one extra-large wide exterior building door per two truck dock positions. With all straight-in enclosed docks, the delivery-truck maneuvering area is outside the building in the truck yard. The delivery-truck unloading area is inside the building, and the delivery truck backs straight up in the unloading area to the dock edge. The straight-in enclosed-dock delivery truck backup options are to have a short truckunloading lane for the delivery trailer that is dropped inside the enclosed area onto a landing-gear pad, or to allow the tractor to travel to the exterior truck yard or with a longer lane, to accommodate both tractor and trailer in the enclosed area. The straight-in enclosed-dock method is designed for an across-the-dock operation that has a manual or mechanized direct or temporary stage unload, transport, sorting, and load method for single items, flat wear, GOH, master cartons, or pallets. When the side-entrance enclosed dock is compared to the straight-in enclosed dock, the straight-in method is preferred due to lower investment and operational costs. Side-Unloading or Finger Dock The side-unloading-dock or finger-dock design is used primarily for flatbed delivery trucks, open-sided vans, or side-opening vans with side doors that open for unloading pieces. This dock design is basically a cutout in the building dock-area interior floor. The finger dock cutout is directed inward from the building exterior wall into the dock staging area. The finger dock or opening in the dock area’s floor length and width is sufficient in size to permit a flatbed delivery truck or open-sided van to back full length into the opening. Concrete platforms that permit forklift right-angle turns on both sides of the cutout or opening permit forklift trucks to unload pallet loads from the truck. To improve dock safety, on the platform edge yellow-coated posts and chains surround the cutout. The finger-dock method is designed for an across-the-dock operation that has a manual forklift truck direct or temporary stage unload, transport, sorting, and load method for pallets. Drive through the Facility or In-Facility Dock The drive-through dock or in-facility dock design is used for flatbed or open/sided delivery vans. The van drives into the building and on the floor surface. At the proper location, forklift trucks side-unload the pieces from the delivery truck. This design requires one-way travel of trucks through a facility, or delivery trucks are backed up into the facility. This design is used in a pallet across-the-dock operation and requires temporarily staging the pallet. Staggered- or Saw-Tooth-Dock Design When there is limited truck-yard maneuvering area, the staggered or saw-tooth dock design is preferred for the delivery dock area. The design requires a one-way delivery-truck flow in the truck yard. This delivery-truck flow matches the approach


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to the angle of the staggered- or saw-tooth-dock positions. This arrangement requires either a counterclockwise or clockwise delivery-truck flow pattern. For efficient unloading activity, the delivery-truck unloading area requires the delivery truck’s rear-bed height to be level with the dock edge. The disadvantages are that the method requires approximately twice the building dock space for fewer docks and that the building construction requirements and costs are greater. The staggered or saw-tooth method is designed for an across-the-dock operation that has a manual or mechanized direct or temporary stage unload, transport, sorting, and load method for single items, flat wear, GOH, master cartons, or pallets. Pier-Dock Design If the delivery-dock side of the building does not have sufficient wall space for the required delivery-dock number or the building interior layout does not permit dock construction, the pier-dock design has the potential to provide the required delivery dock positions. In this design a wide enclosed section or building with a very wide aisle extends outward from a building wall. Dock positions are located on each extension side. This means one entrance side is the receiving-truck dock area and the other side is the shipping dock area. The extension width permits a forklift truck turning aisle or other in-house material handling transport and sorting method. With the pier dock design there is a truck-yard maneuvering area on both sides of the pier dock. This method is designed for an across-the-dock operation that has a manual or mechanized direct unload, transport, sorting, and load method for GOH, master cartons, or pallets. If single items or flat wear are handled by the operation, the single-item or flat wear sorting operation is located in the facility’s other section. Freestanding-Dock or Dock-House Design The freestanding or dock-house design is placed in the building door front. The dock house is a shell that has two walls and a roof. This structure and the facility door permits forklift-truck travel between the delivery truck and the dock area. The dock house represents an additional cost and has some limited applications in an across-the-dock operation. The freestanding-dock design is a hardened metal mobile ramp with a flat top section. The ramp slopes and travel-path surface permit a forklift to travel up the slope and into the delivery truck. For an across-the-dock operation, the freestanding dock’s limitations make it unsuitable for an across-the-dock operation. Delivery-Truck Dock-Door Design Considerations The delivery truck’s dock door is a building device (Figure 7.10). When a door is open, it permits passage between the dock space and delivery trailer, and when a door is closed, it provides security and energy conversation. The three most common truck dock-door types are (1) vertical lift, (2) vertical and horizontal movement, and (3) roll-up. The type and selection are determined by the building’s floor surface to ceiling design considerations and available funds.



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FIGURE 7.10 Dock door details. (From Rite Hite, Milwaukee, WI. With permission.)

The other important truck dock-door considerations include windows in the door panel. The small window reduces an employee’s need to open the dock door to verify that a delivery truck is at the dock position. The door should be lockable. A lockable dock door is designed with a device to lock the door with an industrial paddle lock from the building interior. This feature as well as the truck dock-door window improves the facility security. The third feature in cold and windy climates is weather stripping along the truck dock door, frame, and bottom to reduce energy loss. In warm climates a folding gate covers the entire truck dock-door passageway. During warm and sunny days, the folding gate is pulled closed and locked in position across the door opening. In this position, the gate prevents personnel from passing through the door. This arrangement maintains good security and does permit a cool breeze to enter the building. In a warm climate with a flush dock to reduce energy loss is a short dock house that extends outward from the exterior of the building at each dock position. Similar to a dock house, the short dock house surrounds the delivery truck’s rear and reduces warm air movement into the building. The truck dock-door considerations are the truck dock-door heights and widths (Figure 7.11). The truck dock-door dimensions are determined by the delivery truck’s rear-door dimensions, dock seal or shelter type, and required internal environmental conditions within the facility. A delivery truck’s dock doors are an energy loss and a security problem. In a conventional store and hold operation, the truck dock-door number is kept as small as possible. With an across-the-dock operation, the maximum truck dock doors are preferred to ensure a constant piece flow between the receiving area and shipping area. For the average across-the-dock facility, the truck’s dock-door widths range from 8 to 9 feet to match the corresponding delivery truck rear 8-foot to 8-foot, 6-inch dimensions. When a delivery truck is backed up to the truck’s dock door, this arrangement permits the delivery truck to have a slight variation from an exact center position. The trend in delivery-trailer design is to use 102-inch-wide delivery trailers that permit an increase in the pallet-carrying capacity. The 8-foot, 6-inch- or 9-foot-wide dock door is preferred for the delivery-trailer dock doors on a new facility.

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FIGURE 7.11 Truck-door considerations: (a) delivery-vehicle dimensions; (b) door centerlines; and (c) bumper locations. (From Rite Hite, Milwaukee, WI. With permission.)





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For regular over-the-road delivery trailer unloading activity with a 4-foot-high dock edge, the truck dock-door heights range from 8 to 10 feet high. The 8-foothigh truck door permits a 7-foot- to 7-foot, 6-inch-high pallet travel over a dock leveler. A 9-foot-high dock door with 3 inches to the top clearance permits a pallet height over a dock leveler of 8 feet, 9 inches. The 10-foot-high truck dock door handles a high-cube delivery trailer. One important dock door height principle is that at least one dock door has a 13-foot, 6-inch to 14-foot clear height to accommodate a forklift truck collapsed mast height. Delivery-Truck Dock Height The best delivery-truck dock height provides the smallest variance between the dock edge and the delivery truck’s rear bed. To accommodate a delivery truck’s bed height variety to the delivery dock-edge height, and the height differential between the dock edge and truck bed, a loading ramp (dock plate) or dock leveler bridges the gap between the bed and dock edge. As the height differential between the dock edge and bed increases, the incline and decline slope of the bridge device increases. If this slope increases to a high degree, as a pallet truck or an extendible conveyor wheel travels over the dock leveler, hang-up problems occur on the dock leveler. These problems decrease employee productivity, increase the need for pallet truck maintenance, and decrease dock safety. A delivery dock height for most delivery trucks ranges from 46 to 52 inches. If there is a wide variety of delivery truck bed heights, the delivery-truck dock designs are to allow and design separate delivery-truck docks for specific delivery truck bed heights; on the floor-dock surface, to use an extra-long dock leveler (up to 12 feet long) with an 18-inch vertical travel from the dock edge; in the delivery truck-unloading or loading yard area, to install a delivery-truck leveler to raise and lower the entire delivery truck; and in the delivery-truck unloading or loading yard area, to use rear wheel risers to elevate a low delivery-truck rear bed. How to Bridge the Gap between the Dock Edge and Delivery-Truck Bed The next important across-the-dock facility design consideration is to properly equip the delivery-truck docks. At the edge of the dock, the dock leveler bridges the open gap between the dock edge and the delivery truck’s rear bed. To bridge the gap, the dock leveler extends from the truck’s rear-bed dock edge inward into the facility. In the facility, one dock plate end rests on the floor surface or the dock leveler is level with the floor surface. The dock leveler is the factor that permits pallet trucks to unload pallets from the delivery truck, with some carton conveyor methods to enter and exit the delivery truck, and with GOH on a GOH cart to unload or load the delivery truck. The dock leveler ensures high employee productivity and safety.


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The height variation between the dock edge and delivery truck’s rear bed is a factor that determines the GOH, master carton, or pallet material-handling equipment that is used in the receiving or shipping function. The other dock-leveler selection factors are delivery frequency, piece-handling equipment, dock type, piece type, available dock space; dock-edge and delivery-vehicle height variance, and available capital. Dock equipment needed to bridge the dock edge and delivery-truck gap devices are a portable walk ramp, a portable dock plate with a T-bar on the underside, a portable dock board, a mobile dock, a recessed pit or manual or hydraulic dock leveler, a manual or hydraulic vertically stored dock leveler, front of dock, edge of dock, hydraulic jack in the floor, scissors lift, pit-installed scissors lift, dock-leveler lift, and truck-trailer gate. Portable Walk Ramp The portable walk ramp is an aluminum ramp that is designed with a skid resistant travel path. A portable walk ramp is not preferred for an across-the-dock operation. Portable Dock Plate The portable dock plate with an equalizing bend is an aluminum plate with a 2-to5-foot length and a 5-to-6-foot width that handles a delivery-truck bed and dockedge height differential from 3 to 10 inches. At the delivery-truck dock, a short dock plate handles a low height differential and a long dock plate handles a high height differential. To reduce pallet truck skids on the dock-plate surface, the dock plate has a diamond-pattern travel-path surface. To secure the dock-plate position in the truck and building gap, the dock plate has a locking leg (T-bar) that is attached to the underside, extends downward, and fits into the truck and building gap. This lightweight and low-cost dock plate with handles on both sides is easily moved by two employees to the required delivery dock. Yellow safety side-strips along both sides of the dock-plate travel path minimize pallet truck runoff. The dock plate has sufficient structural strength and width to handle a pallet truck. When a high differential exists between the truck bed and dock edge, prior to dock plate’s placement in the delivery truck’s rear bed a forklift truck removes the rear two pallets from the delivery truck. For an across-the-dock operation, the portable dock plate with equalizing bend at the top is a restriction and is not considered for use with a mobile extendible belt carton conveyor method and GOH cart across-the-dock operations. The portable dock plate has limited application in a pallet across-the-dock operation that uses manual or electric-powered pallet trucks. Portable Dock Board The portable dock board with an equalizing bend is an aluminum device that permits an electric pallet truck or rider forklift truck to unload or load a delivery truck. To reduce pallet truck skids, the dock board has a diamond-pattern travel-path surface, and to secure the dock board in the truck bed and building gap, locking legs (Tbars) are attached to the underside, extend downward, and are inserted in the delivery truck bed and building gap. Yellow safety curbs help eliminate equipment runoffs. The dock-board weight requires a forklift truck to move and position the dock board at the required dock.



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The portable dock board has the same restrictions in a carton conveyor and GOH cart across-the-dock operation but has some application in a pallet load across-thedock operation with rider forklift trucks and manual or electric-powered pallet trucks. Mobile Yard Ramp, Scissors Lift, Bascule Bridge Dock, In-Floor Hydraulic Lift, Tailgate Trailer, Manual Wheel Lift, and Dock-Leveler Lift For an across-the-dock operation, the mobile yard ramp, scissors lift, bascule bridge dock, in-floor hydraulic lift, tailgate trailer, manual wheel lift, and dock-leveler lift to bridge the delivery truck’s bed and building gap are not preferred for use in an across-the-dock operation. The reasons are low productivity, higher investment, and limited flexibility. Recessed Dock Leveler For most across-the-dock operations that have a building dock edge at 4 feet above the ground level, the recessed dock-leveler method is a common device used to bridge the dock edge and truck bed gap. Each dock leveler is installed in a pit or in a cutout of the facility floor (Figure 7.12). The recessed dock leveler has a diamondpattern travel-path surface with a flexible lip. The dock leveler’s surface is raised

FIGURE 7.12 Dock-leveler details. (From Rite Hite, Milwaukee, WI. With permission.)


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FIGURE 7.13 Grade table for pallet transport. (From Rite Hite, Milwaukee, WI. With permission.)

up with the lip. The lip extends outward and lowers to rest on the delivery truck rear bed. The dock leveler’s structural strength permits forklift trucks or pallet trucks, GOH carts, and carton conveyors to travel between the delivery trailer and dock surface. With electric pallet trucks, the dock leveler is 6 feet long and handles a 7to-8-inch height differential. A 12-foot-long dock leveler handles a 15-to-16-inch height differential. As a gas-powered forklift truck travels over a 12-foot-long dock leveler, the dock leveler compensates with a 17-to-18-inch height differential. As an electric-powered pallet truck travels over a 12-foot-long dock leveler, the dock leveler compensates with a 13-to-14-inch height differential. The most common recessed dock leveler length is 8 feet; it handles a 10-inch height differential (Figure 7.13). The recessed dock leveler width has a range from 6 to 7 feet. The 7-foot-wide leveler is best for an 8-foot-wide delivery truck and has a tapered lip on each side to compensate for a delivery truck that is spotted off center or for a narrow delivery truck. When a tapered dock leveler is used at the dock position, it creates a pallet truck or forklift truck drop-off zone as a result of the space that is created by the tapered ends. When a 12-foot-long dock leveler is in the dock area, the dock leveler extends further into the facility’s dock area. This feature compensates for the extreme height differential, increases the facility area requirement, increases the cost, and reduces the dock staging area. The standard recessed dock-leveler lip is 16 inches long, permitting a 12-inch extension into the delivery truck rear. Another lip feature is that the lip edge permits the lip to stay in firm contact with the delivery truck bed. With a refrigerated delivery trailer, to reduce pallet truck wheel hang-up in the truck bed drain, the lip projection length is a very critical factor.



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The disadvantages are higher capital investment and the fact that each dock position requires the use of a dock leveler. Advantages are compensation for a wide dock edge and truck-bed height differential; ability to handle powered forklift trucks or pallet trucks, GOH carts, and conveyors that have a low grade range; flexibility to service a wide vendor or customer delivery truck range; ability to handle a heavier load; long life; high employee productivity; dock area safety; and ability to handle all unloading or loading methods. The recessed dock-leveler options that improve dock safety, energy conservation, and sanitation are full range tow guards on both sides of a dock leveler, ICC bar truck or trailer restraints to prevent vendor or customer delivery trailer roll-away, a dock restraint lip to prevent forklift trucks from running off an open dock, weather seals between the dock leveler edge and the finished floor curb channel to improve sanitation and conserve energy, and dock-position occupancy lights. The recessed dock-leveler types are the hydraulic or automatically operated dock leveler and the mechanical or manually operated dock leveler. Hydraulic-Recessed Dock Leveler

The hydraulic-recessed dock leveler has a hydraulic pump and motor in the pit that moves the dock leveler’s travel-path surface to the desired elevation. The dock leveler is controlled by push buttons that are located on the building wall interior, adjacent to the dock position. After the delivery truck is positioned at the dock, an employee presses the button that causes the dock leveler to automatically rise and lower in a flat level position with the lip inside on the delivery truck bed. With the lip on a delivery truck’s rear bed, a dock leveler’s travel-path surface is relatively level as a bridge between a dock edge and truck bed. At a level position, pallet and forklift trucks, GOH carts, and conveyors easily enter and exit a delivery truck. With few mechanical parts and structural members in the pit, the hydraulicrecessed dock leveler is very reliable, requires little maintenance, and permits pit cleaning. This dock leveler has a higher capital investment and is considered for an acrossthe-dock operation that has a manual or mechanized direct or temporary stage unload, transport, sorting, and load method for single items, flat wear, GOH, master cartons, or pallets. Mechanical-Recessed Dock Leveler

The mechanical-recessed dock leveler has a diamond-pattern travel-path surface and an upwardly biased ramp with a spring mechanism that is held down by a releasable ratchet device. To operate, an employee walks onto the ramp and pulls on the release chain that is connected to the ratchet mechanism. This pulling on the ratchet releases the ramp and the ramp rises to its uppermost position. During the upward movement, the ramp lip is automatically extended forward. The employee walks forward onto the extended ramp that is forced down toward the delivery truck’s bed. With the lip on the rear bed, the dock leveler is ready for the unloading or loading activity. The advantage is that it costs less than the hydraulic model. The mechanical recessed dock leveler is considered for an across-the-dock operation that has a


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manual or mechanized direct or temporary stage unload, transport, sorting, and load method for single items, flat wear, GOH, master cartons, or pallets. Vertically Storing Dock Leveler The vertically storing dock leveler is a ramp that is withdrawn in the vertical position inside the building. The standard vertical storing ramp is available in 5-foot length with a 6-to-7-foot-wide travel path surface. The 6-foot-wide leveler is best for a delivery truck that is less than 96 inches wide. The lip projection and bend have a standard 16-to-18-inch lip length and a 12.5% grade break. This allows the vertically storing dock leveler to handle a dock edge and delivery-truck bed 6-inch height differential. The vertically storing ramp pivots on hinges that are installed in the dock area interior wall in a step-down. The step-down is a continuous pit that runs on a steel channel along the entire wall face that parallels the dock doors. The vertically storing dock leveler does not have a pit, so it reduces the sanitation problem. Other energy control features are a tighter seal on a flush dock and a tighter dock seal on a delivery truck at the dock. This dock leveler is available in a hydraulic or automatic model and a mechanical or manual model. With the hydraulic dock leveler, the dock employee controls the lip and ramp with push buttons from a control panel that is located on the building interior wall. After the use of the dock leveler, the vertically storing dock leveler is locked in the vertical position. At this point, the dock leveler is physically pushed by an employee to another dock position. The mechanical vertically storing dock leveler is manually moved between dock positions. The lip is in the extended position and is manually retracted. At the required dock position, the dock employee manually lowers the ramp onto the delivery truck’s bed. Counterbalanced springs assist in the lowering effort. When not in use the vertical storing ramp is returned to the vertical position. The vertically storing dock leveler is considered for an across-the-dock operation that has a manual or mechanized direct or temporary stage unload, transport, sorting, and load method for single items, flat wear, GOH, master cartons, or pallets. The disadvantages are a higher capital investment per each dock leveler, and the fact that the step down collects debris. Advantages are low maintenance, energy control improvements, and lower total dock investment due to increased ramp mobility. Edge-of-Dock Leveler The edge-of-dock leveler is a basically a short ramp with a flexible lip. The dock leveler is mounted to a steel channel that is embedded in the dock front. The dock leveler is available in 27- and 30-inch lengths and 66- and 72-inch widths. It has a standard 15-inch lip with an 11 1/2-inch lip projection. Edge-of-dock levelers with a 17-inch lip provide a 13 1/2-inch lip projection into a delivery truck. These devices are available in both standard profile and low profile types. The low-profile type is best used for across-the-dock operations that use a forklift truck or pallet truck with a low clearance. It is not used with high-speed forklift trucks or vehicles with a low under-clearance.



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The edge-of-dock leveler is a hydraulic or manually operated device. An employee controls the hydraulic dock leveler with push buttons that are located on the building interior wall. When activated, the hydraulic model pushes the ramp upward with the lip in the extended position. After reaching full extension, the lip is lowered onto the delivery truck’s rear bed. After the delivery truck departs from the dock, the edge-of-dock leveler automatically returns to the stored positions. The edge-of-dock leveler requires a low capital investment but handles a delivery truck bed and dock edge only 5 inches above or 5 inches below the level height differential. The edge-of-dock leveler is considered for an across-the-dock operation that has a manual or mechanized unload and load method for single items, flat wear, GOH, master cartons, or pallets. It is preferred for an across-the-dock operation that uses nonpowered or powered extendible carton conveyors. Front-of-Dock Leveler The front-of-dock leveler is a bridge device that has its own built-in bumpers and is bolted to a dock concrete wall. It is available with a 30-inch length and a 72-inch width. The front-of-dock leveler is available in both high-profile and low-profile types with a standard flexible lip 11-inch projection. The high-profile front-of-dock leveler serves a delivery-truck bed and dock-edge height 6 inches above and 4 inches below, and the low-profile device serves a truck and building height 4 inches above and 1 1/2 inches below. If powered conveyors are used in the unloading or loading activity, the edge of dock leveler reduces the total dock-area investment. To operate, a dock employee manually lifts a ramp with the counterweights’ help, flips the ramp into the horizontal position, and lowers the dock leveler onto the delivery truck’s rear bed. The front-of-dock leveler is not recommended for an unloading or loading activity that uses high speed forklift trucks, pallet trucks, or GOH carts. After the delivery truck departs from the delivery dock, the front-of-dock leveler automatically lowers to the stored position. The disadvantages are that it cannot service all unloading and loading forklift trucks or pallet trucks, and that it accommodates only limited building and truck height differentials. The advantages are low capital investment and ease of relocation. In most pallet load across-the-dock operations, the front-of-dock leveler is not considered for the dock operation due its limitations. If the operation has a low height differential between the dock edge and vendor or customer delivery truck and a manual or mechanized extendible conveyor method is used to load and unload cartons, the front-of-dock leveler is considered for the dock operation. Hydraulic Wheel Lift The next device to bridge the gap between the dock edge and delivery-truck bed is the hydraulic wheel lift. The hydraulic wheel lift is located in the unloading or loading truck yard area. The hydraulic wheel lift has a diamond-pattern travel-path surface and is pit-installed directly below the dock position. The surface’s width is 10 feet wide by 14 feet long. A 5-inch-high wheel locator is an elevated middle


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section. When a delivery truck is backed up to the dock, the wheel locator is between the delivery truck’s two rear wheels. The hydraulic controls are located on the inside building wall and have the ability to raise and lower a delivery truck’s rear end to the required building and truck height for easy access over a dock board or dock leveler. When using the wheel lift device, attention is given to the delivery truck’s new slope and the delivery-truck and dock height. The new delivery-truck slope has a bed that is higher at the dock edge and lower at the vendor or customer deliverytruck nose. To unload a delivery truck, the new slope creates an upgrade or pull for an employee with a pallet or GOH cart. During the loading activity, the new slope creates a downgrade. To reduce delivery-truck or piece damage or employee injury, the unloading or loading employee is extremely careful due to a new (decline or incline) slope that is created inside the delivery truck. Due to its limitations, a hydraulic rear-wheel device is not considered for a single-item, flat wear, GOH, master carton, or pallet across-the-dock operation. Options to Improve Dock Safety and Efficiency For an efficient and safe dock operation, your across-the-dock operation could require additional devices and other dock types and bridge-the-gap devices to reduce the height differential between the dock edge and vendor or customer delivery truck. These devices and areas are located in front of and behind the dock door. The various devices are wheel chocks, exterior guard posts or metal truck guides, dock bumpers, interior door guard posts, dock-leveler lips, truck canopies, dock ladders and personnel entrances, fifth wheel lock jacks, guide lines, dock or door identification, and truck delivery stripes or guide rails. Dock Seals and Dock Shelters Dock seals and dock shelters are exterior-dock door frames and jam features that extend outward from the building wall and permit the delivery truck’s rear door sides and top to be flush against this extension. These two devices ensure that there is no gap on the delivery truck’s two sides and top and the building dock door frames and jam. With no gap, this condition improves dock security and energy conservation. The dock seal (Figure 7.14) consists of two foam-filled pads or two air pads on each dock door frame and one head curtain along the door jam top. Some dock seals have moveable head curtains that are manually adjusted vertically to match the delivery truck’s height. Yellow strips or pads with yellow strips are options on the dock seal’s exterior sides. These yellow strips help the driver to properly locate the delivery truck at the dock position. These pads extend the dock seal’s life by reducing wear from the delivery truck’s rear-side movement which rises or lowers as the delivery truck is unloaded or loaded by the across-the-dock receiving employees. Dock shelter conserves energy and improves dock area security. The dock shelter has two fixed frame structures or flexible frame structures with a head curtain that extends outward from the building wall. The dock shelter frame’s two sides hang onto the delivery truck’s rear sides and roof. These three sections conform to the truck’s rear door. Both dock shelter types have steel channel protectors to reduce



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FIGURE 7.14 Dock seals. (From Rite Hite, Milwaukee, WI. With permission.)

delivery truck damage to the dock shelters as the delivery truck is backed up to the receiving or shipping dock. Yellow strips on the pads or plain pads serve the same purpose as the yellow seal pads. Dock Lights Dock lights are adjustable and moveable devices that provide light into the delivery truck’s interior. The dock light has a single lamp that has a flexible arm. The arm reaches to the truck’s rear-door side and upper portion. Most dock lights are located between two delivery-truck dock doors and service both dock doors. Some dock light arms provide light to a single dock door. Lockable screens protect the lamp from damage and theft.


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A dock-light option is a wire prong that extends in the dock-door path. As an employee opens the dock door, the wire prong automatically turns the dock light on as the dock door is moved into the open position. As an employee closes the dock door, the wire prong comes in contact with the dock door and turns off the dock light. ICC Bar Lock or Hook Device The ICC bar lock or hook device is a dock-leveler option that improves forklifttruck safety in the dock area. The ICC lock or hook is a device in the dock-leveler pit area and is controlled from the dock area to extend forward and upward. When a delivery truck is spotted or backed up at the dock, the hook motion and new position is in the delivery truck’s ICC bar front. The hook in this position restricts the delivery truck’s forward movement, thus preventing roll-away or unexpected truck departure. Stop and Go Lights Stop and go lights are red and green lights on each dock’s inside and outside. When a delivery truck is at the dock location with an open-dock door, the light color is red and signals to both the forklift-truck operator and the delivery truck driver that the delivery truck is in the dock position and is not ready for departure. When the light color is green, the green color signals to both drivers that the delivery truck is ready to depart from the dock position and it is not safe to enter the delivery truck. Receiving Office An important dock-area feature is the receiving office complex. The receiving office complex has a receiving area supervisor and clerk office area for document control. Other office features are restrooms for employees and separate toilets for commoncarrier truck drivers. The common-carrier or vendor delivery-truck driver’s area has pay phones, vending machines, and a sliding window on the office wall for document transfer. Some companies provide their truck drivers with sleeping areas with full toilet facilities and locker rooms. Dock Ramp The dock ramp is a building structure or portable metal structure with side guards and handrails that permits powered forklift and pallet truck travel between the facility finished-floor surface and the ground. The ramp slope is determined by the height differential between the facility finished-floor surface and the ground, the forklift and pallet truck grade-climbing ability and grade clearance, and the available space to complete the travel path. Dock-Lift Method In a distribution dock area, the dock lift’s purposes are to replace the incline ramp for powered forklift trucks or pallet trucks as the means to move the vehicles and



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pallets between the ground level and the facility dock-area floor surface, to serve as a dock leveler that bridges the gap between the dock edge and delivery truck’s rearbed height, and to serve as a vertical movable and adjustable dock leveler that bridges the gap between the facility dock edge and a lower or higher than the normal delivery truck’s rear-bed height. The adjustability permits a nonpowered or powered vehicle to transfer pallets between the dock area and the delivery truck. The characteristics are that the method occupies less facility space and land; permits forklift and pallet truck travel between the ground level, delivery truck and the dock area; is a safe operation; and handles wide differentials between a dock edge and a delivery truck’s rear bed. Distribution design operational professionals consider that a dock ramp or dock lift is a very important dock consideration.

UNLOADING METHOD When you consider an across-the-dock piece unloading activity, you are considering the physical piece movement from a vendor delivery truck onto the receiving dock. The methods to move pieces from a vendor delivery truck are (1) manual method, (2) mechanical method, and (3) automated method.

MANUAL-UNLOADING METHODS The first unloading methods are the manual-unloading methods. With these methods, an employee is required to carry the pieces or to pull or push a wheeled carrier with pieces from a delivery truck onto the dock. The manual methods are applied to any piece type. In an across-the-dock operation, these methods and associated pieces are the employee carrying for GOH, manual or powered pallet truck for master cartons or pallets, GOH cart for GOH, four-wheeled trolley cart for GOH, and extendible trolley boom for GOH. Employee Walk Method The employee-walk unloading method is considered the simplest and most basic for unloading delivery trucks. To improve employee productivity, some manual-unloading methods have an employee use a two-wheeled hand truck, a roller dolly or pallet roller, a four-wheeled platform truck, a freight pry bar, and a four-wheeled cart with shelves or a hang bar. The manual-unloading methods require an employee to carry the pieces or to push or pull a wheeled carrier from a delivery truck and the dock. Due to the slow unloading activity, the manual-unloading method requires a large dock staging area and a maximum time to handle a delivery truck. Other disadvantages include employee injury, a need for the greatest employee number, a need for the greatest dock number, low employee productivity, and delivery-truck slow turns. The advantages are low capital investment and capacity to handle all SKU types. When other methods are down, the method is able to be used at the across-the-dock operation. In most across-the-dock operations, the manual-carry method is considered as a last resort for delivery-truck unloading.


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Manual Pallet Truck The manual pallet-truck unloading method has an employee push or pull a manualpowered pallet truck. The manual pallet truck has an operator handle, two loadcarrying wheels, two load-carrying forks, two steering wheels, and a hydraulic mechanism to elevate and lower the two forks. The two forks extend forward from the wheel base, and the length matches the pallet board’s length. To lift a pallet, the employee pushes the set of forks into the pallet board’s opening and operates the hydraulic mechanism to lift the pallet board above the floor surface. To deposit the pallet load in the delivery truck, the employee releases the hydraulic mechanism and pulls the forks from the pallet board’s opening. To unload a delivery truck, an employee pushes or pulls the pallet truck into the delivery truck, picks up a pallet, and pushes or pulls the pallet from the delivery truck to the dock area for deposit. With a manual pallet-truck method, the unloading of a delivery truck ranges from 2 to 3 hours. Disadvantages are that the method handles a medium volume, a piece is required on a pallet, traveling up grades is difficult, and a backrest is required to reduce piece damage. Advantages are reduced employee physical effort and injury risk, low capital investment, improved employee productivity, improved vendor delivery-truck turn time, reduced dock-position number, the ability to deposit a pallet in the dock area, and the ability to be used in other distribution operation activities. In most acrossthe-dock operations, the manual pallet-truck method is considered a last-resort delivery-truck unloading method. Garment Trolley Cart The next unloading device is the garment trolley-cart method. The method uses a four-wheeled cart with two structural members and a trolley bar that has two adjustable end stops. The load bar has the capacity to carry one fully loaded GOH trolley. With the end stops in the closed position, the trolley cart secures the trolley on the load bar and is used to unload GOH from a GOH (rope) delivery truck onto the dock staging area. In the dock staging area, the GOH trolley is positioned at a facility trolley in-feed rail section. An employee adjusts the end stops to an open position, allowing an employee to release the trolley to the facility trolley’s nonpowered rail system. To operate, an employee places an empty trolley onto the cart’s trolley load bar and sets the adjustable end stops to the desired position. An employee pushes or pulls the cart into the delivery truck and the individual GOH pieces are removed from the delivery truck’s hang ropes and are placed onto the trolley. When the trolley is at capacity, the cart is pulled or pushed to the dock staging area and aligned with the facility’s nonpowered trolley in-feed section. The employee releases the end stop and pushed the trolley from the load bar onto the facility’s nonpowered trolley rail. With this method, a full GOH on rope delivery trailer is handled in 6 to 8 hours. Disadvantages are that the method requires a dock leveler at the dock position, it is difficult to handle a large volume, and it requires a trolley rail system in the



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facility. Advantages are low capital investment and increased efficiency in handling a low GOH volume that is delivered on a rope vehicle. Extendible Hanging-Garment Trolley Boom The extendible trolley-boom method is a specialized manually operated GOH unloading device. The method is used at a GOH facility that handles a high volume of GOH pieces on trolleys. The extendible boom has extendible channels that have headers and support devices with a trolley rail that has an end stop. When the delivery truck (rope GOH) is at the delivery dock, the extendible boom is extended from the dock area into a delivery truck and is supported from a delivery truck’s roof or by upright frame structures. To unload a vendor delivery truck, an employee places an empty trolley on the extendible boom rail and transfers GOH pieces from the delivery truck’s rope loops onto the trolley load bar. When the trolley is full or after the trolley queue, an employee gently pushes the trolleys forward on the extendible boom rail to queue against an end stop that is located on the dock. The trolleys are released to the facility’s nonpowered trolley rail system. With the extendible trolley-boom method, a full GOH rope delivery truck is unloaded in 3 to 4 hours. Disadvantages are high capital investment, the need for a trolley rail system in the facility, and the ability to serve only one dock position. Advantages are high employee productivity, the fewest dock positions, the ability to handle a high volume, and compactness due to the fact that the extendible boom does not require dock area floor space when not in use.

MECHANICAL-UNLOADING METHODS The second unloading method group consists of the mechanical-unloading methods. These methods have gravity-, electric-, or fuel-powered material-handling vehicles or conveying surfaces to move master cartons or pallets from the delivery truck onto the dock. These methods are an electric-powered pallet truck with a set of forks, an electric-powered pallet truck with a slip attachment, a powered forklift truck with a set of forks, a powered forklift truck with a slip-sheet attachment, a nonpowered or powered extendible and retractable skate wheel, and roller and belt conveyors. Electric-Powered Pallet Truck with a Set of Forks The first mechanical unloading method is the electric-powered pallet truck. The electric-powered pallet truck is a three-wheeled vehicle with one wheel as a rubbercovered drive and steer wheel and two other wheels that are hardened plastic and are the load-carrying wheels under each fork. These wheels and forks elevate or lower the pallet onto the floor surface. The various vehicles are walkie or walk-behind, walkie/rider, and rider. Optional full-height load backrests and fork-entry wheels improve pallet-handling productivity and reduce product and equipment damage. To unload a delivery truck, an employee steers or drives the pallet truck onto a delivery truck, picks up a pallet, and drives the pallet truck with the pallet from the


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delivery truck onto the dock staging area. A pallet delivery truck is unloaded in 1 to 2 hours. Disadvantages are the need for more employee training, the need for a separate battery charging area, the difficulty of handling double-stacked pallets and inability to transfer pallets to an elevated position, and a moderate grade clearance requirement. The advantages are that the method requires a moderate capital investment, handles a high volume, travels up grades, reduces employee injury, requires fewer dock positions, and is used in other activities. Electric-Powered Pallet Truck with a Slip-Sheet Attachment The second mechanical unloading method is the electric-powered pallet truck with a slip-sheet attachment. In this method, an electric-powered pallet truck has a specially designed platen and lip clamp device that handles a slip-sheet load. The slip-sheet delivery method allows pieces to be handled as a unit load rather than as individual cartons. To operate, an employee drives the pallet truck into the delivery truck and uses the slip-sheet clamp device to extend outward and grab and hold the slip-sheet lip. After the unit load is completely pulled onto and rests on the platens, the employee drives from the delivery truck to the dock area and deposits the slip-sheet onto the dock floor surface. In a pallet across-the-dock method, the loaded slip-sheet truck travels to the appropriate customer delivery truck and deposits the slip-sheet load in the customer delivery vehicle. With the slip-sheet method, the delivery truck is unloaded in 2 to 2 1/2 hours. The pallet truck advantages apply to the slip-sheet truck method. The additional disadvantage is that the slip-sheet pallet truck handles only slip-sheet unit loads. An additional advantage is that the pieces are shipped without pallets, which means that the delivery truck carries the maximum capacity in piece weight and the slip-sheet has a lower cost than a pallet. Powered Forklift Truck with a Set of Forks The electric battery or internal combustion powered forklift truck is the next mechanical-unloading method. The powered forklift truck is an electric battery, gas, liquefied petroleum gas, or diesel powered forklift truck that is a sit-down or stand-up model. These forklift trucks have three or four wheels, an overhead guard, a set of forks that extend outward from the mast and move a pallet vertically on the mast, and an operator’s area. Many dock forklift trucks have masts with a full free-moving forklift. The overall collapsed mast and overhead guard height permit a forklift truck to enter a delivery truck. Inside a delivery truck, the set of forks lifts a pallet, then exits the delivery truck and places the pallet onto the dock staging area. With the full free set of forks lift option, the forklift truck set of forks elevates approximately 4 feet without moving the mast upward. With a very light load, this set of forks free-lift feature permits the forklift truck to handle double stacked pallets inside the delivery truck. For maximum unloading employee productivity and to reduce piece damage,



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forklift-truck fork side shift and tilt and spotlights on the forklift truck mast are considered options for the dock-area forklift truck. To operate the forklift-truck unloading method, an employee drives the forklift truck into a delivery truck, picks up a pallet, and drives with the pallet from the vendor delivery truck onto the dock area. In the dock area, the forklift-truck operator deposits the pallet load in an assigned area or delivers a pallet to the customer delivery truck. With a forklift truck method, a truck is unloaded in 1 to 2 hours. When this method is compared to the electric-powered pallet truck method, the additional disadvantages are higher capital investment and the need for additional employee training. The additional advantages are that the method handles stacked pallets, travels over a higher grade clearance, has fewer employee injuries, handles a heavier and longer load, is used in other facility functions, and is equipped (in the case of some models) with attachments to handle slip-sheet loads. Electric-Powered Forklift Truck with a Slip-Sheet Attachment The next mechanical unloading device is the electric-powered forklift truck with a slip-sheet attachment. The slip-sheet attachment permits the forklift truck to handle a slip unit load. With the slip-sheet delivery method, an electric-powered forklift truck has a slip-sheet attachment on its mast. The slip-sheet attachment is a permanent or temporary attached device that has a platen and a lip clamp device that handles a slip-sheet load. The slip-sheet delivery method is an alternative to the pallet or floor-stack delivery-truck method that allows pieces to be handled as a unit load rather than as individual cartons. To operate, an employee drives the forklift truck with a slip-sheet attachment into a vendor delivery truck and uses the slip-sheet clamp device to extend outward and grab and hold the slip-sheet lip. After the unit load is completely pulled onto and rests on the platens, the employee drives from the delivery truck to the dock area and deposits the slip-sheet onto the dock floor surface, or travels to the customer delivery truck and deposits the slip-sheet on delivery truck floor. Using a forklift truck with a slip-sheet attachment, a delivery truck is unloaded in 2 to 2 1/2 hours. When compared to the forklift truck with a set of forks method, the additional disadvantage is that the forklift truck with a slip-sheet handles only slip-sheet unit loads. Additional advantages are that the pieces are shipped without pallets, which means that the delivery truck carries the maximum capacity in piece weight, and the slip-sheet has a lower cost. Slip-Sheet Back Stop To ensure maximum slip-sheet transfer onto a pallet productivity, most companies in the receiving area have a slip-sheet backstop. The slip-sheet backstop is two long sheets of hardened metal that are welded together at right angles and form a V. The bottom section is a hardened metal plate that is secured to the floor surface. The right angle metal sheets’ height allows a pallet stack on the bottom sheet. When a forklift truck with a slip-sheet load places the slip-sheet load onto the top pallet, with the V-shaped metal backstop the slip-sheet load transfer onto the pallet is easy and quick.


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Nonpowered and Powered Extendible or Retractable Skate Wheel, Roller, or Belt Conveyor The next mechanical-unloading method handles master cartons. The unloading device is the extendible and retractable conveyor group. The extendible and retractable conveyor group uses nonpowered and powered conveyor methods. These conveyors have the ability to extend or retract a master-carton conveyor travel path between the dock area and a vendor or customer delivery truck. In most mastercarton across-the-dock operations, the carton extendible or retractable conveyor method is used to unload vendor and load customer delivery trucks. These extendible or retractable conveyors are located in the receiving or shipping dock areas and are the connecting link between a delivery truck and an across-the-dock carton transport or sorting method. When considering an extendible and retractable conveyor method for your carton across-the-dock receiving operation, the considerations are dock number serviced by the conveyor, frequency of use, available electrical power, and investment funds. Another consideration is how to bridge the gap between the deliverytruck bed and building dock edge and to ensure that the conveyor travel transition is smooth. The various methods to bridge the gap were reviewed previously in this chapter. Other considerations include the delivery truck’s bed length. For maximum unloading and loading employee productivity, the extendible conveyor extends to within 3 feet from the delivery truck’s nose. Next are your carton characteristics and carton conveyability over a nonpowered carton conveyor travel path. These features ensure a constant carton flow from a vendor or customer delivery vehicle and good employee unloading productivity. The next consideration is setting the extendible and retractable conveyor travel path to one side of the dock, which permits pallet truck entry into a delivery truck. When required to unload nonconveyable cartons or pallets from the delivery truck, this feature allows easy and quick pallet truck travel between a delivery truck and receiving dock area and minimizes piece damage and employee injury. The final considerations are employee ability to move the non-powered conveyor sections; locked rear wheels or anchored rear sections of the facility floor surface, which facilitate forward or reverse movement of the extendible and retractable conveyor; under the rear section a guide track to improve retraction; and a method that merges the unloading extendible conveyor travel path with the in-house powered transport and sorting conveyor. Extendible and Retractable Conveyor Merge with Transport and Sorting Conveyor Options The extendible and retractable unloading conveyor merging with the in-house carton transport and sorting powered conveyor travel path ensures that the across-the-dock master cartons continuously move from the vendor or customer delivery truck to the in-house carton transport and sorting powered conveyor method or customer delivery truck. The extendible and retractable conveyor travel path merging with the in-house carton transport and sorting powered conveyor travel path designs are to



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attach an incline/decline conveyor section to the extendible and retractable conveyor frame, and to locate an incline/decline conveyor section at each merge location. The first option is the incline/decline conveyor section attachment to the extendible and retractable conveyor frame. This design has the incline/decline belt conveyor placed onto the extendible and retractable conveyor frame (Figure 7.15). This powered incline/decline belt conveyor extends upward from the extendible and retractable conveyor bed to merge with the in-house carton transport and sorting powered conveyor travel path. When compared to the other extendible and retractable conveyor merge design, this feature reduces the total conveyor investment, but requires a wider clear path for the extendible and retractable conveyor movement between two docks. This feature means a larger receiving or shipping dock area, but a low equipment investment. The second option is to have the incline/decline conveyor section located at each in-house transport and sorting powered conveyor merge location. This incline/decline conveyor section extends downward from the in-house carton transport and sorting powered conveyor travel path to the mobile unloading conveyor travel path. This design increases the total-carton conveyor investment, but requires a narrowed and clear path for the extendible and retractable conveyor between two docks. This feature means a smaller receiving or shipping dock area and conveyor investment. Various Extendible and Retractable Conveyors With the extendible and retractable carton unloading conveyor group, the conveyors are as follows: • • • • • • • •

Nonpowered manual setup skate-wheel straight carton-unloading travelpath conveyor Nonpowered manual nesting (retractable) and extendible skate-wheel straight or flexible travel-path conveyor Nonpowered manual nesting (retractable) and extendible roller straight or flexible travel-path conveyor (Figure 7.16) Manual nesting (retractable) and extendible skate-wheel travel-path conveyor Manual nesting (retractable) and extendible roller travel-path conveyor Mobile-position nesting (retractable) and extendible powered-belt travelpath conveyor Fixed-position nesting (retractable) and extendible powered-belt travelpath conveyor Fixed-position fixed-bed mobile forward and reverse powered-belt travelpath conveyor (Figure 7.17)

Nonpowered Manual Setup Skate-Wheel or Roller Straight Carton-Unloading Conveyor Travel Path The nonpowered manual setup skate-wheel or roller straight carton-unloading travelpath conveyor method is the first manual method. Prior to the unloading/loading activity, the method requires your dock employees to set up the conveyor travel path


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FIGURE 7.15 Extendible truck conveyor. (Photos courtesy of Siemens Dematic [www.siemansdematic.us]. With permission.)



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NESTED CONVEYOR

EXTENDED CONVEYOR

FIGURE 7.16 Flexible conveyor.

FIGURE 7.17 Roller and skate-wheel conveyor. (Illustrations courtesy of Siemans Dematic [www.siemans-dematic.us]. With permission.)


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on the dock and in the delivery truck. For the unloading and loading activity, as the delivery-truck carton loaded/unloaded quantity changes, the employees are required to add or remove conveyor travel-path sections. The conveyor options are the carton conveyor type or travel-path surface (skate wheel or roller conveyor), and the method to support the conveyor travel path. The nonpowered or gravity skate-wheel conveyor method has several small wheels that are attached to an axle and turn on the axle (Figure 7.18). The skate wheels have a plastic, metal (steel or aluminum), or rubber travel-path surface that comes in contact with the carton’s bottom exterior surface. With most straight travelpath conveyor models, each axle end is attached to a conveyor frame. The flexible model has each skate wheel attached to a bracket, and the bracket base is connected to a large wheel on a swivel caster. To have optimum carton travel over the skatewheel conveyor travel path, your across-the-dock shortest-length carton has at least three skate wheels and two axles under a carton bottom surface. These axles and skate wheels have the structural strength to support the maximum carton weight. The nonpowered or gravity roller conveyor method has rollers (Figure 7.19). Each roller is attached to an axle and turns on the axle. The rollers have a plastic, metal (steel or aluminum), or rubber surface that comes in contact with the carton’s bottom surface. With the straight conveyor travel-path models, each axle end is attached to a conveyor frame. The flexible travel-path conveyor has each roller attached to a bracket and, at the bracket base, connected to a large wheel on a swivel caster. To have optimum carton travel over the roller conveyor travel path, your acrossthe-dock shortest-length carton has at least three rollers under a carton’s bottom surface. These rollers and axles have the structural strength to support the maximum carton weight. When the steel conveyor travel path and conveyor frame is compared to an aluminum conveyor travel path and conveyor frame, the steel travel path and conveyor frame is heavier in weight and the aluminum is lighter. When we compare the nonpowered skate-wheel conveyor method to the nonpowered roller conveyor method, the conclusions are that the skate-wheel conveyor method has lighter weight; it has faster carton travel speed and directs the carton travel or provides carton tracking over the conveyor travel-path surface. The roller conveyor is a heavier method; it handles a wider master-carton mix, but a meshed skate-wheel conveyor handles smaller sized cartons. In addition, the roller conveyor allows a slower carton travel speed over the conveyor surface, has a slightly higher cost, is more able to withstand the impact of cartons being transferred onto the conveyor travel path. The nonpowered or gravity skate-wheel or roller conveyor travel-path support methods are the fixed conveyor travel path that is permanently attached to the delivery truck’s bed and two or three tripod conveyor stands under each conveyor frame or section. The fixed conveyor travel path in the delivery truck is a carton conveyor unloading method that is used with a captive delivery-truck fleet. The delivery trucks have nonpowered conveyor sections that are permanently mounted on the delivery-trailer floor. The conveyor travel path is located to one delivery-truck side. In the U.S., as



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FIGURE 7.18 Skate-wheel conveyor details. (Courtesy of Siemens Dematic [www.siemansdematic.us]. With permission.)

you enter the delivery truck, the preferred side for the fixed conveyor travel path in the delivery truck is on the delivery truck floor’s left side. The reasons for this location are that all public-highway soft shoulders are on the right side and that public roads are lower on the right side. The disadvantages are some increased weight and loss of some cube in the delivery trailer, use for floor-stacked loads, and additional investment in the delivery trailer. The advantages are reduced unloading conveyor setup time; lower investment in extendible conveyors; no facility space required to store the used conveyor sections, and the ability to be used at all locations in your logistics strategy.


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FIGURE 7.19 Conveyor roller spacing and position. (Courtesy of Siemens Dematic [www.siemans-dematic.us]. With permission.)

The tripod-conveyor method is the second manual-conveyor unloading method. With this method, your employees set up tripods (conveyor support stands) on the warehouse dock finished-floor surface and on the delivery truck floor. With this arrangement, the carton conveyor travel path is placed onto the tripods and is, as required, extended from the dock area to the delivery truck’s nose. The disadvantages are longer setup time, which reduces application in an acrossthe-dock supply chain logistics strategy, and a lower conveyor investment. In addition, to minimize employee injury, the carton conveyor travel path has aluminum rollers or skate wheels and is most frequently a skate-wheel conveyor. Extendible and Retractable Conveyors The next delivery truck carton unloading or loading method is the extendible and retractable conveyor method group that has various extendible and retractable conveyors. The extendible and retractable conveyor group has nonpowered and powered carton conveyors that have the ability to extend or retract the carton conveyor travel path between the dock area and the delivery truck. In most carton across-the-dock operations, the carton extendible or retractable conveyor method is used to unload and load cartons from the delivery trucks. These extendible or retractable conveyors are located in the receiving and shipping dock areas. Considerations for an extendible and retractable conveyor for your carton acrossthe-dock receiving and shipping dock operation are the dock number that is serviced by one conveyor travel path, frequency of use, available electrical power supply, and investment funds. Other considerations are determining how the gap is bridged



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between the delivery truck’s bed and dock edge and determining if the transition is smooth. The various methods to bridge the gap between the delivery truck’s bed and building dock edge were previously reviewed in this chapter. Other considerations include the delivery truck’s bed length. For maximum employee productivity, the extendible and retractable conveyor length extends to within 3 feet from the longest delivery truck’s nose. Next is the master-carton characteristics and conveyability of the piece in a nonpowered or powered carton conveyor travel path. This feature ensures a constant carton flow from the delivery truck to the in-house transport conveyor travel path and good employee productivity. Next is setting the conveyor travel path to one side of the dock, which permits pallet truck entry to the delivery truck. When required to load nonconveyable pieces or pieces on pallets, this feature allows pallet trucks to travel between a delivery truck bed and dock area and minimizes piece damage and employee injury. Other considerations include available dock space, an employee’s ability to move the nonpowered conveyor sections, locked rear wheels or anchored rear-conveyor section to improve extendible or retractable conveyor travel-path forward and reverse movement, under the rear section a guide track to improve conveyor retraction, and a method to merge the unloading and loading extendible conveyor travel path with the main transport and sorting conveyor travel path. Dock Area Merge to In-House Transport Conveyor Travel Path The designs for merging the portable unloading or loading extendible or retractable conveyor travel path with the main in-house transport and sorting carton conveyor travel path are to attach the incline or decline conveyor to the extendible or retractable conveyor housing, and to have an incline and decline conveyor section at each required merge location on the main transport travel path. Attached to Housing The first option has the incline or decline belt conveyor travel path attached to the extendible unloading or loading conveyor housing. This incline or decline conveyor travel path extends upward from the extendible mobile conveyor base to the carton merge location on the carton main transportation or sorting conveyor travel path. This feature means that as the extendible conveyor travels between two docks, the incline or decline conveyor section moves with the extendible conveyor section. This feature reduces the total conveyor investment but requires a wide clear travel path for the extendible conveyor, which means a wider receiving or shipping dock or building area. Attached to the In-House Transport Travel Path The second option has an incline or decline conveyor travel-path section that is at each required merge location on the main in-house transport conveyor travel path. The incline or decline conveyor section extends downward from the main transport and sorting conveyor travel path toward the extendible conveyor travel path. This design increases the total conveyor investment, but requires a narrower travel path for the extendible conveyor to move between two dock doors, which means a smaller receiving and shipping dock or building area.


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Various Extendible and Retractable Conveyors Within the extendible and retractable carton conveyor group, the conveyor types are as follows: • • • • • • •

Nonpowered manual nesting or retractable and extendible skate-wheel straight or flexible conveyor travel path Nonpowered manual nesting or retractable and extendible roller straight or flexible conveyor travel path Manual nesting or retractable and extendible powered skate-wheel conveyor travel path Manual nesting or retractable and extendible powered roller conveyor travel path Mobile-position nesting or retractable and extendible powered belt conveyor travel path Fixed-position nesting or retractable powered belt conveyor travel path Powered extendible or retractable belt conveyor with a fixed support for the belt conveyor travel path

Nonpowered Nesting (Retractable) and Extendible Skate-Wheel Straight Conveyor The first master carton unloading conveyor method is the nonpowered nesting (retractable) and extendible skate-wheel conveyor. The nonpowered nesting (retractable) and extendible skate-wheel conveyor features are two stages (extended stage and retracted stage) and two types (straight-frame carton conveyor travel path and flexible carton conveyor travel path). The retracted nesting and extendible skate-wheel conveyor has all the skatewheel conveyor frame sections pushed (retracted) under the rear conveyor frame section. In the retracted stage, the nesting extendible conveyor has its shortest or fully retracted length. A nesting extendible skate wheel conveyor’s full retracted length is 11 feet to 11 feet, 6 inches. In the fully extended or active stage, the skate-wheel conveyor is in its longest stage. The skate-wheel conveyor section number determines the conveyor’s full extended length: with 2 conveyor sections, the conveyor travel path extension is 20 feet; with 3 conveyor sections, the conveyor travel path extension is 30 feet; and with 4 conveyor sections, the conveyor travel path extension is 40 feet. The nonpowered nesting (retractable) and extendible skate-wheel conveyor’s components are support members and casters or wheels; straight conveyor frame sections; and skate wheel, transfer rollers, or carton travel path. The nonpowered manual nesting extendible skate-wheel conveyor support members have sleeve legs that adjust the conveyor travel-path surface elevation above the dock-area floor or delivery truck bed. The leg adjustment feature permits these adjustments to the conveyor travel path slope: the charge end has a 10-inch elevation change and the discharge end has a 2-inch elevation change. This conveyor travelpath elevation change ensures the best carton travel speed and carton tracking over



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the conveyor travel path. To improve conveyor travel-path rigidity and stability, knee braces are attached at right angles to the support legs and conveyor frame. The straight conveyor is extended and retracted in one direction and each conveyor section leg has a 4-inch diameter wheel on a rigid caster. The outside rail to the outside rail or carton travel path dimension may be 12, 15, 18, or 24 inches wide. The straight-conveyor design serves as a guide as the various conveyor sections are retracted under the rear conveyor section. Nonpowered Nesting (Retractable) and Extendible Skate-Wheel Straight Conveyor The next nonpowered manual nesting extendible skate-wheel conveyor component is the carton conveyor travel path. The carton conveyor travel path has skate wheels and transfer rollers. The various skate-wheel types are as follows: steel- or zincplated at 1 5/8 inches diameter with a 5/8-inch face, and a skate-wheel surface that provides a 30-pound capacity; aluminum at 1 5/16 inches diameter with a 5/8-inch face, and a skate-wheel surface that provides a 15-pound capacity; and plastic or nylon at 1 5/16 inch diameter with a 5/8-inch face, and a skate-wheel surface that provides a 30-pound capacity. Skate wheels are placed on 2 1/2-inch centers on a 1/4-inch thread axle and are locked to the conveyor frame ends. For good carton conveyance, there are at least three skate wheels under the shortest carton length. The next carton conveyor travel-path component is the hinged transfer (transition) roller section. The transfer roller section is located on each conveyor section discharge end except the last conveyor travel path section discharge end. These transfer roller sections are 1-inch diameter 18 gauge rollers on 1 1/4-inch centers. As a hinged component, the roller transfer device bridges at a downward angle the gap between two extendible conveyor sections. The last conveyor travel path section discharge end has a pull handle and a carton stop device. The weight comparison based on a 40-foot long carton conveyor travel path and various width skate-wheel straight carton conveyor travel paths is as follows: a 12inch-wide conveyor travel path has a 583-pound weight, a 15-inch-wide conveyor travel path has a 626-pound weight, an 18-inch-wide conveyor travel path has a 681pound weight, and a 24-inch-wide conveyor travel path has a 789-pound weight. As an unloading conveyor, the conveyor section inside the delivery trailer has a higher elevation and declines onto the dock conveyor section. The skate-wheel carton unloading conveyor method has a lighter weight. Nonpowered Nesting (Retractable) and Extendible Roller Straight Conveyor The nonpowered nesting (retractable) and extendible roller conveyor components are support members and casters or wheels, straight conveyor frame sections, and rollers, transfer rollers, or carton travel path. The support members of the nonpowered manual nesting extendible roller conveyor have sleeve legs that adjust the conveyor travel-path surface elevation above the dock-area floor or delivery-trailer bed. See the skate-wheel section for the elevation adjustment description.


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The next nonpowered manual nesting extendible straight roller conveyor component is the carton conveyor travel path. The carton conveyor travel path has rollers and transfer rollers. The first roller type is a steel galvanized roller that has a 3/8-inch diameter and 11 gauge steel. These rollers have free-floating ball bearings and spring loaded axles. The second type has a 1 5/6-inch diameter roller and 16 gauge steel. These rollers have free-floating ball bearings and spring loaded axles. The third type has a 1 5/6-inch diameter roller that is a 5/6-inch thick aluminum roller. The weight comparison is based on a 40-foot-long carton conveyor travel path and various width roller straight carton conveyor travel paths: a 12-inch-wide conveyor travel path has a 694-pound weight, a 15-inch-wide conveyor travel path has a 790-pound weight, an 18-inch-wide conveyor travel path has an 863-pound weight, and a 24-inch-wide conveyor travel path has a 1000-pound weight. The rollers are placed on 1- or 1 1/2-inch centers on the conveyor frame. For good carton conveyance, there are at least three rollers under the shortest carton length. The next carton conveyor travel path component is the hinged transfer (transition) roller section which is the same as the skate-wheel hinge. As an unloading conveyor, the conveyor section inside the delivery truck has a higher elevation and decline onto the conveyor section on the dock. Nonpowered Nesting (Retractable) and Extendible Skate-Wheel and Roller Flexible Conveyor The skate wheel and roller extendible and retractable carton unloading conveyor method is designed as a flexible expandable and nesting skate-wheel or roller conveyor. This flexible conveyor travel path means that a carton conveyor travel path has curves. The flexible carton unloading conveyor method has a support leg with a 5- or 6-inch diameter swivel caster. The flexible carton conveyor travel path has aluminum scissor components that expand and contract as the carton unloading conveyor travel path is moved outward or retracted by an employee. The scissors top skate-wheel or roller axle center spacings are 3, 4, and 5 inches. The skate-wheel carton unloading conveyor expansion and contraction ratio is 4 to 1, which means a 3-foot contracted conveyor is extended to a 12-foot-long carton conveyor travel path. The carton conveyor contraction and extension travel path is 2 feet, 8 inches contracted length to 8 feet extended length; 4 feet contracted length to 12 feet extended length; 5 feet, 4 inches contracted length to 16 feet extended length; 6 feet, 8 inches contracted length to 20 feet extended length; and 8 feet contracted length to 24 feet extended length. When we compare the nonpowered extendible and retractable skate-wheel and roller flexible carton unloading conveyor methods, the skate-wheel carton unloading conveyor method has a light weight. The weight comparison is based on a 30-footlong skate wheel carton conveyor travel path with a 30-inch-wide skate-wheel carton conveyor travel path that has a 406-pound load weight and a 30-foot-long roller carton conveyor travel path with a 30-inch-wide roller conveyor travel path that has a 546-pound weight.



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Electric-Powered Extendible and Retractable Skate-Wheel Flexible Conveyor The next extendible and retractable carton unloading conveyor method is the electricpowered extendible and retractable skate-wheel flexible carton conveyor. This method is similar to the manual extendible and retractable gravity-powered skate-wheel carton unloading conveyor method. The similarities are the type of carton unloading travel-path surface and skate-wheel center spacing or axles along the carton conveyor travel path, the conveyor expansion and contraction ratio of 4 to 1, the carton unloading conveyor travel-path support method and swivel casters, and the carton unloading conveyor travel-path width. The electric-powered extendible and retractable skate-wheel flexible conveyor, in addition to the manual skate-wheel components, has an electric-powered (motorized) conveyor lead end that sits on a series of wheels. When the motorized end is active, it is manually controlled to move forward its wheels from the dock area into the delivery truck. The skate-wheel conveyor travel path is a powered conveyor. The method uses grooved sheaves, driver motors, and drive trains. The small electric-drive motor is a 1/4-horsepower motor. The drive trains are located every 12 feet on the conveyor travel-path length. Each conveyor drive motor is controlled by an off/on switch at the drive train charge and discharge end. The conveyor travelpath speed is adjustable from 0 to 100 feet per minute. The drive train has two strands of number 20 roller chain. These roller-chain travel paths are in the carton conveyor travel-path middle width. Each roller chain is routed over the first skate wheel axle top and under the second skate wheel axle, which creates a zigzag route pattern. As the roller chain is routed over an axle top, the chain travel path is over a tooth-grooved sheave. The roller-chain travel path under the axle is over a smooth plain-face sheave. All sheaves have sealed ball bearings. The drive-train chain travel path is designed with sufficient flexibility to prevent employee limb injury, but has sufficient force to turn the carton conveyor load-carrying surface that propels the carton forward over the carton conveyor travel path. Electric-Powered Extendible and Retractable Flexible Roller Conveyor The next extendible and retractable carton unloading conveyor method is the electricpowered extendible and retractable roller flexible carton conveyor. The method’s features are a roller conveyor travel-path surface as the manual conveyor option and a drive train, motor, and operational characteristics as a powered skate wheel conveyor. The unique features are as follows. The roller conveyor travelpath speed is adjustable from 0 to 85 feet per minute. In addition to the chain travel path, the sheave has two grooves for polyurethane or O-ring drive belts. Each Oring drive belt is looped over a sheave groove and over a carton-carrying roller groove. This feature means that all conveyor travel path rollers are driven carrier rollers. The second top sheave is a smooth sheave, which is the chain return travel path to the drive motor and sprocket.


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All bottom sheaves are smooth and plain grooved sheaves that are attached to a separate axle. The first bottom sheave is a powered chain travel-path part and serves as a guide for the travel between two top sheaves. The second bottom sheave is a smooth plain face sheave and is considered a guide for the return chain travel path. All sheaves have sealed ball bearings. The drive-train chain travel path is designed with sufficient flexibility to prevent an employee limb injury, but has sufficient force to propel the load-carrying surface to move a carton forward over the carton conveyor travel path. Mobile-Powered Extendible and Retractable Powered Belt Conveyor The next extendible and retractable unloading carton conveyor method is the mobile powered extendible and retractable powered-belt conveyor method. This method improves your employee unloading vendor delivery-truck productivity, reduces employee unloading injuries, and decreases the total dock-activity area investment. The method’s components are several sections with a powered belt conveyor travel-path surface that extends into a delivery truck’s bed and retracts onto the dock area, and a traverse parallel between two dock doors. The mobile-powered extendible and retractable powered belt conveyor method components are base support structural members; retractable boom, boom drive motor, and boom drive; traversing rails, wheels, and traversing drive; belt cartoncarrying travel-path surface; conveyor-belt drive motor, drive train, end pulley, and take-up device; guards; and controls. The method’s first component is the base or support section. The base section has several 1/4-inch-thick steel plates and 3/16-inch-thick steel slide bed plates. These steel plates are welded structural members and are coated per the manufacturer’s standard color or per your company specifications. These components provide an enclosed housing for the electrical and mechanical components and drive train, the structural support for a boom and conveyor-belt travel path, and locations for counterweight and wheel attachment. The next components are the extendible and retractable boom, boom drive motor, and boom drive. These components provide the support for the carton travel path between a delivery truck and dock area, and the power to move the carton conveyor travel path between a vendor delivery vehicle and dock area. The boom has several 3/16-inch-thick steel slider bed plates, structural angle members, and side plates. These steel slider bed plates are welded structural members and are coated per the manufacturer’s standard color or per your company specifications. The first type of extendible and retractable boom includes two boom sections per unit which have a 26-foot, 4-inch retracted length with a 37-foot maximum boom extension. This overall conveyor-belt travel path includes a base and a 36-foot, 45-inch boom extension with a 67-inch overall width. The second type has three boom sections per unit, which have an 18-foot, 6-inch retracted length and a 37-foot maximum boom extension. The overall conveyor-belt travel path (base and boom extension) is 55 feet, 6 inches long and 72 inches in overall width. Both boom types have a



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1-horsepower drive motor with Flexidyne™, a sheave, and a V-belt. With tooth sprockets and a closed loop link chain, the boom is designed to extend the belt conveyor travel path in a cantilevered position. The maximum outward carton conveyor travel path length is 37 feet long. The boom extension and retraction travel speed is 40 feet per minute. The third component group consists of the traversing rails, traversing wheels, and traversing drive motor. These components allow the conveyor unit base to travel over a fixed metal travel path between two docks. The conveyor unit base traversing rails are two 3-inch-high crane hardened steel guide rails or tracks with a 1 3/4-inch top travel path. These traversing rails have welded side width anchor hooks and are recessed and anchored into a pit in the floor. Each traversing rail is located approximately 32 5/8 inches from each conveyor unit base and runs the entire traversing distance. End stops at each traversing track end are provided to stop the conveyor unit base travel. The mobile-powered belt conveyor has four traversing wheels. These four wheels permit the mobile belt conveyor unit base to travel over the two rails and to arrive at the adjacent dock. These traversing wheels have an 8 7/8-inch diameter with a flange. These wheels are made from crane hardened steel wheel and sealed ball bearings. Each wheel face matches the iron face and rear traversing rail. The power to traverse the powered belt conveyor unit between two docks is provided by the traversing drive motor and drive train. The traversing drive motor and drive train is a 1-horsepower motor with a Flexidyne drive sheave, V-belt, and sprocket and chain. The conveyor unit traversing travel speed is 30 feet per minute. The fourth mobile-powered extendible and retractable powered belt conveyor is the carton conveyor belt. The belt conveyor is the carton travel path between a delivery truck and dock area. The standard conveyor belt is an 18-inch-wide 3-ply bare duck belt that is installed with the smooth rubber side facing down onto the boom plate surface. The conveyor belt is routed from the drive pulley, over the boom top surface, over the various end pulleys, through the snubber pulley, and through the take-up device. The extendible and retractable powered belt conveyor as a receiving conveyor determines the conveyor belt direction of travel. The receiving unloading conveyor application has the belt conveyor direction of travel from the dock door to the dock. The next powered belt conveyor components are the belt drive motor, drive train, end pulley, and take-up device. These components determine the belt conveyor travel speed and ensure that the conveyor belt travels at the appropriate speed over the conveyor travel path. The conveyor belt drive motor is a 3-horsepower motor that is located at the conveyor charge end. The drive motor tooth sprocket associated open-link, closed-loop chain and drive pulley tooth sprocket turns the drive pulley, which is a 12-inch diameter pulley with a laggard and crown surface. The various end pulleys are located at strategic locations to ensure that the conveyor belt completes the belt travel path around the extendible boom end and through the base. The next belt drive train component is the snubber. The snubber is a 4inch diameter pulley that helps with the belt take-up and belt tracking through the belt travel path. Per the conveyor belt travel direction, on the receiving and unload-


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ing conveyor application, the snubber is located past the belt travel around the drive pulley. The next belt drive train component is the belt take-up device. The belt take-up device ensures that the belt conveyor surface moves at the desired travel speed, first by providing the proper belt tension. As required by the conveyor belt condition, the take-up pulley is moved forward from the drive pulley to increase the conveyor belt travel path for a slack conveyor belt condition, and toward the drive pulley to decrease the conveyor belt travel path for a tense conveyor belt condition. During the boom retraction from the extended position, the take-up pulley provides the available space inside the housing to store the unused conveyor belt length and an extension to allow the conveyor belt to be transferred from the housing to the boom carton conveyor travel path surface. On the receiving or unloading conveyor application, the take-up pulleys are located past the conveyor belt travel path around the drive pulley. A two-boom belt conveyor unit has one fixed and two counterweight take-up pulleys. A three-boom belt conveyor unit has two fixed and three counterweight pulleys. The belt conveyor drive motor and drive train ensure that the conveyor belt travel speed is 85 feet per minute. With the mobile-powered extendible and retractable powered belt conveyor method, the next component is the guards to protect the operator. During the conveyor unit traverse travel, there are safety tow plates with emergency stop (E-stop) movement devices along the housing or base bottom sides. When these traversing E-stop panels strike an object or an employee’s limb, the conveyor unit traveling stops at that moment. Other guards include an extendible boom drive guard or hinged safety plate at the boom front end. When this front end E-stop plate strikes an employee or object, the boom extension movement is stopped at that moment. Per your across-the-dock operation, side guards or guard rails are considered options that are attached to the mobile conveyor unit base top. These devices ensure carton flow across the extendible conveyor travel path surface. The last mobile-powered extendible and retractable powered belt conveyor components are the control devices. The control devices are the push button stations and limit switches for conveyor belt travel, boom extension and retraction, and boom traverse travel. These controls are located at the operator station, and at the boom front end is located a conveyor belt start/stop button and a E-stop safety switch. Stationary-Powered Extendible and Retractable Powered Belt Conveyor The next powered carton-unloading conveyor method is the stationary-powered extendible and retractable powered belt conveyor method. The method has similar features to the mobile-powered extendible and retractable powered belt conveyor. The different features are that this method services one dock; that with one conveyor belt travel path per dock door, it increases the total receiving dock investment, but has a lower cost per extendible powered belt conveyor unit; and that the booms with a powered conveyor belt travel-path surface extend into a delivery truck’s bed and retract onto a fixed dock location. When the stationary-powered extendible and retractable powered belt conveyor method is compared to the mobile-powered extendible and retractable powered belt



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conveyor method, many components are similar and few are different. The similarities are base or support structural members; boom drive motor and boom drive unit; conveyor belt carton-carrying travel path or surface; and conveyor belt drive motor, drive train, end pulley and take-up device. The differences are foot anchors, guards, and controls. The extendible and retractable powered belt conveyor method is a stationary method; the base is permanently anchored to the receiving dock area floor surface. This feature minimizes the amount of counterweight in the belt conveyor rear housing. With no conveyor travel path or boom traversing capability, the required side guard panels, switches, and wiring are eliminated from the stationary conveyor belt unit. The stationary belt conveyor unit does not traverse; the control devices are the push button stations and limits switches for the conveyor belt travel and boom extension and retraction. These controls are located at the operator station, and at the boom front end is located a conveyor belt start/stop button and a boom extension E-stop safety switch. Stationary Extendible and Retractable Conveyor Unit with a Fixed Support for the Powered Belt Conveyor The next powered carton unloading conveyor method is the stationary extendible and retractable powered belt conveyor with a fixed support for the powered belt conveyor. This method has similar features to the fixed position extendible and retractable powered belt conveyor. The different features are slightly lower cost per unit; a fixed support for the powered belt conveyor; and four wheels, drive motors, and drive trains to move both the fixed support unit, the powered conveyor belt, and fixed structural members that are supported on four wheels. These structural members provide the support on the conveyor belt travel path’s full length. (It is permanently fully extended.) When in a vendor delivery truck or on the receiving dock, the carton conveyor travel path has a fixed length and requires space on a receiving dock that is directly behind the receiving dock door. When the stationary extendible and retractable powered belt conveyor with a fixed support for the powered belt conveyor is compared to the mobile-powered extendible and retractable powered belt conveyor, there are some similarities and several differences. The similarities are a conveyor belt carton-carrying travel path or surface; a conveyor belt drive motor, drive train, end pulley, and take-up device; and controls. The differences are base or support structural members, four wheels and forward and reverse conveyor travel path, fixed unit drive motor, and belt take-up device. The stationary extendible and retractable powered belt conveyor with a fixed support for the powered belt conveyor has structural steel coated members that are welded together to provide support and form the conveyor belt travel path platform, support legs for the four wheels, and an operator handle at the front for steering the conveyor unit. The four wheels are pneumatic wheels. Each wheel has a rubber tread cover and a rigid caster. Each rubber wheel is located under each rectangle shaped conveyor unit corner. The fixed casters and large pneumatic wheels improve the conveyor unit’s ability to enter and exit a delivery truck over the device that is used to bridge the gap between a delivery truck’s bed and dock edge and to travel on the dock floor. To assist with the forward and reverse conveyor unit travel, guide rails are


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attached to the floor surface. The two guide rail locations are on the inside of the conveyor wheels’ travel path. A 1-horsepower drive motor and drive train provide the force to move the conveyor unit forward or in reverse over the dock floor surface, over the device to bridge the gap, and into a delivery truck. With a fixed conveyor belt conveyor travel path, the powered belt take-up device is a manually adjusted screw device or an automatic counterweight take-up device. As the belt conveyor is moved forward and reverse, this fixed carton conveyor travel path is supported on four wheels. With one wheel under each rectangle shaped conveyor travel path corner, there is minimal counterweight in the conveyor base rear section. With this feature and when not in a delivery trailer, the conveyor unit requires dock space. The conveyor belt method does not traverse; the control devices are the stop and start push button stations and limit switches for conveyor belt travel and conveyor fixed travel forward and reverse movement. These controls are located at the operator station, and at the boom front end is located conveyor belt start/stop buttons and a unit E-stop safety switch. Pallet-Handling Device The mechanized pallet-unloading method for an across-the-dock operation is the pallet-handling device (PHD) method. The PHD method is a stationary or mobile fully automatic device that is used to unload a delivery truck that has pallets or loads in containers. The PHD base is on the receiving dock with a powered roller pallet conveyor travel path that is fixed to the base top; this design provides the staging area for the pallets. Unloading a delivery truck at the dock has the delivery-truck pallet pattern loaded into the PHD method microcomputer. The PHD method sensor devices determine the first pallet location; the PHD method is ready to receive or unload pallets from the delivery truck. When the PHD method forks extend forward into the delivery truck, the fork sensors determine the pallet openings. With a proper analysis, the PHD method extends the set of forks forward into the pallet fork openings and elevates the pallet onto the set of forks. With the pallet on the set of forks, the PHD method returns from the delivery truck to the receiving dock position and raises the pallet for placement onto the live roller conveyor travel path that is on the base top. With the single set of forks, the PHD method device handles a 3500-pound pallet and a full delivery truck (18 pallets) in 30 minutes. If the delivery-truck spotting time is required, add 15 to 30 minutes. With a double set of forks, the PHD method handles a total of 3500 pounds, the combined total for two pallets. When compared to the single pallet PHD device, the individual pallet weighs 1750 pounds. With two pallets per trip, the unloading activity time is reduced to 20 to 25 minutes for each truck. The fork sensors and the PHD method handle a pinwheel delivery-truck loading pattern. With four-way pallets or containers, the PHD method handles stacked pallets or containers. To ensure dock area safety and minimize damage, the PHD method has a safety stop device plus safety stop-light curtains that extend on both receiving dock sides from the dock door to the PHD method base. The PHD method has the capability to handle all delivery truck lengths. The disadvantages are capital investment and large dock area requirement of 36 to 40 feet, and to achieve the objective unloading pallet rate, the pallet loads are



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handled in a fluid manner without interruption to the pallet flow. Advantages are minimal labor expense; no dock leveler investment or security guarding for the dock doors and walls; minimal requirement for dock area and delivery-truck dock lights; reduced building dock area and receiving equipment investment; and reduced piece, building, and equipment damage and maintenance. Pallet-Flow Device The next automatic pallet unloading and device handles pallets between a delivery truck and a facility dock. This method has air pressure, powered strands of chain or mobile rails, and conveyors that move the pallets between a delivery truck and dock. Specially designed delivery trucks have specially designed floors, and the facility dock floor has a specially designed push and pull device with conveyors. After a delivery truck is located at the dock, an employee activates the dock area section to push the pallets forward from the dock area onto the delivery truck floor conveyor. The entire load is pushed into the delivery truck. The truck driver ensures that the load is secured in the delivery truck and the building power electrical cable is disconnected from the dock. The disadvantages are capital investment in the delivery truck, facility dock area investment, increased maintenance, and the fact that both the receiving and shipping locations must be designed to handle the unique load. The advantages are less dock time, fewer docks, fewer employees, and less equipment.

PIECE CHANGE Some companies that are involved in an across-the-dock supply-chain logistics strategy realize a piece change. With this strategy, as the piece flows through the across-the-dock facility or segment, the piece (master carton or pallet) has the possibility to change its physical characteristics. With a master carton or pallet load piece, the options are for a piece to retain the same characteristics, for pieces to be removed individually or multiply from the master carton and sent to the customers, and for individual or multiple master cartons to be removed from a pallet and sent as master cartons to customers. In most single-item, flat wear, or GOH across-the-dock operations, single item, flat wear, and GOH are received at the facility as master cartons or a large piece quantity and sent as individual or multiple SKUs to the customers. For across-the-dock applications in a company’s supply-chain logistics strategy to be cost-effective and efficient, the across-the-dock facility or segment requires conveyable master cartons. Each carton has a discrete bar-code label and each facility has mechanized carton transport and sorting along with a good forklift-truck or pallet-truck method to handle nonconveyable SKUs.

SMALL-ITEM ACROSS-THE-DOCK OPERATION CUSTOMER-ORDER SHIPPING PIECE

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As the small items flow through an across-the-dock sorting area, the pieces change from small items in a master carton or a sleeve to an individual small-item (price-


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labeled or not) mix that is sorted (collected) per each customer-order. With the operational characteristic, small-item across-the-dock operations are required to (1) provide a secure container for this wide piece product mix, (2) hold the largest piece quantity, (3) have a low-cost container, and (4) provide a container that is handled by the supply chain logistics segments. Small-item across-the-dock operations use a cardboard carton, reusable plastic shipping container, or plastic or paper bag.

SMALL-ITEM, FLAT WEAR, OR GOH ACROSS-THEDOCK OPERATION When you consider a small-item, flat wear, or GOH across-the-dock operation for your company supply-chain logistics strategy, the small-item, flat wear, or GOH methods are manual, mechanized, or automated. If your across-the-dock operation handles single item, flat wear, or GOH SKUs that are received as single item, flat wear, or GOH SKUs or in master cartons, your operation options are to have the SKUs separated by individual customer location, or, per the customer-order, price ticketed and packed by one of your employees. With this price-ticket option your across-the-dock operation requires a processing (opening, ticketing, sorting, and packing) area. These across-the-dock valued processing activities are sequentially located between the receiving area and the shipping area. In a single-item, flat wear, or GOH opening, ticketing, sorting, and packing across-the-dock facility, the receiving department separates each SKU’s delivered quantity in its style, color, or size. This piece separation by style, color, and size ensures that the ticketing and sorting activities are cost effective and efficient.

MASTER-CARTON OPEN ACTIVITY After the small-item or flat wear pieces in a master carton are unloaded from a delivery truck and are inspected and approved, the across-the-dock piece flow is as follows: all vendor priced pieces flow directly to the customer-order sorting area, and all nonpriced pieces flow through a price-ticketing process. The master cartons with nonpriced pieces are placed onto the assigned opening lanes. If there is no space available on one opening lane, the master cartons are placed into temporary storage positions. These storage positions are floor-stacked pallets, stacking frames or portable racks, storage racks, or carton conveyor lanes. When an opening lane or workstation becomes available, and per the acrossthe-dock operation, the master cartons are transferred from a temporary storage position to the assigned vacant opening lane or work station. The opening methods are tabletop and gravity or nonpowered carton conveyor flow lane.

SKU TICKETING Per your across-the-dock operation and prior to the pieces’ arrival at the customerorder sorting area, all nonprice ticketed individual pieces receive a price ticket.



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Tabletop Price-Ticketing Methods The tabletop piece price-ticketing method has a 4- to 6-foot by 30-inch flat rectangular-shaped surface table that has a full pallet or nonpowered conveyor placed on the rectangle table’s right end. The price-ticket employee transfers one master carton from the pallet or conveyor onto the tabletop and removes the SKUs from the carton. During this process, the employee verifies the SKU quantity and attaches a price ticket to each SKU. The price-ticketed SKUs are returned to the carton or placed into a new carton, plastic container, or captive tote. The cartons or totes are placed onto an empty pallet or a second nonpowered conveyor. The empty pallet or conveyor is located on the table’s left side. All price-ticketed SKUs (cartons or totes or pallets) are transferred by pallet truck or powered conveyor from the ticket area to the sorting area. The other transport methods are four-wheeled carts, nonpowered roller or skate wheel conveyors, and powered or nonpowered overhead trolleys with a basket. The disadvantages are low volume, low employee productivity, and increased piece handlings. The advantages are low investment, ease of operation, and low employee training. Gravity or Nonpowered Conveyor Price-Ticketing Method The second piece price-ticketing method has nonpowered carton flow conveyors, a powered zero-pressure queue roller, powered belt conveyors, conveyable cartons, totes, work shelves, and platforms. The pieces or master cartons are placed onto opening lanes in an arrangement that has one SKU (size, color, and style) occupy one lane. A lane is a gravity-flow conveyor travel path that permits the carton to flow from the receiving area to the opening position. On the lane’s opening side is a fixed end stop. If there is more than one SKU per receiving pallet, the SKU arrangement is by color and style with the largest SKU size on the flow-lane bay’s right-hand side. This side is the right side of the receiving person who faces the gravity carton conveyor lanes or bay. As the master carton arrives at the opening station, an opening employee removes the SKU pieces from the carton, counts the pieces, and places the SKU pieces in a carton or tote. Empty new cartons or plastic totes are supplied by a powered conveyor travel path. The merchandise is placed in the tote in an arrangement that has the SKU piece-ticketing location face the tote direction of travel. When possible the SKU pieces are standing vertically in the tote. The opening employee enters all SKU piece counts onto a tally sheet, radio frequency (RF) device, or personal computer (PC). As required, empty cartons and other trash are thrown into the trash take-away system. The price tickets for all the SKUs are placed in the first tote. If there are several totes, a SKU piece identification tag is attached on the first tote’s front end. As the totes arrive in the ticketing area, a lane-control employee directs the lead tote with the piece identification tag and price tickets into an open-pricing gravity conveyor lane. The trailing totes are allowed to flow into the assigned gravity flow


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lane until the next tote with a new lead piece identification tag and price tickets arrive in the ticketing in-feed area. The price-ticketing gravity conveyor lane end is the pricing station. The totes arrive with the SKU piece pricing location facing the direction of travel and the pricing employee. A ticketing employee removes the price tickets from the lead tote and leaves the SKU pieces in the tote. The price-ticketing process has an employee attach a price ticket to each piece. During the pricing activity, the SKU identification tag remains on the lead tote. After the price tickets are attached to all SKU pieces and totes, the totes are transferred and queued in another gravity flow lane. Per a SKU ticketing activity completion schedule, the totes are released from the ticketing lane onto the distribution take-away gravity-flow conveyor lane. At the end of the distribution gravity-flow conveyor lane is a tote end stop. When all the styles, sizes, and colors of the merchandise are ticketed, a lanerelease employee releases the full totes from the ticket lanes to the merchandise distribution lanes. As the totes arrive at the distribution gravity-flow conveyor lanes, a lane-control employee directs the totes into vacant gravity flow lanes. Adjacent gravity-flow conveyor lanes are used for the merchandise, or the next lead tote with a new piece identification tag arrives at the transfer station. At the distribution gravity-flow lane’s discharge end, the SKU pieces are allocated to customer orders. The disadvantages are high capital investment, employee training, and management control and discipline. The advantages are a high volume and wide product mix, work position flexibility, labor allocation by skills, and queues prior to workstations.

VARIOUS SMALL-ITEM, FLAT WEAR, SORTING METHODS

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GOH ACROSS-THE-DOCK

The various small-item, flat wear, and GOH across-the-dock sorting methods ensure from a SKU piece mix group for several customer orders that the appropriate SKU and SKU quantity is allocated to a customer pack station or lane. At the pack station or lane, the mixed pieces for one customer-order are consolidated and packaged in a customer delivery carton for transfer onto the transport and sorting method. The transport and sorting method moves the customer-order carton to the assigned customer staging area or directly onto a customer delivery truck.

ACROSS-THE-DOCK SMALL-ITEM ORDER SORTING

OR

FLAT WEAR APPAREL

OR

CUSTOMER-

When properly ticketed or nonticketed small-item or flat wear apparel pieces arrive at the across-the-dock customer-order sorting area, the receiving and price ticketing departments have completed their across-the-dock activities. The next activity is the customer-order sorting activity. The heart of a single-item or flat wear apparel across-the-dock operation is the customer-order sorting activity. This activity ensures that your customer receives the appropriate ordered small-item or flat wear quantity.



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The various small-item or flat wear apparel sorting methods are the manual method, which includes racks and shelves; and the mechanized methods, which include waterfall or store dump, powered conveyor and divert spurs, carousel, rapid pack or hotel, and indexing powered conveyor; and automatic methods, which include Bombay drop, SBIR, flap sorter, Nova sort, gull wing, and tilt tray. Manual Small-Item or Flat Wear Apparel Across-the-Dock Sorting Methods The first across-the-dock small-item and flat wear apparel sorting method is the manual sorting method that has an employee perform all sorting activities. The sorting activities include SKU movement through the sorting area and completed customer-order transfer to a take-away travel path. The manual small-item or flat wear apparel across-the-dock sorting methods are to have SKUs occupy a shelf or rack position, and to make the customer sorting location a shelf or rack position. These methods have similar design parameters and operational characteristics. The first sorting method has empty rack or shelf positions that are on both sides of a sorting aisle. As an employee travels through the sorting aisle with a SKU quantity and rack- or shelf-position assignment instruction, the employee transfers each small-item or flat wear SKU into each assigned rack or shelf position. Each rack or shelf position is identified with a discrete identification — alphabetic characters or digits — that is the SKU’s temporary holding position. For best performance, the SKU locations are sequenced in a routing pattern by the SKU identification number: first digit and second digit, first digit and last digit, or last digit and next-to-last digit. The selection of the sequence is based on the random digits to your SKU identification numbers. During the sorting across-the-dock activity, employees with a paper customersorting document walk in the aisle with a load-carrying surface vehicle. The document is arranged in SKU sequence (which matches the SKU shelf or rack sequence). The load-carrying surface or vehicle positions are arranged in customerorder number sequence. As an employee travels through the aisle, the employee matches the paper customer SKU sorting number to the SKU discrete number that appears on the rack or shelf position. As directed by the paper customer-sorting instruction document, the employee transfers the appropriate SKU quantity from the rack or shelf position to the customer-order assembly location of the loadcarrying surface or vehicle. The mobile vehicle load-carrying surface is divided in several compartments or positions. Each position on the mobile vehicle load-carrying surface is considered a discretely identified customer sorting location. The location is a container captive to the sorting operation, a vacant position with three solid or meshed sides, or a customer-order shipping carton. Per your company’s sorting practice, the sorting is for a single customer-order or a batch of customer orders. With the latter option, the employee sorts the SKUs to the mobile vehicle’s appropriate bin (or position). The next sorting method has each customer sorting location occupy a rack or shelf position. Each rack or shelf position is discretely identified with alphabetic


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characters, numeric digits, or a combination, which is a discretely identified customer sorting location with a container captive to the sorting operation, a threesided wall vacant position, or a customer-order shipping container. The customerorder numbers are in arithmetic progression from lowest to highest number, with the lowest number at the entrance and the highest number at the last position. There is an aisle between the two rack or shelf rows. An employee with a recap batch customer-order sorting instruction form for one or several SKUs travels through the sorting aisle. If there are several SKUs per sorting trip, the employee uses a manualpowered or electric-powered vehicle that has the load-carrying surface designed with the capability to carry several SKUs. As directed by the recap sorting document, which is in customer number sequence and shows the customer ordered SKU quantity, the employee stops at the appropriate customer-sorting location and transfers the appropriate SKU pieces from the load-carrying surface to the appropriate customer sorting location. With the manual across-the-dock small-item or flat wear apparel sorting method, after the completion of the customer-order sorting activity, each customer-order sorted SKU quantity is transferred into a captive or customer shipping container and is transported to a check station. In the across-the-dock method, the next activity is the check and pack activity to verify accurate sorting and carton packing. In some applications with RF scanning in the customer-sorting activity, the customer-order shipping carton is sealed and sent directly to a manifesting or shipping station. Other design considerations for a manual sorting method are as follows: instead of static rack or shelf sorting positions, use carton gravity conveyor flow lanes, push back conveyor flow lanes, or slides. To obtain maximum employee productivity, the SKUs are moved by an employee with an apron, tote, or sack; an overhead nonpowered trolley with a basket that has several compartments; or with a four-wheeled nonpowered cart or a powered vehicle with a load-carrying surface. With any of these vehicle transport methods, to obtain maximum employee productivity and minimize damage to the vehicle or sorting equipment, the vehicle has an aisleguidance travel method. The final consideration is an RF scan for each transaction. The disadvantages are potential sorting errors, a low small-item or flat wear quantity, paper or RF device sorting instruction, the need for an employee to read, ability to handle only a few SKUs, low employee productivity, and the need for a large square-foot area. The advantages are the low investment, ability to set up in any facility, ability to handle a wide SKU mix, minimal employee training, and flexibility to handle volume fluctuations; there is also no need for a computer program to print bar-code labels. Mechanized Across-the-Dock Small-Item or Flat Wear Apparel Sorting Methods The second group of across-the-dock small-item or flat wear apparel sorting methods is the mechanized-sorting method group. These methods require that all customer piece or order sorting locations are arranged in a predetermined sequence. This sequence is along a nonpowered conveyor, powered conveyor, or



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nonpowered overhead trolley with a basket travel path on one side or both sides. All SKUs and customer sorting locations are discretely identified with the appropriate code. The mechanized across-the-dock small-item or flat wear apparel sorting methods are waterfall or store dump, powered conveyor and divert spurs, horizontal carousel, flow rack or rapid pack, and indexing powered conveyor. Waterfall or Store-Dump Method The first mechanized small-item or flat wear apparel across-the-dock sorting method is the store-dump or waterfall method. The store-dump or waterfall method layout has multiple-shelf customer-sorting locations. Each location has a full customer shipping container take-away conveyor system, an employee and mobile equipment aisle, a staging area for SKU transport devices at each customer location front, and an empty shipping container replenishment system. With the shelf arrangement, each shelf level holds one customer shipping container. Each shipping container is identified with the customer discrete identification code. A staging area is provided prior to the sorting aisle. The SKU transport device (mobile cart, tote on conveyor, or trolley basket) is moved by employee from the staging area into the sorting aisle, which is located between two shelf lanes. Walking in the aisle, an employee looks at the sorting instruction form, matches the customer sorting instruction number to the customer identification code and transfers the appropriate SKU quantity from the mobile device to the shipping container in the customer sorting location. With crossover aisles, this sorting equipment and aisle layout permits empty cartons, trolleys, or totes to be removed from the sorting area and for other mobile devices with other SKUs to flow through the sorting area with minimal queues. Empty shipping containers are supplied to the sorting area by an overhead conveyor system or an employee with a two-wheeled hand truck. All full customer shipping containers are pushed forward from the customer sorting shelf onto a takeaway conveyor for transport to the checking, sealing, and manifesting area. An option for the printed sorting document method is a sort-to-light instruction method. For additional sort or pick-to-light instructions, we refer the reader to the pick-to-light section in the small-item or flat wear apparel order-fulfillment methods in Chapter 3. The disadvantages are employee walking distance, difficulty of obtaining high employee productivity, and management control and discipline. The advantages are the ability to handle a medium volume, a medium customer number, and a wide product mix; there is also less need for employees to lift full customer shipping cartons. Powered Smooth-Top Belt-Conveyor and Divert-Spur Method The next small-item or flat wear apparel across-the-dock sorting method is the powered smooth top belt conveyor with locations along the conveyor travel path. On the main conveyor travel path each piece of small-item or flat wear apparel with a bar-code label is individuated and travels on the conveyor travel path past a bar-code scanner. At the scanner transfers the SKU discrete divert location to a


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microcomputer. The microcomputer and a tracking device control the appropriate divert device to transfer the small-item from the main conveyor travel path onto the appropriate customer sorting location. If the SKU is not required at the divert station, the small-item continues travel on the main conveyor travel path until it arrives at the required divert spur. The sorting spur directs the small items onto a slide or chute, into a captive tote, or into a shipping container. After the sorting activity is completed, as required, an employee transfers the customer small items from the slide or captive container into a customer shipping container or transfers the customer shipping container onto a take-away conveyor travel path. The take-away conveyor travel path transports a customer shipping container to a check, package, and seal station. The disadvantages are capital investment; the use of a computer program, barcode label, and scanner; the requirement of a large floor area; and SKU physical characteristics that permit the small-item or flat wear apparel SKU to travel on the conveyor travel path and a divert device to operate. The advantages are employee productivity, reduced sorting errors, minimized employee injury, the ability to handle a medium volume, the ability to handle a wide piece mix, and the ability to handle a large number of customer locations (with the batch customerorder method). Horizontal Carousel, Indexing Inverted Power and Free Conveyor, and S.I. Cartrac The next mechanized small-item or flat wear apparel across-the-dock sorting method group includes horizontal carousel, indexing inverted power and free conveyor, and S.I. Cartrac®. The horizontal carousel, inverted power and free conveyor, or S.I. Cartrac small-item sorting designs are similar; each has a small-item in-feed conveyor, a bar-code scanner, an empty container or carton conveyor travel path, and a sorting instruction method. For a cost-effective and efficient horizontal carousel method, there are 3 to 4 horizontal carousel units that interface to one customer sorting location. The sorting instruction options are a bar-code scanner with a discrete bar-code label on the customer location and a light display unit, or a sorting paper document with discrete alphabetic characters, numeric digits, or a combination of both on each customer sorting location. Each horizontal carousel, inverted power and free conveyor, or S.I. Cartrac method has baskets as the customer sorting location. At the sorting location are the required visual display lights or paper document sorting instructions. With the visual light display method, at the sorting location as the horizontal carousel, inverted power and free conveyor, or S.I. Cartrac method customer location (shelf, basket, or bin) travels past the bar-code scanner, the scanner sends the customer discrete number to a microcomputer. The microcomputer activates the visual display light to show the appropriate customer number and SKU quantity that is required for the customer-order. When the across-the-dock carton of small-item or flat wear apparel SKUs with a discrete identification arrives at the sorting station, a bar-code scanner reads the SKU bar code and sends the SKU description to the microcomputer. The micro-



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computer determines the SKU quantity for each customer-order, and this SKU quantity is displayed on the sort to light display screen. Per the sort-to-light or paper sorting instruction, a sorting employee transfers the appropriate SKU quantity from the across-the-dock small-item or flat wear apparel SKU conveyor travel path to the appropriate customer container or location on the horizontal carousel, inverted indexing power and free conveyor, or S.I. Cartrac unit. After the SKU transfer is completed, the employee has the horizontal carousel, inverted indexing power and free conveyor, or S.I. Cartrac unit advance forward to have the next customer sorting location arrive at the sorting station. After all SKU sorts are completed, the next across-the-dock customer-ordered small-item or SKU is advanced forward to the sorting station. A SKU entry option has an employee with a handheld scanner scan the bar-code label. A sorting instruction option is to have an employee read and match the horizontal carousel, inverted power and free conveyor, or S.I. Cartrac method shelf, basket, or bin discrete customer identification to the paper document sorting customer identification. With a match the employee completes the sorting activity. All full customer shipping containers are released onto a take-away transport conveyor travel path. A separate conveyor travel path supplies empty customer shipping containers, and a separate bar-code printer prints the appropriate discrete bar code for the customer sorting location. Prior to customer shipping container transfer to the horizontal carousel, inverted indexing power and free conveyor, or S.I. Cartrac location, an employee or label application machine places the bar-code label in the appropriate location on the customer shipping container. This location faces outward from the horizontal carousel, inverted power and free conveyor, or S.I. Cartrac method load-carrying surface. This label orientation permits the barcode scanner and employee to read a customer discrete identification. With several horizontal carousels, inverted indexing power and free conveyors, or S.I. Cartrac units facing one sorting station, this machine paced sorting activity in a small area has high employee productivity. The disadvantages are capital investment; a requirement of two or three horizontal carousel, inverted indexing power and free conveyor, or S.I. Cartrac units; the need for a computer program, hardware, and bar-code scanner or other dataentry device; and management control and discipline. The advantages are improved employee productivity, the ability to handle a high piece or small-item quantity, paper or paperless sorting, the ability to handle a large customer-order number, reduced errors, reduced employee walking distance and time, fewest employee number, the ability to handle a wide piece mix and large SKU number, and online and accurate inventory updates. Carton Flow-Rack or Rapid-Pack Sorting Method The next mechanized small-item or flat wear apparel across-the-dock sorting method is the carton flow-rack or rapid-pack sorting method. The carton flow-rack sorting method has alternative designs. In the first design all customer-order containers travel continuously in sequential customer-order numbers on a closed-loop conveyor travel path past each SKU sorting or transfer station. In the second design a slug or specific customer-order group travels on a conveyor travel path and as required


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a specific customer-order group is held in a temporary holding or queue area. As required by a microcomputer command, these containers are released for travel to the sort station. In these small-item or flat wear apparel across-the-dock sorting methods, the powered conveyor travel path transports the customer shipping container past gravity conveyor flow lanes. Each lane contains small-item or flat wear apparel SKUs. Both sides of the gravity conveyor flow lane have a discrete position identification. As a lane-loading or replenishment employee sends the master carton or small-item tote into the gravity conveyor flow lane, the SKU discrete identification is sent to the microcomputer. As the customer shipping container arrives at the specific sort area, prior to sorting a bar-code scanning device reads a customer discrete bar-code label and sends the bar-code information to the microcomputer. With the identification entered into the computer along with the SKU discrete identification in each sort gravity conveyor flow lane, the microcomputer sends to the sort-zone controller the customer SKU quantity for each SKU or gravity conveyor flow lane in the sort zone. The controller activates each gravity or SKU gravity conveyor flow lane’s indicator lights, which indicate the required SKU quantity for the customer-order. Each gravity conveyor flow lane’s digital display unit (activated by the scanning device and computer) directs the sorting employee. A sort instruction option is a paper-printed document. The sort instruction method provides the sorting employee with the SKU quantity that is to be transferred from the gravity conveyor flow lane to the customer shipping container. When a full container is present on the sorting conveyor travel path, a sorting employee scans the container’s bar-code label. At the sorting station, this message has a printer to print a new customer discrete bar-code label. From the empty shipping carton conveyor an empty carton is removed and placed onto the sorting conveyor travel path. The new bar code-label is placed onto an empty or new container, and the new carton is placed onto the sorting conveyor travel path. All full customer shipping containers are pushed onto a shipping take-away conveyor travel path for transport to the check, fill, seal, and manifest station. The disadvantages are high investment; the need for a computer program, hardware, and bar-code scanner or other data entry device; and management control and discipline. The advantages are employee productivity; high piece or customer-order small-item or flat wear apparel quantity; paper or paperless sorting; ability to handle a large number of customers; reduced errors; reduced employee walking distance and time; few employees; a wide product mix or a large SKU number; and online and accurate inventory updates. Automatic Small-Item or Flat Wear Apparel Sorting Methods The last across-the-dock small-item or flat wear apparel sorting method group is the automatic small-item or flat wear apparel across-the-dock sorting group. The automatic sorting methods have similar design and operational characteristics. When compared to the manual or mechanized sorting methods, the automatic sorting methods have the following characteristics. Small-item or flat wear apparel SKUs are discretely identified and delivered in batches to a manual or automatic



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customer discrete identification encode device or station. Each SKU exterior surface requires a human- and machine-readable discrete identification. The sorting method of the sorting stations has an arithmetic progression along the sorting travel path. Each customer sorting location is a slide, captive container, or customer shipping container. Other characteristics include a completed or full customer shipping container take-away transport system, and an empty customer shipping container replacement and discrete identification label print system. The automatic across-the-dock small-item or flat wear sorting methods are Bombay drop, SBIR, flap sorter, nova sort, gull wing, and tilt tray. Each automatic across-the-dock small-item or flat wear apparel sorting method’s SKUs are discretely identified and delivered together at an induction station. At the induction station, an induction employee or mechanized belt conveyor travel path places an individual SKU onto the sorting method load-carrying surface. With the manual induction system, the employee enters via keypad the SKU discrete identification into the sorting method microcomputer. With the automatic induction system, the discrete identified SKU travels on a conveyor travel path past a bar-code scanner that enters the SKU discrete identification into the sorting method microcomputer. After the induction activity, the automatic sorting method load-carrying surface travels along the sorting method travel path and is programmed to transfer the SKU from the load-carrying surface onto a customer divert location. The divert location is a slide, captive container, or customer shipping container. Prior to the load-carrying surface return to the induction station, the sorting method prepares the load-carrying surface to accept another SKU. Each across-the-dock automatic small-item or flat wear apparel sorting method’s different characteristics are sorting capabilities that handle a different SKU mix and volume, square-foot area requirements and operational procedures, and interface with a SKU induction method. To obtain the maximum return on investment, you consider an across-the-dock small-item or flat wear apparel sorting method that satisfies your across-the-dock operational requirements. With dual induction and a loop-sorting conveyor travel path design on an SBIR, flap sorter, tilt tray, or nova sort method, the across-the-dock sorting method options are to handle a larger sorting volume for small-item or flat wear SKUs, or to have one induction station for loose small items or flat wear and sorting on the straight conveyor sorting travel path and a second induction station for shipping carton induction and sorting on the dock side conveyor sorting travel path. The disadvantages are high capital investment and the need for a bar-code label, bar-code scanner, and associated computer programs and hardware. Most methods have a difficult time handling low profile or round objects mixed with heavy weight SKUs. It is difficult to handle crushable and fragile objects, and the method increases your maintenance requirements. The advantages are accurate sorting, handling of a high volume, reduced employee reading requirements, few employees on site, and reduced employee injuries. For additional information on small-item induction and automatic sorting methods, we refer the reader to the small-item or flat wear apparel order-fulfillment sections in Chapter 3.


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What Happens to the Residual Across-the-Dock SKUs After completion of the across-the-dock sorting activity, all extra or residual SKU pieces go to a storage/pick area. These SKUs are held in the storage/pick area, and in the future, as the customer orders require additional SKUs, there are two options. The first option is that the small-item or flat wear apparel SKUs are picked as batched customer orders, are sent together to the across-the-dock sorting method, and are combined with the across-the-dock customer-ordered SKUs. Together these combined cartons are handled by the across-the-dock sorting method as normal across-the-dock SKUs. The second option is that SKUs, per the customer-order, are individually picked and packed into separate containers. These containers are sent to the appropriate customer shipping dock area or directly to the customer delivery truck. The option that is selected by your across-the-dock operation is determined by SKU physical characteristics and volume; pick area, transport, and sorting method required investment; and time required to complete the customer-order and delivery cycle.

PACKING VERIFICATION In a small-item or flat wear apparel across-the-dock operation, the packing operation activities are to verify the SKU quantity and quality, fill the voids in the customerorder shipping container, seal the customer shipping container, place the customer delivery address label on the shipping container exterior surface, manifest the customer shipping container, and ensure that the customer shipping container is placed in the appropriate staging area or is loaded directly onto a customer delivery truck. In most across-the-dock operations, to perform the SKU quantity or quality check, the order-check activity station may perform a random check, a specific customer check, or a 100% check. The check options are to use a manual check method that has an employee perform an actual detailed SKU check compared to the SKUs that appear on the packing slip and a SKU quantity check to the SKU total that appears on the packing slip, and an automatic, “on the fly” or stationary check weigh method. There are two options for this latter method. The first option is to have an employee transfer a customer-order shipping container to an in-line stationary scale. With the container on the stationary scale, the scale display shows the actual shipping container weight. After the employee scans the customer bar code into the microcomputer, the microcomputer display screen shows the computer projected weight. The second option is that on a powered conveyor travel path, after a gap is pulled between two cartons, the customer shipping container travels on the conveyor travel path past a bar-code scanner that sends the data to the microcomputer. After the scanner, the carton travels over an in-line scale. The scale enters the actual customer shipping container weight into the computer. With either the manual or automatic scanning method, the microcomputer compares the projected customer-order shipping container weight to the actual customer-order shipping container weight. If the two weights match, the customer-ordered SKU quantity and quality check is positive and the customer-order shipping carton travels over the conveyor travel path to the



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next activity station. If the two weights do not match, the customer-order SKU quantity and quality check is negative and the customer-order shipping container is transferred from the main conveyor travel path onto a problem-order conveyor for 100% check by an employee. With the automatic on the fly or stationary check weigh method, the computer and scale interface options are that the in-line scale has a direct interface to the main computer, and an interface to a microcomputer that has received all customer-order estimated weights. These customer-order weights were downloaded to the microcomputer from the main or host computer. For additional information on the customer-order shipping container check methods, we refer the reader to the customer-order shipping container check methods in Chapter 3.

FILLING

THE

CUSTOMER SHIPPING CONTAINER VOIDS

The next small-item or flat wear apparel across-the-dock operational activity is to fill the customer-order shipping container voids. Filling the voids with a filler material ensures that there is minimal piece damage as the customer-order shipping container is delivered to the customer delivery address via a delivery truck. The customer shipping container filler materials are crushed paper, which includes the mechanical paper-crusher method, the employee crushed-paper method, and shredded paper; corrugated, which includes preformed pieces and the mechanical crushed method; peanuts, which are polyurethane or processed corn and employee transfer, gravity flow, or pneumatic flow; and foam in place, which includes manual dispensed and automatic dispensed. For additional information on the customer-order shipping container void filling methods and materials, we refer the reader to various customer-order shipping container void fill methods in Chapter 3.

SEAL

THE

CUSTOMER SHIPPING CONTAINER

The next across-the-dock operational activity is to seal the customer shipping container. To protect the small items in a customer-order shipping container from damage or being lost during delivery to the customer address via a delivery truck, the customer-order shipping container top is sealed to make the container top secure. The customer-order shipping container seal methods are gummed tape, which is dispensed by an electric-powered tape machine; self-adhesive tape, which is applied by an employee or a mechanical device; plastic strap, which is applied by an employee or a mechanical device; and plastic or metal seals. For additional information on the customer-order shipping container seal methods and materials, we refer the reader to the various customer-order shipping container seal methods in Chapter 3.

SHIPPING ADDRESS

ON THE

CUSTOMER SHIPPING CONTAINER

The next across-the-dock operational activity is to address the customer shipping container. The customer address label has the customer delivery address, your com-


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pany’s return address, the customer discrete identification, and other required company information. The customer address label is placed in the appropriate location on the customer-order shipping container’s exterior surface. This appropriate location satisfies your company’s operational requirements and meets your delivery truck company’s standards and specifications. With today’s delivery-truck companies, the discrete customer identification label has a bar code and a human-readable language that is printed onto its face. This feature permits the customer package to be handled by an employee or a bar-code-scanner-based sorting method. The customer address label purpose is to ensure that the delivery truck company understands the delivery address for your customer shipping container, and to ensure that the customer shipping container is tracked through the delivery truck’s activity. In an across-the-dock small-item or flat wear apparel operation, a customer shipping container is either a corrugated or chipboard carton or a plastic container. During the across-the-dock small-item or flat wear apparel sorting activity, the attachment or placement of the customer discrete identification or address label on the customer shipping container exterior surface has three options. These are at the start of the sorting line, as required at the sorting station, and at the end of the sorting line. The key factors that determine the customer discrete identification location on a customer-order shipping carton are the customer-order shipping container flow through the sorting area; customer discrete identification address label preprinted or printed on demand; available funds for customer discrete identification address label printers; methods to print the customer address label, which are handwritten, ink stamp, and machine printed; container number per customer-order; required customer address label code type, which is human-readable, human- and machinereadable, or machine-readable; correct label location on the customer-order shipping container’s exterior surface (top, side, front, rear, or bottom); type of label backing material (self-adhesive or nonadhesive); and the method to apply a label to a customer shipping carton (manual or mechanical). The label application methods are as follows: an employee-applied label method for a nonadhesive label (a glue pot or clear plastic tape), self-adhesive labels, and machine-applied self-adhesive labels. For additional information on the customer-order shipping container address identification methods, materials, and application methods, we refer the reader to the various methods, materials, and application methods in Chapter 3.

MANIFESTING

AND

LOADING CUSTOMER SHIPPING CONTAINERS

After the across-the-dock operation employee checks, fills the voids in, seals, and addresses the customer-order shipping container, the next across-the-dock smallitem operational activity is to manifest and ship the customer-order shipping container. The customer-order shipping container manifest activity records the customerorder shipping container discrete identification number. The activity ensures that the customer shipping container was transferred from the across-the-dock operation to a customer delivery truck.



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The customer-order shipping container manifest activity options are to manually record the customer-order shipping container identification number onto a paper document, or to have a bar-code scanner read each customer discrete identification and send this information to the microcomputer. The microcomputer places the customer discrete identification into its memory for storage for later download to a diskette or to print a paper document. The customer-order shipping container loading activity options are to have the customer-order shipping containers separated into units on a pallet or cart for later loading onto a customer delivery truck, or transported directly onto the customer delivery truck. The customer direct-load methods are the manual, gravity skate wheel, or roller extendible conveyor; powered skate wheel, roller, or belt extendible conveyor; and a nonpowered or powered pallet truck. For additional information on the customer shipping container manifest and shipping methods, we refer the reader to customer shipping container manifest and shipping section in Chapter 4.

HANDLING GOH OR HANGING GARMENTS IN AN ACROSS-THE-DOCK OPERATION The next merchandise that is handled by an across-the-dock facility is GOH or garments in boxes. In an across-the-dock operation that handles GOH or garments in boxes, the activities are to receive GOH on rolling racks, a trolley on a cart, or a trolley that travels on an extendible boom; to receive garments in boxes by the method used for master cartons; and to transfer an individual garment from a box onto a hanger. The GOH are placed onto a cart or trolley load bar. In some GOH receiving applications, to ensure accuracy, to secure the garments on the load bar and to ensure good employee handling productivity, the GOH SKUs are bundled with a rubber band in a three-to-five quantity. GOH are sorted by color or style, and each GOH piece is ticketed. The next step is to steam and remove the wrinkles from the GOH and place the GOH in a protective paper or plastic bag. Per the customer-order, sort the GOH by cart loop, rail loop, dynamic flow rail, rapid pack, programmable trolley, Promech method, or trolleyless method. Transfer the GOH to a customer shipping cart, cart, box, or rope. This activity includes the methods to secure and protect the GOH from becoming lost or damaged and to discretely identify the customer shipping cart, device, or box. Next, manifest and ship the GOH by a delivery truck with rope loops that are attached to the delivery truck roof, a GOH cart, or a box. The ways to receive GOH at an across-the-dock facility are GOH from a ropeloop delivery truck, four-wheeled cart, or hanger box, or as flat garments in boxes that require an employee to remove the garments from the boxes and transfer an individual garment to a hanger that makes the SKU a GOH. The GOH are transferred to an overhead trolley load bar, on a four-wheeled cart load bar, or with a trolleyless method for transport through the across-the-dock sorting activity.


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UNLOADING

Order-Fulfillment Concepts, Design, and Operations OF

GOH

An across-the-dock operation uses several options to unload GOH. The first option is the manual pushed or pulled GOH with a load bar. After the GOH cart load bar is full, an employee pushes or pulls the cart from the delivery truck, over the dock leveler, onto the receiving and checking dock area, and onto the sorting area. The GOH wheel-cart method handles a low volume, has a low capital investment, and is used for an across-the-dock operation that has no trolley rail system. The next option is a manual pushed or pulled four-wheeled trolley cart that has two adjustable load-bar stops. After an empty trolley is placed onto the trolley cart load bar and both end stops are placed in the closed position, an employee pushes or pulls the trolley cart into a delivery trailer. In the delivery truck an employee transfers the GOH onto a trolley load bar. When the trolley is full, an employee pushes and pulls the fully loaded trolley cart from the delivery truck, over the dock leveler, and onto the receiving and checking dock area. In the dock area, an employee positions the trolley cart to transfer the trolley onto a rail spur, adjusts the appropriate end stop to the open position, and pushes the full GOH trolley from the cart load bar onto the overhead trolley rail system. The four-wheeled cart with a trolley load bar method handles a low-to-medium volume, has a low capital investment, and is used at an across-the-dock operation that has an overhead trolley rail system. The third option is an empty trolley hung on an extendible trolley boom rail that extends from the receiving dock area into a delivery truck. After an employee transfers GOH to fill the trolley load bar, the fully loaded trolley is programmed, pushed or pulled from the delivery truck, and merged with an overhead trolley rail system. This method is used in an operation that has an across-the-dock overhead trolley rail system, a high volume, and a medium investment.

HANDLING HANGING GARMENTS

IN

BOXES

When garments in boxes are received at an across-the-dock facility, the unload options are to first use nonpowered skate-wheel or roller extendible and retractable conveyors that are used to move the garments in boxes from the delivery truck to a pallet loading station on the receiving dock area or to merge with a carton transport conveyor. The method handles a low volume, requires a low investment, and handles floor-stacked delivery trucks. The second option is powered skate wheel, roller, or belt extendible and retractable conveyors for transport of cartons from the delivery truck to a pallet loading station or to merge with the carton transport method. The powered conveyor handles a high volume and has a higher investment. The third option is a manual or powered pallet truck method, used to unload pallets from a delivery truck. The features are a high volume and medium investment.

UNLOADING OBJECTIVE When GOH or garments in boxes are unloaded from a vendor delivery truck, the objective is to unload the delivery truck and obtain a total GOH piece count. An efficient GOH or garment-in-box across-the-dock operation includes the handling GOH at other workstations; the GOH pieces are sorted onto trolleys or GOH carts



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by purchase order, style, color, and size. This GOH sorting requires the garments in boxes or GOH pieces to be transferred to a garment open, count, sort, ticket, and sorting area. The GOH condition and your company policy determine the other across-thedock hanging-garment activities. In many across-the-dock operations, the GOH activities are a GOH steaming station and bagging station. If GOH has a wrinkled condition, the GOH is sent a GOH steaming station. If GOH is not contained within a protective paper or plastic bag, the GOH is sent to a GOH bagging station. For additional information on GOH steaming and bagging workstation methods, we refer the reader to GOH steaming and bagging workstation methods in Chapter 4.

GOH SORTING The next across-the-dock GOH activity is the GOH sorting activity. The GOH sorting activity ensures from a wide GOH piece SKU and customer-order mix that customerordered GOH pieces are separated and transported to the next across-the-dock GOH customer activity. The GOH sorting methods are GOH carts with a load bar, a nonpowered trolley on an overhead nonpowered rail loop, a programmable trolley on an overhead powered conveyor travel path, Promech, and trolleyless. GOH-Cart Sorting Method The first across-the-dock GOH sorting method is considered a manual GOH sorting method. The GOH-cart sorting method uses manual GOH carts. Each GOH cart’s components are four swivel type casters and wheels at each rectangular-shaped bottom frame corner, structural top and bottom support members with two or four upright posts, and a hanger load bar that is connected to the cart upright posts. The method requires an aisle between two cart rows. The aisle width between the two cart rows is sufficient for an employee to push an inbound cart with GOH pieces the aisle, and, as required, to have an employee transfer the appropriate GOH SKUs and pieces from the inbound cart to the appropriate customer cart load bar. Both cart rows have empty carts with load bars. Each cart or a section of a cart load bar is divided and assigned as a customer sorting position. Each customer position is discretely identified with the customer’s alphabetic characters, numeric digits, or a combination of both that creates the customer discrete identification. The customer discrete identifications are arranged in sequential order. An employee with a paper sorting instruction document that has each customer ordered GOH quantity printed in a sequential arrangement pushes an inbound GOH cart (GOH SKUs are on the sorting instruction form) through the aisle. An employee travels down the sorting aisle and matches the sorting document customer discrete identification with the customer sorting cart position discrete identification. After the employee stops the cart forward movement, the employee transfers the appropriate GOH piece number from the inbound cart load bar to the customer sorting position on the cart load bar. After completing the GOH transfer, to verify the transaction, the employee


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places a mark on or adjacent to the customer discrete identification that appears on the sorting paper document. All full customer sorting carts are pushed from the sorting area to the customer-assigned shipping dock staging area or are loaded directly onto the customer delivery truck. Another empty cart with the customer discrete identification is transferred to the vacant sorting position. The disadvantages are low employee productivity, sorting cart setup time, a customer discrete identification that is attached to each cart, large finished-floor area, possible sorting errors, a minimum SKU number, and low volume and customer number. The advantages are low investment and minimal employee training; the method is also easy to implement and simple to operate. Rail-Loop Sorting Method The second across-the-dock manual GOH hanging-garment sorting method is the manually operated overhead trolley and rail sorting method. This method has three overhead nonpowered trolley rail travel paths. Each overhead nonpowered trolley rail travel path is ceiling-hung or floor-supported and has an adjustable end stop. The method has two trolley rail travel paths for empty trolleys. Each trolley or position between two pins on the trolley load bar has the customer discrete identification. Each discrete customer identification has the alphabetic characters, numeric digits, or a combination of both, and the discrete identifications are arranged in a sequential order. Between these two customer sorting rails is the inbound GOH trolley rail travel path. The aisle width between the two customer staging rails and the inbound GOH trolley rail travel path has sufficient width for an employee to push or pull down-aisle a fully loaded trolley and complete all GOH sorting transaction activities. A paper-printed sorting instruction document has the customer discrete identifications that are arranged in a sequential order and the customer-ordered GOH SKU quantities. An employee pushes a trolley or trolley train on an inbound overhead sorting rail travel path. When the employee matches a customer discrete identification on the sorting instruction paper document to customer discrete identification on the sorting trolley position, the employee stops the trolley forward movement on the overhead sorting rail travel path. At the aisle location, the employee transfers the required GOH piece quantity from the inbound trolley to a customer sorting position on the trolley and places a mark in the appropriate location on the sorting instruction paper document. After completing a GOH sorting activity, each customer sorting position or trolley is pushed over the rail travel path from the sorting area to the customerassigned outbound staging area or directly onto the customer delivery truck. The disadvantages are trolley setup time and proper trolley customer discrete identification, possible errors, a medium volume, medium SKU number and customer orders, and the need for a ceiling-hung or floor-supported overhead trolley travel path. The advantages are the method’s low-to-medium investment, ease of implementation, increased productivity, and minimal training; the method is also easy to relocate and simple to operate. When designed as a ceiling-hung method, it frees up floor area.



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Programmable Hanging-Garment Trolley Sorting Method The next GOH across-the-dock sorting method is a mechanized GOH sorting method. This GOH method is the programmable trolley GOH sorting method that sorts a GOH trolley. The programmable trolley is a device that has a load bar that is supported by two necks. The trolley lead neck has a programmable code device which consists of 1, 2, or 3 wire prongs, each prong having a setting from 0 to 9; 1, 2, or 3 photo reflective tabs, each tab having a setting from 0 to 9; or a bar-code label. At each neck end are two spool sets. The next component is an overhead trolley rail travel path that is tubular rail, creased strut, C-channel, or flat-angle iron. Over or adjacent to the trolley rail travel path is a motor-driven powered chain travel path. Attached to the powered chain at predetermined intervals are hard and soft pusher dogs that extend downward or outward to engage the trolley lead spool. Readers along the trolley travel path communicate the trolley code setting to the microcomputer. This microcomputer activates the proper divert device. As required by the sorting method, divert devices and diverted trolley rail travel spur paths are along the main trolley travel path. Between a trolley’s two necks is the load bar that has a series of antislide pins. Most trolley load bars have the ability to carry 20 to 25 heavyweight winter GOH pieces or 40 to 50 lightweight summer GOH pieces. Attached to each neck top are four spools. These spools ride on an overhead trolley travel path. The powered chain has hard rubber or hardened metal pendants that are outward or downward extending pendants (pusher or puller dogs). A pusher dog engages the trolley lead neck and pulls the trolley over a fixed overhead trolley travel path. Along the fixed overhead trolley travel path at predetermined locations is a reading device that reads the trolley code. The code is sent to a microcomputer that triggers a divert device downstream on the trolley travel path to divert the appropriate trolley from the main travel path onto a divert spur trolley travel path. In a GOH across-the-dock operation, the programmable trolley sorting method is to move and sort GOH large quantities from the receiving dock area to the sorting area and to the customer staging area or directly to staging area behind the customer delivery truck, to move a completed customer-order on a trolley from the sorting area to the customer staging area or directly to the staging area behind the customer delivery truck, or to move residual GOH SKUs from the sorting area to the storage area. For additional information on programmable trolleys, powered chain with pusher dogs, and nonpowered and powered overhead trolley rails or travel paths, we refer the reader to GOH programmable trolleys and nonpowered and powered overhead trolley rails or travel path methods in Chapter 4. Promech Hanging-Garment Sorting Method The next GOH across-the-dock sorting method is the Promech overhead GOH sorting method. The Promech overhead GOH sorting method is an automatic individual GOH piece or a six-piece same SKU quantity GOH sorting method. The Promech method has a GOH in-feed station, which is a manual or automatic station; a clasp-levered hook that is attached to a powered rope conveyor; a solenoid mag-


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netically operated divert station; and a hanger slick-rail divert-spur travel path. At the end is a customer GOH cart or pack station for a GOH box. Lastly, a computer system controls the sorting method by SKU or customer discrete identification. The Promech overhead GOH sorting method sorts GOH from the main trolley travel path onto an individual customer divert location and with six SKUs to one customer location. The Promech sorting method starts at the GOH in-feed station. If your customerorder has more than one GOH per order, a ring that holds up to six GOH pieces is used to in-feed the GOH pieces onto the Promech sorting method. The Promech GOH manual or automatic in-feed station is the location that has a GOH attached to the closed-loop rope conveyor travel path. Whenever possible, six pieces maximum are placed onto a ring and the ring is attached to the closedloop rope conveyor travel path. The travel path travels past the in-feed station and each customer divert or sorting station. At the manual in-feed station, the rope conveyor travel path declines, which causes each clasp hook to open for an employee to transfer a GOH piece onto the clasp hook. The employee enters the discrete GOH SKU identification number into a computer terminal. On the display screen, a customer-order quantity or the total required GOH piece quantity appears to the infeed employee. On a display screen appears the first active customer divert station that requires the GOH SKU. As directed, the employee transfers a GOH onto a hook and presses the dispatch button. This employee action enters the GOH-required customer sorting discrete number into the computer and permits the hook to be propelled by the rope conveyor forward over the conveyor travel path. With a multiple quantity for one GOH SKU, and if the ring is not used in the operation, the multiple quantity for a GOH SKU requires multiple listing and individual GOH travel on a hooks. This feature reduces the sorting method’s productivity. The GOH travels on the Promech hook past a photo eye that activates the appropriate solenoid magnetic divert device. The divert device is the first customer sorting station that requires the GOH SKU. As the GOH approaches the appropriate customer divert station, the solenoid magnetized divert station device lifts the trip bar into the levered hook wheel’s travel path. As the levered hook wheel travels onto the elevated trip bar at this customer sorting location, the levered hook wheel travels up the trip bar diverter that permits the hook clasp to move upward. The hook clasp’s upward action releases the GOH SKU or ring onto the customer divert or sorting slide rail for travel to the customer packing station. As the levered hook wheel passes to the upper end of the trip bar, it forces the trip bar to the lowered position, which permits the levered hook device to pass the divert device. This discharge action disengages the trip bar magnet and the customer sorting station is in the neutral position. In the neutral position, the divert device permits another GOH SKU on a levered hook to travel on the conveyor travel path past the divert station onto the next assigned customer sorting location. When the Promech GOH sorting method uses the automatic GOH in-feed station, one GOH piece is fed onto one Promech rope conveyor travel path hook. The automatic in-feed station method is controlled by a microcomputer. The microcomputer controls a spindle that is driven by a motor. The control system regulates the spindle speed in a sequence with the speed for the levered hook wheel travel



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on the rope conveyor travel path. The rope conveyor travel path elevates and declines prior to the automatic in-feed station. This decline permits the clasp hook to open because the location and levered hook wheel weight forces the clasp open. When the levered hook is in the open position, a GOH piece slides onto the open levered hook wheel. Special sensing devices are in the spindle area to locate two hangers on the same spindle. If two hangers are on one spindle, an alarm is sounded and the rope conveyor travel is stopped to prevent damage. An employee removes the hangers and reactivates the rope conveyor. Trolleyless Hanging-Garment Shipping Methods An across-the-dock operation ships GOH pieces to the customer delivery location. There are several GOH shipping options for your company. The first option uses a GOH group on rope loops that extends downward from the delivery truck’s interior ceiling or specially attached structural member. Each loop holds 6 to 12 GOH pieces. The second option is hanging on a GOH load bar with tape or a cardboard cap taped over the hanger hooks and the load bar. The third is an individual folded and draped GOH in a box or a GOH piece with other GOH pieces in a hang bar box.

MASTER-CARTON ACROSS-THE-DOCK SORTING METHODS When we look at a master-carton across-the-dock operation, the across-the-dock operation sorting options are the manual-carton sorting method and the mechanizedcarton sorting method. Both these methods ensure accurate and on-time transfer of the customer discretely identified master carton from mixed customer discretely identified cartons onto a conveyor travel path for travel to the customer-assigned shipping dock staging area or directly onto a customer delivery truck. The across-the-dock carton sorting methods are manual and mechanized or mechanical methods. The latter includes active sorting methods, passive sorting methods, and a combination of active and passive sorting methods. When the across-the-dock carton sorting activity is in the batch mode in which your customer-ordered cartons with other customer-ordered cartons are unloaded from a vendor delivery truck onto a conveyor travel path, each carton has a discrete customer identification code. After the code is attached to the carton, the cartons travel on the sorting conveyor travel path past an employee or bar-code scanner device. The employee reads the code and completes a carton transfer from the conveyor travel path to a customer pallet or cart. The bar-code scanner reads the code and sends the carton customer discrete identification to the microcomputer. The microcomputer and tracking device ensure that the carton arrives on the sorting conveyor travel path at the appropriate divert or sorting location. At this customer divert or sorting location, a divert device transfers the carton from the sorting conveyor travel path and with mixed (batched) customer cartons sorts a customer discretely identified carton onto a divert spur. This divert spur is a conveyor travel


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path for customer-assigned carton transport to a customer-assigned dock staging area or directly onto a customer delivery truck. In an across-the-dock batched customer-order carton method, after customer carton sorting, the customer carton travel-path options are to temporarily hold the customer cartons in an assigned shipping dock area on powered conveyor lanes, pallets, or carts, and, as required, release them for later loading onto a customer delivery truck; or to direct load the carton travel onto a customer delivery truck and to handle the number of customer delivery trucks.

CARTON CONVEYOR TRANSPORTATION AND SORTING IS OF THE BATCHED ACROSS-THE-DOCK METHOD

THE

HEART

If your across-the-dock operation or facility handles a large master-carton volume for a large customer number, to have an on-time, efficient, and cost-effective acrossthe-dock operation, you use a batched across-the-dock customer-ordered carton sorting method. This method is the heart of your across-the-dock operation. The method uses a microcomputer that separates your daily customer orders into predetermined groups or batches. These discretely identified cartons travel over the transport and sorting conveyor travel path. The sorting method sorts all active customer cartons with the appropriate customer discrete identification label from the sorting travel path onto the assigned divert travel path.

ACROSS-THE-DOCK CARTON SORTING DESIGN PARAMETERS AND FACTORS A batched customer-order across-the-dock carton sorting method’s design parameters are as follows: on each carton a discrete customer identification label that is at least human-readable or human- and machine-readable, a conveyor transport and sorting travel-path method with the ability to queue cartons prior to the induction station and prior to each unit station or direct load station, and the capacity to handle the customer carton volume for each batch and the daily vendor and customer delivery truck number with the associated divert transactions Prior to carton across-the-dock sorting method design and implementation, your design parameters include each carton’s length, width, height, and weight, which includes minimum, average, maximum, and top, side, and bottom exterior surface; cartons per average and peak weekday and per customer-order; work hours for each workday and customer-order number; bar-code type and label size and how to read the bar code; for the bar-code scanner and sorting device, the required gap between two cartons; crushability and fragility of the cartons; the ability to ensure that all cartons are sealed and have a conveyable bottom exterior surface; and the ability to provide sufficient accumulation or queue prior to each activity or workstation. A conveyor across-the-dock carton sorting method implementation with insufficient carton queue creates an out-of-balance situation between the unloading, scanning, sorting, and loading functions. This out-of-balance situation between these various across-the-dock activities does not permit the unloading or loading employees to achieve the budgeted productivity rates.



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After these design parameters have been determined for the across-the-dock carton sorting method, you design a building to house the carton sorting method or fit the carton sorting method within an existing building. With an across-the-dock order, batched cartons are labeled and placed onto the across-the-dock transport and sorting conveyor travel path. The across-the-dock carton sorting methods are manual sorting methods and mechanical sorting methods.

MANUAL ACROSS-THE-DOCK CARTON SORTING METHODS A manual across-the-dock carton sorting method is the basic and simple carton sorting method because it requires a simple conveyor transport travel path and a human-readable label. An employee places the human-readable label onto the carton’s exterior surface in a location that is easy to read. These carton label placement locations are as follows: the best is the carton’s top; the next best is the carton’s side that faces the pallet-loading station; and the worst is the carton’s front, rear, or bottom. The batched customer-ordered cartons are labeled and transported over the conveyor travel path to the manual sorting area that is located in the shipping dock area. As the cartons travel on the conveyor travel path, a sorting employee reads the carton human-readable label and matches the human-readable identification label number to a customer human-readable identification on the employee-assigned sorting position. When there is a match, the employee transfers the carton from the sorting conveyor travel path onto the appropriate customer shipping cart, slip-sheet, or pallet. All full pallets, carts, or slip-sheets are transferred to a staging area or loaded onto a customer delivery truck. Few and large characters or digits for the customer carton and sorting position identification mean better sorting employee productivity and fewer sorting errors. In a manual sorting method, the sorting employee handles 10 to 15 cartons per minute with little damage impact on the carton’s contents. For best employee carton sorting productivity, the maximum carton weight is 40 to 50 pounds and the average weight is 20 to 30 pounds per carton. To ensure efficient carton handling, the sorting conveyor travel path maintains a 3-to-6-inch gap between two cartons, and the carton sorting conveyor is a low- or zero-pressure queue conveyor. The manual across-the-dock carton sorting method group’s four basic sorting conveyor travel path designs are one conveyor, double stacked conveyors, recirculation conveyor, and apron conveyor. One Conveyor Travel Path In this manual across-the-dock carton sorting method, the sorting conveyor travel is along all your customer unit stations. The low- or zero-pressure queue conveyor sorting travel path has a 1-inch-high far side (from the unit station) along the guardrail’s full length and an end stop. This far side or rear guard rail ensures that the cartons are retained on the conveyor travel path. The low- or zero-pressure queue conveyor travel path allows the sorting employee, with no new cartons on the sorting conveyor travel path, to move an unsorted carton in a reverse direction on top of the conveyor travel path to the appropriate customer sorting location, and to easily create


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a gap between two cartons. If an employee stops a carton on the sorting conveyor travel path, there is no carton forward pressure. The disadvantages are possible sorting errors, the need for a large and clear sorting label, a low volume, a few customers, difficulty of handling unsorted cartons, a large employee number, and a high potential for employee injury. The advantages are low impact on the cartons, minimal capital investment, and simple operation and control. As required with the guard rail this is a bilateral sorting method. Double-Stacked Conveyor Travel Paths The across-the-dock double-stacked conveyor design has two conveyor travel path levels that are located along sorting fronts. The lower conveyor travel path level is a low- or zero-pressure queue conveyor that is the sorting conveyor travel path. The upper conveyor travel path level is the unsorted carton conveyor travel path. This upper conveyor travel path is a low- or zero-pressure queue or nonpowered roller conveyor. If the sorting employee at the first customer sorting station did not sort the customer carton, the employee at the next sorting station removes the unsorted carton from the sorting conveyor travel path and transfers the unsorted carton onto the upper carton conveyor travel path. The elevated carton conveyor travel-path direction of travel slope or power returns the unsorted carton to the first customer sorting station. In addition to the one-sorting conveyor travel path method disadvantages, the disadvantages are additional investment and the need for an employee to lift the carton. In addition to the one-sorting conveyor travel path method advantages, the advantage is that the method minimizes the employee’s unsorted carton transfer effort. Recirculation or Loop Sorting Conveyor Sorting Method The across-the-dock carton recirculation or loop-sorting conveyor travel-path method sections include, first, a one-conveyor travel path that has two straight conveyor travel path sections. One section is an in-feed conveyor travel path and the other is a recirculation conveyor travel path. The next section consists of two 180˚ curves or two right angle transfer sections; the third is a separate merge location for new cartons and a separate merge location for unsorted cartons. From the in-feed conveyor travel path, all across-the-dock cartons on the sorting conveyor travel path travel past customer sorting stations. When a unsorted carton passes the customer sorting station, then the carton continues travel on the sorting conveyor travel path and is reintroduced to the sorting conveyor travel path. This feature has carton travel on the sorting conveyor travel path past the customer sorting location. The recirculation loop-sorting conveyor method has two designs. These are a straight conveyor section with two powered 180˚ curves, and two straight conveyor travel path sections with two right-angle transfer locations. The powered 180˚-curve across-the-dock carton sorting method has two powered 180˚ curves, an in-feed conveyor with a photo-eye-controlled stop device, a straight conveyor travel path from the unloading conveyor that is the sorting conveyor travel path, and a second straight conveyor travel path as the recirculation loop. Each



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straight conveyor travel path has a photo-eye. This sorting conveyor travel path photoeye controls the in-feed conveyor travel path. The recirculation conveyor travel path photo-eye controls the unsorted recirculation conveyor section. In addition there are two merge conveyor sections and as required guardrails on all conveyor travel paths. The disadvantages are same as the double stacked conveyor method. The additional disadvantage is that there is a higher conveyor investment. The additional advantages are that the employees do not lift unsorted cartons and that the method handles a higher volume. In the two straight conveyor travel path section design, the components are one straight conveyor travel path from the unloading conveyor, which is the sorting conveyor travel path, and a second straight conveyor travel path that is the recirculation conveyor travel path; an end stop at each straight sorting conveyor travel path end; and guardrails between the sorting and recirculation conveyor travel paths or a gap plate full length along the straight conveyor travel path. The gap plate is a solid piece of metal or hardened plastic with a slight bow in the middle and is attached to the of each conveyor bed tops. The gap plate serves as a transition plate for the sorting employee to push an unsorted carton from the sorting straight conveyor travel path to the recirculation straight conveyor travel path. A guardrail directs the carton flow over the sorting and recirculation conveyor travel path. If an unsorted carton appears on the sorting conveyor travel path, the sorting employee at the next sorting station gently pushes the carton from the sorting conveyor travel path, across the gap plate, and onto the recirculation conveyor travel path. The recirculation conveyor travel path moves the carton to a location prior to the first sorting station. At this location, the sorting employee pulls the carton from the recirculation travel path, across the gap plate, and onto the sorting conveyor. On the sorting conveyor travel path the unsorted carton is reintroduced to the sorting conveyor travel path. Circular Apron Conveyor The final manual across-the-dock carton sorting conveyor method is the circular apron method. The circular apron conveyor method has a photo-eye and conveyor network that allows cartons from the unloading conveyor to enter the apron conveyor sorting conveyor travel path and to have unsorted cartons automatically recirculate onto the sorting conveyor travel path. The advantages and disadvantages are the same as for the recirculation loop conveyor method, except that there is an additional investment in the apron conveyor and photo-eye controls.

MECHANIZED CARTON SORTING The mechanized-carton across-the-dock sorting operation has all customer discrete identified master cartons transferred from a vendor delivery truck; they travel over a transport and sorting conveyor travel path. The across-the-dock transport and sorting conveyor travel path has each carton with a discrete identification travel through an induction station and over a sorting conveyor travel path to the assigned divert station for transfer from the sorting conveyor travel path onto customer-assigned storage


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sorting station or shipping lane. From the shipping lane these cartons are loaded directly onto a customer delivery truck or loaded on pallets onto a pallet board, slip-sheet, or cart. At a later time, these carts, slip-sheets, or pallet boards are transferred from the customer-assigned shipping dock staging area onto the customer delivery truck. For the carton across-the-dock mechanized sorting method to operate efficiently, it requires each carton to have human-readable or human- and machine-readable discrete identification label. The discrete identification label contains the assigned customer sorting location. After a human or bar-code scanning device inducts the carton discrete identification into the microcomputer, the microcomputer and tracking device controls the sorting activity to occur at the proper time. This sorting activity transfers the carton from the sorting conveyor travel path onto the customer shipping staging lane for transfer onto a pallet board, slip-sheet, or cart, or direct loading into the customer delivery truck. The mechanized-carton across-the-dock sorting method components are unloading conveyors; transport conveyor travel path; induction station area with a brake, meter, and induction conveyors; “no read” conveyor; sorting conveyor travel path with divert device; customer shipping lane or unit station; clean-out station; and recirculation conveyor travel path. When you consider a carton across-the-dock sorting method implementation, you ensure that there is adequate and clean electrical power in the area and that there is a drain for the air compressor condensation. Unloading Conveyors The unloading conveyors are the previously mentioned nesting or extendible conveyor methods. These conveyors ensure that your vendor master cartons are unloaded from a delivery truck. As required, your receiving-dock employee places a customer discrete identification onto each master carton, and these cartons are transported from the receiving dock area to the main carton transport conveyor travel path. Transport Conveyors The transport conveyor travel path ensures that there is sufficient carton queue and that the cartons travel from the unloading area to the induction station area. Prior to the induction station, all cartons are individuated or lined up in a single file. On the transport conveyor travel path a gap is created between two cartons by brake and metering belt conveyors, conveyor travel speed, or a stop device. This gap space between two cartons ensures that your induction employee or the bar-code scanning device reads or enters the carton discrete identification label data into the microcomputer and that a divert device has sufficient space to complete a carton divert from the sorting conveyor travel path onto a customer assigned shipping lane. Induction Conveyor The induction or in-feed station is carton conveyor travel-path location where your customer discrete identification is entered into the sorting conveyor microcomputer. Prior to the induction station, your conveyor travel-path design has sufficient conveyor queue to provide a constant carton flow cartons to the induction area and onto the sorting conveyor travel path.



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The induction methods are manual or keypad, semiautomated or handheld scanner, and automated with a fixed-position scanning device. Manual Induction In the manual induction method, each carton has a large human-readable label on its top or side surface. Adjacent to the carton travel path is a keypad that is connected to the sorting method microcomputer and tracking device. As the carton passes the induction station, an induction employee reads each carton human-readable discrete identification and keys the discrete identification into the keyboard. The keyboard transmits a customer discrete identification to the sorting method microcomputer and tracking device. Most keypads have 10 digit (0 to 9) buttons with a repeat button, scan off/on button, error signal, cancel key, a 5-digit light emitting diode (LED) display, E-stop button, and a send key. To achieve high manual induction productivity, the human-readable discrete code has large and bold print and contains the minimum digit number. Most keypad applications prefer two digits. The disadvantages are that it increases need for employee training; handles a low volume; has potential induction errors; requires the greatest number of employees; and at the induction station, requires all customer discrete codes to face one direction of travel. Advantages are low capital investment and ability to serve as a backup entry method for the other induction methods. Semiautomatic or Handheld Scanning Induction In the semi-automatic induction method each carton has a human- or human- and machine-readable customer discrete label on its top or side. As the carton travels on the conveyor travel path past the induction station, the brake belt and metering belt conveyors or speed controls create an open space (or gap) between two cartons. At the induction station, an employee takes a handheld scanning device (finger, wand, or gun) and scans the carton label. After scanning the label, the activities are that the carton discrete identification is sent to the microcomputer and that the carton passes the induction photo-eye and is released onto the sorting conveyor travel path. Carton travel on the sorting conveyor travel path is under the control of the sorting method microcomputer and tracking device. At the assigned location on the sorting conveyor travel path, these devices trigger the appropriate divert device to transfer the carton from the sorting conveyor travel path onto the customer-assigned shipping lane. The microcomputer sends a customer discrete identification to a manifesting system. Disadvantages are additional investment and additional employee training. Advantages are reduced induction errors, a higher volume, and accurate and on-line information transfer. Automatic Scanning or Induction The automatic induction or fixed-position bar-code scanning method requires that a bar-code label on each carton appear on the front, side, top, bottom, or rear. This bar-code label is the customer discrete identification.


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After the carton achieves the proper spacing on the transport conveyor travel path, the carton travels to the scanning station. At the scanning station, the carton customer discrete identification is read by a fixed position fixed beam scanning device, a waving beam, or a moving beam scanning device. As the carton passes the induction photo-eye, the carton is transferred to the sorting conveyor travel path. The customer discrete identification is transmitted to the sorting conveyor microcomputer and tracking device to ensure an accurate and complete sorting. The customer discrete identification is held in the microcomputer for manifest preparation. This automated induction method is used on a smooth-top belt conveyor, roller conveyor, tilt tray, tilt slat, SBIR, or gull wing transportation and sorting conveyor travel path. After the induction station, the carton travels on the sorting conveyor travel path past the induction photo-eye and is transferred onto the sorting conveyor travel path. The customer discrete identification or bar-code location is sent to the microcomputer. The sorting conveyor travel path constant travel speed ensures that the carton arrives at the appropriate divert location and the microcomputer and tracking device activates the appropriate divert device to transfer the carton from the sorting conveyor travel path onto the customer assigned conveyor lane. The disadvantages are capital investment and a human- and machine-readable label. Advantages are reduced induction errors, few employees, a high volume, and accurate and online information. “No Read“ Conveyor In all across-the-dock carton sorting methods and especially in an automatic induction method, a second activity is the reintroduction of “no read” cartons. A no read carton is a carton that had a customer discrete identification entry problem at the induction station. After the automatic bar-code label scanning station, a no read divert device and conveyor short travel path is located on the sorting conveyor travel path. The no read divert device and conveyor spur on the sorting conveyor travel path is located at 12 to 15 feet from the bar-code scanner station and is the first divert location past the bar code scanning station. The no read sorting station is designed to receive all discretely identified or unlabeled cartons that were not read by the bar-code scanning device. The no read conveyor travel path returns the unread cartons to the induction station. At the induction station, the carton is automatically read by the automatic bar-code scanner a second time or is manually or semiautomatically inducted onto the sorting conveyor travel path.

VARIOUS SORTING SURFACES

OR

CONVEYOR TRAVEL PATHS

A major carton across-the-dock sorting method component is the carton sorting conveyor travel path. The carton conveyor sorting travel paths are roller conveyor, smooth-top belt, slat tray, tilt tray, SBIR or moving belt conveyor, and gull wing. The across-the-dock carton sorting conveyor surface or travel path ensures that it moves a carton at a constant travel speed and provides the carton travel path from the induction station to all sorting conveyor travel path sorting locations. The sorting



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conveyor travel path designs are the single straight-line conveyor travel path and the endless loop conveyor travel path. Single Straight-Line Sorting Conveyor Travel Path The straight-line across-the-dock sorting conveyor travel-path design has a sorting conveyor travel path as a straight line from the induction station to the last sorting station. After the last sorting station, the sorting conveyor travel path ends and the conveyor travel path declines to the floor surface. The alternative straight-line sorting conveyor travel-path designs are L-shaped or straight-line layout and horseshoe or U-shaped layout. The unique characteristics of this design are that there is no unsorted carton automatic recirculation to the induction station. In the straight-line sorting conveyor travel path design, all the unsorted cartons are created by a full sorting lane or a divert device malfunction. The carton handling options are manually returned to the induction station or manually transferred to the unit station. At the unit station, an employee with a handheld scanner verifies that the carton was loaded onto the customer delivery truck. After completion of the delivery truck activity to create a manifest, a handheld scanner is downloaded to a microcomputer. On the sorting conveyor travel path, these unsorted cartons are removed from the sorting conveyor travel path. All cartons are diverted to the last divert location, or after the last divert station, the carton sorting conveyor travel path declines to the floor on a run-out conveyor lane. At the end of the divert lane or travel path, an employee separates the cartons into units and places them on a cart or pallet board. These cartons are manually transported to the induction station or the proper unit station. Disadvantages are that it requires additional employees, requires employees to physically move cartons, and handles a low volume. The advantage is a lower conveyor investment. Endless-Loop Carton Sorting Conveyor Travel Path In an endless loop, the across-the-dock carton sorting conveyor travel path starts at the induction station and ends at the induction charge end. The endless-loop carton sorting conveyor travel path method designs are L-shaped, U-shaped, O-shaped or elliptical, and rectangular-shaped. In each endless-loop carton sorting conveyor travel-path design, all unsorted cartons are automatically recirculated via a recirculation conveyor travel path to the induction station. At the induction station, the unsorted cartons are reintroduced to the sorting travel path by the employee or bar-code scanning device. The disadvantages are that the recirculation carton volume adds to the sorting method carton design volume, and that there is an increased carton induction and sorting volume. The advantages are few employees, minimal employee injuries, high volume, and automatic recirculation.


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MECHANICAL DIVERT COMPONENT The next across-the-dock carton sorting conveyor component is the mechanical divert device. The mechanical divert device provides the means to transfer a discretely identified customer carton from the sorting conveyor travel path onto a customer assigned unit station or shipping lane. A divert device is designed to pull, push, tip, slide, or pass the carton from the sorting conveyor travel path onto a customerassigned divert lane. The carton sorting conveyor travel path divert lane design requires an arithmetic progression for the sorting station from the induction station to the last sorting station. The sorting stations are in an arithmetic progression with all numbers that end with odd numbers on the carton sorting travel path’s left side and all numbers that end with an even number on the carton sorting travel path’s right side. These mechanical carton divert designs are the active sorter design, the active/passive sorter design, and the passive sorter design. Active Sorter The active sorter design has a powered induction station, a conveyor surface, and a mechanical divert device that pushes or pulls a carton from the carton sorting travel path onto a customer-assigned sorting lane. Active/Passive Sorter The active/passive sorter design has a manual induction station and a powered conveyor surface that tips or plows a carton from the carton sorting travel path onto the appropriate customer sorting lane. Passive Sorter The passive sorter design has a manual induction station and a powered conveyor with gravity force to remove a carton from the carton sorting travel path to the customer-assigned sorting lane.

VARIOUS DIVERT DEVICES

OR

METHODS

The various across-the-dock carton sorting divert devices are solid metal deflector, pusher diverter (Figure 7.20); powered belt diverter; plow diverter; SBIR or moving belt; tilt tray; Nova sort; tilt slat; gull wing; sliding shoe (Figure 7.21); pop-up diverts that include pop-up wheel (Figure 7.22), pop-up chain, and pop-up chain with a blade); rotating paddle; and flap sorter. Solid Metal Deflector The solid metal deflector sorting method is a passive sorting method. The method is a low-cost carton divert method that is considered a basic method to divert cartons from a mechanized carton sorting travel path. This basic deflector is a solid metal pneumatically or hydraulically actuated bar or arm. To divert a carton the deflector



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FIGURE 7.20 (a) Pusher and (b) sorter. (Photos courtesy of Siemens Dematic [www.siemansdematic.us]. With permission.)

or divert device is extended at an angle across the carton sorting conveyor travel path. At the extended angle, the deflector blocks the travel path of the carton. The power of the conveyor travel path, the carton forward movement, travel speed, and the deflector angle guide the carton from the smooth-top belt or roller sorting conveyor travel path onto an customer-assigned divert lane. When not required to divert a carton from the sorting conveyor travel path, the deflector is retracted to the sorting conveyor travel path’s side. The solid metal deflector divert design does not change a carton’s direction of travel as the carton is transferred from the sorting conveyor travel path to the shipping lane, and handles a low volume with a 20 to 40 carton rate per minute. To achieve the high sort rate, the carton sorting conveyor method handles a carton slug for one divert location. The carton weight is 10 to 50 pounds; a 3-to-5-foot distance is required between two divert locations; and the carton impact is medium. Pusher Divert The pusher carton divert method is an active sorter device and the designs are the side-mounted pusher/puller divert device and the overhead pusher or paddle divert device. The different designs are the attachment on the sorting conveyor travel path and the divert device movement across the sorting conveyor travel path surface. The method requires at the divert location a pusher on the sorting conveyor travel path far side. After the carton is inducted onto the carton sorting conveyor travel path, and as the carton arrives at the customer discretely assigned sorting location, the pusher divert device is activated by the sorting method microcomputer and an impulse from the tracking device. As the divert device pushes the divert blade across the carton sorting conveyor travel path, the pusher blade engages the carton’s side. As the pusher blade extends forward, the carton is pushed from the sorting travel


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FIGURE 7.21 Sliding shoe or slat sorter. (Photos courtesy Siemens Dematic [www.siemansdematic.us]. With permission.)

path onto the customer assigned divert lane. The divert device moves the carton onto the shipping lane, and the carton travel on the shipping lane has a different direction of travel than the carton direction of travel on the sorting conveyor travel path. The average pusher sort number per minute is 25 to 30 cartons, the maximum carton weight is 125 pounds, the spacing between two divert locations is the maximum carton length plus 6 to 12 inches, and the diverter impact on the carton is medium. The puller divert device sort rate is 35 to 40 cartons sorts per minute, the carton weight capacity is 10 to 100 pounds, and diverter impact on the carton is medium


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FIGURE 7.22 Pop-up wheel sorter. (From Siemens Dematic [www.siemens-dematic.us] and Hytrol, Jonesboro, AR. With permission.)



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to rough. The puller sorting mechanical functions are similar to the pusher sorting method, except that the carton is pulled across the carton sorting conveyor travel path onto the customer-assigned sorting location. The overhead mounted pusher diverter method handles approximately 30 diverts per minute. The overhead pusher diverter with customer divert locations on a sorting conveyor travel path’s both sides has the ability to push or divert a carton from the carton sorting conveyor travel path on the outgoing stroke and to push another carton on the return stroke onto a second divert station. With the proper identified carton sequence on the sorting conveyor travel path, the overhead mounted pusher diverter method completes 35 to 40 carton sorts per minute, but requires increased carton control in-feed and carton spacing on the sorting conveyor travel path. In most across-the-dock sorting applications, the carton discrete identification label sequence on the sorting conveyor travel path is a random occurrence. This reduces the maximum carton sorting rate to a normal cart sorting rate. These carton sorting conveyor travel paths are roller conveyor or smooth-top belt conveyor. Powered Belt Diverter The powered belt diverter method is an active sorting divert method. The divert method has arms that are located along the carton sorting conveyor travel path. The sorting conveyor travel path is a powered roller conveyor. Each divert arm has a small powered belt. After the carton is inducted onto the carton sorting conveyor travel path and prior to its arrival at the customer discretely identified divert location, the divert arm swings across the sorting conveyor travel path and the divert arm belt starts to move. This divert arm position, roller conveyor sorting conveyor travel path surface, carton forward movement, travel speed, and divert arm belt movement that quickly grabs the carton side, move the carton from the sorting conveyor travel path and onto the customer assigned sorting station. On the customer-assigned sorting station, the carton direction of travel is the same direction of travel as on the sorting conveyor travel path. The typical carton weight is 1 to 50 pounds, divert locations are 3 to 5 feet apart, and the diverter impact on the carton is medium to rough. The powered belt diverter method handles 20 to 30 cartons per minute. When there is a carton slug for one customer location, the divert rate is increased to 30 to 40 cartons per minute because the arm is not required to move for the next carton divert. In most across-the-dock sorting applications, the carton or discrete identification label sequence on the sorting conveyor travel path is a random occurrence. This means that the sorting method achieves a normal sorting rate. Plow Diverter The plow diverter is an active/passive across-the-dock sorting device that is a curved metal divert arm or plate. These divert arms are programmed to swing across the carton sorting conveyor travel path. The carton sorting conveyor travel path is a roller conveyor surface. The plow diverter is designed with one plow end attached



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to the sorting conveyor travel path’s far side, while the other end moves toward to the sorting conveyor travel path’s near side. In an extended position, a plow diverter is across the carton sorting conveyor travel path and is in the carton direction of travel. The plow metal curved divert arm position, the carton forward movement, and carton travel speed on the smooth roller conveyor surface cause the carton slowly to follow the divert arm plow curve. The divert arm curve directs the carton from the carton sorting travel path onto the appropriate shipping lane. The plow diverter is best used on a carton sorting roller conveyor travel path that sorts a carton slug that is diverted onto a shipping conveyor lane. The sorting travel path’s design parameter specifies 2 to 5 feet between two divert locations. The plow diverter does not change the carton direction of travel on the sorting travel path. With a relatively slow divert plow movement, the plow diverter method handles 15 to 20 cartons per minute. The cartons have a weight range of 1 to 50 pounds, and impact on the carton is medium and gentle. In most across-the-dock sorting applications, the carton or discrete identification label sequence on the sorting conveyor travel path is considered a random occurrence. This feature has the plow divert method achieve a normal sorting rate. SBIR or Moving Conveyor Belt The SBIR or moving conveyor belt carton sorting method is an active and sophisticated carton across-the-dock sorting method that has individual carton-carrying surfaces. Each carton-carrying surface is an individual belt conveyor surface that is mounted on four wheels. These individual belt conveyors are designed to travel in a closed-loop sorting conveyor travel path. Each SBIR carton-carrying surface travels past an induction station. At the induction station, a carton has its discrete identification read by a bar-code label scanner device. The device sends the bar-code label information to a microcomputer. The microcomputer, constant travel speed, and tracking device ensure that the individual belt-carrying surface is activated as the carton arrives at the customer assigned sorting location. The customer assigned divert location is on the load-carrying surface’s right or the left side. As the belt-driven load-carrying surface arrives at the customer-assigned sorting location, the surface turns forward and discharges the carton from a belt load-carrying surface onto a customer shipping lane. The carton orientation or direction of travel on the customer sorting lane is different from the carton direction of travel on the carton sorting conveyor travel path. The SBIR carton sorting method has a gentle impact or no impact on the carton and handles a carton weighing up to 50 pounds. The divert device performs a high sort number per minute, is a two-way sorting method, and requires a capital investment. Tilt Tray The tilt-tray carton across-the-dock sorting method is an active/passive carton sorting method. The tilt tray carton sorting method has slightly concave-shaped tilt trays with four wheels that constitute a carton carrying surface (or platform). These trays ride on a closed-loop travel path and are pulled by a motor-driven chain or electric


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bus bar and aluminum interior. Tilt-tray methods have the capability to handle one long carton on two trays. The methods are a bull wheel and drive, which is old technology; a caterpillar drive, which drives most existing tilt-tray sorting systems; and new tilt-tray technology that has an electric bus bar propel the tilt tray forward over the travel path. The forward force is created by the reaction from an electric wave pushing forward an aluminum tilt-tray foot. After the carton with a bar code facing upward is manually or automatically inducted onto a tilt-tray sorting travel path, the tilt tray travels under a bar-code scanner that sends the bar-code discrete identification to the microcomputer. As the tilt tray with the customer discrete label travels on the conveyor travel path, the tilt tray is under the microcomputer control and tracking device. The tilt tray is electrically or pneumatically tilted at the customer-assigned sorting location. This customer sorting location is on the tilt-tray chain travel path’s left or right side. For best results, odd numbered divert locations are on the chain travel path’s left and even numbered divert locations are on the chain travel path’s right side. Most tilt-tray chain applications have the lowest numbered sorting location as the first sorting location past the induction station. The tilt-tray tilting action creates a gravity force and the tilt-tray forward travel speed causes the carton to slide from the tilt tray onto the customer assigned shipping lane. After the tray is tilted and prior to the tilt tray conveyor travel path induction station, all trays pass a clean-out lane that tips each tray. This tray tilting action removes all unsorted cartons from the tilt-tray sorting travel path. These unsorted cartons are reintroduced to the tilt-tray induction station or are manually delivered to the assigned customer shipping lane discharge end. If these cartons are manually delivered to the shipping lane, the carton is manually scanned by a handheld or finger scanner and the carton is placed onto a tray and is downloaded to the microcomputer. After this clean-out or unsorted carton station, a tilt-tray travel-path device latches or levels all the tilt trays. At the induction station, the latched tilt tray can receive another carton. Most carton tilt-tray sorting methods have the trays set on 27-inch centers, and the sorting locations are on 3-to-4-foot centers. The tilt tray and divert centers vary according to the maximum carton size, carton weight, and travel speed of the tilt tray chain. The tilt tray conveyor tilt rates are 180 to 241 trays per minute, and the handling capacity is 25 pounds maximum per tilt tray. The carton direction of travel is either changed or not changed on the customer sorting lane and the impact on the carton is medium. An employee or an automatic induction method on a tilt tray that travels over a fixed closed-loop sorting conveyor travel path inducts a carton discrete identification label. The sorting conveyor travel path has customer sorting locations on one or both sides of a tilt tray conveyor travel path. In many applications, the tilt-tray sorting method is designed with dual induction stations. Dual induction stations require two tilt-tray clean-out chutes, two tilt-tray latching stations, and two induction stations. The dual induction operation increases the tilt-tray sorting capacity. After one induction station there is one straight conveyor travel path run for sorting to



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customer shipping lanes, and after the second induction station there is a second straight run conveyor travel path sorting conveyor travel path for sorting to customer shipping lanes. Nova Sort The Nova sort is a modular across-the-dock carton sorting method that has a closed loop fixed sorting travel path. The Nova sort consists of a motor-driven train with three to four trays. Each wheeled tilt tray has a 500-pound load carrying capacity and the tray tilts to the travel path’s left or right. Each modular tilt-tray train has a microcomputer, a fixed travel path that has an electric-powered bus bar, and sensing devices that detect an object or employee limb in a Nova sort tilt tray travel path. The Nova sort vehicle travel path is ceiling hung or floor supported, travels vertically over a slight grade, and travels over 90˚ and 180˚ curves. The sorting travel path directs the Nova sort tilt-tray vehicle train past an induction station and the customer sorting stations. At the induction station, an induction employee or automatic transfer belt places a discretely identified carton onto an empty tray and a bar-code scanner reads the bar code. The scanner sends the information to the microcomputer. The discrete information assigns the carton to a specific customer sorting location. As the tilt-tray train travels over the travel path, the microcomputer and tracking device ensure that the appropriate vehicle tilt-tray tilts and discharges the carton from the tilt tray onto the customer-assigned sorting location. With the onboard microcomputer, at a sorting location a tilt-tray train is unloaded and loaded by the sorting location employee. After all tilt trays are tilted at the required customer sorting locations, the tilt-tray train travels on the fixed travel path and queues prior to the induction station or continues traveling to the maintenance spur. On the maintenance spur, the tilt-tray train waits or queues for the next assignment. As an option, each tilt-tray train has a fixed load-carrying surface and has the capacity to handle one carton on one tray or one long carton on two trays. For expansion for additional customer sorting locations, additional sorting travel-path track is added to the existing travel path. The Nova sort’s design parameters and operational characteristics are similar to the tilt-tray sorting method. The disadvantages are a medium volume, capital investment, possible queues on asingle tray travel path, and an induction platform that requires employee egress and access paths. Advantages are that, as required, cartons are transported over the travel path; that the method is ceiling-hung and floor-supported; that both loading and unloading is performed at a sorting station; and that expansion is easy. Tilt Slat The next across-the-dock sorting method is the tilt-slat carton sorting method that is an active/passive sorting method. The method has wheeled slats that ride on a closed-loop travel path. A motor-driven chain pulls these slats. A predetermined number of slats serve as carton load-carrying surfaces.


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After the carton is inducted by an employee or automatic bar-code scanning device that reads the carton’s discretely identified label, the carton is transferred by an employee or automatic transfer device (several short belt conveyors) onto the tiltslat sorting conveyor method. The bar-code discrete identification is transferred to the microcomputer and tracking device. The constant travel speed and these devices ensure that the customer-assigned carton arrives at the assigned sorting station. At this station, slats are tilted and the carton slides on the customer-assigned shipping lane. The customer sorting station is located on the right or left side of the closedloop travel path. The tilt-slat operational characteristics and disadvantages and advantages are similar to the tilt-tray operational characteristics and disadvantages and advantages. After the carton sorting onto the customer shipping lane, the carton has a new direction of travel. With the capability of the tilt tray method to handle a long carton on two trays, the tilt-slat technology is considered old technology. Gull Wing The next across-the-dock carton sorting method is the gull-wing carton sorting method, which is an active/passive carton sorting method. The gull-wing carton sorting method has many four-wheeled carton load-carrying surfaces that ride on a closed-loop travel path. Customer sorting locations are on both sides of the sorting conveyor travel path. A motor-driven chain pulls the gull-wing-shaped devices over the travel path. The gull-wing carton carrying device is in the shape of a bird’s (a gull’s) wing or in a V-shape. After the carton is placed onto the gull-wing carrier, it is inducted onto the conveyor sorting method. As the gull wing travels past the bar-code label scanning station, the carton discrete identification is entered into the sorting microcomputer. When the carton arrives at the assigned sorting location, the microcomputer activates the appropriate tipper device along the sorting travel path to tip the carrier. The gull wing tipping action has gravity force and the sorting conveyor forward travel speed to slide the carton from the gull-wing carrier onto the customer-shipping lane. The gull-wing operational characteristics and disadvantages and advantages are similar to the tilt trays. The gull-wing sorting method handles a wide carton variety ad has a low capacity; on the customer shipping lane the carton direction of travel is changed from that on the sorting travel path. Sliding Shoe The next across-the-dock carton sorting method is the sliding-shoe sorting method, which is an active/passive carton sorting method. This method has many powered slat surfaces with shoes located between two slats. The open space allows the shoe to slide across the carton travel path. The method is designed as a single sliding shoe or a dual sliding shoe sorting method. These sliding shoes are located and travel along the sorting location’s opposite side. This feature requires that the slat sorting conveyor travel path be wide enough to handle widest carton plus the sliding shoe’s dimensions.



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At the induction station, the carton has its discretely identified bar-code label customer sorting location read and sent to the sorting microcomputer. The microcomputer, constant travel speed, and tracking device ensure that the carton travels on the sorting conveyor and arrives at the assigned sorting station. Prior to the carton’s arrival at the assigned sorting location, the sliding shoes start to move across the carton travel path. The sliding shoes move from the sorting window’s far side to the sorting window’s near side. The sliding shoes’ position on the sorting conveyor travel path forms an angle that causes the carton to move from the sorting travel path onto the customer shipping lane. The carton direction of travel or orientation on the customer shipping lane is the same as the carton direction of travel on the sorting conveyor travel path. The sliding shoe carton sorting method handles 130 to 150 cartons or sorts per minute, or a sorting conveyor travel speed of 400 feet per minute, with a gentle impact on a carton. Pop-Up Diverter Method The pop-up divert conveyor group is an active sorter group that includes pop-up wheel, pop-up chain, pop-up slat, and pop-up roller. These carton conveyor sorting methods have similar characteristics and are installed slightly below the live roller conveyor travel path surface. Another similarity is these carton sorting methods handle the carton’s bottom exterior surface. The pop-up wheel and roller diverter method are the first carton sorting methods from the pop-up carton sorting group. The pop-up wheel and roller diverter method has one wheel, two strings of wheels, or a predetermined short length roller number that is located on the carton sorting conveyor travel path. These pop-up devices’ top surfaces are set at an elevation that is slightly below the wheels or roller tops. At the carton sorting beginning, these pop-up wheels and rollers are angled (skewed) to the conveyor travel path’s left or right. The pop-up wheel or roller skew is toward the customer sorting location. After the inducted carton leaves the induction station, the carton travel on the carton sorting conveyor travel path is under the microcomputer and tracking device control. As the carton arrives at the customer sorting location, the microcomputer activates the pop-wheels or rollers to rise slightly above the carton sorting conveyor travel-path surface or the wheel or roller tops. With the pop-up wheel or roller elevation slightly above the surface, the wheel or roller angle and turning action grabs the carton bottom exterior surface and directs a carton from a sorting conveyor travel path onto a customer shipping lane. After the carton sorting is on the customer shipping lane, the pop-up wheels or rollers return to the lowered elevation that is slightly below the carton sorting conveyor travel-path surface. This wheel or roller position allows other cartons to travel across the sorting location onto the customer-assigned sorting location. The pop-up wheel carton sorting method handles 65 to 150 sorts per minute with a gentle impact on the carton, the carton interface is from the carton’s bottom, sorting location spacing is 4 to 5 feet, and handling capacity is a carton weight of 30 pounds. The pop-up roller carton sorting method handles 15 to 20 cartons per minute with sorting locations on closer centers and handles a carton weight of 200 pounds.


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The pop-up wheel and pop-up roller carton sorting methods maintain the carton sorting conveyor travel-path orientation or direction of travel as the carton travels on the customer shipping lane. The pop-up chain is the second pop-up carton sorting method from the pop-up divert group. The pop-up chain carton sorting method is an active carton divert method that transfers a carton from a roller conveyor sorting travel path onto a rightangle customer shipping conveyor travel path. This carton divert method does change the carton direction of travel on the customer shipping conveyor. After the carton is inducted onto the sorting conveyor travel path and the carton arrives at the assigned sorting location, two chain strands sandwiched between two conveyor rollers are raised slightly above the roller conveyor travel path surface. These rollers engage the carton’s bottom exterior surface. With the surface on top of the chain, it is above the sorting conveyor travel-path roller surface and is transferred from the sorting conveyor travel path onto the customer shipping lane. The next pop-up divert method is the pop-up chain divert method, which is a chain with an attached blade or bar. As the carton is diverted from the carton sorting conveyor travel path, the chain turns and the blade engages the carton’s bottom side. As the chain moves forward, the carton moves over the smooth roller conveyor travel path onto the customer shipping lane. The pop-up chain carton sorting method handles approximately 10 to 20 carton sorts per minute and a carton weight up to 75 pounds. The pop-up chain divert locations are on 4-to-5-foot centers, have a gentle impact on the carton, and interface with a carton bottom. Rotating Paddle The rotating paddle pusher is the next carton across-the-dock sorting method. The rotating paddle pusher is an active carton sorting method. The rotating paddle is a spherical-shaped sorting device with three to four paddles or three to four flat surfaces that extend outward toward the sorting travel path. When not activated to divert a carton, the rotating paddle device does not extend toward the carton sorting conveyor travel path. As the carton arrives at the customer-assigned sorting location, the paddle rotates and comes in contact with the carton side. This paddle contact and carton forward travel speed over a smooth roller conveyor surface forces the carton from the carton sorting conveyor travel path onto the customer shipping lane. In this carton sorting method, a carton travels in a direction of travel on the customer shipping lane rather than on the carton sorting conveyor travel path. The rotating paddle handles a 1-to-75-pound carton with a medium-to-rough impact on the carton and performs 50 to 70 carton sorts per minute. On the carton sorting conveyor travel path, the customer sorting locations are on 9-foot centers. Flap Sorter The next carton sorting conveyor method is the flap sorter method. The flap sorter method is an active/passive sorting method. It has belt conveyor sections that make up the carton sorting conveyor travel path. This belt conveyor travel path has several



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fixed belt conveyor sections that are between two customer sorting locations and several flap or moveable belt conveyor sections. The flap belt sorting conveyor section is designed as a unidirectional sorting conveyor section with a belt conveyor end that moves or is angled downward. This downward angled sorting travel path has a carton diverted from the sorting conveyor travel path onto a shipping conveyor travel path. The shipping sorting location is located below the sorting location. After carton sorting or for a predetermined time period, the downward angled sorting belt conveyor end returns to the horizontal level. The horizontal conveyor travel path allows other customer cartons to travel past the sorting location. The flap sorter method is design with a fixed unsorted carton divert location or a closed loop sorting conveyor travel path with a recirculation conveyor section. After a discretely coded carton is read by a scanning device and communicated to the microcomputer, the microcomputer and tracking device ensures that the carton is sorted at the appropriate customer sorting location. This sorting location is directly past and under the flap belt conveyor section. As the carton on the sorting conveyor travel path arrives at the assigned customer sorting location by traveling over a series of fixed belt conveyor and flap belt conveyor sections, the microcomputer and tracking device triggers the appropriate flap belt conveyor section to swing down. This flap belt conveyor section’s swinging downward action, combined with the carton’s forward travel movement and carton acceleration due to gravity, sorts the carton from the sorting conveyor travel path into the appropriate customer sorting location. The disadvantages are capital investment and a one-way sorting method. Advantages include batched customer cartons and a high volume. Customer Shipping Lane or Conveyor The next across-the-dock carton sorting method component is the customer shipping lane or conveyor. The customer shipping lane is the carton travel path between the sorting conveyor travel path and the customer pallet-loading station or direct load conveyor. To minimize carton damage, along each customer shipping lane a photoeye is located in the shipping lane’s middle. When a carton blocks this photo-eye, the microcomputer activates the partially full shipping lane alarm. This is a signal to management and employees that there is a problem at the shipping lane loading end and this problem is causing cartons to queue on the shipping lane. The photoeye may also be located near the sorting conveyor travel path. When a queued carton blocks this photo-eye, the photo-eye communicates the status to the microcomputer. The microcomputer deactivates the sorting conveyor travel associated customer sorting device. The deactivated sorting device causes additional customerassigned cartons to recirculate on the closed loop sorting conveyor travel path or at the unsorted carton location to discharge from the one way conveyor sorting travel path. Full-length side guards are attached to the carton shipping travel path. The side guards ensure that the cartons are retained on the travel path. The customer carton shipping lane conveyor travel path surfaces are gravity metal, strand metal, fiberglass or plastic coated wood slide, or chute; gravity skate-


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wheel conveyor or roller conveyor; powered belt conveyor; and roller-controlled low-pressure live roller conveyor. Solid-Gravity Slide or Chute The solid-gravity slide is basically a piece of galvanized sheet metal, fiberglass, or coated wood that has a flat or concave bottom surface carton travel path. All gravity slides or chutes require the carton sorting travel path to have a charge end that has a higher elevation at the customer divert location and a lower elevation at the discharge end. The gravity slide’s length determines the length for the side runners, underside number supports, cross support members, and floor surface support legs or ceiling hangers. If a slide travel path requires more than one section, the top travel-path section overlaps the next travel path section. This travel-path overlap feature is similar to roof shingles and reduces carton hang-ups on the travel path. To ensure smooth carton travel over the slide travel path, the factors are that the slide charge transition end has a crown shape, the slope and material are determined from carton flow tests, and the discharge transition end has a convex shape. The concave-bottom slide configuration provides some carton flow or travel control over the travel path. This controlled carton flow minimizes carton jams in the slide travel path. The slide travel path relies on gravity force to convey a carton from the sorting conveyor travel path to a pallet-loading or direct load station. To achieve some carton queuing on a slide travel path, a step is added in the slide travel path’s bottom and an adjustable end stop is added to the slide discharge travel-path end. With a closed adjustable end stop, cartons queue in the slide travel path and the stop permits cartons to ride on the queued cartons and queue against an end stop. The first gravity slide design option is a straight carton travel path. The straight gravity travel path requires a larger building area and requires a lower investment. The second option is a spiral carton travel path. The spiral gravity travel path requires a small building area but a higher investment. The slide or chute interfaces with an active or passive carton sorting conveyor method and provides limited carton queuing. The slide or chute handles a wide carton size variety and shapes, but due to uncontrolled line pressure, the carton has noncrushable or nonfragile characteristics. The slide or chute conveys cartons a short travel distance. To reduce carton jams on the slide travel path, the preferred travelpath design is the concave design. Most concave slide or chute designs do not change the carton direction of travel on the travel path. Gravity Strand Slide The next gravity decline carton transportation method is the gravity strand slide. The gravity decline strand slide has coated metal strands that run the full length of the carton travel path. Each slide has three strands at minimum that are evenly spaced across the slide width. Per good conveyor travel, there are three strands under the narrowest carton bottom exterior surface. Per your carton width and weight mix, additional strands are added to the strand travel-path width. The gravity strand slide method has the same design parameters and operational characteristics as the solid-bottom gravity slide travel path.



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Gravity Skate Wheel or Roller Conveyor The gravity skate-wheel or roller conveyor travel path is the next customer carton shipping lane that requires the carton sorting conveyor travel path customer divert charge end to have a higher elevation than the customer unit divert location or discharge end. The floor-supported legs or ceiling hangers are determined by conveyor frame sections and the queued weight on the conveyor travel path. The gravity skate-wheel conveyor has several skate-wheel conveyor sections connected together. A skate-wheel conveyor section has skate wheels on an axle span. The axle is attached onto two frame sections. The conveyor frames are floor supported or ceiling hung. As the carton flows over the skate-wheel conveyor travel path, the skate wheels turn on the axles. To ensure good carton flow, there are at least three skate wheels under the narrowest carton’s bottom exterior surface. The gravity roller conveyor has roller conveyor sections connected together. A gravity roller conveyor section has rollers that span the conveyor travel path width. Each roller axle’s ends are attached onto two frames. These conveyor frames are floor supported or ceiling hung. As the carton flows over the roller conveyor travel path, each roller turns on its axles. To ensure good carton flow, there are at least three rollers under the narrowest carton’s bottom exterior surface. The gravity skate-wheel conveyor or roller conveyor is an extension of an active sorting device and the carton has the same direction of travel or orientation on the customer shipping lane as on the sorting conveyor travel path. To reduce carton hang-ups, carton damage, and smooth carton travel, the carton sizes and shapes are standard; the carton is noncrushable or nonfragile; the charge transition end has a nonpowered nose-over and the discharge transition end is designed with convex shaped plate; side guards are full length; and to determine the proper conveyor travelpath slope, carton flow tests are conducted by a conveyor manufacturer. If the carton travel speed is excessive on a gravity conveyor customer shipping lane, to slow a carton travel speed the options are that the conveyor travel path is slightly tilted to one side, which causes one carton side to ride or rub against a guard rail; that a skate wheel or roller’s turning ability is restricted with a washer; that, from an overhead structure, several plastic stripes extend downward into the carton travel path and rub on the carton top surface; and that a brake device is added on a conveyor travel path. Powered Belt Conveyor or Low-Pressure Roller with Brake Rollers Conveyor The powered belt or low-pressure roller conveyor with brake rollers customer shipping lane methods require the sorting conveyor travel path to be set at an elevation that is slightly higher than the charge customer sorting location or to have a powered conveyor transfer section. The powered belt and roller conveyor customer shipping lane methods interface with an active sorting method. The powered conveyor customer shipping lane methods are similar to the gravity conveyor customer shipping lane methods, except that a powered conveyor shipping lane method requires an investment and handles a wider carton mix, and the belt conveyor has controlled carton travel.


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CARTON CONVEYOR CUSTOMER SHIPPING-LANE DESIGN The carton conveyor customer shipping-lane design options are the straight travel path and the serpentine or loop travel path. The straight travel-path design features are that the sorting conveyor travel path runs along the opposite wall from the shipping docks or has a slope that is from the divert device’s high elevation to a low elevation on the shipping dock floor. The design requires a large building area but a lower conveyor investment. The serpentine or loop travel path’s design features are that the sorting conveyor travel path runs along the wall above the shipping docks and has a slope, pitch, or angle in relation to the conveyor travel path. As the conveyor travel path approaches the wall opposite the shipping docks, the shipping conveyor lane travel path makes a 180˚ turn back toward the shipping dock. After the 180˚ turn, the shipping conveyor lane travel-path slope declines to the low elevation on the shipping dock floor. The design requires a small building area but has a slightly higher conveyor investment.

CONVEYOR CONSIDERATIONS When you consider a carton conveyor unload or load transport and sorting method for your across-the-dock operation, the important considerations that determine the across-the-dock conveyor method’s effectiveness are to ensure proper carton travel speed and carton queuing prior to each activity station along the sorting and transportation conveyor travel path. To obtain proper carton travel speed across the carton transport conveyor, as the conveyor travel path progresses from one conveyor activity area to the next conveyor activity area, the next conveyor activity area has a slightly faster travel speed. In most conveyor transport applications, a conveyor activity area travel speed is 5 feet per minute faster than the previous conveyor activity area travel speed. This increased conveyor travel speed has sufficient difference to ensure that the cartons are moved forward under control over the entire across-the-dock conveyor travel path. To ensure that there is a constant carton flow to an activity station on the conveyor sorting or transport travel path (such as a merge location at a loading station, an unloading station, check weigh, bar-code scanner, fill carton, or seal machine), most conveyor professionals have nonpowered, powered live roller, or skate-wheel carton low- or zero-queue conveyor travel paths prior to each activity station. The queue conveyor length and type is determined by your conveyor manufacturer and company transport method design parameters. The guide to using a nonpowered or powered live roller carton queue conveyor is based on the conveyor travel path slope or decline. If the conveyor travel-path section prior to the activity station is a horizontal travel path, the conveyor travelpath queue section is a powered live roller or skate-wheel low- or zero-pressure accumulation conveyor. In most across-the-dock conveyor sorting and transport methods, these activity stations are at the unloading conveyor incline top, prior to a merge station, prior to the check weigh station, prior to the carton fill station, prior to the carton seal station, and prior to the bar-code scan station.



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The powered live roller queue conveyor types are low pressure or zero pressure. The difference between the low-pressure and zero-pressure live roller queue conveyor is that when carton travel is halted on the conveyor travel path, a zero-pressure live roller conveyor means that the live or driven roller surfaces do not exert a forward movement pressure on each stopped carton bottom exterior surface; a low-pressure live roller conveyor means that the live or driven roller surfaces exert a minimal forward movement pressure on each stopped carton bottom surface. If the conveyor travel-path section is an incline travel path, the conveyor travelpath section is a powered belt conveyor, spiral belt, or vertical lift. The incline is used to transport cartons from the receiving dock to an elevated transport or sorting conveyor travel path, or to make a controlled carton elevation change between two conveyor travel paths. The powered belt conveyor travel path has a full-length belt conveyor surface. A powered tail and nose-over with a slope of 15˚ to 20˚ ensures carton travel up an incline travel path. The first belt conveyor travel-path option is a slider bed. The slider-bed conveyor method has a solid sheet metal full length or under the belt conveyor travel path. The second option is a roller bed. The slider-roller-bed belt conveyor has skate wheels that are evenly spaced and protrude through the sheet metal surface to provide support for the belt conveyor travel path. This feature provides a solid conveyor travel-path surface with a low coefficient of friction or drag on the conveyor belt. The third option is a slider roller bed. The roller-bed belt conveyor method has several rollers that are evenly spaced under the belt conveyor travel path to provide support for the belt travel path. The roller-bed belt conveyor provides the lowest coefficient of friction on the conveyor belt. The spiral belt or hard plastic conveyor is another carton conveyor method that transports cartons over an incline travel path. The spiral conveyor travel path is considered a circle travel path that inclines around a center post. The conveyor travel slope increases as the vertical travel completes a circle. The vertical conveyor travel surface provides carton control travel; evenly spaced cartons ensure minimal line pressure and require a small area. The next incline carton travel-path method is the vertical lift method. This lift method has several carton carryings slats that move over a fixed vertical travel path between two horizontal travel paths on different elevations. The space between two slats is determined by your tallest carton. The carton carrying slats are in constant movement and, from a low level transport path, pick up a carton, move the carton up to the elevated level, and discharge the carton onto the transport path. With the vertical lift conveyor, there is no line pressure, only a small area is required, and there is controlled carton movement. If the conveyor travel-path section is a decline travel path, the conveyor travel path options are powered belt conveyor, powered low-pressure live roller conveyor with selected brake rollers, vertical lift, and nonpowered queue skate-wheel or roller conveyor. When you consider a nonpowered decline queue carton conveyor travel path, the important considerations are the slope and line pressure, the type of carton bottom exterior surface, and conveyor design. The powered belt conveyor decline travel path with a power tail and nose-over is a decline conveyor travel path. The belt surface provides a high coefficient of


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friction to ensure maximum carton control and minimal line pressure; the belt handles flat surface cartons and functions with a 15˚ to 20˚ slope. With the cartons evenly spaced on the belt conveyor travel there is minimal carton queuing. The second decline conveyor travel path is a low-pressure live roller with selected brake rollers. The live roller conveyor with brake rollers travel has on the decline conveyor travel path several brake rollers. The distance between the brake roller is determined by your carton length and weight. As a carton starts decline travel, the carton travel activates the appropriate brake roller to control or momentarily stop the carton travel to ensure minimal line pressure, controlled travel, and minimal carton queuing. The third decline carton conveyor is the vertical lift conveyor, which has the same design parameters and operational characteristics as the incline vertical lift except that the carton travel path has a different direction of travel. The next carton decline travel-path method includes nonpowered skate-wheel or roller conveyor. The decline nonpowered or gravity carton conveyor travel-path slope design factors are required elevation change; available building space; and carton physical characteristics, which includes bottom exterior surface, desired controlled travel speed, and line pressure. The nonpowered conveyor travel path surface is a skate-wheel conveyor or roller conveyor. The skate wheel conveyor consists of a series of evenly spaced skate wheels. Each skate wheel is attached to an axle and spans and is attached to each conveyor frame. Enclosed ball bearings allow the skate wheel to turn as the carton flows over the conveyor travel path. The roller conveyor is a round-shaped object that has an axle with encased bearings on each end. The ball bearings allow the roller to turn on the axle as the carton flows over the conveyor travel path. The roller spans the open space between the two frames, and roller axles are connected to the frames. These frames are ceiling-hung or floor-supported to maintain the conveyor travel path’s proper slope. With either nonpowered carton conveyor type, there are three skate wheels or rollers under the narrowest carton’s bottom exterior surface. To ensure smooth and continuous carton travel over the conveyor travel path, the carton’s bottom surface requires a smooth and hard bottom exterior surface; the carton is placed onto the conveyor travel path in the proper direction of travel. The proper direction of travel has the carton’s bottom flaps or length in the direction of travel over the conveyor travel path. The next nonpowered or gravity conveyor travel path consideration is controlled carton travel speed. When a carton travels over a decline travel path, the carton travel path requires a carton travel speed control device, side guards, and photo-eyes. The carton travel speed devices, side guards, and photo-eyes improve safety, minimize carton damage, and ensure a constant carton flow. The various methods to control carton travel or slow carton travel speed over a decline conveyor travel path are low degree of slope, and slight tilting of the conveyor travel path to one side so that the carton side rides or rubs along the side guard. The feature increases the coefficient of friction or resistance to the carton travel. At predetermined locations on the conveyor travel path, retarders are placed on the



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rollers or skate wheels. Directly above the conveyor travel path, plastic strips that hang down into the carton travel path and ride over the carton top exterior surface. The various carton conveyor travel-path side guards or guardrails are on the conveyor travel path from the charge end to the discharge end. The side guards ensure that the cartons are retained on the conveyor travel path. The side guard options are solid sheet metal, one or multiple level C-channels, skate wheel, pipe side guards, and angle iron. The photo-eyes are carton control flow devices along the conveyor travel path that communicate the conveyor travel path status to the microcomputer. The photoeye has a light beam, reflector, receiver, communications network to a microcomputer, and an alarm. When the photo light beam is blocked by an unmoving carton, a message is sent to a microcomputer that activates an alarm or deactivates a divert device. The photo-eye types are partial full line and full line. The partial full-line photo-eye is located in the travel path’s middle. When the photo-eye is blocked by an unmoving carton on the decline conveyor travel path, the microcomputer receives the signal and activates a visual or audible alarm to indicate the conveyor travel path condition. Employees or the sorting travel path divert device continue to divert cartons onto the shipping lane while management takes corrective action. The full-line photo-eye is located near the travel path’s charge end. When a nonmoving carton on the conveyor travel path blocks the photo-eye, the microcomputer receives the signal to deactivate the appropriate divert device. Cartons on the sorting travel path that are assigned to the deactivated divert station are recirculated or are diverted onto a clean-out lane; the employees or management takes corrective action.

TEMPORARY HOLD AREA

OF

ACROSS-THE-DOCK SORTED CARTONS METHOD

The across-the-dock sorted cartons method temporary hold area is designed to hold your customer across-the-dock ordered and sorted cartons that are staged prior to a customer delivery truck loading activity. When your carton across-the-dock facility handles a large volume and the vendor cartons arrive before your customer delivery truck arrival at the shipping dock, or the customer delivery truck does not show, the temporary storage method is an option. This temporary sort and hold method is very similar to a pick to belt conveyor method, except an employee transfers the cartons from the across-the-dock conveyor transport and sorting travel path into a temporary (standard or flow pallet rack) position. When required, per the customer delivery truck arrival schedule, an employee transfers these cartons from the temporary position onto the across-the-dock transport and sorting conveyor travel path. These conveyor travel paths move these cartons from the across-the-dock facility into the customer delivery truck. Disadvantages are additional building investment, additional material handling equipment investment, double-handling of cartons, and potential pallet-loading errors. The advantages are the ability to handle a large customer number, the removal of peaks and valleys from the receiving and shipping dock activities, the ability to have an across-the-dock operation without a customer delivery truck at the dock, and the ability to handle cartons from a small-item across-the-dock repack operation.


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ACROSS-THE-DOCK SHIPPING SORTING METHOD The across-the-dock shipping sorting method is more common than the temporary hold method. In the across-the-dock shipping sorting method, your customer acrossthe-dock sorted carton placement options are onto your customer delivery cart, slipsheet, or pallet, or directly onto your customer delivery truck. In this method your customer across-the-dock labeled cartons are sorted for placement onto the appropriate customer delivery cart or pallet. As the discretely labeled carton leaves the receiving dock area and travels to the sorting method encode station, the carton customer discrete identification is entered into the microcomputer. With this information, the microcomputer along with the sorting method tracking device activates the appropriate sorting method divert device at the required time to divert the carton from the sorting conveyor travel path onto the customer-assigned shipping lane.

DIRECT

OR

FLUID LOAD

OF

ACROSS-THE-DOCK CARTONS

In an across-the-dock direct load operation, your customer-ordered across-the-dock cartons travel from a sorting travel path on a shipping lane or conveyor travel path. This shipping conveyor travel path has either a serpentine or straight gravity conveyor travel path from the sorting conveyor travel path onto an extendible conveyor that extends into a customer delivery truck. In the customer delivery truck, these cartons are transferred from the extendible conveyor and are placed onto the customer delivery-truck floor. The extendible conveyor is a powered belt, powered roller or skate wheel, or nonpowered roller or skate-wheel conveyor travel path. The disadvantages are conveyor investment, a recirculation conveyor travel path or increased employee handling of unsorted cartons, and the need for a sorting method and bar-code label scanning method. The advantages are less dock space and fewer dock doors, less holding area requirement, no carton double handling, and the need for customer delivery trucks at the dock.

SEPARATING SHIPPING CARTONS

INTO

UNITS

In the across-the-dock shipping carton method for separating into units, your customer-ordered across-the-dock cartons travel on the shipping lane conveyor travel path. This shipping conveyor travel path is a conveyor travel path from the sorting conveyor travel path onto a unit station. At the station, the across-the-dock cartons are transferred from the conveyor travel path and are placed onto a cart, slip-sheet, or pallet board. After the cart, slip-sheet, or pallet board is separated into units up to a predetermined height, the full cart, slip-sheet, or pallet board is identified with the customer discrete code and transferred from the unit station to an assigned outbound staging area, or is placed onto the customer delivery truck. The disadvantages are the need for a cart, slip-sheet, or pallet board separatinginto-units area; some double handling; additional shipping dock space; and a pallet or slip-sheet handling device. The advantages are easy loading and increased unloading of conveyable and nonconveyable customer delivery loads; the method also allows the customer cartons to be handled without a customer delivery truck at the shipping dock, and is preferred for a customer with a cart delivery method.



MIMIC DISPLAY

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CONTROL PANEL

The last components of a carton sorting method are the sorting conveyor travel path mimic display and control panels. The mimic display indicates to your manager or operators the actual carton sorting conveyor section status (off, on, or jam condition) and the control panel permits an operator to turn any conveyor section off or on.

NONCONVEYABLE ACROSS-THE-DOCK CARTON SORTING It is the focus of this section to review the various nonconveyable carton across-thedock sorting methods, operational characteristics, and disadvantages and advantages. In the past years, many companies have implemented highly mechanized conveyable master carton across-the-dock carton sorting methods to reduce operating expenses, increase throughput volume, improve sorting accuracy, and enhance customer service. One segment of the across-the-dock operation that is not handled by these mechanized carton across-the-dock methods is the nonconveyable SKUs. A nonconveyable SKU is characterized as oversized, odd- (irregular) shaped, highcube, or heavyweight. These SKUs account for 5 to 25% (varies per industry and business) of the carton volume that is handled by an operation. The nonconveyable carton across-the-dock handling methods considered for an carton across-the-dock supply-chain logistics strategy or segment are to sort cartons from pallets onto a customer location, which is a cart, pallet, or nonpowered vehicle, and onto a customer-order sorting vehicle or pallet with cartons in rack positions. The first option has an employee with a sorting instruction push a vehicle with master cartons through an aisle between two rack-row pallet positions. These pallet positions are the customer sorting locations; are arranged in customer identification sequence; and are single-deep pallet, gravity flow-rack pallet, or floor-stack pallet positions. The sorting instruction has the same customer identification sequence and the customer-ordered quantity. When the employee matches the customer identification on the sorting instruction to the customer identification on the pallet position, the employee stops the vehicle and transfers the SKUs from the vehicle to the appropriate customer location. The second method has an employee with a customer-order sorting instruction push an empty vehicle through an aisle between two rack-row pallet positions. These pallet positions have master cartons and are arranged in a sequence with the high cube and heavy SKUs in the first positions. Each position is discretely identified with a customer alphabetic character or numeric digit identification. This customerorder sorting method permits a single customer-order handling method or a batched customer-order handling method. Batched customer-order sorting methods have more than one customer order (at least several customer orders) sorted per employee trip or customer-order wave. The employee pulls or pushes a nonpowered fourwheeled cart or load-carrying surface or controls a powered pallet handling vehicle through the aisle. When the customer sorting instruction matches the customer discrete identification, the employee stops the nonpowered or powered vehicle. Per the customer sorting instruction document, the customer-ordered SKUs are transferred from the single-deep pallet positions, gravity flow-rack pallet positions, or floor-stack pallet positions onto the vehicle carrying surface.


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Pallet Floor-Stack, Single-Deep Pallet Rack, or Pallet Flow-Rack Sorting Method The pallet floor-stack method has pallet positions on the facility floor surface that are located on both sides of the sorting aisle. The method requires a wide aisle, provides minimal pick faces, has a low cost, and requires frequent replenishment transactions. The single-deep pallet rack method has one or two high rack pallet positions that are on both sides of the sorting aisle. The method requires a wide aisle, has the maximum pick faces, has a medium cost, and requires the most frequent replenishment transactions. The pallet flow-rack method has one to three deep pallet flow-rack positions that face both sides of the sorting aisle. The pallet gravity flow rack requires a replenishment aisle or push-back rack, provides the fewest pick faces, has a high cost, and requires few replenishment transactions. Various Nonconveyable Carton Across-the-Dock Sorting Method Vehicles or Transport Surfaces The nonconveyable carton across-the-dock sorting methods vehicles include those for the manual methods, which include manual push or pull four-wheeled cart, pallet truck, or platform truck; electric-powered pallet truck or tug with a train of carts; and nonpowered pallet roller conveyor. The mechanized methods are powered roller conveyor, inverted power and free conveyor, and S.I. Cartrac. Employee sorting productivity with these various carton across-the-dock sorting methods is generally lower than the manual conveyable carton sorting methods for several reasons. These are that the SKU physical characteristics make the SKUs more difficult for an employee to handle and to build a load, and that a smaller number of cartons or units of product are handled per trip. The latter increases the employee’s unproductive travel time and distance. Various Manual Nonconveyable Carton Across-the-Dock Sorting Methods The nonconveyable carton across-the-dock sorting carton manual movement methods require an employee to physically move or steer a nonpowered or powered pallet-handling vehicle through the sorting aisle. At the required sorting location, the employee performs the sorting transactions. These various methods are manual or nonpowered four-wheeled push cart, pallet truck, or platform truck; electricpowered pallet truck or tug with a cart train; and pallet roller conveyor. Manual Four-Wheeled Push Cart, Pallet Truck, or Platform Truck The first manual nonconveyable carton across-the-dock sorting method has an employee manually push or pull a four-wheeled cart, pallet truck, or platform truck. An employee pushes or pulls the four-wheeled cart, pallet truck, or platform truck with a load-carrying surface through the sorting aisle. On each sorting aisle side are located floor-stacked pallets, single-deep pallet rack positions, or flow-rack pallet positions. As required by the sorting instruction form, the employee stops in the



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aisle at the correct position and transfers the appropriate SKU quantity from the pallet position to the customer vehicle load-carrying surface. This method is used for a single customer-order carton across-the-dock sorting operation, but provides the lowest employee productivity, requires employee effort, and presents the possibility of injury. In a dynamic or high-volume business, the nonpowered vehicle is not preferred because it requires an employee’s physical effort, has a high potential of product damage due to several stops and starts, makes it difficult to build a stable unit load, and has a low employee productivity of 30 to 45 units per hour. The advantages of the method are that the cost is low on a per vehicle basis and that it provides a very flexible operation. Electric-Powered Pallet Truck Method In an electric-powered pallet nonconveyable carton across-the-dock sorting method, the employee controls and drives an electric-powered vehicle with a pallet-carrying surface through the sorting aisle. Per the across-the-dock sorting instruction form, the employee stops the powered vehicle travel at the appropriate position and transfers the required SKUs from the pallet position onto the customer vehicle loadcarrying surface. The electric-powered pallet truck models are the walkie pallet truck, where the employee walks with the pallet truck and controls its movement by an operator handle, and the walkie/rider pallet truck, which has the pallet truck controls available to the employee from the operator platform. This permits the employee to walk or ride on the pallet truck through the sorting aisle. The final model is the remote-controlled pallet truck, which has a remote device that is attached to the employee. This feature allows the employee to walk in the sorting aisle between the pallet positions and the vehicle load-carrying surface and to control the pallet truck’s forward movement. This feature also permits the employee to control the pallet truck from any side of the pallet truck and improves the safety of the operation. When there are several electric-powered, remote-controlled pallet trucks in an across-the-dock facility and the facility is located near an airport or government facility, then special consideration is given to the design of the remote control system. Other pallet truck features include a single pallet vehicle with a step platform. The step platform permits easier employee access to the elevated pallet positions. Another feature is a double-pallet load-carrying capacity. The double-pallet trucks transports two pallets. As an employee travels through the sorting aisle, the sorting transactions and activities are characteristically the same as with the manual method. The advantages are that the employee handles a heavier load and travels greater distances in a shorter time; this increases the productivity to 30 to 45 cartons per hour. The disadvantages are medium economics per pallet truck and the need for a batterycharging location. Electric-Powered Tug with a Cart Train The electric-powered tug with a cart train method has an employee travel with an electric tug and a cart train though the sorting aisle. Per the sorting instruction form, the employee stops the tug and transfers the appropriate SKU quantity from a pallet position to the correct cart or location on a cart.


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Various electric-powered tug models are gasoline- or diesel-powered tug models that are used outdoors, and electric rechargeable battery-powered tugs. One type of electric-powered tug includes the manually controlled vehicle that requires an employee to have physical access to all tug forward and reverse movement controls. Some models have an operator handle that permits the order picker to walk in the aisle and control the vehicle. The other type of electric-powered tug is a remote controlled tug that has the same operational characteristics as the remote-controlled, electric-powered pallet truck. The tug with a cart train across-the-dock sorting method has the ability to batch sort customer orders. With a cart train, each cart has one to two shelf levels; each cart or shelf level is a customer sorting location. When compared to the other manual across-the-dock sorting methods, this feature of batch customer-order sorting improves employee sorting productivity to 30 to 45 cartons per hour and economics are medium per tug. Nonpowered Pallet Short-Length Roller Conveyor Method The nonpowered pallet short-length roller conveyor is the last manual nonconveyable across-the-dock sorting method. The method has a nonpowered pallet short-length roller conveyor travel-path full length of the sorting aisle with a pallet floor-stack, single-deep pallet positions, or pallet flow-rack positions on both sides of the sorting aisle. When the customer sorting location is the pallet board on the pallet roller conveyor, the SKU locations are on both sides of the pallet roller conveyor travel path. As an employee pushes the pallet board on the short-length roller conveyor travel path through the sorting aisle, and per the customer-order or sorting instruction, the employee stops the pallet board and transfers the appropriate carton quantity from the pallet position onto the pallet board on the roller conveyor travel path. The roller conveyor design components are the pallet roller conveyor travel path with a slight pitch, support members attached to the floor surface, two strands of flanged short roller conveyors or wheels, and a pallet with excellent bottom deck boards or a slave pallet board with side runners. These features reduce the pallet board coefficient of friction on the roller conveyor travel path and ensure good pallet board tracking or travel over the roller conveyor travel path. Pick-Aisle and Pick-Position Arrangement The master carton across-the-dock method has SKU positions or customer sorting locations that are arranged parallel to the vehicle or roller conveyor travel path or that face an aisle that is perpendicular to the vehicle roller conveyor travel path. SKU Positions Are Parallel to the Roller Conveyor Travel Path The first SKU or customer sorting position arrangement has SKU or customer sorting positions that are parallel to or directly face the vehicle or roller conveyor travel path. This pallet position arrangement has one customer sorting location or one SKU position on each roller conveyor travel path side. These positions are every 4 feet on centers. For a small number of high-cube or fast-moving SKUs, these locations and positions are floor-stack or rack pallet positions. For high-cube or high-volume



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SKUs in the operation, the SKU positions are pallet flow lanes. This method is best for an operation with few customers or SKUs. Customer Sorting Locations or SKU Position Faces Are Perpendicular to the Roller Conveyor Travel Path The second SKU or customer position arrangement has the SKU or customer sorting positions in positions that are perpendicular to the vehicle or roller conveyor travel path. As an employee enters an aisle, the employee routing pattern is a loop arrangement because the employee completes one aisle side and then completes the aisle’s other side. This customer or SKU position sorting layout provides the maximum customer or SKU sorting positions per vehicle travel path or roller conveyor travel path linear foot. The loop arrangement’s components are the standard roller conveyor travel path, which is in the middle of the sorting area, with an employee walkway between each roller conveyor or vehicle travel path and each perpendicular module; the employee walkway or forklift-truck aisles, which are perpendicular to the roller conveyor or vehicle travel path; and customer or SKU positions, which are perpendicular on both sides of the aisle and face the employee walk or forklift-truck aisles. These SKU positions are floor-stack, single-deep pallet, or two- or three-deep flowrack pallet positions, and each perpendicular aisle has three or four SKU or customer sorting positions. Per the customer-order sorting instruction, the employee walks from the roller conveyor or vehicle travel path into the perpendicular aisle, completes the customerorder sorting transaction, and returns with the carton to the roller conveyor or vehicle travel path. With a vehicle method the employee drives or rides the vehicle into the perpendicular aisle. The employee adds the carton to the pallet on the roller conveyor travel path and pushes the pallet forward on the roller conveyor travel path to the next position. The sorting employee handles single or batched customer orders. With permanent SKU or customer sorting positions which are close to one another, there is a reduction in sorting errors, a reduction in unproductive employee walk or travel time, and the capability to handle a large number of SKUs or customer orders. The anticipated employee productivity is 50 to 60 cartons per hour. The perpendicular aisle and conveyor travel path method has a greater potential for employee injury because the employee carries the carton between two locations. Mechanical Nonconveyable Carton Across-the-Dock Sorting Methods The next nonconveyable carton across-the-dock sorting method group is the mechanical group. In these methods, the SKU or customer sorting positions are mechanically moved over a fixed conveyor travel path past each employee sorting station. At the sorting station, per customer sorting instruction the employee completes the required sorting transaction. The mechanized nonconveyable carton across-the-dock sorting methods are powered roller conveyor, inverted power and free conveyor, and S.I. Cartrac.


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Powered Pallet-Queue Roller Conveyor Method The first mechanical nonconveyable carton across-the-dock sorting method is the powered pallet-queue roller conveyor method. This method has the motor-driven carrier rollers on close centers. The carrier rollers propel the pallet forward until the rollers are stopped by the action of a queue device due to a pallet that is queued on the roller conveyor travel path. With an activated queue device, the carrier rollers reduce the forward pressure on the pallet bottom. At the powered roller conveyor travel path end is a gravity pallet roller conveyor run-out, end stop, powered curve, or right angle transfer device. Along the conveyor travel path there is a photo-eye that stops and starts the powered roller conveyor travel path. The powered roller conveyor travel path is directly along the SKU positions or customer sorting positions or perpendicular aisles. With the required conveyor elevation, the chain-driven powered roller method is a one-sided sorting method. If the SKU or customer position is on the powered roller pallet conveyor, with a stop device an employee stops the pallet on the powered queue roller conveyor travel path and transfers the SKU carton quantity between the pallet and the conveyor travel path and rack location. The customer or SKU rack locations face the powered pallet-queue roller conveyor travel path or are arranged in a loop design. With the pallet as a SKU position or customer sorting location on the travel path, employee effort is reduced to move the pallet over the conveyor travel path. With a powered roller conveyor, there is one-sided sorting activity and the employee productivity is 40 to 50 cartons per hour. The powered pallet conveyor has high economics. Inverted Power and Free Conveyor The inverted power and free nonconveyable carton across-the-dock sorting method is a motor-driven endless closed-loop chain that pulls several load-carrying surfaces. The load-carrying surfaces are customer sorting locations or SKU positions and each has a set of wheels. These wheels ride on a rail and the load platform is employeeor microcomputer-controlled to stop momentarily at the appropriate location front. When the inverted power and free carrier is stopped, employees per the customerorder sorting instruction form perform the customer sorting transaction. The customer sorting location and SKU position layouts and arrangements in the power and free conveyor method are the same as those for the powered roller pallet conveyor method. The sorting employee productivity is 40 to 50 cartons per hour and the method’s economics are high. S.I. Cartrac Method This mechanized nonconveyable carton across-the-dock sorting method is the S.I. Cartrac method. The S.I. Cartrac has many four-wheeled carts and each has a loadcarrying surface. Each cart travels on a fixed closed-loop travel path. The travel path is a rotating shaft that propels forward the load-carrying surface. As required the method is designed to make 90˚ or 180˚ turns. By pressing a foot pedal at the sorting position, the employee stops the cart and completes the sorting transaction. The S.I. Cartrac is designed to handle the SKU position or customer sorting location on the load-carrying surface. The method moves many carts between the



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pallet pickup and delivery station and the employee sorting station. At the pallet pickup and delivery station a forklift truck transfers the pallet and at the employee sorting station the employee completes the carton transfer transaction. This transfer transaction is from the S.I. Cartrac platform to the customer sorting location. After completing a carton transfer transaction activity, the cart is released to the next sorting station. With the S.I. Cartrac method, the sorting employee productivity is 40 to 50 cartons per hour. The method’s economics are high. Mechanical Nonconveyable Carton Sorting Design Parameters Prior to the implementation of a nonconveyable carton across-the-dock sorting method in your operation, the nonconveyable sorting design parameters are the customer-order or information transmission method; paper flow; sorting instruction format; sorting employee productivity rate and employee availability; SKU characteristics; SKUs per customer-order, which is SKU mix and density and concentration; throughput volume, which is the daily customer average and peak demand or customer orders; material-handling equipment; carton transport methods and procedures; available utilities, available floor space, and facility and sorting equipment layouts; customer-order and delivery cycle; sorting employee requirement and employee routing patterns; and available capital investment. The other important nonconveyable carton across-the-dock sorting method considerations are that the nonconveyable sorting area is permanent or temporary, and that the method transports the consolidated nonconveyable cartons from the sorting area to the customer shipping staging area or directly onto the customer delivery truck.

PALLET OR UNIT-LOAD ACROSS-THE-DOCK METHODS A pallet or unit-load across-the-dock operation’s activities are to unload pallets or unit loads from a vendor delivery truck and transport these pieces to the shipping staging dock area or customer delivery truck. The method’s components are low-lift or pallet forklift trucks with a set of forks to handle all pallets and various forklift attachments to handle a unit load; pallet or unit load bottom support device; sufficient aisles in the receiving and shipping dock areas; and dock leveler, dock lights, and other equipment. A pallet or unit-load across-the-dock operation requires pallet- and unit-loading mobile-handling vehicles to enter a vendor delivery truck and pick up a pallet or unit load; to transport the pallet or unit load over the aisles; to enter a customer delivery truck and deposit a pallet or unit load; and per the unit load for the forklift, to handle a unit-load attachment. In many distribution operations this equipment is used to handle pallets and unit loads. The various forklift attachments are slip-sheet, clamp, and double set of forks. The pallet or unit-load bottom support devices provide the pallet or unit load with structural support and permit a pallet or forklift truck set of forks or attachment


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to lift, transport, and deposit the pallet or unit load. The various bottom support devices are pallet, which includes wood, corrugated, pressboard or fiber board, rubber, or metal or metal clad; slip-sheet, which includes a plastic or a corrugated slip-sheet that has one lip or tab, two lips or tabs on opposite sides, or four lips or tabs; skid; and container with open mesh or solid walls and bottom. In most pallet or unit-load across-the-dock operations, the most common pallet or unit load support devices are two. These are the wood pallet and the corrugated slip-sheet.

PALLET

AS THE

ACROSS-THE-DOCK UNIT-LOAD SUPPORT DEVICE

In a pallet or unit-load across-the-dock operation, the pallet is used by most operations because it is available in a wide variety as a stringer or block pallet with open deck, closed or solid deck, two-way entry, four-way entry, partial four-way or notched, single wing, double wing, nonreversible, and take it or leave it; because of the ability to support a heavy pallet load; because it interfaces with most across-thedock material-handling equipment; because a four-way or partial four-way pallet accommodates most vendor and customer delivery-truck loading patterns; because the durability permits the maximum transactions in the across-the-dock supply-chain logistics strategy; and because it is used at the final customer location.

IMPORTANT PALLET DIMENSIONS In a pallet across-the-dock operation, the pallet’s dimensions determine the material handling equipment set of forks, the pallet or forklift type, the SKU “ti and hi” or pallet-loading pattern, the facility operational or handling requirements, and the vendor and customer delivery truck loading pattern. The pallet dimensions are length, width, and height. The pallet board length (bearer or stringer) is stated first. In most across-the-dock applications, the pallet board length is 4 to 6 inches longer than the forklift truck set of forks length. The width includes the forklift truck set of forks opening or openings and is the second stated dimension. The third pallet board dimension consists of the height dimensions. The first height dimension is the pallet board overall height, which is the distance between the bottom deck board or block and the exterior top deck board. The pallet board’s overall height influences the pallet’s overall height. The second dimension is the forklift truck forks’ opening height. This height is the open space between the bottom deck board interior and the top deck board interior. The internal set of fork’s opening height determines the type and height for the set of forks on the across-the-dock material handling equipment. In most pallet across-the-dock operations a general rule of thumb is that the pallet board stringer length determines the delivery-truck loading pattern and dock area material-handling set of forks length. In most applications, the most popular pallet board is 48 inches long by 40 inches wide with a 5 1/2-inch overall height nonreversible partial four-way and open deck pallet board. Generally a counterbalanced forklift truck with a chisel set of forks or an electric-powered pallet truck requires a 3-to-5-inch-high pallet board fork opening.



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BASIC PALLET DESIGNS The first pallet board design is the block pallet. The block pallet has equally spaced blocks along its width and length. To assure proper spacing the top open deck boards are attached to a stringer board. This deck board is attached to the blocks and the blocks create the forklift truck fork opening. A block pallet board is used in a pallet across-the-dock operation. The second design is the stringer pallet. The stringer pallet has two exterior stringers and one interior stringer for top and bottom deck board attachment. The stringers create the forklift truck fork opening. Some stringer pallet boards have two exterior stringers. The exterior stringers are solid or have two notches (or openings) in the stringer side. The notches are additional forklift truck fork openings that permit a forklift truck with a chisel set of forks to handle the pallet board from any side. This feature allows a delivery truck to have any pallet-loading pattern. Across the warehouse and distribution industry, the stringer pallet board with notches is the most common pallet board and is widely used in an across-the-dock supply-chain logistics strategy.

SLIP-SHEET In an across-the-dock supply-chain logistics strategy, the slip-sheet is the next most frequently used unit-load bottom support device. Per the slip-sheet material and lip specifications, the slip-sheet base and lip have sufficient tensile strength for a push/pull device to complete one or two transactions. Other important slip-sheet considerations include humid environmental conditions, which reduce the tensile strength. A four-lip configuration accommodates any vendor delivery-truck loading pattern, and the slip-sheet requires a forklift truck with a slip-sheet attachment. The various slip-sheet materials are corrugated slip-sheet, fiberboard or solid Kraft board slip-sheet, and plastic slip-sheet with plain-surface polypropylene or dimpled-surface polyethylene. Corrugated Slip-Sheet The corrugated slip-sheet has two Kraft linerboard outside surfaces with corrugated interiors that are bonded together. This bond provides the required tensile strength for a push/pull clamp device to be clamped to the slip-sheet lip once or twice by the forklift truck push/pull gripper bar. The corrugated slip-sheet is a one-way slip-sheet because the slip-sheet lip is easily torn or has low tensile strength. With this feature the corrugated slip-sheet is not preferred for use in an across-the-dock operation. Fiberboard or Solid Kraft Slip-Sheet The fiberboard or solid Kraft slip-sheet has several solid fiberboard plies or layers that are laminated together. This bond of several flat sheets (usually three or four) increases its tensile strength. This high tensile strength permits the slip-sheet or lip to be clamped by the forklift truck push/pull gripper bar several times (at least two


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or three times). This feature allows the fiberboard or solid Kraft slip-sheet to be used in an across-the-dock operation. Plastic Slip-Sheet The plastic slip-sheet is made of a combination of polymerized materials that includes polyethylene or polypropylene. This material gives the plastic slip-sheet lip the greatest tensile strength, which allows the slip-sheet to be used at least four or five times. This feature makes the plastic slip-sheet a very durable slip-sheet for use in an across-the-dock operation that has several stops or segments. The plastic slip-sheet is available as a plain slip-sheet or a dimpled slip-sheet. The plain plastic slip-sheet design has a flat surface. The plastic dimple slipsheet is a vacuum-formed polyethylene sheet that has spherical dimples on very close centers. These dimples cover the entire bottom surface and extend downward to the vendor or customer delivery truck bed. In a vendor or customer delivery truck, the dimples provide a product cushion and do not damage the product. Slip-Sheet Design Parameters In an across-the-dock supply-chain logistics strategy, important slip-sheet specifications are load size and weight; product description and length, width, and height; stabilization method, which includes the cartons ti and hi or pallet-loading pattern; push/pull device type and slip-sheet lip gripper; expected life or times pushed or pulled; environmental transport conditions; possible requirement for holes; vendor or customer delivery-truck loading pattern; and lip or tab number and locations. Tips on Slip-Sheet Use In an across-the-dock supply-chain logistics strategy, the factors that decrease product damage and increase employee productivity are, first, to ensure that the product edges or cartons on the slip-sheet top match the slip-sheet edges. If there are open spaces between the product or carton ti and hi pattern, the open spaces are in the pallet’s middle. The product or cartons should be secured with a stabilization method that minimizes product or carton movement on the slip-sheet surface. When loading a vendor or customer delivery truck, use dunnage between the unit loads and vendor customer delivery-truck walls, and use securing devices in a delivery truck. Types of Slip-Sheet Forklift Trucks In your across-the-dock operation, the forklift truck is a very important consideration. The material-handling equipment most commonly used in a slip-sheet operation is a counterbalanced forklift truck with a removable set of forks and removable push/pull device. This forklift truck popularity is due to the fact that the counterbalanced forklift truck is used as a slip-sheet truck. A second piece of material-handling equipment that is used in a slip-sheet operation is the low-lift electric-powered rider pallet truck with a permanently attached push/pull device. This rider pallet truck only transports the slip-sheet. The



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rider pallet truck with a slip-sheet attachment has limited application in an acrossthe-dock operation that has double stacked unit loads. Slip-Sheet Attachments The slip-sheet or push/pull attachment is permanently or temporarily attached to the counterbalanced forklift truck. The push/pull device has a pantographic arm that extends forward from the forklift truck mast; a backrest; a gripper bar; and a platen, a set of platens, or a series of chisel type forks. An operator controls the pantographic arm that extends the gripper over a platen, a set of platens, or a series of tines. The operator activates the gripper; it grips the slip-sheet lip or tab and holds the lip firm between the backrest bottom and gripper bar. The operator controls the hydraulic system that has the pantographic device lift the slip-sheet lip upward. This slip-sheet lip-lifting action raises the slip-sheet side upward. In the raised position, the pantographic device and slip-sheet are pulled over the platen, set of platens, or series of tines to the forklift truck mast. With the slip-sheet under the hardened metal of the platen, set of platens, or a series of tines, the forklift truck transports the unit load from a vendor delivery truck to the receiving dock, deposits the slip-sheet onto a pallet, or deposits the slip-sheet in a customer delivery truck.

VARIOUS PALLET ACROSS-THE-DOCK TRANSPORTATION METHODS In a pallet across-the-dock operation, an important consideration is the method to transport or transfer a pallet between a vendor delivery truck and the receiving dock area, and into the customer assigned shipping dock staging area or directly onto a customer delivery truck. The objectives of the transport method or link between the receiving dock and shipping docks are to enter and exit the delivery truck; to lift and lower the pallet or unit load; and to transport, sort, and deposit the pallet or unit load at the customer-assigned shipping dock staging location or to place the pallet or unit load into a customer delivery truck. The pallet or unit load across-the-dock transport methods are powered forklift truck with a set of forks; counterbalanced forklift truck with a slip-sheet attachment; manual- or electric-powered pallet truck with a set of forks or slip-sheet attachment; electric-powered tug with a cart train; in-floor tow line; overhead Towveyor®; and automatic guided vehicle (AGV).

VARIOUS FORKLIFT TRUCKS The second important component in a pallet load across-the-dock operation is the material handling equipment that is used to unload, transport, sort, and load a pallet or slip-sheet load from a vendor or customer delivery truck or between two dock locations. Material-handling equipment includes a powered forklift truck with a set of forks or slip-sheet attachment; a manual-powered pallet truck with a set of forks; and an electric-powered pallet truck with a set of forks or slip-sheet attachment. These vehicles complete all the pallet across-the-dock activities. The forklift truck with the slip-sheet attachment handles all across-the-dock slip-sheet activities.


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The basic forklift truck types are defined by the right-angle turn requirement. Each major forklift truck subgroup is identified by the vehicle’s power source and ability to travel outside the storage area, and the storage area’s aisle width. The three basic forklift truck classifications are wide-aisle (WA) forklift truck, narrow-aisle (NA) forklift truck, and very narrow-aisle (VNA) forklift truck. The VNA forklift truck vehicles are heavy, have very tall masts, require an aisle guidance system, and travel up slight grades; these factors restrict the VNA vehicle for a pallet across-the-dock operation. Wide-Aisle Forklift Trucks The first forklift truck group is the WA lift truck group. These forklift trucks operate in a 10-to-13-foot-wide aisle. In this group, the two types are sit-down counterbalanced forklift truck and stand-up counterbalanced forklift truck. Sit-Down Counterbalanced Forklift Truck The sit-down counterbalanced forklift truck has a long wheel base, good underclearance, and a low mast and overhead guard. These features make this forklift truck a very maneuverable and versatile pallet load or slip-sheet handling vehicle. The forklift truck is used as a receiving dock, transport, storage area, and shipping dock vehicle that requires a normal floor surface. The forklift truck travels up a 15˚ grade or ramp, which permits the forklift truck to enter and exit vendor or customer delivery trucks. The forklift truck is designed with a set of load-carrying forks that elevate and lower on a telescopic mast and an operator area with a seat. From the seat, the operator has access to all horizontal vehicle and vertical fork movement controls. Some models have see-through masts that provide the operator with a complete view of the vehicle travel path. The vehicle counterweight is located in the rear chassis; the vehicle has a long wheel base and high undercarriage clearance. These features provide the vehicle with the ability to offset the pallet load or slipsheet weight and to travel over grades or ramps. A rechargeable electric battery powers the most common indoor counterbalanced forklift truck. When the forklift truck is used as an outdoor vehicle in an open dock area, the power source is an internal combustion engine that uses fuel such as diesel, liquid propane (LP) gas, or gasoline. The vehicle has three or four wheels, with one wheel as a drive wheel and a steering wheel. The wheels are fitted with pneumatic tires for outdoor use and cushioned solid polyurethane or rubber tires for indoor use. These counterbalanced forklift trucks are available with 1-, 2-, 3-, or 4-stage masts that provide the forklift truck with a stacking height of 16 to 18 feet. Counterbalanced forklift trucks are used to handle a standard pallet or slip-sheet load that has a weight range from 2000 to 4000 pounds. Some forklift trucks have additional counterweight and the wheel base to handle heavier loads. Fork side-shift and masttilt devices are options that increase operator productivity and reduce product and equipment damage. An experienced forklift truck operator makes 20 to 25 transactions per hour. The four-wheeled counterbalanced forklift truck with its long wheel base and chassis weight is fitted with various attachments such as a slip-sheet push/pull device. For any given forklift truck, however, verify with the manufacturer



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that the forklift truck accepts the attachment weight and new center of load and performs an elevated transaction without the forklift truck moving forward. Forklift-Truck Masts The first forklift truck component is the mast. The fork overall extended or lift height allows the vehicle to elevate and lower unit loads. The lowered or collapsed mast height is the clearance for the forklift truck to enter and exit vendor or customer delivery trucks. The forklift truck’s clearance height is affected by the overhead guard height, which may be higher than the mast. In this situation the forklift truck’s ability to pass into a delivery truck is the restriction. The masts available for a forklift truck are a single mast, which has limited application in an across-the-dock operation; a two-staged nontelescopic mast, which has little or no fork free lift (this means that as the set of forks start to rise, the forklift-truck mast starts to rise); a standard two-staged mast; a two-staged mast with a high free lift (this means that the forks rise upward for a distance without the mast moving upward); a three-staged mast with full free lift, which has the same characteristics as the two-staged mast with full free lift; a four stage mast; and a rigid mast. These last two masts have overall heights that prevent entry into a delivery truck. Forklift-Truck Stability As the counterbalanced forklift truck picks up a pallet, the fulcrum (balance point) for the counterbalance action is the front wheels’ centerline. The pallet weight plus any attachment is counterbalanced by the forklift truck’s counterbalance weight and wheel base. The forklift truck’s weight includes the battery weight and the counterbalance weight. Forklift-Truck Capacity The forklift truck capacity is the amount of weight that a forklift truck safely lifts. Each forklift truck has a capacity that is stated by the manufacturer. This weight capacity decreases as longer loads are handled by the forklift truck. The forklift truck handles the normal pallets up to the weight limit that is specified by the manufacturer. As the pallet length increases outward beyond the standard 24-inch center, the forklift truck handles less weight. If a pallet is heavier than or over the standard dimensions, a bigger, heavier, and more expensive forklift truck is needed to handle the pallet. Forklift-Truck Maneuverability The next important factor is the forklift truck’s maneuverability, the ability to make a right-angle turn or to turn into an intersecting aisle. A right-angle turn is the distance that is required for a forklift truck to turn and make a transaction from a floor position or rack position. This distance is the aisle width. An easy way to determine the aisle width is to take a conventional pallet length or stringer length plus the distance from the face of the set of forks to the centerline of the forklift truck drive wheel plus the outside turning radius. For excellent forklift-truck operator


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productivity and reduced product and equipment damage, 6 to 12 inches is added to the above calculation. If there is product overhang on the pallet, the overhang dimension is added to the stringer length. In planning an across-the-dock area’s aisles with the forklift-truck manufacturer’s aisle width recommendation, for good lift truck-operator productivity and low product and equipment damage, the dock area’s aisle width is the forklift-truck manufacturer product-to-product aisle width plus 6 to 12 inches. Forklift-Truck Wheel Base The counterbalanced forklift-truck wheel base determines the aisle width. The wheel base is the distance between the front and rear wheel. A forklift truck with a short wheel base requires a narrow right-angle turning aisle. A forklift truck with a short wheel base makes the forklift truck very maneuverable. A forklift truck with a long wheel base requires a wide right-angle turning aisle, but has improved ride, steering traction, and stability. The second maneuverability factor is the forklift truck’s ability to climb a ramp or travel over a dock leveler. This is also known as forklift-truck grade ability and under-clearance. Forklift-Truck Grade Ability The forklift-truck grade ability is the steepest percent grade (ramp or dock leveler slope) that a forklift truck climbs or travels with a pallet on the set of forks. An electric forklift truck’s steepest grade is 15%. The grade for an internal combustion engine forklift truck is 20 to 25%. Forklift-Truck Under-Clearance The forklift-truck under-clearance is the steepest grade percentage that the forklift truck climbs or travels without under-clearance problems. Under-clearance problems occur at the top of the ramp or dock leveler as a hang-up of the forklift truck bottom, or at the ramp bottom or dock leveler with the load or set of forks hitting the floor. The forklift-truck under-clearance is the distance between the floor surface and the lowest part of the forklift truck’s undercarriage. The important forklift-truck under-clearance location is midway between the wheel base and the bottom of the mast, because of the mechanical truck’s operating parts in this area. In considering a forklift truck’s ability to climb or travel over ramps or travel over dock levelers and enter and exit vendor or customer delivery trucks and forklift trucks for outdoor operations, grade ability and under-clearance are two important factors to avoid future repair expenses and forklift-truck downtime. A forklift truck with a short wheel base and high under-clearance is suited to travel over ramps and dock levelers and do outdoor work. Stand-Up Rider Counterbalanced Forklift Truck The stand-up rider counterbalanced forklift truck is considered part of the WA group. The forklift truck has similar design features and operational capabilities to



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those of the sit-down rider counterbalanced forklift truck. The major difference is that the operator stands up on the operator platform. This feature allows a shorter wheel base. With a shorter wheel base, the forklift truck makes a right-angle turn in a 9-to-10-foot-wide aisle and places a 2000-to-3000-pound unit load into a pallet position 18 feet above the floor surface. The 24- or 36-volt electric-powered rechargeable battery-powered mobile-aisle forklift truck is very maneuverable and versatile, performs all activities on a normal floor, and unloads and loads all delivery vehicles. Some models in addition to the mast tilt and set of fork’s side-shift option have an option for a trackable overhead guard that permits easy delivery vehicle entry and exit. Narrow-Aisle Forklift Trucks The second forklift truck group is the NA forklift truck. This group includes the straddle, straddle reach, and double-deep reach forklift trucks. These forklift trucks operate in 7-to-9-foot-wide aisles. The straddle-reach forklift truck is designed with two load-carrying wheels and one drive and steer wheel. The set of forks elevates and lowers on a telescopic mast; other features include an overhead guard, two stabilizing straddles or outriggers that extend outward from the forklift truck’s mast, and an operator platform. Some models have a bar or hardened metal member to protect the operator platform area. The operator platform area has both horizontal truck and vertical set of forks movement controls. To elevate or lower and transport a pallet load, the outriggers assume the majority of the unit-load weight. The straddle forklift truck’s straddles (or outriggers) surround the majority of the pallet length; it is difficult for the forklift truck to enter and exit a delivery vehicle.


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Index A ABC method, 23, 280, 308, 432, 537–538 Across-the-dock operations, 1–2, 563–589 activities, 7–13, 18, See also Order-fulfillment operations; specific activities annual logistics costs, 564 benefits of effective performance, 18–19 company departments involved, 566 conveyor considerations, 670–673, See also Carton sorting methods; Conveyor systems definition, 565 dock design, See Dock design facility design, See Facility design; Project management importance of dock areas, 575–577, See also Dock design master carton, 576, See Carton across-thedock operations objectives, 4, 9, 565–566 operational requirements, 564 pallet, See Pallet across-the-dock operations performance, 19–20, See also Employee productivity improvement piece and information flows, 2–3 piece characteristics, 565 sorted labeled, 575 unsorted labeled, 574 unsorted unlabeled, 574 piece flow strategy, 567, 571–574 distribution cross-docking, 573, 577 dock locations, 576–577 manufacturing cross-docking, 572–573, 576–577 terminal cross-docking, 573–574, 577 piece transformations, 627–628 powered-screw system, 212–216 controls, 215–216 guard rail and accessories, 215–216 motor and drive unit, 212 operations, 216 rotating shaft and spiral wire strand, 213 structural support, 213–215 projected dock requirements, 577–583, See also Dock design purchase order, 567

receiving, See Receiving operations resources, 3 shipping and packing operations, 638–641, See also Packing; Shipping operations container sealing, 639 filling container voids, 639 labeling and manifest, 639–641 truck loading, 641 weight check methods, 638–639 small-items and flat wear, See Small-item and flat wear across-the-dock operations sorting, See Across-the-dock sorting methods supply-chain logistics strategy, 563–565 trends and issues, 4 truck unloading and loading, See Unloading methods unloading, See Unloading methods value of, 3 vendor and customer involvement, 566 yard design, See Truck yard design Across-the-dock pallet transportation methods, 685–689, See also Pallet across-thedock operations Across-the-dock shipping sorting method, 674 Across-the-dock sorting methods automatic, 636–637, 645–647 customer shipping lane or conveyor, 667–670 fate of residual units, 638 hanging garments, 642–647, See also Garment-on-hanger (GOH) sorting methods manual, 631, 643–644, 649–651 master cartons, 647–681, See also Carton sorting methods mechanized, 632–636, 645, 651–667 nonconveyable cartons, 675–678 small items or flat wear, 630–638, See also Small-item and flat wear across-thedock sorting methods Active/passive sorter, 656 Active sorter, 656 Adjustable end stops, 193 A-frame systems, 123–126 AGV, See Automatic guided vehicles Air circulation, 146, 306–307, 439 Air compressor, 74

691


692


Air-flow pallet pick-position method, 337–338 Air flow racks, 533 Air pipe path, 74 Air supply, 62 Air-supported facility, 313 Aisle space potential ratio, 106–107 Ampere hours, 351 Annual operating expense budget, 35, 37–43, See also Budgeting Architect scale, 85 Architects, 53–54 Arithmetic progression order-picker routing patterns, 32–33, 277, 359–360 sorting conveyor travel path divert lane design, 656 ASRS vehicles, 317, 438, 511–512, 518–523 front-end carton-pick method, 416–418 in-house transport, 522–523 load-handling devices, 519–520 pickup and delivery stations, 522–523 trolley storage and pick method, 250–251 vehicle commands, 520 Automated carton-pick systems, 331 Automated order-fulfillment method, 311 Automated order-pick methods, 419–422 Automatic guided vehicles (AGV) across-the-dock transportation methods, 685 anticollision methods, 551–552 control methods, 550 design parameters, 552–553 dispatch methods, 550–551 pallet-carrying surfaces, 554 pickup and delivery stations, 554 types, 553–554 driverless “stop and drop” pallet truck, 553 pallet load, 553–554 towing, 553 Automatic or spring-loaded cross-through switch, 190 Automatic stacking wire-guided vehicle, 518 Automatic storage and retrieval system (ASRS), See ASRS vehicles Automatic unloading systems, 471–472 Auto-positive drawing, 84 Average piece or customer-order volumes, 144, 305, 437

B Bag bottoms, 163–164, 254 Bagging hanging garments, 164–165 Bands and straps, 299–301, 501, 503 Bar chart, 68–69, 89

Bar code, 204, 263–264 Bar-code scanning, 569 bar-code orientation, 572 carton counting, 325 check weigh method, 570–571, 638 customer-order checking, 294 employee productivity improvement, 30 hanging-garment identification, 205, 223, 263–264 induction conveyor, 653 pallet transaction verification, 548 replenishment transaction verification, 429–430 sorting methods, 15, 647 Bascule bridge, 463, 476 Batch control methods, 387–388 Batched customer orders, 386–388 picking method, 21–22 sorting method, 282–283, 403–412, 648 Batteries, 350–351 Battery charger, 350–351 Battery-powered trucks, See Forklift trucks; Pallet trucks and load-handling devices Bid process, 61–65 return procedure, 64 review or evaluation, 64–65 Block drawing, 153, 321, 444 Block order-picker routing patterns, 363–364 Block pallet, 493, 496, 683 Blueprints, 82, See also Drawings BMC, 289 Boxes or cartons, 291–293 Bridge pallet racks, 530 Budgeting capital expenditure justification, 43–47 contingency cost factor, 50 controllable and non-controllable expenses, 38–41 cost estimate, 49, 51 depreciation expenses, 43–46 employee productivity data, 109 facility construction cost estimates, 49–53 fringe benefits and taxes, 42 line-item and man-hour short-interval scheduling method, 35, 37–43 management salary, 41 nonworking hour expenses, 41 other controllable expenses, 42–43 using productivity data, 35 Building construction, See Facility design; Project management Building contractor selection, 53–54 Building layout drawing, See Drawings Burden-carrier method, 344


Index

693

C Cantilevered flush dock, 454, 488–489 Cantilevered pallet racks, 534 Cantilevered rack storage and pick method, 246–247, 340 Capital expenditure justification, 43–47 Captive-aisle (CA) vehicles, 317, 522 Captive containers, 14 Captive pallet boards, 493 Car-in-rack pallet racks, 518, 535 Carousel systems, 129–132 GOH storage/pick, 266–272 nonconveyable cartons, 424 pick-position to employee method, 414–415 put systems, 132 sort methods, 634 vertical GOH transport, 236–237 Cart carousel, 415, 424 Carton across-the-dock operations master-carton open activity, 628 objectives, 576 pick-aisle and pick-position arrangement, 678–679 parallel to conveyor, 678–679 perpendicular to conveyor, 679 separating shipping cartons into units, 674 sorting methods, See Carton sorting methods truck unloading conveyor system, 610–626, See also Extendible or retractable truck unloading conveyor systems Carton carousel, 414–415 Carton-count methods, 325 Carton flow racks, 114–116, 334–335, 635–636 Carton identification, 325–326 Carton loading and shipping, 17 Carton makeup and labeling, 10, 14 Carton order-fulfillment facility design and layout, 306–317 base operational and pick-area information, 303–304 building shape and size, 312–315 carton or order volume projection, 304–306, 322–323 floor surface, 314–315 infrastructure, 315 layout philosophy and principles, 307–311 pick and sorting principles, 311–312 pick area, See Carton pick lines or aisles rack-supported facility, 312–313 storage/reserve space and methods, 315–317 Carton order-fulfillment operations, 303–434 activities list, 322 batched customer orders, 386–388

customer-order volumes, 304–306, 322–323 facility design, See Carton order-fulfillment facility design and layout in-house transport, 326, See also Carton transport vehicles or systems labor expense, 330 manifesting and shipping, 327 objectives, 330 order-pick method, See Carton order-pick method purpose, 323 receiving activities, See Carton unloading and receiving replenishment, 311, 427–434 storage, 326 transaction verification and inventory tracking, 428–430 Carton order-picker routing patterns, 359–364, 403 block, 363–364 high-rise truck, 383–385 horseshoe (“U”), 362–363 loop, 362 no routing pattern, 359 sequential patterns, 359–364 serpentine travel, 360–361 single side, 361–362 stitch, 364 straight in-and-out, 360 “Z”, 363 Carton order-pick method, 311, 326–332 automated systems, 311, 331, 419–422 conveyable and non-conveyable cartons, 331, See also elevated employee walkway, 402–403 employee-to-stock travel and carry, 330, See also Pallet trucks and load-handling devices employee riding, 343–356 employee walking, 340–342 HROS methods, 340, 374–385 in-house transport, See Carton transport vehicles or systems manual systems, 311, 330–332, 340–356 mechanized (conveyor) systems, 96–97, 311, 330, 385–412, See also Conveyor systems employee riding, 412–414 employee walking, 385–412 nonconveyable cartons, 422–427, See also Nonconveyable carton pick/sort methods order-handling method, 327–328 order-picker instruction method, 328–329, 364–368


694


order-picker routing patterns, 329–330, 359–364, 403, See also Carton order-picker routing patterns order-pick philosophy, 327 order-selection method, 330 order sorting method, 311–312, 403–412, See also Carton sorting methods pallet stack options, 358 pick activity description, 358–359 pick area, See Carton pick lines or aisles picked carton identification, 326 pick-position devices, 332–340, See also Carton pick-position methods pick-position identification, 368–371 pick-position philosophy, 318, See also Carton pick-position methods sorting, 326, See Carton sorting methods stock-to-employee pick method, 414–419 cart carousel, 415 carton carousel, 414–415 mini-stacker, 418–419 S.I. Cartrac, 415 sort link, 416 storage areas or ASRS front-end method, 416–418 storage withdrawal and replenishment, 326–327 Carton pick lines or aisles, 318–323, See also Carton order-pick method; Carton pick-position methods design parameters, 322–323 pick area design, 318–322 drawings, 321–322 flow patterns, 319–321 Carton pick-position methods, 329–330, 332–340, See also Carton order-pick method allocation to pick area, 431–432 cantilevered rack, 340 decked or hand-stacked cartons, 339 drive-in or drive-through, 336–337 fixed position, 427 floor-stacked, 332–333 gravity- or air-flow, 337–338 gravity-flow rack, 334–335 mobile or sliding rack, 339–340 nonconveyable cartons, 426–427 pallet cage, 333–334 pallet-stacking frame, 333–334 pick-position identification, 368–371 pick-position to employee method, 414–419 pick tunnel, 340, 396 pier rack, 333–334 push-back, 335–336 random, floating, or variable location, 428

standard pallet-rack, 338–339 standard shelf or slotted-angle shelf, 339 Carton piece flow patterns, 8 Cartons or boxes, 291–293, 303 Carton sorting methods, 326, 403–412, 647–681 cartons on carts or pallets, 405 conveyor considerations, 648, 670–673, See also Conveyor systems; specific applications, systems conveyor with divert devices active/passive sorter, 656 active sorter, 656 flap sorter, 666–667 gull wing, 664 Nova sort, 663 passive sorter, 656 plow, 660–661 pop-up, 665–666 powered belt, 660 pusher, 657–660 rotating paddle, 666 SBIR or moving belt, 661 sliding shoe, 664–665 solid metal, 656–657 tilt slat, 663–664 tilt tray, 661–663 customer shipping lane or conveyor, 667–670 design features, 405–406, 648–649 direct loading, 405, 674 manual-sorting conveyor, 406–408 apron, 408, 651 double-stacked conveyor, 407, 650 one-conveyor, 407, 649–650 recirculation loop, 407–408, 650–651 mechanical-sorting conveyor, 408–412 mechanized methods, 651–652 automated or fixed-position scanner, 410–411 conveyor with divert component, 647–648, 656–667, See also Divert devices endless-loop path, 655 induction conveyor, 652–654 induction or in-feed conveyor, 409–410 manual or keypad, 410 no-read conveyor, 411, 654 order-pick area conveyor, 409 recirculation conveyor, 412 semiautomated or hand-held scanner, 410 shipping conveyors or lanes, 412 single straight-line path, 655 sorting conveyor with divert devices, 411 surfaces or travel paths, 654–655 transport conveyor, 404, 652 unloading conveyors, 652


Index mimic display and control panel, 675 nonconveyable cartons, 675–678 design parameters, 681 inverted power and free conveyor, 680 manual carts or trucks, 676–677 non-powered pallet roller conveyor, 678 pallet floor-stack method, 676 powered pallet trucks, 677 powered roller conveyor, 680 powered tug with cart train, 677–678 S.I. Cartrac, 680–681 vehicles or transport surfaces, 676 shipping-sorting, 404–405, 674 temporary hold area, 404, 673 Carton storage method, 315–316 Carton structural support strength, 155 Carton transport vehicles or systems, 323, 340–359, 371–385 advantages/disadvantages, 364 burden-carrier method, 344 conveyors, See Conveyor systems conveyable and non-conveyable cartons, 331 customer shipping lane or conveyor, 667–670 electric cart with towed cart, 344–345 electric tractor or tugger, 371–373 electric vehicle components, 350–352 electric vehicle operational features, 352–356 employee-picks-to-conveyor, 385–414, See also Conveyor systems empty pallet stack, 358 end-of-aisle slowdown devices, 379–381 floor requirements, 356 forklift truck method, 374, See also Forklift trucks hand-carry, 341 high-rise methods, 374–385 counterbalanced, 381 high-rise order-picker trucks, 381–382 high-rise truck, 383–385 HROS consideration, 383–385 order-pick devices, 383 picking cage, 383 platform, 382 routing methods, 383–385 straddle, 382 very-narrow-aisle (VNA), 382 non-powered carts or trucks, 340–343 four-wheeled cart, 342 manual pallet-truck or jack, 342–343 platform truck or dolly, 341–342 two-wheeled hand truck, 341 nonconveyable cartons, 422–425, 675–678 pick activity description, 358–359 pick car, 413 pick-position to employee method, 414–419

695 powered pallet trucks, 345–359, See also Pallet trucks and load-handling devices powered walkie pallet trucks, 343 powered walkie tow tractor, 343 rail guidance, 375–379 spiral-chute (decombe) truck, 413–414 storage vehicles, 316–317 tow tractor, 371–373 truck unloading conveyor system, 610–626, See also Extendible or retractable truck unloading conveyor systems Carton unloading and receiving pallet or carton identification, 325–326 receiving and checking, 325 storage area deposit activity, 326 truck-unloading conveyor system, 610–626, See also Extendible or retractable truck unloading conveyor systems truck yard control, 324 unloading, 324 Casters or wheels, 172–174 Catalog and direct-market order packing, 295–297 C-channel or rail, 199–201, 206–207 Ceiling fans, 146, 306–307, 439 Chamfered pallets, 345 Charts, 88–89 Check weigh method, 139, 570–571, 638–639 Chipboard box, 292–293 Chopper trolley in-feed method, 208 Clipboard document holder, 356–357 Closed or solid deck pallet boards, 495 Combination docks, 447–448 Communications system, 307, 439 Computer-assisted drafting (CAD), 54, 82, 84–85 Computer-controlled anticollision methods, 551–552 Computer-controlled order-pick methods, 368, 419–422 Computer-controlled replenishment, 433–434 Computer-controlled storage retrieval vehicles, 518–523 in-house transport, 522–523 load-handling devices, 519–520 pickup and delivery stations, 522–523 vehicle commands, 520 Computer-directed pallet transaction instruction method, 543–544 Computer dock simulation, 580–581 Computer projected weight method, 17 Computer simulation, 228, 480–481 Consultants, 90–95 Contingency cost factor, 50 Contract administration, 51, 66, 69–70, 76


696


Control issue, 63 Conventional floor, 314 Conveyor systems, 385–414, 670–673 across-the-dock small-item or flat wear sorting methods, 633–636 batched customer orders, 386–388 carton-flow or decked pallet rack, 392–393 carton sorting, 649–681, See also Carton sorting methods carton travel, 399–400 angled deflector, 399–400 skewed roller, 399 sleeve-wrapped or taped rollers, 399 curve width determination, 397 customer shipping lane or conveyor, 667–670 design clearances, 488–489 divert devices, 565, 647–648, 656–667, See also Divert devices empty pallet queue, 401–402 extendible/retractable system for truck unloading, 610–626, See also Extendible or retractable truck unloading conveyor systems frame, 397 GOH transport methods, 289–290 incline/decline travel paths, 671–672 induction, 652–654 mimic display and control panel, 675 nonconveyable carton sorting, 423, 678 non-powered or gravity travel paths, 672 pallet-flow device, 627 pallet flow-lane issues, 394–395 pallet flow rack parallel to conveyor, 393–394 pallet flow rack perpendicular to conveyor, 395–396 pallet orientation, 389–390 pallet rack parallel to conveyor, 390–391 pallet rack perpendicular to conveyor, 391–392 pallet return, 400–401 photo-eyes, 667, 673 pick car, 413 pick faces, 389 pick tunnel, 396 price ticketing methods, 629–630 queue conveyor design, 670–671 roller capacity, 397 safety issues employee crossing paths, 397–399 underside deck or netting, 396 side guards, 673 sorting method, 403–412, See also Carton sorting methods speed control, 672 spiral-chute (decombe) truck, 413–414

travel path, 396–397 travel speed, 670 truck unloading, 610–626, 652, See also Extendible or retractable truck unloading conveyor systems Corrugated box, 292 Corrugated slip-sheets, 683 Cost estimation, 49–53 Count-on-the-fly method, 325 Counterbalanced vehicles, 275, 381, 382 operator-down side-loading, 515 rising cab side-loading, 517 sit-down forklift truck, 506–507, 686–687 stand-up rider forklift truck, 506, 688–689 walkie/stacker forklift truck, 504–505 Cross-belt sorter, 126–129 Cross-docking piece flow methods distribution, 573, 577 manufacturing, 572–573, 576–577 terminal, 573–574, 577 Cube of order pick, 25–26 Customer-order batches or groups, 386–388 Customer-order carton or container makeup, 14 Customer-order check methods, 293–294 check weigh, 139, 570–571, 638–639 Customer-order cycle efficiency ratio, 105 Customer-order entry and download, 10, 13–14 Customer-order profile, 279 E-commerce technologies, 4–5 GOH operational design parameters, 142 Customer-order volume, 304–306, 322–323, 436–438, 446 average, 144, 305, 437 GOH operational design parameters, 142–144 most frequent, 144, 305, 437 peak, 143, 305, 437 Customer returns, 327 Customer satisfaction, 18–19 Customer service, 19–20 Customer shipping lane, 667–670 gravity skate-wheel or roller conveyor, 669 solid-gravity slide, 668 Cycle efficiency ratio, 105

D Decombe truck, 413–414 Deep-reach forklift truck, 511 Delivery truck dimensions, 586–587 Depreciation, 43–46 Dimensions pallet racks, 526–527 Direct-employee handling loss ratio, 104 Direct-loading sorting method, 405 Display-picking systems, 132–136


Index Display-put systems, 137–138 Distribution activities (overview), 7–8 Distribution cross-docking, 573, 577 Divert devices, 565, 647–648, 656–657 active/passive sorter, 656 active sorter, 656 flap sorter, 666–667 gull wing, 664 Nova sort, 663 passive sorter, 656 plow, 660–661 pop-up, 665–666 powered belt, 660 pusher, 657–660 rotating paddle, 666 SBIR or moving belt, 661 sliding shoe, 664–665 solid metal, 656–657 tilt slat, 663–664 tilt tray, 661–663 Dock curtains, 455, 590 Dock design, 453–466, 587–605 across-the-dock facility design aspects, 575–577 across-the-dock piece flow methods, 576–577 bridging dock-trailer interface, 453, 458–464, 595–602 bascule bridge dock, 463, 476 dock-leveler lift, 464, 597 edge-of-dock leveler, 461–462, 600–601 front-of-dock leveler, 601 ICC bar lock or hook device, 604 in-floor hydraulic lift, 462, 597 mobile yard ramp, 459, 597 portable board or plate, 458–459, 596 recessed leveler, 459–461, 597–600 scissors lift, 462–463, 597 truck tailgate, 463 vertically stored leveler, 461, 600 wheel lift, 464, 601–602 building design features, 576 delivery truck dimensions, 586–587 determining required number, 577–581 calculation, 579 piece flow method and, 581 simulation, 579–581 dock-area size determination, 481 dock height, 595 dock house, 457 dock-lift method, 604–605 dock ramp, 604 dock seals, 602 dock shelters, 603–604 doors, 457–458, 465, 592–595 drive-through-dock, 456

697 enclosed dock, 455–456, 591–592 floor space considerations, 581 flush dock, 453–455, 588–589 freestanding dock, 457 ICC bar lock or hook, 466 improving safety and efficiency, 602 lights, 466, 603–604 locations, 447–450, 576 combination docks, 447–448 scattered, 448–449 separated receiving, 448 truck access, 449–450 material-handling methods and, 576 open dock, 455, 589–590 pier dock, 457 projecting required number of docks, 480–481 railcar dock area, 472–474 bridging dock-railcar gap, 475–476 inside rail dock, 474 mobile dock ramp, 474 rail platform dock, 473–474 receiving office, 604 seals and shelters, 465–466 separate receiving and shipping, 576 staging area, 479, 481, 563, 581 stop and go lights, 604 truck access, 581–583 Dock house, 457, 592 Dock leveler lift, 464, 597 Dock levelers, 453, 458–464, 595–602, See also Dock design, bridging dock-trailer interface Dock-lift method, 604–605 Dock ramp, 604 Dollies, See Hand-trucks, carts, or dollies; specific types Double-deep pallet racks, 527–528 Double-rail guidance system, 375–376 Double-wing pallet boards, 496 Drawings, 54–61, 82–88 auto-positive, 84 block, 153, 321, 444 building layout, 55–56 CAD applications, 54, 82, 84–85 carton pick area design, 321–322 cost estimation, 51–52 detailed view, 83 documenting changes, 67–68 drawing components, 86–87 drawing materials, 86 electrical drawings, 58–59 elevation view, 83 GOH order-fulfillment operations, 153 GOH transport systems, 166–167 isometric, 84


698


method and equipment drawings, 57–61 method bid process, 62, 63 metric measurements, 88 overlay, 84 pallet order-fulfillment facility, 444 photocopies, 86 plan-view, 83, 153, 321–322, 444 review process, 67, 69 scale and not-to-scale, 85 scale tools, 85 site drawing, 55 sketch, 84 small- and large-scale, 85 standard template and layout board, 84 two- and three-dimensional, 82–83 utility system, 59 vertical hanging garment transport systems, 227 Drive-in or drive-through pallet racks, 336–337, 530–531 Driverless “stop and drop” pallet truck, 553 Drive-through-dock, 456 Dual cycle pallet activity, 22 Dynamic rail storage and pick systems, 260–266

E E-commerce applications, 4–5 Economic justification factors, 43–47 Economies of scale, 3 Edge-of-dock leveler, 461–462, 600–601 Electrical drawings, 58–59, 74 Electrical equipment installation, 73–74 Electrical power supply, 315 Electrical specifications, 62 Electric pallet trucks, 345–359, See Pallet trucks and load-handling devices Electric power supply, 307, 439–440 Electric surge protector, 439 Electromagnetic aisle guidance system, 377–378, 381 Elevated employee walkway, 402–403 open or grated deck, 402–403 solid-deck, 402 Elevated operator and load pallet truck, 349 Elevation view drawing, 83 Elevator or fire-door switch, 190–191 Employee productivity, 95 business factors affecting, 95–96 GOH operational design parameters, 143 measurement, 99–102, See also Performance measurement measurement standards, 107–108

operational vs. support employee hours, 102–103 supply-chain logistics strategies, 564 Employee productivity improvement, 20–35, 95–103 ABC theory, 23 arithmetic progression through pick aisle/line, 32–33 automatic identification, 30 batched customer orders, 386–388 batched order-picking, 21–22 budget information, 109 changing employee procedures, 96 changing from paper-based pick instruction format, 27–28 changing work method, 96 company income and, 44 cost analysis, 20–21 cost-effectiveness, 107 cube order picker activity, 25–26 employee allocation, 30 employee numbers, 20–21, 99 equipment improvements, 29–30 even and odd pick position numbers, 33 improving work area, 97 instruction simplicity and clarity, 24–25 labor cost budgeting, 35 layout and piece flow design, 28 machine paced system, 29, 98 measurement standards, 107–108, See also Performance measurement mechanized methods, 96–97 motivational methods, 33–34, 97–98 off-line pick and pack, 30–31 order-picker routing, 277 pallet dual cycle, 22 pallet handling components, 489 part-time employees, 26–27 pick position elevation, 27, 33, 111, 147 piece volume design level, 34–35 reducing travel time and distance, 22 replenishment, 31 sequential order pick patterns, 25 simplicity and clarity, 107 single-item picker starting point, 31–32 SKU groupings, 23–24, 111–112 SKU hit concentration and density, 22–23 smoothing or averaging daily work volume, 26, 97 successful program guidelines, 98–102 timely information, 107 tracking, 35–37, See also Short-interval scheduling Employee ratio, 103–104 Employee safety, See Safety issues


Index

699

Enclosed dock, 455–456, 591–592 End-of-aisle slowdown devices, 379–381 End-rider pallet truck, 346–348 Engineer’s scale, 85 Environmental storage conditions, 440 Equipment acceptance test, 79–81 Equipment and building punch list, 79–81 Equipment or method operational test, 78–79 Equipment utilization ratio, 106 Exchange pallet boards, 490 Executive management time, 93 Extendible or retractable truck unloading conveyor systems, 610–626, 652, 674 in-house conveyor merge, 610–611, 617 manual nesting, 618–620 manual setup, 611, 614 manual tripod, 616 mobile-powered, 622–624 powered flexible roller, 621–622 stationary powered, 624–626 Extendible hanging-garment trolley boom method, 159, 607

F Facility design, See also Project management bid package preparation, 54 building height, 151 building shapes, 149–151 carton order-fulfillment options, See Carton order-fulfillment facility design and layout checking and inspecting, 72–75 contract administration, 51, 66, 69–70, 76 cost estimates, 49–53 design outline criteria, 59–60 docks, See Dock design drawings, See Drawings hanging garment operations, 144–147, 149–151, See also under Garmenton-hanger (GOH) order-fulfillment operations important clearances or open spaces, 486–489 important rack and facility dimensions, 484–486 information needs and price sources, 52–53 installation office, 72 layout philosophy and principles, 307–311, 537–540, See also Pick aisles or lines ABC method, 23, 280, 308, 432, 537–538 aisle direction, 281, 310 aisle length, 281–282, 310–311

Pareto’s Law, 22–23, 136, 280, 308, 537 product rotation, 309–310, 539 product or SKU groupings, 22–24, 111–112, 147–149, 280, 308–309, 440, 538 unloading and loading ratios, 23, 308–309, 538 operational testing, 78–79 outline building criteria, 56 pallet order-fulfillment facilities, See Pallet order-fulfillment facility design preliminary specifications, 53 project management, See Project management rack-supported facility, 312–313 selecting architects and contractors, 53–54 truck yard, See Truck yard design vendor/contractor meetings, 70–72, 78 Facility or method drawings, See Drawings Family groups, 309, 318, 432, 538 Fans, 146, 306–307, 439 Fiberboard slip-sheets, 683–684 FIFO rotation, 309–310, 539 Financial analysis, See Budgeting Finger docks, 456, 591 Fire-door switch, 190–191 Fire extinguisher, 357 Fire protection, 315 vertical transport systems, 234–235 Fire sprinklers, 73, 315 facility design clearances, 486–487 First-in-first-out (FIFO) rotation, 309–310, 539 Fixed cost estimate, 49 Fixed end stops, 193 Flap sorter, 666–667 Flashing light, 358 Flat floor, 314 Flat scale, 85 Flat wear across-the-dock operations, See Smallitem and flat wear across-the-dock operations Floating pick position, 427 Floor and floor surface design, 314–315 electric vehicle requirements, 356 Floor-stacked carton or pallet storage/pick methods, 332–333, 523–524 Floor-stacked pallet unloading method, 477 Flow-rack carton design, 334–335 Flow-through pallet racks, 532–533 Flow chart, 89 Flue pallet boards, 494 Flush dock, 453–455, 588–589 Flush pallet board, 495 Forklift trucks, See also Pallet trucks and loadhandling devices


700


across-the-dock transportation methods, 685–689 capacity, 507, 687 carton order-picking method, 374 computer-controlled storage retrieval or ASRS, 518–523 counterbalanced rising cab side-loading, 517 deep reach, 511 dual-cycle activity, 22 entry wheels, 356 facility design clearances, 487 forks, 351–352 four-directional, 511 grade-climbing ability, 509, 688 load anti-slip devices, 334 man-controlled and man-down, 513 man-controlled and man-up, 515 man-controlled storage retrieval (MSR), 517 maneuverability, 508, 687–688 mast, 507–508, 687 mechanical unloading methods, 608–609 narrow-aisle (NA) vehicles, 509–511, 689 operator-down counterbalanced side-loading, 515 operator-down side-loading turret, 514 operator-down vs. operator up, 517 operator-up side-loading, 516 operator-up side-loading turret, 516 outrigger stand-up or sit-down truck, 517 overhead clearance, 83 pallet-container storage and pick method, 249 rider side-loading, 513–514 S.I. Cartrac method, 415 sit-down counterbalanced, 506–507, 686–687 sit-down rider counterbalanced side loader, 514–515 slip-sheet attachments, 499–500, 609, 684–685 stability, 507, 687 stand-up rider counterbalanced, 506, 688–689 stand-up rider double-deep, 511, 514 stand-up rider straddle, 510–511 truck unloading methods, 470, 477–478 pallet claw, 470–471 slip-sheet device, 470 two-deep, 511 under-clearance, 509, 688 very narrow-aisle (VNA) vehicles, 511–518 walkie/stacker, 504–506 wheelbase, 508–509, 688 wide-aisle (WA) vehicles, 504–509, 686–687 advantages/disadvantages, 509 45º lever or manual switch, 188 Four-directional forklift truck, 511 Four-way pallet boards, 495

Freestanding dock, 457, 592 Fringe benefits and taxes, 42 Front-of-dock leveler, 601

G Gantt chart, 89 Garment bagging, 164–165 Garment-on-hanger (GOH) across-the-dock operations, 563, 628, 641–647 sorting methods, 630, 642–647 unloading methods, 605–607, 642–643 Garment-on-hanger (GOH) order-fulfillment operations, 141–301, See also specific garment-on-hanger activities activities overview, 154 customer order profiles, 142 facility design, 144–147 height, 151 shape, 149–151 garment bagging, 164–165 garment steaming, 162–163 hangers, 14, 142 hanging garments or GOH items, 142 in-house transport, See Garment-on-hanger (GOH) transport vehicles or systems operational design parameters, 142–143 pick aisle or pick line design, 151–153 design parameters, 154–155 drawings, 154 pick-area design, 149 product allocation or profile methods, 148–149 product and order flow patterns, 151–153 product location, 147–148 sequence of activities, 155–156 piece flow patterns, 8 plastic bag bottoms, 163–164, 254 product type and volume determination, 155 projected order volumes, 142–144 shipping container options, 14 storage and pick methods, 242–277, See also Garment-on-hanger (GOH) storage and pick methods unique characteristics, 141 unloading and receiving, 156–162, 605–607 box opening and garment hanging, 159–160 extendible boom method, 159, 607 hand-carry, 157, 605 quality assurance, 162 rolling-rack or GOH cart, 157, 606 sort-and-count activity, 160–161


Index transferring hanging pieces, 161–162 trolley cart, 157–159, 606–607 Garment-on-hanger (GOH) packing, 288–293 catalog and direct-market orders, 295–297 materials and methods, 291–293 order checking, 293–294 package-securing methods, 299–301 piece accumulation, 287–288 retail store orders, 297–299 shipping label and documents, 294–295 station layout, 288–290 station surface, 290–291 Garment-on-hanger (GOH) sorting methods, 642–647 batch-pick, 282–283, 648 GOH cart method, 643–644 manual systems, 283–284 powered chain and programmable trolley, 287, 645 programmable hanging-garment trolley, 645 Promech, 284–287, 645–647 rail-loop method, 644 trolleyless, 287, 647 Garment-on-hanger (GOH) storage and pick methods, 242–277 aisle structural support, 246 aisle surface materials, 245–246 AS/RS trolley concept, 250–251 cantilevered rack, 246–247 design considerations, 242–243 dynamic-rail pick position method, 260–266 in-feed trolley travel path, 264–265 out-feed trolley travel path, 266 pick spur and aisle or walkway, 266 structural support, 265 trolley identification, 262–264 hang rail in rack or shelf bay, 258 human travel to pick position, 255 dynamic rail, 260–266 static rail, 242–260 multilevel methods, 255, 259–260, See also Garment-on-hanger (GOH) transport systems, vertical (multilevel) one rail deep, one or two rails high, 256 order-picker routing, 277–278 order-pick philosophy, 282–288 order-pick vehicle, 273–275, See also Garment-on-hanger (GOH) transport vehicles or systems packing, See Garment-on-hanger (GOH) packing pallet-container, 249–250 pick-area design, 278–282 pick-area layout philosophy, 279–281

701 pick position aisle barrier, 282 pick-position identification method, 251–254, 273, 275–277 cardboard triangles, 253 donuts, 252–253 GOH SKU identification considerations, 254 labels, 252, 253 placards, 252, 253 pipe-with-rail, 247–249 push-back method, 259 rail capacity, 243 rail module, 258 rails above pit, 257 raised aisle method, 257 SKU groupings, 280–281 sorting methods, 282–288, 641–647, See also Garment-on-hanger (GOH) sorting methods standard pallet-rack method, 243–246 stock to pick-position carousel method, 266–272 storage and pick position design, 278–282 three rails high with rolling ladder, 257–258 transport methods, 288–290, See also Garment-on-hanger (GOH) transport vehicles or systems two or three rails deep, 256–257 Garment-on-hanger (GOH) transport systems, vertical (multilevel), 226–242 advantages and disadvantages, 242 carousel, 236–237 computer simulation, 228 design factors, 226 design parameters, 227–228 fire-protection options, 234–235 flow control, 231 human-carried method, 229 lift, 237–240 nonpowered trolley, 231 objectives, 226–227 powered chain with trolley, 232–236 safety requirements, 226 slick or slide rail, 229–231 storage and pick methods, 255, 259–260 systems, 229 trolley lift, 240–242 trolley load-bar antislide pins, 235 Garment-on-hanger (GOH) transport vehicles or systems, 165–167 BMC or four-wheeled four-sided cart, 289 conveyor, 289–290 design parameters, 166–167


702


drawings, 227 four-wheel carrier, 221 GOH carts, 168–174, 288, 606, See also GOH carts nonpowered overhead trolleys, 288 objectives, 165–166 order-pick vehicle, 273–275 HROS or man-up powered vehicle, 275 rolling ladders, 274 stepladder and cart, 274 stepstool, 275 order take-away method, 289 tote on conveyor, 289 trolleyless, 217–226, 287, 288–289, See also Garment-on-hanger (GOH) transport vehicles or systems, trolleyless concepts unloading methods, 605–607 Garment-on-hanger (GOH) transport vehicles or systems, non-powered, 167–195 carts, 168–174, 606, See also GOH carts human-carried method, 167 overhead transport, 174–195, See also Overhead trolley systems Garment-on-hanger (GOH) transport vehicles or systems, powered, 196–226 C-channel or rail, 199–201 controls and panel, 211 description of operation, 211–212 drive motor and sprocket, 197–198 nonpowered travel path, 209 pallet-rack storage and pick method, 243–246 powered-screw conveyor, 212–216, See also Powered-screw conveyor system powered chain, 197 programmable trolley, 202 code reading or scanning, 204–205 coding methods, 202–204 divert devices and sensors, 196–197, 205–206 pusher dogs and trolley queues, 199 rail types and paths, 196 return travel path, 211 structural support, 206–207 take-up devices, 198–199 travel path protection (guards), 210 trolley in-feed methods, 207–209 trolleyless concepts, See Garment-on-hanger (GOH) transport vehicles or systems, trolleyless concepts trolley run-out section, 210–211 vertical multilevel systems, See Garment-onhanger (GOH) transport systems, vertical (multilevel)

Garment-on-hanger (GOH) transport vehicles or systems, trolleyless concepts, 217–226, 287, 288–289 advantages and disadvantages, 219–220 divert devices and travel paths, 223–224 GOH piece identification, 223 in-feed station, 222–223 modular transport system, 217–219 multiline/multiquantity pick application, 225–226 operations, 219 single-unit pick applications, 224–225 storage area applications, 224 200 G system, 220–222 Garment-on-hanger unloading methods, 156–159, 605–607 Glue or adhesive, 503 GOH carts, 168–174, 288, 606 casters or wheels, 172–174 design, 169–171 functional specifications, 171 method, 288 push handle or bar, 172 securing pieces, 171–172 sort-and-count application, 161 structural support, 169 truck unloading methods, 157 Golden zone, 27, 33, 111, 147, 318 Grade-climbing ability, 509 Grated deck walkway, 402–403 Grated-plank aisle surface, 245 Gravity-flow pallet rack, 334–335, 532–533 pick-position method, 337–338 Gravity skate-wheel or roller conveyor, 669 Gravity strand slide, 668 Growth rate, 46 Gull wing sorting method, 664 Gummed tape, 299

H Hand-trucks, carts, or dollies, 341–343, 422, 605, See also GOH carts; Pallet trucks and load-handling devices; specific applications, types low-lift pallet, 467 manual pallet truck or jack, 342–343 nonconveyable carton sorting, 676 platform truck or dolly, 341–342, 422 Hanger box, 298 Hangers, 14, 142 Hanging garments, 141, 142, See Garment-onhanger (GOH) order-fulfillment operations


Index

703

Hazardous products classification, 440 High-rise order-selector (HROS) trucks, 275, 317, 381–382 carton order-pick method, 340, 374–385 end-of-aisle slowdown devices, 379–381 order-picker routing methods, 383–385 High-rise pallet racks, 534 High-rise storage rack, 316 High-speed control, 357 Hinged knife elevator or fire-door switch, 190–191 Honeycomb pallet boards, 493 Horizontal carousel, 634 Horn, 357 Horseshoe (“U”) order-picker routing patterns, 277, 362–363 Hourly wage rate, 40 Housekeeping, 28 HROS vehicles, See High-rise order-selector (HROS) trucks Hydraulic lifts, See Dock design, bridging docktrailer interface; specific types

I ICC bar lock or hook, 466, 604 In-feed conveyor, 409–410 In-feed trolley methods, 207–209, 264–265 In-floor hydraulic lift, 462, 597 Indexing inverted power and free conveyor sorting method, 635 Induction conveyor, 409–410, 652–654 Industrial bands, 503 Inflation rate, 46 Information flows, 2–3 Information management systems (IMS) customer-order entry and download, 10, 13–14 host computer download of customer orders, 18 Insurance coverage, 62 Internet applications, 4–5 Inventory control, 13–14 Investment justification, 43–47 Isometric drawing, 84

J Julian dates, 88 Just-in-time (JIT) replenishment, 564

K Kit groupings, See Family groups

L Labeling, 12, 18 garment-on-hanger shipping, 294–295 price ticketing, 628–630 GOH SKU pick-position identification, 252, 253 order-pick instruction methods, 366–367 pallet identification, 541–542 pick-position identification, 370 shipping, 639–641 supply-chain logistics strategy, 567 Labor costs, 20–21, 330, See also Employee productivity; Employee productivity improvement company income and, 44 controllable and noncontrollable expenses, 38–41 employee productivity measurement, 109 forecasting and budgeting, 35–43 fringe benefits and taxes, 42 management salary, 41 nonworking hour expenses, 41 other controllable expenses, 42–43 part-time employees and, 26–27 supply-chain logistics strategy, 563 Labor ratios, 103–104 Land cost estimates, 49 Landing gear pad, 451, 584 Laser aisle guidance system, 378–379 Last-in-first-out (LIFO) rotation, 309–310, 539 Leg pallet boards, 493 LIFO rotation, 309–310, 539 Light, flashing, vehicle, 358 Light display order-picker instruction method, 132–136, 367 Lighting dock areas, 466, 603–604 fixtures, 28–29, 73, 146, 278, 306, 439 Loading methods, 17, 641, See Across-the-dock operations; Dock design; Unloading methods; specific applications across-the-dock shipping and packing operations, 638–641 container sealing, 639 filling container voids, 639 labeling and manifest, 639–641 truck loading, 641 weight check methods, 638–639 catalog and direct-market order packing, 295–297 GOH, 288–293, See also Garment-on-hanger (GOH) packing order pick cube, 26 packing materials and methods, 291–293


704


chipboard box, 292–293 corrugated box, 292 retail-store order packing, 297–299 Local area network (LAN), 146 Loop order-picker routing patterns, 362 Low-lift pallet, 467

M Machine-readable identification, See Bar-code scanning Magnetic paint, 378 Maintenance, 18, 28 personnel training, 81 Management salary, 41 Manifesting, 640–641 Manually-adjustable stops, 194 Manual low-lift pallet, 467 Manual order-fulfillment method, 283–284, 311 Manual-sorting conveyor method, 406–408 Manual switch, 186 Manufacturing cross-docking, 572–573, 576–577 Masonite-on-plywood aisle surface, 245 Master-carton open activity, 628 Master carton piece flow patterns, 8 Master project schedule, 68–69 Masts, forklift trucks, 507–508, 687 Material-handling ratios, See Order-fulfillment or across-the-dock ratios Measures of performance, See Performance measurement Mechanical design criteria, 59–60 Mechanical-sorting conveyor method, 408–412 Mechanized-carton employee-walking pick method, 385–412, See also Conveyor systems Mechanized order-fulfillment method, 96–97, 311 Metal floor-plate aisle surface, 245 Method and equipment drawings, 57–61 Method bid package preparation, 54 Method drawings, See Drawings Method measurement, See Performance measurement Metric measurements, 88 Mezzanine method for multilevel GOH storage and pick, 259–260 Mid-control rider pallet truck, 348–349 Military time, 88 Mini-stacker, 418–419 Mobile-aisle (MA) vehicles, 274–275, 317, 522 Mobile dock ramp, 474 Mobile or sliding pallet racks, 532 Mobile rack pick-position method, 339–340 Mobile ramp, 459, 474, 597

Mole, 518, 535 Most frequent piece or customer-order volumes, 143, 305, 437 Multilevel storage and pick methods, 255, 259–260, See also Garment-onhanger (GOH) transport systems, vertical (multilevel) Murphy’s Law, 73 Mylar drawing material, 86

N Narrow-aisle (NA) vehicles, 317, 509–511, 689 National Wooden Pallet and Container Association (NWPCA), 491 Netting, 502–503 Nonconveyable carton pick/sort methods, 331, 422–427, 675–678 cart carousel, 424 design parameters, 681 inverted power and free conveyor, 680 manual carts or trucks, 676–677 non-powered pallet roller conveyor, 678 non-powered trucks, 422 pallet floor-stack method, 676 pallet on conveyor, 423 pallet truck, 424 picked-carton flow, 425–426 pick position arrangement, 426–427 piece or customer identification, 571 powered pallet trucks, 677 powered roller conveyor, 680 S.I. Cartrac, 423–424, 680–681 tugger with cart train, 424–425, 677–678 vehicles or transport surfaces, 676 Nonreversible pallet boards, 496 No-read conveyor, 411, 654 Nova sort, 663

O Off-line pick and pack, 30–31 One-way flow, 320, 443 Open deck pallet boards, 495 Open deck walkway, 402–403 Open dock, 455, 589–590 Operating expense budget, See Budgeting Operational personnel training, 81 Operational testing, 78–79 Order cycle efficiency ratio, 105 Order-fulfillment and across-the-dock capital expenditure justification, 43–47


Index Order-fulfillment and across-the-dock facility design, See Facility design; Project management Order-fulfillment and across-the-dock operation performance measurement, See Performance measurement Order-fulfillment and across-the-dock performance standard, 19–21, See also Employee productivity improvement Order-fulfillment method drawings, See Drawings Order-fulfillment operations, 1, See also specific activities, equipment, functions, procedures benefits of effective performance, 18–19 garment-on-hangar, See Garment-on-hanger (GOH) order-fulfillment operations objectives, 4, 9 pick activities, overview, See also specific activities order pick activities, 7, 10, 13–15 postorder pick activities, 7, 10, 15–18 pre-order pick activities, 7, 9–14 piece flow patterns, See Piece flows receiving activities, See Receiving operations resources, 3 systems, See Order-fulfillment systems time frame, 2 in-house transport, See Transport methods or systems; specific applications, methods, systems, vehicles systems, See Order-fulfillment systems trends and issues, 4 value of, 3 Order-fulfillment or across-the-dock ratios, 103–107 aisle space potential, 106–107 direct-employee (labor) handling loss, 104 employee (labor), 103–104 equipment utilization, 106 order cycle efficiency, 105 piece or order movement, 104 space utilization efficiency, 105–106 Order-fulfillment systems, 111–140 A-frame, 123–126 carousels, 129–132, See also Carousel systems check weighing, 139 complex picking methods, 138–139 garment-on-hanger applications, See Garment-on-hanger (GOH) orderfulfillment operations; Garment-onhanger (GOH) storage and pick methods general pick-line layout, 118

705 multilevel methods, 255, 259–260, See also Garment-on-hanger (GOH) transport systems, vertical (multilevel) multiple methodologies, 111 parallel picking operations, 113 picking operation profiling or slotting analysis, 111–112 pick to carton, 138–139 pick-to-light and pick-to-display, 132–136 put system basics, 113 put-to-display systems, 137–138 RF or voice, 121–123 split-case order picking, 111 storage or picking media, 113–118 tilt-tray or cross-belt sorter, 126–129 types, 118–121 advantages and disadvantages, 120–121 cart, 120 location identification, 120 pick-to-paper, 120 Ordermatic, 419–421 Order of magnitude cost estimate, 49 Order pick cube, 25–26 Order-picker instruction methods, 364–368 aisle and position identification format, 544–547 carton, 328–329, 364–368 computer-controlled, 368, 543–544 instruction content, 365 pallet transaction, 543–547 paper labels, 366–367 paperless methods, 367–368 pick position, 365 pick-to-light and pick-to-display, 132–136, 367 RF device, 368, 543 simplicity and clarity, 364 voice-directed, 368, 543 Order picker productivity, See Employee productivity improvement Order-picker routing patterns, 277–278, 359–364, 403 block, 277, 363–364 high-rise, 277, 383–385 horseshoe (“U”), 277, 362–363 loop, 277, 362 no routing pattern, 359 pallet facilities, 547 sequential patterns, 359–364 serpentine travel, 360–361 single side, 277, 361–362 stitch, 277, 364 straight in-and-out, 360 “Z”, 277, 363


706


Order-pick method, cartons, See Carton orderpick method Order-pick methods, automated, 419–422 Out-of-season piece activity, 17 Out of stocks, 13 Outline building criteria, 56 Overhead clearance, 83 Overhead door switch, 192–193 Overhead towveyor, 557–561 Overhead trolley systems, 277 components, 177–183 accessories and options, 180–183 heads, 178–179 load bars, 180 necks or arms, 179–180 spools, 177–178 GOH transport methods, 288, 644 non-powered GOH transport systems, 174–195 rail components and paths, 183–186 slick or slide rail method, 174, 176 stops, 187, 193 adjustable end, 193 fixed end, 193 manually-adjustable, 194 swing-rail, 193–194 support structure, 194–195 switches, 186–193 automatic or spring-loaded cross-through, 190 45º lever or manual, 188 hinged knife elevator or fire-door, 190–191 manual, 186 overhead door, 192–193 parallel-stacking, 191–192 removable-rail section, 190 spring, 186 spring or automatic straight, 187–188 three-way master, 189 two-way master, 189 Overlay drawing, 84 Overstock piece transfers, 17

P Pack carton structural support strength, 155 Package-securing methods, 299–301 bands, 299–301 sealing, 16 tape, 299–300 Package weighing, 17 check weigh method, 139, 570–571, 638–639 Packaging, 12–13, 16

Packing, See also Shipping operations across-the-dock shipping and packing operations, 638–641 container sealing, 639 filling container voids, 639 labeling and manifest, 639–641 truck loading, 641 weight check methods, 638–639 catalog and direct-market order packing, 295–297 GOH, 288–293, See also Garment-on-hanger (GOH) packing order pick cube, 26 retail-store order packing, 297–299 Packing materials and methods, 291–293 chipboard box, 292–293 corrugated box, 292 Pallet(s), See Pallet boards Pallet across-the-dock operations, 681–689 preferred dock design, 589, See also Dock design transportation methods, 685–689, See also Pallet trucks and load-handling devices Pallet boards, 249, 489–490 advantages and disadvantages, 493 basic designs, 493–494, 683 block, 493, 683 flue or rippled, 494 leg or honeycomb, 493 solid, captive, or slave, 493 stringer, 493–494, 683 chamfered bottom deck boards, 345 components, 494–495 dimensions, 493, 682 materials, 491–492 types or configurations, 490–491, 495–496 block, 496 closed or solid deck, 495 double-wing, 496 exchange, 490 flush, 495 four-way, 495 nonreversible, 496 open deck, 495 reversible, 496 single-wing, 496 specially designed or engineered, 490–491, 496 take-it or leave-it, 490, 496 throwaway, 490 two-way, 495 wing, 495 Pallet-board unloading method, 477 Pallet cage pick position, 333–334


Index Pallet-container storage and pick method, 249–250 Pallet dimensions, 446 Pallet distribution order-fulfillment operations, 8 Pallet dual cycle, 22 Pallet flow, 441–444 Pallet flow device, 472, 627 Pallet flow lanes, 117 Pallet-handling device for truck unloading, 626–627, See also Pallet trucks and load-handling devices Pallet height options, 389–390 Pallet identification, 325–326, 540–542 Pallet in-house transportation methods, 549–561 AGV, 518, 550–554 carton-flow or decked pallet rack, 392–393 conveyor-based systems, 390–396 empty pallet queue, 401–402 empty pallet return, 400–401 flow-lane issues, 394–395 forklift truck, 549, See Forklift trucks overhead towveyor, 557–561 pallet orientation, 389–390 pallet trucks, 549, See Pallet trucks and loadhandling devices powered vehicle with cart train, 549, See Tow tractors or tugs rack parallel to conveyor, 390–391, 393–394 rack perpendicular to conveyor, 391–392, 395–396 tow-line cart, 556–557 tow line, 554–556 Pallet load, 489 AGV, 553–554 dimensions, 485–486 stabilization, 500–502 glue or adhesive, 503 industrial bands, 503 netting, 502–503 shrink wrap, 502 stretch wrap, 501–502 string, 501 tape or bands, 501 ti and hi, 500–501 storage/pick position methods, 523–536, See also Pallet racks Pallet order-fulfillment facility design, 438–440 aisle dimensions, 479 customer order volume, 446 dock design, See Dock design drawings, 444 floor space, 479 important clearances or open spaces, 486–489 back-to-back racks or walls, 488 conveyors, 488–489

707 fire sprinklers, 486–487 floor-stacked pallet clearance, 488 food facility requirement, 488 rack base plate, 487–488 rack bay width, 487 straddle forklift trucks, 487 tall-rack facility requirements, 487–488 important rack and facility dimensions, 484–486 floor to ceiling, 485 pallet load bottom support device, 486 pallet load dimensions, 485–486 space between building columns, 484–485 infrastructure, 438–440 layout philosophy, 537–540 pallet height, 538 projecting required number of docks, 480–481 rack-row and vehicle-aisle, 445–446 shipping and receiving docks, See Dock design size and shape, 438 storage-area design, 440–441 yard design, See Truck yard design Pallet order-fulfillment operations, 383, 435–561 ASRS vehicles, 438 automatic unloading systems, 471–472 decked or hand-stacked cartons, 339 drive-in or drive-through pick position, 336–337 facility design, See Pallet order-fulfillment facility design factors affecting employee productivity, 489 floor-stacked pick-position method, 332–333 general truck unloading and loading, 476–479, See also Across-the-dock operations; Unloading methods gravity- or air-flow pick positions, 337–338 list of activities, 444–445 mobile or sliding rack, 339–340 narrow-aisle vehicles, 689 nonconveyable cartons, 423, 676–678 operational design parameters, 435–436 physical components, 489, See also Pallet boards; Pallet load; Pallet trucks and load-handling devices projected customer order volumes, 436–438 projected vehicle needs, 438 push-back pick position, 335–336 receiving activity, 479 replenishment method, 432 sequence of activities, 446 standard pallet-rack pick position, 338–339 storage/pick position guidelines, 440 truck yard control, 446–447, See also Truck yard control; Truck yard design


708


Pallet pickup and delivery stations, 520–521, 554 Pallet racks, 523–536 aisle and position identification format, 544–547 bridge, 530 cantilevered, 534 car-in-rack (mole), 518, 535 dimensions, 526–527 double-deep, 527–528 drive-in, 530–531 drive-through, 531 floor stack or block storage/pick methods, 523–524 GOH storage and pick method, 243–246 gravity or flow-through, 532–533 high-rise, 534 installing used racks, 529–530 mobile or sliding, 532 push-back, 533–534 sort-link, 518, 535–536 stabilization, 525 standard, 524–527 standard rack openings, 534–535 tier rack or stacking frames, 524 Pallet slip-sheets, 496–500 Pallet stack, 358 Pallet-stacking frame pick position, 333–334 Pallet stop, 357 Pallet storage methods, 315–316, See also Pallet racks storage area design, 440–441, 479 Pallet transaction instruction methods, 543–547 aisle and position identification format, 544–547 computer directed, 543–544 paper document, 542–543 RF and digital display, 543 voice directed, 543 Pallet transaction verification, 547–548 Pallet trucks and load-handling devices, 345–349, 503–504, 522, 549, 681, See also Forklift trucks across-the-dock transportation methods, 685–689 advantages/disadvantages, 364 AGVs, 518, 550–554, See also Automatic guided vehicles automated storage and retrieval systems, 438, 511–512, See also ASRS vehicles capacity, 507 captive aisle vehicle, 522 chamfered pallets, 345 electric truck components, 350–352 elevated operator and load, 349

end-rider, 346–348 entry wheels, 345 floor requirements, 356 forks, 351–352 fork tips, 346 grade-climbing ability, 509 gripper or claw, 470–471 maneuverability, 508 manual low-lift pallet, 467 manual truck or jack, 342–343 mid-control, 348–349 mobile aisle vehicle, 522 narrow-aisle (NA) vehicles, 509–511 four-directional forklift truck, 511 stand-up rider double-deep forklift truck, 511 stand-up rider straddle forklift truck, 510–511 nonconveyable carton sorting, 676–678 operational features, 352–356 operator step platform, 349 options and accessories, 357–358 backrest, 345–346 clipboard document holder, 356–357 fire extinguisher, 357 flashing light, 358 fork entry wheels, 356 fork height, 353–354 high-speed control, 357 horn, 357 length, 352–353 load weight and carrying capacity, 354–355 mast, 507–508 maximum grade, 354 pallet stop, 357 quick-pick handle, 357 stabilizing casters, 357–358 travel direction, 355–356 turning radius, 354 wheel base, 353 pallet stack options, 358 pick activity description, 358–359 remote-controlled, 349 roller pallets, 467 routing patterns, 547 side rider, 350 slip-sheet attachments, 499–500, 608, 681–682, 684–685 stability, 507 T-car, 522–523 truck unloading methods, 469–472, 477, 606–608, See also Pallet unloading methods under-clearance, 509


Index very narrow-aisle (VNA) vehicles, 511–518 AGVs, 518, See also Automatic guided vehicles automatic stacking wire-guided vehicle, 518 computer-controlled storage retrieval or ASRS forklift truck, 518–523 counterbalanced rising cab side-loading forklift truck, 517 man-controlled man-down forklift truck, 513 man-controlled man-up forklift truck, 515 man-controlled storage retrieval forklift truck, 517 operator-down counterbalanced sideloading forklift truck, 515 operator-down side-loading turret forklift truck, 514 operator-down vs. operator up forklift truck, 517 operator-up side-loading forklift truck, 516 operator-up side-loading turret forklift truck, 516 outrigger stand-up or sit-down truck, 517 rider side-loading forklift truck, 513–514 sit-down rider counterbalanced side loader forklift truck, 514–515 stand-up rider double-deep forklift truck, 514 walkie pallet truck, 677 walkie/rider pallet truck, 677 walkie single or double, 346–348 wheelbase, 508–509 wide-aisle (WA) vehicles, 504–509, 686–687 advantages/disadvantages, 509 sit-down counterbalanced forklift truck, 506–507, 686–687 stand-up rider counterbalanced forklift truck, 506, 688–689 walkie/stacker forklift truck, 504–506 Pallet unloading methods, 476–479 container, 478–479 floor-stacked, 477 forklift truck, 608–609 pallet-board, 477 pallet-flow device, 627 pallet-handling device, 626–627 pallet trucks, 607–608 slip-sheet, 477–478 Paper drawing material, 86 Parallel-stacking switch, 191–192 Parallel picking operations, 113 Pareto’s Law, 22–23, 136, 280, 308, 537 Passive sorter, 656

709 Payroll tax, 42 Peak piece or customer-order volumes, 143, 305, 437 Peak volume periodsusing part-time employees, 26–27 Perforated metal aisle surface, 246 Performance measurement cost as percentage of sales, 101 cost per piece or order handled, 101 dollar cost measurement, 100 employee hours consistency, 102 industry standard, 107–108 material-handling ratios, 103–107, See also Order-fulfillment or across-the-dock ratios number of pieces or orders handled, 102 unit of measure, 99 weight of pieces or orders handled, 101–102 Performance standard, 19–21, See also Employee productivity improvement Personnel training, 81 PERT chart, 89 Photocopies, 86 Photo-eyes, 667, 673 Pick aisles or lines aisle length, 281–282, 540 arithmetic progression through, 32–33, 277 carton order-fulfillment facility layout, 318–323, See also Carton pick lines or aisles direction of flow, 281, 310, 539 end-of-aisle slowdown devices, 379–381 even and odd pick position numbers, 33 GOH pick-area design, 278–282 GOH product location, 147–148 housekeeping, 28 kick plates and handrails, 246 layout philosophy, 118, 279–282, 307–311, 537–540 ABC method, 23, 280, 308, 432 length, 281–282, 310–311 order-picker routing patterns, 359–364 pallet-rack GOH storage and pick method, 245–246 productivity-maximizing design, 28–29 rail guidance systems, 375–379 sequence of activities, 155–156 storage or picking media, 113–118 structural support, 246 surface materials, 245–246 Pick efficiency improvement, See Employee productivity improvement Pick equipment utilization ratio, 106 Picker productivity, See Employee productivity improvement


710


Picking cage, 383 Picking media, 113–118 carton flow racks, 114–116 pallet flow lanes, 117 picking modules, 117–118 static shelving, 114–116 Picking modules, 117–118 Picking operation profiling or slotting analysis, 111–112 Picking systems, See Order-fulfillment systems Pick-pack operations, 138 Pick-position elevation, 27, 33, 111, 147, 318 Pick-position identification methods, 120, 251–254, 368–371 cardboard triangles, 253 digital display, 371 donuts, 252–253 GOH dynamic-rail pick position method, 262–264 GOH SKU identification considerations, 254 labels, 252, 253, 370 manual printing, 369–370 no method, 369 pallet facility, 544–547 pallet identification, 325–326, 540–542 placards, 252, 253, 370 RF device, 371 Pick-position-to-employee method, 414–419 Pick-to-carton methods, 138–139 Pick-to-light and pick-to-display order-picker instruction method, 132–136, 367 Pick-to-paper systems, 120 Pick tunnel, 340, 396 Piece flows, 2–3, 8 across-the-dock strategy, 567, 571–574 carton pick area design, 319–321 GOH operational design considerations, 151–153 master-carton open activity, 628 one-way, 320, 443 pallet order-fulfillment, 441–444 piece transformations, 627–628 productivity-maximizing design, 28 speed measurement, 80 two-way, 320, 443–444 vertical up-and-down flow, 321 Piece or customer identification, 567–571, See also Labeling automation, 30 carton order-fulfillment, 326 GOH dynamic-rail pick position method, 262–264 hanging garments, 223, 251–254 machine-readable identification, See Bar-code scanning

nonconveyable units, 571 receiving operations, 12 sorted labeled, 575 unsorted labeled, 574 unsorted unlabeled, 574 Piece or order movement ratio, 104 Piece replenishment, See Replenishment Piece volume level, 34–35 Pier dock, 457, 592 Pier rack pick position, 333–334 Pipes, 247–248 Pipe-with-rail storage and pick method, 247–249 Placards, 370 Plan view, 83, 153, 321–322, 444, See also Drawings Plank grating aisle surface, 245 Plastic bag bottoms, 163–164, 254 Plastic slip-sheets, 684 Platform truck or dolly, 341–342, 422 nonconveyable carton sorting, 676 Plow divert method, 660–661 Plumbing design criteria, 60 Plumbing system drawings, 59 Plywood aisle surface, 245 Polytexture aisle surface, 245 Pop-up chain sorting method, 666 Pop-up divert method, 665–666 Powered belt conveyor travel path, 671 Powered belt divert method, 660 Powered chain and programmable trolley GOH sorting method, 287 Powered conveyor and divert spurs sorting method, 633–634 Powered-screw conveyor system, 212–216 controls, 215–216 guard rail and accessories, 215–216 motor and drive unit, 212 operations, 216 rotating shaft and spiral wire strand, 213 structural support, 213–215 Power supply, 146, 307, 439–440 Price ticketing, 12, 567, 628–630 conveyor methods, 629–630 tabletop methods, 629 Product or SKU groupings, 23–24, 111–112, 147–149, 280–291, 309, 318, 538 ABC method, 23, 280, 308, 432, 537 pallet storage/pick areas, 440 popularity and Pareto’s Law, 22–23, 136, 280, 308, 537 season, 17, 149, 280, 318 Product profiling or slotting, 147 Product rotation, 309–310, 539 Productivity improvement, See Employee productivity improvement


Index

711

Programmable trolley, 202 code reading or scanning, 204–205 bar code reader or scanner, 205 photoreactive tab reader, 205 sliding pin reader, 204–205 coding methods, 202–204 bar codes, 204 photoreflective tabs, 203–204 sliding pins or tabs, 202–203 divert devices and sensors, 196–197, 205–206 GOH sorting method, 287, 645 Project management, 47–48, See also Facility design; specific activities bid package preparation, 54 bid process, 61–65 checking and inspecting, 72–75 checking vendor’s labor force, 74–75 consultants, 90–95 contract administration, 69–70 contracts, 51, 66 controlling job extras, 75–76 cost estimation, 49–53 dos and don’ts, 82 drawings, See Drawings equipment acceptance test and punch list, 79–81 installation office, 72 letter of intent, 66 method purchase order, 65–66 operational testing, 78–79 process, 48 progress report, 76 record-keeping and documentation, 77–78 scheduling, 66–67 charts, 88–89 master project schedule, 68–69 vendor/contractor meetings, 70–72, 78 Project management team, 92–93 Project manager, 93 Project specialists, 93 Promech, 284–287, 645–647 Punch list, 79–81 Purchase order, 65–66, 567 Push-back racks, 335–336, 533–534 Pusher sorting method, 657–660 Put systems, 113 carousels, 132 display systems, 137–138

Q Quality assurance (QA), 12, 162 Quality check, 11 Quantity check, 11

Queue conveyor design, 670–671 Quick-pick handle, 357

R Rack-supported facility, 312–313 Radio frequency (RF) systems, 30, 121–123, 146, 307, 368, 371, 543 Rail-based guidance systems, 375–379 aisle entry guides, 375 double-rail system, 375–376 electronic guidance, 377–379 wire, 377–378 installation parameters, 375 laser, 378–379 magnetic paint, 378 magnetic tape, 378 single-rail system, 376–377 Rail bumper method, 381 Rail-loop and overhead trolley GOH sorting method, 644 Railcar docks and unloading operations, 324, 472–476 bascule bridge, 476 bridging dock-railcar gap, 475–476 dock boards, 475 double railcar unloading, 475 inside rail dock, 474 mobile dock ramp, 474 rail platform dock, 473–474 selective railcar unloading, 475 single railcar unloading, 474 yard control, 11 Ramp, mobile yard, 459, 597 Ramp lift, 462 Random or floating pick position, 279 Random replenishment, 430 Rapid-pack sorting method, 635–636 Rate of return, 46 Receiving operations, 1, 11–12, See also Acrossthe-dock operations; Dock design; Unloading methods carton, See Carton unloading and receiving GOH operations, 156–162, 605–607 box opening and garment hanging, 159–160 extendible boom method, 159, 607 hand-carry, 157, 605 quality assurance, 162 rolling-rack or GOH cart, 157, 606 sort-and-count activity, 160–161 transferring hanging pieces, 161–162 trolley cart, 157–159, 606–607 pallet, 479


712


quantity and quality check, 11 schedule and truck yard control, 446–447, See also Truck yard control sort-and-count activity, 160–161 Receiving and shipping docks, See Dock design Receiving dock site drawing, 55 Receiving office, 604 Recessed dock leveler, 459–461, 597–600 Recirculation conveyor, 412, 650–651 Record-keeping and documentation, 77–78 Regression analysis, 108 Remote-controlled pallet trucks, 349 Remote-controlled tow tractor, 372–373 Removable-rail section switch, 190 Replenishment, 10, 15–16, 31 allocation to pick area, 431–432 automated methods, 420–421 carton or pallet, 427 computer-controlled, 433–434 conveyor-based carton transport, 391–396 mechanized carton order-fulfillment, 311 quantities, 432–433 random, 430 SKU grouping and errors, 112 slug, 430 sweep, 430–431 timing, 433–434 transaction verification and inventory tracking, 428–430 WMS, 431 Resource utilization, 3 Retail-store order packing, 297–299 Returns processing, 1, 327 Reversible pallet boards, 496 Rippled pallet boards, 494 Roller conveyor, 672 Roller pallet, 467 Rolling ladders, 274 Rotating paddle sorting method, 666

S S.I. Cartrac, 415, 423–424, 634–635, 680–681 S.I. Ordermatic, 419–421 Safety deck or netting, 396 Safety gate, 398 Safety issues conveyor crossing paths, 397–399 dock design considerations, 602 underside deck or netting, 396 vertical hanging garment transport systems, 226, 234 Sanitation, 18 Saw-tooth dock, 456–457, 591–592

SBIR or moving belt divert method, 661 Scale tools, 85–86 Scattered docks, 448–449 Scheduling, See Project management Scissors lift, 462–463, 597 Sealing methods, 16, 639 Seasonal product groups, 17, 149, 280, 318 Security, 18 truck yard, 451–452, 582, 585 Self-adhesive tape, 299–300 Separated receiving docks, 448 Sepia drawing material, 86 Sequential order pick patterns, 25 Serpentine travel method, 360–361 Shelving, 114–116 Ship ladder, 398–399 Shipping and receiving docks, See Dock design Shipping conveyors or lanes, 412 Shipping dock site drawing, 55 Shipping operations, 1, 638–641, See also Packing container makeup, 14 container sealing, 639 filling container voids, 639 labeling and manifest, 639–641 package weighing, 17 truck loading, 641 weigh check methods, 638–639 Shipping-sorting method, 404–405, 674 Short-interval scheduling (SIS), 35–37 line-item and man-hour budget method, 37–43 Shrink wrap, 502 Side-entrance enclosed dock, 456, 590–591 Side-loading or finger docks, 456, 591 Side-rider pallet truck, 350 Simulation, 228, 480–481, 579–581 Single-rail guidance system, 376–377 Single-side order-picker routing patterns, 361–362 Single-wing pallet boards, 496 Sit-down counterbalanced forklift truck, 506–507, 686–687 Sketch drawing, 84 SKU hit concentration and density, 22–23 SKU identification, See Piece or customer identification SKU sorting, See Sorting Slave pallet boards, 493 Slick or slide rail, 174, 176, 229–231 Sliding pallet racks, 532 Sliding rack pick-position method, 339–340 Sliding shoe sorting method, 664–665 Slip-sheets, 469, 470, 496–500, 608, 609, 681–685 back stop, 609


Index corrugated, 683 design parameters, 684 fiberboard or solid Kraft, 683–684 pallet unloading method, 477–478 plastic, 684 tips on using, 684 Slotted-angle shelf carton-pick method, 339 Slotting, 111–112, 147 Slug replenishment, 430 Small-item and flat wear across-the-dock operations, 628–641 master-carton open activity, 628 packing and shipping, 638–641 piece changes, 627–628 piece flow patterns, 8 price ticketing, 628–630 Small-item and flat wear across-the-dock sorting methods, 630–638 automatic methods, 636–637 manual methods, 631–632 mechanized methods, 632–636 carton flow-rack, 635–636 horizontal carousel, 634 indexing inverted power and free conveyor, 635 powered conveyor and divert spurs, 633–634 rapid-pack, 635–636 S.I. Cartrac, 634–635 waterfall or store dump, 633 Smoke detectors, 235, 315 Solid deck walkway, 402 Solid-gravity slide, 668 Solid Kraft slip-sheets, 683–684 Solid metal divert method, 656–657 Solid pallet boards, 493 Sort-and-count activity, 160–161 Sorted labeled pieces, 575 Sorting, 15, See also Across-the-dock sorting methods batched customer orders, 388 cartons, 311–312, 326, 403–412, 647–681, See also Carton sorting methods hanging garments, 282–288, 641–647, See also Garment-on-hanger (GOH) sorting methods small items or flat wear, 630–638, See also Small-item and flat wear across-thedock sorting methods Sort-link, 416, 518, 535–536 Space utilization efficiency ratio, 105–106 Specially designed or engineered pallet boards, 490–491, 496 Special or promotional pick philosophy, 281 Speed measurement, 80

713 Spiral-chute (decombe) truck, 413–414 Spiral belt, 671 Split-case order picking, 111 Spring-loaded cross-through switch, 190 Spring or automatic straight switch, 187–188 Spring switch, 186 Sprinkler system, 73, 315, 486–487 Stabilization pallet racks, 525 Stabilizing casters, 357–358 Stacking frames, 524 Staggered dock, 456–457, 591–592 Stairs, 403 Stand-up rider counterbalanced forklift truck, 506, 688–689 Stand-up rider straddle forklift truck, 510–511 Standard pallet racks, 338–339, 524–527 Standard rack openings pallet racks, 534–535 Standard shelf carton-pick method, 339 Standard template and layout board drawing, 84 Standards, order-fulfillment and across-the-dock performance, 19–21 Static rail storage and pick systems, 242–260 Static shelving, 114–116 Steaming hanging garments, 162–163 Stepladder and cart, 274 Stepstool, 275 Stile, 398 Stitch order-picker routing patterns, 277, 364 Stock-keeping unit (SKU) flows, See Piece flows Stock out, 13, 31 Stop and go lights, 466, 604 Stops, 187, 193 adjustable end, 193 fixed end, 193 manually-adjustable, 194 swing-rail, 193–194 Storage, 1, 13 Storage and pick methods, garments-on-hangers, 242–277, See also Garment-onhanger (GOH) storage and pick methods Storage equipment utilization ratio, 106 Storage or picking media, 113–118 carton flow racks, 114–116 pallet flow lanes, 117 picking modules, 117–118 static shelving, 114–116 Storage rack design, 315–316 Store dump-sorting method, 633 Straddle truck, 275 counterbalanced straddle walkie/stacker forklift truck, 504–505 facility design clearances, 487 Strad-O-Lift, 471–472 Straight in-and-out method, 360


714


Straight-in entrance enclosed dock, 456, 591 Stretch wrap, 501–502 String, 501 Stringer pallet, 493–494 Supply-chain logistics strategy, 563–565 Sweep replenishment, 430–431 Swing-rail stops, 193–194 Switches, 186–193 automatic or spring-loaded cross-through, 190 45º lever or manual, 188 hinged knife elevator or fire-door, 190–191 manual, 186 overhead door, 192–193 parallel-stacking, 191–192 removable-rail section, 190 spring, 186 spring or automatic straight, 187–188 three-way master, 189 two-way master, 189

T Tachometer, 80 Tailgate lift, 463 Take-it or leave-it pallet boards, 490, 496 Tape, 299–300, 501 T-car, 522–523 Temporary-storage sorting method, 404 Terminal cross-docking, 573–574, 577 Testing, 78–81 Testing and acceptance section, 62 Three-way master switch, 189 Throwaway pallet boards, 490 “Ti and hi,” pallet order-fulfillment operations, 485, 500–501 Tier rack or stacking frames pallet racks, 524 Tile-on-plywood aisle surface, 245 Tilt slat, 663–664 Tilt-tray sorter, 126–129, 661–663 Time-study employee productivity measurement standard, 108 Time system, 88 Totes, 120 Towing AGV, 553 Tow line, 554–556 Tow-line cart, 556–557 Tow tractors or tugs carton order-picking methods, 371–373 electric walkie tugger, 343 nonconveyable carton sorting, 424–425, 677–678 tow-line cart, 556–557 tow line, 554–556 Towveyor, 557–561

Training, operational and maintenance personnel, 81 Transaction verification and inventory tracking, 428–430 Transport methods or systems, 13 aisle-guidance systems, 375–379 AGVs, See Automatic guided vehicles automated storage and retrieval system, See ASRS vehicles carousels, See Carousel systems carton, See Carton transport vehicles or systems conveyors, See Conveyor systems end-of-aisle slowdown devices, 379–381 forklifts, See Forklift trucks hand trucks or dollies, See Hand-trucks, carts, or dollies hanging garment, See Garment-on-hanger (GOH) transport vehicles or systems high-rise or HROS, See High-rise orderselector (HROS) trucks non-powered carts or trucks, 340–343 overhead trolleys, See Overhead trolley systems pallet trucks, See Pallet trucks and loadhandling devices productivity improvement issues, 29–30 trolleys, See Trolleys trolleys, programmable, 202–206, See also Programmable trolley yard control, 10–11 tuggers with cart-trains, See Tow tractors or tugs Trolleyless hanging-garment sorting method, 287–289, 647 Trolleys AS/RS trolley storage and pick method, 250–251 identification for GOH dynamic-rail pick position method, 262–264 in-feed methods, 207–209, 264–265 load-bar antislide pins, 235 overhead GOH transport, See Overhead trolley systems powered systems for hanging garments, See Garment-on-hanger (GOH) transport vehicles or systems, powered programmable, 202–206, See also Programmable trolley run-out section, 210–211 Truck access, 449–450, 581–583 Truck unloading and loading, See Across-thedock operations; Loading methods; Unloading methods


Index

715

Truck yard control, 10–11, 323, 324, 446–447 Truck yard design access to docks, 449–450, 581–583 delivery-truck canopy, 585 dock locations, 447–450, See also Dock design combination docks, 447–448 scattered, 448–449 separated receiving, 448 truck access, 449–450 holding area, 450–451 landing-gear pad, 451, 584 loading and maneuvering areas, 452–453 other important features, 451, 587 security, 451–452, 582, 585 temporary holding area, 583–584 traffic-flow patterns, 450, 583 truck dimensions, 453, 586–587 unloading and maneuvering area, 585–586 Tubular rail components and paths, 183–186 support structure, 194–195 switches and stops, 186–193 Turning radius, 354 Two-deep forklift truck, 511 Two-way flow, 320–321, 443 Two-way master switch, 189 Two-way pallet boards, 495

U “U” customer-order flow pattern, 320, 443–444 Underground facility, 313 Uninterruptible power supply (UPS), 146, 307, 439, 551 Units of measure, 99 Unloading and loading ratios, 23, 308–309, 538 Unloading methods, 11, 324, 466–479, 605, See also Across-the-dock operations; Dock design automatic systems, 471–472 pallet-handling device, 471 pallet flow device, 472 Strad-O-Lift, 471–472 carton, See Carton unloading and receiving hanging garments and garments in boxes, 156–159, 605–607, 642–643 employee walk, 157, 605 extendible hanging-garment trolley boom, 159, 607 garment trolley cart, 157–159, 606–607 low-lift pallet, 467 pallet truck, 606 roller pallet, 467

manual methods, 156–159, 605–607, 466–468 mechanical methods, 469–471, 608–626 conveyor systems, 610–626, See also Extendible or retractable truck unloading conveyor systems forklift truck, 470, 608–609 pallet-flow device, 627 pallet gripper or claw, 469 pallet-handling device, 626–627 pallet trucks, 607–608 powered pallet truck, 469 pallet unloading methods, 476–479 container, 478–479 floor-stacked, 477 forklift truck, 608–609 pallet-board, 477 pallet-flow device, 627 pallet-handling device, 626–627 pallet trucks, 607–608 roller pallet, 467 slip-sheet, 477–478, See also Slip-sheets railcar, 472–476, See also Railcar docks and unloading operations separating shipping cartons into units, 674 Unloading conveyors, 652, See Extendible or retractable truck unloading conveyor systems “U” order-picker routing patterns, 277, 362–363 Unsorted labeled pieces, 574 Unsorted unlabeled pieces, 574 Utility system design criteria, 60 drawings, 59

V Vehicle anticollision methods, 551–552 Vehicles, See Forklift trucks; Pallet trucks and load-handling devices; Transport methods or systems; specific applications, types Vendor consignment piece distribution method, 572 Vendor labor force, 74–75 Vendor payment schedules, 63–64 Venture manager, 93 Vertical carousel, 270–272 Vertically stored dock leveler, 461, 600 Vertical product flow patterns, 153 Vertical (multilevel) transport systems, hanging garments, See Garment-on-hanger (GOH) transport systems, vertical (multilevel) Vertique, 421–422


716


Very flat floor, 315 Very-narrow-aisle (VNA) vehicles, 317, 382, 511–518 Vestibule flush dock, 454–455, 589 Voice systems, 121–123, 368, 543 Voltage, 350

W Walkie vehicles pallet trucks, 343, 677 double pallet, 346–348 end-rider, 346–348 rider, 677 stacker forklift truck, 504–506 tow tractor, 343, 372 Warehouse management system (WMS), 12, 112 piece and information flows, 2 replenishment, 429–431 Waterfall sorting method, 633 Weighing methods, 17, 139, 570–571, 638–639

W-flow pattern, 321, 444 Wheel base, 353, 508–509, 688 Wheel lift, 464, 601–602 Wheels or casters, 345, 356 Wide-aisle (WA) vehicles, 117, 504–509, 686–689 Wing pallet board, 495 Wire aisle-guidance system, 377–378 Work day smoothing, 26, 97 Work incentive program, 34, 97–98

Y Yard control, See Truck yard control Yard design, See Dock design; Truck yard design

Z Z-frame cart, 170–171 “Z” order-picker routing pattern, 277, 363

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