The Design Guidelines Collaborative Framework: A Design for Multi-X Method for Product Development

The Design Guidelines Collaborative Framework Stefano Filippi · Ilaria Cristofolini The Design Guidelines Collaborat...

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The Design Guidelines Collaborative Framework

Stefano Filippi · Ilaria Cristofolini

The Design Guidelines Collaborative Framework A Design for Multi-X Method for Product Development

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Prof. Stefano Filippi University of Udine DIEGM Department Viale delle Scienze, 208 33100 Udine Italy [email protected]

Dr. Ilaria Cristofolini University of Trento DIMS Department Via Mesiano, 77 38050 Trento Italy [email protected]

ISBN 978-1-84882-771-4 e-ISBN 978-1-84882-772-1 DOI 10.1007/978-1-978-1-84882-772-1 Springer Dordrecht Heidelberg London New York British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Control Number: 2009940605 c Springer-Verlag London Limited 2010 Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms of licenses issued by the Copyright Licensing Agency. Enquiries concerning reproduction outside those terms should be sent to the publishers. The use of registered names, trademarks, etc., in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant laws and regulations and therefore free for general use. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. Cover design: eStudioCalamar, Figueres/Berlin Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

Preface

In the industrial design and engineering field, product lifecycle, product development, design process, Design for X, etc., constitute only a small sample of terms related to the generation of quality products. Current best practices cover widely different knowledge domains in trying to exploit them to the best advantage, individually and in synergy. Moreover, standards become increasingly more helpful in interfacing these domains and they are enlarging their coverage by going beyond the single domain boundary to connect closely different aspects of the product lifecycle. The degree of complexity of each domain makes impossible the presence of multipurpose competencies and skills; there is almost always the need for interacting and integrating people and resources in some effective way. These are the best conditions for the birth of theories, methodologies, models, architectures, systems, procedures, algorithms, software packages, etc., in order to help in some way the synergic work of all the actors involved in the product lifecycle. This brief introduction contains all the main themes developed in this book, starting from the analysis of the design and engineering scenarios to arrive at the development and adoption of a framework for product design and process reconfiguration. In fact, the core consists of the description of the Design GuideLines Collaborative Framework (DGLs-CF), a methodological approach that generates a collaborative environment where designers, manufacturers and inspectors can find the right and effective meeting point to share their knowledge and skills in order to contribute to the optimum generation of quality products. The DGLs-CF integrates several tools to achieve this goal: a method to evaluate the compatibility between the products and the processes adopted to manufacture and verify them, a language and a data structure to formalise the knowledge about products, processes and so on, some procedures to infer new information from the gathered knowledge and, finally, a usable way for information sharing among the different domains. As a result, the DGLs-CF gives the users a sort of to-do list for modifying the product model and/or the physical representation of it through the whole development process, in order to achieve the best compromise between product functionalities and the characteristics of the available technologies.

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Preface

The first chapter deals with the need to clarify the concepts and terms related to the product lifecycle, regarding the context where this project develops. The concepts like the product lifecycle itself, the engineering design process, the Design for X, Concurrent Engineering, the Standards, the design methods, etc., are related to each other like some sort of Chinese boxes. The state of the art of each of them is described and a wide range of references is added to help in detailing further understanding of the topics. The second chapter starts to describe the DGLs-CF by introducing the previous work related to it. The project started around the year 2002 and up to now four releases of design guidelines have been developed. The chapter describes in detail this course for many reasons. First, the DGLs-CF is so complex and articulated that there was the need for this sort of background information to get all the details of it at best. Second, the DGLs-CF development trail put to evidence time by time different aspects, sometimes unexpected, of the product lifecycle management; this has been really valuable in targeting and tuning the authors’ competencies and skills and, hopefully, could be of help to the reader for the same reasons. Third, the examples of the application of the different releases in the field could help in gradually understanding the adoption of this sort of tool in the everyday work of designers, manufacturers and inspectors. The third chapter describes the DGLs-CF in detail. A simple formalism, the IDEF0 — Integration DEFinition — diagrams, has been used to keep track of the development and adoption of the framework. This choice allowed one to describe in a really clear way all the activities required by the DGLs-CF, the interfaces between them in terms of input, output, controls — the standards, other guidelines and, in general, any references used in performing the activities — and, finally, mechanisms — the resources expressed in terms of humans, procedures, software packages, etc. The fourth chapter describes the experiences in applying the DGLs-CF in the field. Some industrial products, together with the available technologies in their design, manufacturing and verification domains, have been evaluated using the DGLs-CF. The redesign/reconfiguration packages, the lists of actions to perform on the product coming as a result from the DGLs-CF elaboration, have been considered and applied. The fifth chapter acts as the final discussion about the project. Now the DGLsCF presents a good level of maturity concerning the methodological aspects and the most of the procedures used in the activities have been detailed as well; nevertheless, much work still remains to be done, especially on implementation and usability issues. This chapter summarises the hints coming from the different releases of the design guidelines and describes if and how the DGLs-CF matches them. These considerations lead to a list of suggestions for future work.

Acknowledgments

The authors would like to thank Dr. Barbara Motyl for her contribution during the development of the case studies described in Chap. 4. Anthony Doyle and Claire Protherough from Springer are also gratefully acknowledged: their precious help and kind patience contributed to the overall production of the book. Thanks are also due to Nadja Kroke and her colleagues from Le-tex: they did an excellent job in the detailed task of typesetting the book. Stefano Filippi would like to thank Prof. Umberto Cugini, who contributed definitely to his profession since the beginning, and Prof. Camillo Bandera, who has been collaborating with him during these last years. Ilaria Cristofolini would like to thank Prof. Giorgio Wolf, who introduced her into the world of engineering design, and Prof. Alberto Molinari, her precious point of reference since the beginning of her studies. She also thanks Marco, Stefano and Elena for their continuous encouragement, patience and smiles.

Contents

1 State of the Art in the Field ............................................................................... 1 1.1 The Product Lifecycle.................................................................................. 2 1.2 The Engineering Design Process ................................................................. 3 1.2.1 Definitions and Concepts ..................................................................... 3 1.2.2 The Problem Solving Process............................................................... 5 1.3 Concurrent Engineering............................................................................... 7 1.4 Standards ..................................................................................................... 8 1.4.1 Fundamentals ....................................................................................... 8 1.4.2 Highlights on the ISO GPS Features.................................................. 10 1.5 Design Methods......................................................................................... 13 1.6 DfX Methods ............................................................................................. 15 1.6.1 Overview ............................................................................................ 15 1.6.2 Design for Manufacturing — DfM .................................................... 15 1.6.3 Design for Assembly — DfA............................................................. 18 1.6.4 Design for Test and Maintenance — DfTM — and Design for Verification — DfV .................................................................................... 19 1.6.5 Design for Reliability — DfR ............................................................ 20 1.6.6 Design for Environment — DfE ........................................................ 21 Summary.......................................................................................................... 22 References ....................................................................................................... 23 2 The DGLs-CF — Introduction and Background .......................................... 31 2.1 Overview of the History of the DGLs........................................................ 32 2.2 First Release of the DGLs. The Beginning................................................ 34 2.2.1 Conceptual Diagram........................................................................... 34 2.2.2 Knowledge Matrix ............................................................................. 35 2.2.3 Case Study.......................................................................................... 37 2.2.4 Discussion .......................................................................................... 40 2.3 Second Release of the DGLs. Improvements and the Synergy with the ISO GPS ............................................................................................ 41 2.3.1 Conceptual Diagram........................................................................... 41 2.3.2 Knowledge Matrix ............................................................................. 42

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Contents

2.3.3 Case Study..........................................................................................44 2.3.4 Discussion ..........................................................................................45 2.4 Third Release of the DGLs. Thinking Big .................................................47 2.4.1 Conceptual Diagram...........................................................................47 2.4.2 Knowledge Matrix..............................................................................49 2.4.3 Roadmap for the Adoption of the DGLs ............................................49 2.4.4 Case Study..........................................................................................49 2.4.5 Discussion ..........................................................................................60 Summary..........................................................................................................63 References........................................................................................................64 3 Detailed Description of the DGLs-CF.............................................................65 3.1 Conceptual Diagram ..................................................................................66 3.2 IDEF0 Fundamentals .................................................................................66 3.3 Purpose, Viewpoint and the Node A-0 of the DGLs-CF IDEF0 Diagram.67 3.3.1 Purpose and Viewpoint ......................................................................68 3.3.2 The Node A-0 — TOP Level .............................................................68 3.4 The Node A0. The Main Phases and the Modules.....................................71 3.4.1 Overview of the Three Main Phases...................................................71 3.4.2 Overview of the Seven Modules ........................................................72 3.5 The Node A1. First Setup ..........................................................................74 3.5.1 Activities ............................................................................................76 3.5.2 Modules of Interest Here ....................................................................77 3.6 The Node A2. Technological Configuration..............................................91 3.6.1 Activities ............................................................................................91 3.6.2 Modules of Interest Here ....................................................................92 3.7 The Node A3. Redesign/Reconfiguration Package Generation .................93 3.7.1 Activities ............................................................................................95 3.7.2 Modules of Interest Here ....................................................................95 3.8 Discussion..................................................................................................99 Summary..........................................................................................................99 References......................................................................................................100 4 Adopting the DGLs-CF in the Field..............................................................101 4.1 Rapid Prototyping — RP — Technologies..............................................102 4.2 Coordinate Measuring Machines — CMMs ............................................102 4.3 First Case Study. A Mechanical Bracket Built Using FDM ....................104 4.3.1 FDM Fundamentals..........................................................................105 4.3.2 First Setup ........................................................................................106 4.3.3 Technological Configuration............................................................119 4.3.4 Redesign/Reconfiguration Package Generation ...............................120 4.4 Second Case Study. A Mould Insert Built Using SLA ............................125 4.4.1 SLA Fundamentals ...........................................................................126 4.4.2 First Setup ........................................................................................128 4.4.3 Technological Configuration............................................................142

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4.4.4 Redesign/Reconfiguration Package Generation ............................... 144 4.5 Third Case Study. An Angle-Shaped Connector Built Using SLS .......... 148 4.5.1 SLS Fundamentals ........................................................................... 149 4.5.2 First Setup ........................................................................................ 150 4.5.3 Technological Configuration............................................................ 163 4.5.4 Redesign/Reconfiguration Package Generation ............................... 164 Summary........................................................................................................ 169 References ..................................................................................................... 169 5 Discussion and Hints for Future Work......................................................... 173 5.1 Conceptual Diagram and Knowledge Organisation................................. 173 5.2 Knowledge Description and ISO GPS Adoption..................................... 174 5.2.1 Product Features and Technological Characteristics........................ 174 5.2.2 Rules, Compatibility Expressions and Actions ................................ 175 5.3 Costs ........................................................................................................ 176 5.4 Implementation/Automatisms.................................................................. 176 5.5 DGLs-CF Adoption Process .................................................................... 177 5.5.1 Activity Timing and Concurrencies ................................................. 177 5.5.2 DGLs-CF Usability .......................................................................... 179 Summary........................................................................................................ 181 References ..................................................................................................... 181 Appendix. Generation of Some Meaningful Compatibility Expressions...... 183

Abbreviations

ABS API ASME CAD CAD/CAM CE CMM D4V DBMS DfA DfE DfM DfMA DfR DfTM DfV DfX DGLs DGLs-CF DMLS DOE DPs DSM EDM FDM FEM FMEA FRs GPS ICOM IDEF

Acrylonitrile Butadiene Styrene Application Programming Interface American Society of Mechanical Engineers Computer Aided Design Computer Aided Design/Computer Aided Manufacturing Concurrent Engineering Coordinate Measuring Machine Design for Verification Data Base Management Systems Design for Assembly Design for Environment Design for Manufacturing Design for Manufacturing and Assembly Design for Reliability Design for Test and Maintenance Design for Verification Design for X Design Guidelines Design Guidelines Collaborative Framework Direct Metal Laser Sintering Design Of Experiments Design Parameters Design Structure Matrix Electrical Discharge Machining Fused Deposition Modeling Finite Element Method Failure Modes and Effects Analysis Functional Requirements Geometrical Product Specifications Inputs, Controls, Outputs, Mechanisms Integration DEFinition

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Abbreviations

ISO TC ISO ISO/TR MET MTBF NC OpenADE PERT RP SADT SLA SLS STL TRIZ UML UV

International Organization for Standardization Technical Committee International Organization for Standardization International Organization for Standardization Technical Report Materials, Energy, Toxicity Mean Time Between Failure Numerical Control Open Assembly Design Environment Project Evaluation and Review Technique Rapid Prototyping Structured Analysis and Design Technique Stereolithography Selective Laser Sintering Stereolithography file format Teoriya Resheniya Izobretatelskikh Zadatch (Theory of Inventive Problem Solving) Unified Modelling Language UltraViolet

1 State of the Art in the Field

This chapter describes the scenario where the DGLs-CF project takes place. Fig. 1.1 shows schematically the main items involved in product development and acts as an index for the present chapter, pointing directly to the description paragraphs.

Product lifecycle (Par. 1.1) Engineering design process (Par. 1.2) Concurrent Standards Engineering (Par. 1.4) (Par. 1.3) Design methods (Par. 1.5) and DfX methods (Par. 1.6)

Fig. 1.1 Items of interest in the product development involved here

Specifically, the figure highlights the role of the engineering design process inside the product lifecycle and its co-existence with standard-related issues in a collaborative environment. All the pieces of information needed for an effective engineering design process must be formalised, elaborated and made usable, and this can be performed by many different design methods and tools, which establish links between the engineering design process and the other phases of the product lifecycle. The term Design for X — DfX — means here the way to place, in terms of time and space, the design methods inside the engineering design process; in other words, a design method becomes a DfX method when a goal and a placement are associated with it.

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Inside this scenario, the DGLs-CF can be considered a DfX method and this is why this chapter is ultimately focused on describing the state of the art in the field of DfX methods. Many authors are considered here, whose work appeared interesting during the development of the DGLs-CF. Some of them are cited explicitly; however, the list does not claim to be exhaustive because of the extent of this research field.

1.1 The Product Lifecycle The product lifecycle may be described by different phases that could be grouped into four areas: product development, production and delivery, use, and end of life (Ullman 2002a). These areas are briefly summarised here, focusing on the need for considering them during the engineering design process to improve the quality of the products, the efficiency of the processes, and to minimise the related costs. Product Development It traditionally concerns what is generally named engineering design process, which is detailed in the next paragraph. Only some particular aspects are mentioned here, to highlight the many different items that could affect this phase. Product development is fundamental in determining the success of a product, and the decisions made in this phase affect profoundly both the product performance (Osteras et al. 2006) and the whole product lifecycle performance (Borg et al. 2000). In trying to define the efficiency and effectiveness of the product development, some concepts were explored by Duffy and O’Donnell (1997) to establish correct metrics to obtain performance values. Nevertheless, it is difficult to define the performance of the product development in a general way, because many different items must be considered and properly modelled, and their relationships must be analysed (Yassine et al. 2003). For example, issues that seem really important in the development of family of products (Alizon et al. 2007; Zhang et al. 2006) may be less decisive when developing flexible systems (Olewnik and Lewis 2006). This implies that sometimes the most reliable models for product development are not general but they are tailored to the development of specific classes of products. Interesting model-based methods to organise the different tasks in product development were proposed by Eppinger et al. (1994). Production and Delivery They concern the phases before the use of the product, from manufacturing to installation. Manufacturing processes actually generate the product and they may profoundly affect its characteristics, so that materials, processes and technologies must be defined both considering product functionality and process efficiency (Chan et al. 1998). Often, in fact, different alternatives must be compared in order to improve manufacturability (Gupta and Nau 1995; Xue 1997), never neglecting the problem of the related costs (Grewal and Choi 2005; Sharma and Gao 2007; Shehab and Abdalla 2001). Alike the manufacturing processes, assembly also determines product characteristics and costs and again it

1.2 The Engineering Design Process

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must be approached systematically (Mantripragada and Whitney 1998), also defining rules for the generation of the assembly sequence (Lin et al. 2007). Techniques called Design for Manufacturing — DfM — and Design for Assembly — DfA — were developed and, because of their importance here, they will be detailed in a specific paragraph. Use The use of a product is, or should be, what mainly determines its characteristics, so that it is pointless underlining that this phase must be considered during the engineering design process (Pahl et al. 2007). Moreover, usability issues should be accounted too during the first stage of the product lifecycle (Nielsen 1993). It must also be considered that a product must guarantee some reliability and thus it may require some maintenance. Some research has been focused on developing reliability predictive models and on assessing reliability tests (Crowe and Feinberg 2001), particularly in the field of electric and electronic engineering (Mehlitz and Penix 2003). Nevertheless, the problems related to reliability now start to be considered in relationship to the whole product lifecycle (Yang 2007). Again, specific techniques have been developed: Design for Reliability — DfR — and Design for Test and Maintenance — DfTM. They will be described later, together with DfM and DfA. End of Life The end of life of a product implies that it is retired, disassembled, reused and/or recycled. The need for considering product disassembly, as well as the possibility of reuse, often implies some modifications in the product characteristics. All these issues are becoming really important, considering the increasing attention of society to the environment. The problem was first approached in terms of recycling and remanufacturing (Hundal 2000), then by developing the wider concept of eco-design (Houe and Grabot 2007). Again, specific Design for Environment — DfE — techniques were developed, also considering the evolving specific legislation.


1.2.1 Definitions and Concepts Focusing on the engineering design process and collecting the main characteristics in a basic definition, it may be described as a thoughtful process based on the laws and insights of science which generates the prerequisites for the realisation of products, processes, or systems, with specified constraints (Cross 2000; Dym and Little 2003; Pahl et al. 2007). As it is easy to imagine, the argument is extremely wide; an exhaustive survey on engineering design research was given by Horvàth (2004); here only a brief description of the aspects of interest is given.

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In the literature there are several models to describe the engineering design process. These models have been classified as descriptive models, prescriptive models and integrative models (Birmingham et al. 1997; Cross 2000; Dym and Little 2003). Descriptive models, more or less detailed, describe only the sequence of the activities occurring in the design process, while prescriptive models propose algorithmic procedures to provide design methodologies. Integrative models focus on the iterative nature of the engineering design process, where the understanding of the problem and the development of the solution are achieved together. In order to define other effective models to describe the engineering design process, many authors focused attention on its different aspects, thus developing sequential design models, cyclical models, and, later, hybrid ones (Dwarakanath and Blessing 1996; Haik 2003; Hubka and Eder 1992; Otto and Wood 2000; Pahl et al. 2007; Pugh 1990; Reymen et al. 2006; Ullman 2002a; Ulrich and Eppinger 2003). Many studies have been focused on an empirical validation of these models (Baumgartner and Blessing 2001; Pahl et al. 1999), and some of them found that the engineering design models are applied rarely as prescribed (Maffin 1998). The engineering design process may also be described using process-based, task-based, and parameter-based models. Process-based models represent a flexible approach, providing a good top-level view of the design process and highlighting clearly the design goals. On the other hand, they often appear just philosophical and difficult to put into practice. Conversely, task-based models may precisely represent a specific design process, but they are not versatile. For each task, the specific goals must be defined in terms of optimisation of functions, minimisation of costs, ergonomic criteria, etc., while the identification of the critical goals is particularly important, especially in case of conflicts. Finally, parameter-based models tend to integrate the advantages of the previous ones, collecting the design tasks characterised by their input parameters. In this way, some flexibility in a task-based model is achieved; the limitation is that the parameters are often unknown at the time of the model development. The engineering design process may be further specified to highlight and differentiate better the activities that implement it. First of all, the origin; in case of a marketing analysis of the customer requirements rather than a specific customer order, the development will be very different. The same happens if an original design must be developed instead of an adaptive design or a variant one, for batch production or mass production, etc. (Eckert et al. 2004; Ullman 2002b). To characterise the engineering design process, the different branches involved — mechanical engineering, chemical engineering, transport engineering, software development, and so on — must be separated, as well as the complexity of the elements to be designed, being they plants, machines, assemblies or parts. The analysis of concepts and the development of conceptual design may prove to be helpful in organising and sharing this information (Alisantoso et al. 2005; Cartwright 1997; Kurakawa 2004). A lot of representation techniques were developed in order to structure the knowledge and enhance the implementation of the models describing the engineering design process. Some of them are PERT — Project Evaluation and


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Review Technique (Meredith et al. 1985; Wiest and Levy 1977), Signal flow graphs (Eppinger et al. 1997; Isaksson et al. 2000), SADT/IDEF0 — Structured Analysis and Design Technique/Integration DEFinition 0 (Ross 1977; Qureshi et al. 1997), DSM — Design Structure Matrix (Steward 1981; Gebala and Eppinger 1991; Smith and Eppinger 1997), Petri Nets (Diaz and Azema 1985), SemanticNet Models (Blanchard and Fabrycy 1981) and Process Specification Languages (Qureshi et al. 1997).

1.2.2 The Problem Solving Process Now that some aspects concerning the models used to describe the engineering design process have been mentioned, attention may be focused on the main activity of the engineering design process, problem solving. To design means solving problems. Engineering design problems may be very different from each other; they have in common just a goal, some constraints and some criteria, which lead the definition of successful solutions. Engineering design problems are generally ill-structured and open-ended; there is no definitive formulation of the problem and any formulation of it may embody inconsistencies. Moreover, formulations of the problem are solution-dependent and the specified constraints are often conflicting with each other (Eide 2001; Howell 2001; Lumsdaine et al. 1999). Anyway, some basic actions in problem solving may be identified (Ullman 2002a), as shown in Fig. 1.2.

Fig. 1.2 The basic actions of problem solving

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First, the problem to solve is recognised and a plan to solve it is established. The development of requirements and the proposal of existing solutions for similar problems help with understanding it. Alternative solutions are generated and evaluated, in terms of compliance to the requirements, and compared with each other. Decisions are made on acceptable solutions. It is interesting to underline that Fig. 1.2 shows the basic, linear process, but these actions are not necessarily taken consequentially, due to the iterative nature of the engineering design process. Throughout this process, it is very important that the results are communicated and discussed. As reported in Ullman’s work (Ullman 2002a), problem solving, i.e. making decisions, necessarily means managing a lot of different pieces of information distributed on different levels, and relating, interpreting and evaluating them. At the bottom level, corresponding to the simplest form of information, there are raw data, which means parameters or values for variables. Models, a form of information of increased value, are derived by the development of relationships among these data, and placed in the next level. Models may be just qualitative or developed by means of equations or empirical relationships, but in any case they are static. If the behaviour of the models is analysed and interpreted, then knowledge is achieved and this corresponds to the third level content. On the basis of knowledge, decisions can be made by judgment, corresponding to the highest level of information value. Decision analysis may be determined by different criteria, which can be considered to establish an integrated approach as by Belton and Stewart (2002), Bennett (1985) and Olewnik and Lewis (2005, 2006). Different types of knowledge are included in the chunks of information elaborated to make decisions: general knowledge, basic, not regarding a specific domain; domain specific knowledge, related to the form and function of specific objects or classes of objects; and procedural knowledge, based on general knowledge and/or on domain specific knowledge and leading to making decisions. Again, many methodologies and systems have been developed to formalise, elaborate and make knowledge useful and usable. They are based on different techniques and mathematical tools and may be focused on general or specific problems. Some researchers focused their attention on new approaches to manage knowledge in the engineering design process, for example by defining a method where both the product and the process models are modified synchronously, coupling relationships between them (Huang and Gu 2006). Others defined methods to express the knowledge in the design process by means of the flexible knowledge concept (Koh et al. 2005), while some proposed systems for an integrated engineering data management (Burr et al. 2005), or information systems to provide new design approaches (Houssin et al. 2006). The knowledge management related to specific manufacturing technologies was also studied, as in the case of hot forging (Kulon et al. 2006; Xuewen et al. 2005), die design (Tor et al. 2005), arc welding processes (Wang et al. 2005), injection moulding (Shehab and Abdalla 2002), powder metallurgy (Smith 2003), etc.

1.3 Concurrent Engineering

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1.3 Concurrent Engineering The description of the engineering design process shows that several elements could heavily influence product functionalities and performance. Designers must define the characteristics of a product considering the different phases of its lifecycle, in order to generate a quality product, well suitable for the manufacturing process, easy to measure and assemble, etc. Thus, the contribution of the knowledge coming from marketing managers, manufacturers, inspectors, materials specialists, assembly managers, etc., is needed at the design stage, because designers’ decisions will affect the whole product lifecycle. Therefore, it is necessary to establish relationships among all these people from the beginning of the engineering design process, in order to share their knowledge in a collaborative environment. In the last few decades, the increasing complexity and variety of products, the many available technologies, and the specific characteristics of the market has led to profound changes in the structure of the design process. The classic Over-thewall process model cited in Ullman (2002a), also known as Waterfall design model in software engineering (Royce 1970), had a linear way, and the different competencies were kept separate. The designers received the communication of the perceived market requirements from the marketing people; after that, they developed the specifications of the product interpreting the request and communicated the result of their work to the production in terms of drawings, bills of materials, verification and assembly instructions, and so on. The information proceeded one-way, thrown over-the-wall, separating marketing from designers, designers from manufacturers, etc., as shown in Fig. 1.3. In this process model, the designer’s interpretation of the market requirements could be insufficient, and/or the choice of materials and technologies inadequate, in terms of availability or costs, thus resulting in poor quality products. This risk increased with the complexity and variety of market requirements, products, technologies, environments, etc., so that in the late 1970s Simultaneous Engineering concepts began to develop. They emphasised the need for considering the manufacturing process simultaneously with the development of the product, so that the communication proceeded from design to production and vice versa. Later on, this concept broadened, becoming Concurrent Engineering — CE, thus implying that an effective product development could be obtained only if the designers and the members owning the knowledge of the different phases of the product lifecycle interact, performing their activities together. In this way, the problems of the Over-the-wall design method became limited and the available resources were exploited as well as possible. The key points of CE may thus be identified in focusing on the whole product lifecycle, establishing engineering design teams, and developing and communicating information about the product and the related processes. The basic principles of Design Coordination may be found in Duffy et al. (1993, 1999), in a

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framework where different models concerning product development, plans, resources, tasks, etc., are used, and their interactions studied.

Fig. 1.3 The Over-the-wall design method

The link between CE and product lifecycle was studied focusing on different aspects; for example, Fleischer and Liker (1997) evaluated the effectiveness of CE in integrating product development across the organisation, while Seif (1998) defined some problem-solution schemes to optimise product design based on a CE approach. A collaborative environment also favours the evolution of the knowledge in the design teams (Wu and Duffy 2002), enhancing the development of systems for data integration (Kleiner et al. 2003) and knowledge sharing (Vergeest and Horváth 1999). Specifically, a CE approach was used to model products using multidisciplinary collaborative design (Liang and Guodong 2006), or to integrate product and process modelling (Nahm and Ishikawa 2004). Others analysed the problem of modelling dependencies in CE processes involving numerous tasks (Park and Cutkosky 1999), or evaluated the design alternatives in the collaborative development of products (Hung et al. 2007). Some other works developed specific systems for CE environments to support dynamic design reasoning (Chiang et al. 2006), or defining a working situation model, where the working situation, its characterising elements, and their relative concepts are defined and integrated (Houssin et al. 2006). Collaborative systems to approach the conceptual design of industrial systems (Veeke et al. 2006) or for selecting materials, processes, and apparatuses (Chan et al. 1998) were developed too.

1.4 Standards

1.4.1 Fundamentals All the phases of the product lifecycle should comply with standards, from those defining the rules for technical drawings to those regulating the recycling and

1.4 Standards

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reuse. In the last years of the past century, a technical committee was constituted, the ISO TC 213 — International Organization for Standardization Technical Committee 213 — to develop and harmonise standards in the scope of Geometrical Product Specifications — GPS. What was particularly interesting and new in the ISO TC 213 vision was the effort to consider and develop the standards as an “improved engineering tool”. In detail, this vision that summarises the goal of ISO TC 213 runs as follows: “This integrated GPS system for specification and verification of workpiece geometry is an improved engineering tool for product development and manufacturing. This GPS system is necessary, as companies are rapidly moving ahead with new technologies, new manufacturing processes, new materials and visionary products in an environment of international outsourcing” (ISO/TC 213 N355 Annex 1). Even if now the attention of the ISO GPS is focused on establishing links between the specification and verification phases, there is a will to consider the phase of manufacturing too, in the near future, to improve the efficiency and effectiveness of the whole process. This philosophy fits at best what has been described up to now, and it has been a basic item in the development of the DGLsCF, as explained in the next chapter. As described in the ISO Technical Report ISO/TR 14638 — GPS Masterplan, all ISO GPS standards are collected in the General GPS Matrix, consisting of four groups of standards: Fundamental GPS standards, Global GPS standards, General GPS standards and Complementary GPS standards (ISO/TR 14638:1995). Fundamental GPS standards establish the fundamental rules and procedures for the characterisation of products; Global GPS standards cover or influence several or all of the so-called chains of standards, described in the following; General GPS standards are the main body of GPS standards, establishing both rules for drawing indications/definitions and verifications principles for different types of geometrical characteristics. Finally, Complementary GPS standards establish complementary rules for specialised categories of features or elements. In the General GPS Matrix, standards are organised into chains of standards (Bennich 1994). Each chain comprehends all the standards related to the geometrical characteristics of a feature, from those dealing with the drawing indication of the product characteristics to those concerning the functional requirements of the measurement equipment used to verify them. Table 1.1 shows an extract of the General GPS Matrix, where each row represents a geometrical characteristic of a feature with the related chain of standards. The concept of chain of standards demonstrates well the linking of all the standards for the geometrical specification and verification of a feature. Features, in fact, define the product geometry and their characteristics are described in some Global GPS standards, mainly ISO 14660-1, ISO 14660-2, ISO 17450-1, and ISO 17450-2. The importance of the ISO GPS features in the scope of this research requires a specific paragraph as follows.

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Table 1.1 Extract from the General GPS Matrix

1.4.2 Highlights on the ISO GPS Features As described in ISO 14660-1, geometrical features exist in three worlds: the world of specification, the world of workpiece — physical world, and the world of inspection. The same feature can differ substantially in the three worlds; the manufacturing processes, environmental conditions and other aspects can affect the geometry of physical workpieces, so that they may become different from the nominal components specified at the design stage. Designers are conscious of this, and they must consider the manufacturing and environmental conditions when they dimension the component, to guarantee the product functionalities. To do this they use dimensional and geometrical tolerances. Thus, the physical workpiece must be measured to verify the conformity to the specified tolerances, and the verification process gives a true representation of the physical workpiece to be compared with the designed one. Coherently with the ISO TC 213 vision, ISO GPS standards aim at determining univocally the different representations of the geometrical features in the three worlds and at establishing relationships among them. The example shown in Fig. 1.4, where a simple cylinder is considered, can help with the comprehension of these concepts. In the world of specification, the cylinder is described by a nominal integral feature — its theoretically exact surface — and a nominal derived feature — its theoretically exact axis.

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Fig. 1.4 Example of relationships between geometrical features

In the world of workpiece — the physical world, the workpiece is represented by its real feature, a quasi-cylinder, different from the nominal one. In the world of inspection, the acquirement of a finite number of points from the real surface generates an approximated representation of the real feature, called extracted integral feature. A sort of axis of the real feature representation — an extracted derived feature — may be related to this approximated representation. The final step consists of associating the extracted integral feature with an integral feature of perfect form. This approach allows one to recognise univocally the features in the different worlds and to determine their relationships.

Fig. 1.5 Procedures and operations to establish biunique relationships among the features in the different worlds

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The biunique relationships among the features in the different worlds are ensured by the use of the same operations in the world of specification and in the world of inspection. The ISO/TS 17450-2 defines an operation as a “specific tool required to obtain features or values of characteristics, their nominal value and their limits”. Figure 1.5 shows this correspondence. For example, the operation “Partition” is used to identify bounded features, both in the nominal model and in the real workpiece. Figure 1.6 shows this concept graphically.

Fig. 1.6 Partition operation in the nominal model — specification, and in the real workpiece — verification

Now, if the same operations are recognisable in the specification and in the verification procedures, the correspondence called the duality principle is realised. The designers define the functional requirements taking into consideration that they must be verified; for this reason, they communicate precisely these requirements to the inspectors. In this way, the inspectors can measure exactly what the designers want, and how they want it to be measured. In this context, datums and datum systems are defined (ISO 5459:1981); they are the elements used to define clearly and measure the relative position and orientation of the features in the parts. The concept of feature of size is also introduced here because of its importance for the DGLs-CF project. ISO 14660-1 defines the feature of size as a “geometrical shape defined by a linear or angular dimension which is a size”, and note 1 clarifies “the features of size can be a cylinder, a sphere, two parallel opposite surfaces, a cone or a wedge”. Features of size are important because they are implicitly associated to dimensions so that they can be immediately related to the dimensional characteristics of parts. Therefore, features of size may characterise products both from the geometrical and the dimensional point of view. Nonetheless, it might be worthwhile to underline that the use of features of size in the standards ASME — American Society of Mechanical Engineers — dates quite far back in time — the Taylor principle dated 1901 is based on them, while their use was less common in ISO standards before the ISO GPS. Finally, the topological relationships among ISO GPS features are defined using situation features — “feature of type point, straight line, plane or helix which allow defining the location and/or the orientation of a feature” — and situation characteristics — “characteristics defining the relative location or

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orientation between two situation features” (ISO 14660-1:1999; ISO 146602:1999). This description of the ISO GPS features reports only the basic concepts, while many other important issues exist, such as the specification of the conventions on how to obtain an extracted feature from the real one, the way to associate the integral feature of perfect form to the extracted one, the problems related to the measurement procedures, the filtration of the acquired data, etc. Some of them are defined in other standards and will be recalled when necessary; some others are still objects of study. Even if this topic is gaining considerable interest, for now the main researchers working on it are those involved in the development of the standards selves. In particular, the work of Choley et al. (2007), Désenfant and Priel (2006), Dovmark (2001), Nielsen (2003, 2006) and Srinivasan (2001, 2008) may be of great help in understanding better the ISO GPS principles.

1.5 Design Methods Considering the increasing complexity of products, processes and systems, and in order to improve the effectiveness of the engineering design process, many design methods have been developed, focused on one or more specific problem solving activities. Some general characteristics of design methods may be pointed out; the description in the following reports those considered of interest in the DGLs-CF project. Regarding the main characteristics required to design methods, they must be helpful in determining optimum solutions, inciting creativity and understanding; they must be compatible with concepts and methods deriving from other disciplines; they must tend to exploit existing solutions; they must allow the electronic formalisation and elaboration of information; and, finally, they must provide an effective communication of the results. Although in accordance with the aforementioned characteristics, design methods may be very different from each other. They may consist in completely new rational procedures, adaptation of procedures deriving from other disciplines, or formalisations of informal ways of working; they may have different goals and be related to different stages of the engineering design process. As a broad classification, design methods may be divided into creative methods and rational methods. Creative methods, as one would expect, tend to stimulate creativity by freely sharing ideas coming from different backgrounds. Rational methods, those most commonly intended as design methods, tend to systematise the approach to the design, not necessarily restraining creativity. Some rational methods try to clarify objectives by identifying sub-objectives and relationships; others focus on establishing functions, on specifying performances, on determining characteristics to satisfy customer requirements, on generating and evaluating alternatives, on improving details, etc. (Cross 2000; Pahl et al. 2007).

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Many design methods have been developed, characterised by a different approach to the several aspects of the engineering design process; among them, some are particularly widespread and are briefly described hereafter. At the conceptual design stage of the engineering design process, the focus is on the general and essential aspects of the products and the approach must necessarily be abstract. This approach is called functional decomposition modelling. The overall function of the product is identified on the basis of the main requirements, and is expressed in terms of flow of energy, materials and information. The overall function can then be defined by sub-functions of lower complexity, again expressed in terms of flows, properly structured and related to each other. In this way, the problem is formulated to an abstract, general level, which allows identifying the optimum solutions far from the influence of conventional or predefined ideas (Cross 2000; Pahl et al. 2007; Sturges et al. 1993; Ullman 2002a). Functional decomposition modelling has also been studied, focusing on some particular aspects of design processes; among them, there are design reuse (Khadilkar and Stauffer 1996; Xu et al. 2006), redesign (Hirtz et al. 2002), and product family design (Zhang et al. 2006). Functions and sub-functions are controlled by parameters; they must be identified and put into relationship. These parameters represent all the factors on which the product and the processes depend and contribute defining the product/process characteristics in terms of geometry, materials properties, etc. Parameter management has also been approached by defining different models for the engineering design process, as a parameter-driven task-based model (Clarkson and Hamilton 2000), or a model for the refinement of the design parameters (Lee and Lee 2004). Many authors have studied the definition of parameters in the component modelling, for example in parallel with the development of CAD — Computer Aided Design — systems. Among them, Abdel-Malek et al. (1999), Hosaka (1992), McMahon and Browne (1998), Salomons et al. (1993) and Shah and Mäntylä (1995). The axiomatic design (Suh 1990, 1998, 1999, 2001, 2005) describes the design process by establishing relationships between the Functional Requirements — FRs — in the functional domain, and the Design Parameters — DPs — in the physical domain. FRs and DPs are mathematically represented by vectors, which are related through matrices. The whole theory develops axioms, corollaries and theorems to describe these relationships. The axiomatic design can also be combined with a creative theory named TRIZ (Kim and Cochrani 2000) or with methods such as Design for Six-Sigma (El-Haik 2005) and Design of Experiments (Engelhardt 2000). TRIZ (Altshuller 1988) is the Russian acronym for the Theory of Inventive Problem Solving (Teoriya Resheniya Izobretatelskikh Zadatch). This theory starts from the consideration that many engineering problems have already been solved, partially or totally, even if often in completely different contexts. Altshuller’s method is based on contradictions and inventive principles. Contradictions occur when the fulfilling of a requirement is disadvantageous to other requirements; TRIZ helps with finding the major contradictions and generates the ideas for

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overcoming them, using 40 inventive principles (Altshuller et al. 2005) derived from the analysis of more than 40,000 patents. Design for Six Sigma, also known as Robust Design or Taguchi method (Taguchi 1999, 2004), concerns one of the most important tasks in the engineering design process, the research of the optimal values to be associated with the parameters in order to optimise the whole product/process characteristics and performances (Park 1996; Phadke 1989; Ross 1996; Wu and Wu 2000). In fact, parameter values are often set without considering tolerances and noises, so that in the detail design phase tight tolerances must be specified to obtain the requested quality. Robustness strategies substantially define parameter values so that they result in less sensitivity to the causes of variation To obtain reliable and robust parameter values, experiments must be precisely planned and defined, as in the design method named Design of Experiments — DOE (Antony 2003; Barrentine 1999; Montgomery 2004; Roy 2001). DOE techniques define the control variables and how they must be collected and analysed to obtain the most reliable robust parameter values. These techniques may be applied to different aspects of the design processes, for example relating the robust design parameters to the customer satisfaction (Jain and Sobek 2006). Optimal value setting is generally considered in the step of detailed design, but interesting studies propose methods to evaluate robust parameter values already at the conceptual design phase (Chen et al. 1996).

1.6 DfX Methods

1.6.1 Overview As said at the beginning of this chapter, design methods become DfX methods when they are focused on particular aspects of the product lifecycle. The role of the DfX methods is schematically represented in Fig. 1.7. The information coming from the several phases of the product lifecycle is used by the DfX methods in the engineering design process. Several DfX methods have been developed, focusing on different phases of the product lifecycle. Some of them are particularly relevant in the DGLs-CF project, so they are detailed hereafter.

1.6.2 Design for Manufacturing — DfM Design for Manufacturing — DfM — defines the characteristics of a product to allow an efficient, high-quality manufacture. The goal also implies the

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minimisation of costs and times. In principle, many manufacturing processes may be chosen for any product, and each manufacturing process shows different characteristics which must be considered during the design (Gupta et al. 1997). DfM methods have been extensively studied by many authors; among them, some analysed DfM methods in their completeness (Andersen 2004; Bralla 1998; Geng 2004; Poli 2001; Shah and Wright 2000), while others focused particularly on specific aspects, such as, for example, the representation and modelling of the manufacturing knowledge (Kulon et al. 2006; La Trobe-Bateman and Wild 2003; Zhao and Shah 2004).

Fig. 1.7 Role of the DfX methods in the product lifecycle

DfM methods and tools may be very different, depending on what aspects of product development they focus on. The type of product, the small or large batch, the continuous or discrete manufacturing process, the kind and amount of related information, and many other issues determine this difference. If the focus is on the product, then shape and geometry constraints are predominantly evaluated, while if the focus is on the process, process complexity, reliability, and tools accessibility are considered. However, some common principles may be identified; for example, the maximisation of the use of standard components, tools and materials (while also considering new processes and materials), the minimisation of the geometrical complexity, loosing tolerances, etc. The methods and tools developed for DfM generally include an evaluation in terms of technological feasibility, and/or economic feasibility, and/or trade-off optimisation (Shah and Wright 2000). The different approaches for determining technological feasibility may be grouped into two classes: variant approaches and generative approaches. Briefly, variant approaches are based on past history, which means that historical data

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concerning production processes and product characteristics are grouped and organised, so that it is easy to find the closest matching production process for a new component (Hyde 1981; Maher et al. 1995). Generative approaches are based on first principles, concerning for example the geometry of the products or physical, kinematic and mechanic issues of the process. Generative approaches may be process-based if analytical models of manufacturing process are developed (Gupta et al. 1997), or feature-based when features are defined as types with which a set of feasible processes is associated (Zhao and Shah 2004). In determining economic feasibility, different models have been developed for estimating manufacturing costs; these models may be more or less specific for different manufacturing processes (Hundal 1993). The cost of a new component can be evaluated in comparison with that of a similar component present in a database, and then adjusted considering materials, batch size, geometric complexity, manufacturing processes, and so on (Grewal and Choi 2005). Otherwise, specific manufacturing processes with known costs can be targeted, so that the cost estimation can be very accurate but less flexible (Chang et al. 1999). Domain independent analyses were also proposed by Zhao and Shah (2002). Finally, in determining an optimisation based on tradeoffs, design is not considered as fixed; design performance and manufacturing cost are studied in order to increase the value of the product. Multi-disciplinary optimisation (Capasso and Périaux 2005), Genetic algorithms (Goldberg 1989), Decision analysis (Figuera et al. 2005; Edwards and Von Winterfeldt 2007), and Quality Function Deployment (Akao 1990) are some of the methods within this area. In order to highlight the importance of the DfM methods in the context of the DGLs-CF project described in this book, it can be pointed out that the first release of the Design GuideLines — DGLs, the methodological approach to the generation of design guidelines that has been the starting point for the research, was developed as a DfM, focused on determining the technological feasibility of products with respect to Rapid Prototyping technologies. The approach was essentially a variant one, aimed at defining design rules on the basis of a knowledge base containing the characteristics of components and technologies. A rough evaluation of costs was also proposed. Instead, the top-down approach of the DGLs-CF, it is now more similar to a generative one, because it allows determining the technological feasibility of the products exploiting the definition of classes of features. Different DfM methods may be applied in different contexts, and often manufacturing issues are considered together with assembly ones (Boothroyd et al. 2002; Molloy et al. 1998). In Design for Manufacturing and Assembly — DfMA — the manufacturability of components is evaluated once they are defined by Design for Assembly — DfA — methods, as shown in Fig. 1.8. For this reason, some basic elements of DfA are discussed in the following.

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Fig. 1.8 Main steps of Design for Manufacturing and Assembly — DfMA

1.6.3 Design for Assembly — DfA Design for Assembly — DfA — methods concern the ease of connecting parts, components or subsystems, to constitute the final product. Quality and costs are strongly affected by the assembly process; this is why its characteristics must be considered in the early design process stages. Clearly, the number of components to assemble increases the assembly times and costs, as well as the number and kind of fasteners; for this reason, the first step in DfA is always the minimisation of the number of components. Each pair of interfacing components is evaluated to establish whether it can be substituted with a single component (Boothroyd et al. 2002; Ullman 2002a). However, the time needed for the assembly process does not depend only on the number of components, so that the efficiency of all the steps in the assembly process must be studied and optimised. The assembly process consists in retrieving components from storage, handling them to establish their relative orientation, and mating them. The geometry of the single parts profoundly affects the efficiency of all these steps and specific rules have been developed to help the design of components, considering characteristics as symmetry, sharpness, thickness, roundness, flexibility, etc. (Andreasen 1988; Boothroyd et al. 2002; Molloy et al. 1998). Data structures have been established to define the functions representing the linked geometry of parts, in order to create an assembly design environment for top-down design, from function to geometry (Gui and Mäntylä 1994; Shah and Rogers 1993).

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Another fundamental aspect determining the efficiency of the assembly process is the assembly sequence. Different theories have been developed to define it, from establishing constraint-consistent assembly sequences through connective data models (Mantripragada and Whitney 1998; Whitney et al. 1999), to the use of contact relation matrices (Lin et al. 2007) or a variant of Petri nets (Wu and O’Grady 1999). A lot of work has been done to integrate assembly information and concepts in CAD systems, as for example in OpenADE — Open Assembly Design Environment (Lyons et al. 1999). Regarding the exploitation of the DfA concepts in the DGLs-CF project, assembly issues have not been considered until now, but the way for organising and deriving the knowledge is clear, well defined and open, so that a further implementation in this sense could be easily approached, as recalled in Chap. 5. The formalisation of features, for example, which is now focused on the technological feasibility and measurability, could consider assembly issues as well. The need for the accessibility to the components should be considered both for assembly and for maintenance and disassembly, as will be pointed out in the following paragraphs regarding the DfTM.

1.6.4 Design for Test and Maintenance — DfTM — and Design for Verification — DfV Design for Test and Maintenance — DfTM, in some cases also called Design for Verification — DfV, deals with the possibility of measuring the performance of the critical functions of a product and maintaining them under given conditions. In DfTM it is necessary first to identify the components associated to critical functions because they must be easily accessed and maintained. This implies that measurement tools should be considered and defined at the beginning of the design phase, in order to provide adequate accessibility. It is also necessary to define preventive maintenance procedures establishing the frequency and modes of check, and provide an adequate stock of critical parts, so as to minimise downtime in case of failure. Design for Verification was developed particularly in the electric and electronic engineering field, where it is often called D4V (Gamma et al. 1995; Lam 2005; Riel 1996; Smith 1996). Plenty of work has been done developing models for test and maintenance of software; for example, models for checking programs were defined (Visser et al. 2000), while semantic models for object-oriented software were generated to organise all the information during the software development lifecycle, with particular regard to testing and maintenance (Deng et al. 2004; Meyer 1997). The attention was also focused specifically on the reliability of components in software development (Fischer 2000; Mehlitz and Penix 2003).

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In the context of the research described in this book, verification issues are approached in a quite different way. First of all, there is particular concern with the physical representation of products, so that the verification concepts are analysed regarding the measurement methods and tools used to evaluate the conformity of the product to the requirements. Moreover, the integration of the ISO GPS principles gives new and particular characteristics to the proposed approach to the development of design guidelines regarding the verification issues. Maintainability and reparability concepts are also related to product reliability, which is analysed by DfR. However, they are also part of disassembly issues, which are analysed by DfE, together with the aspects related to reuse or recycling of products at the end of their lifecycle. All these topics are presented in the following paragraphs.

1.6.5 Design for Reliability — DfR Design for Reliability — DfR — considers how the quality of a product, in terms of performance under stated conditions of use and maintenance, is maintained over time. Reliability is ensured if the parameters that could determine a failure are identified and monitored. In this sense, DfR is close to DfTM; the maintainability concept, in fact, can be associated with the probability of repairing a component before it fails, if appropriate procedures are defined and performed. Exhaustive studies may be found in the work of Crowe and Feinberg (2001), Dhillon (1999), Wassermann (2002), Crespo Márquez (2007), or Ebeling (1997), and Thompson (1999), where reliability and maintainability are considered together in the design process. Reliability is defined by means of failures, which are intended as unsatisfactory performances, and precisely by means of the Mean Time Between Failures — MTBF — indicator, or by its inverse function, the failure rate (Finkelstein 2008). The most widespread technique for identifying potential failures is called Failure Modes and Effects Analysis — FMEA, which may be of great help in DfR (Stamatis 1995). During the product development process, the possibility of failure must be evaluated for each function, also identifying the possible effects on the parts of the product. The cause of the failure must then be identified — design or manufacturing errors, changes due to operational conditions, etc. — so that corrective actions may be defined. These could be redesign actions, manufacturing process changes and operational conditions changes, aimed at minimising the effect of the failure. It is very important to understand how the different parts of a product affect reliability. If parts may be considered as working in series, the failure of a part will mean the failure of the whole product. In this case, the reliability of the product will be given by the product of the reliabilities of its parts. In redundant

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systems, the parts may be considered as working in parallel, so that the failure of a part does not imply the failure of the whole product. For critical parts, redundancy is often considered a good way to improve the reliability; however, this increases costs and might add other failure modes. In any case, a good estimation of the reliability implies necessarily a deep knowledge of failure modes, which may be obtained through experiments, analysis of historical data, use of models of physical phenomena, and information sharing among experienced specialists in the different fields in a collaborative environment. The DGLs-CF project has not considered reliability issues until now, but this information could be further introduced, for example by developing procedures to highlight the most critical product features and/or process characteristics, as discussed again in Chap. 5.

1.6.6 Design for Environment — DfE Design for Environment — DfE — concerns all the issues of the product lifecycle which may affect the environment, such as product manufacturing, distribution, use, retire, reuse or recycle (Bras 2006; Graedel and Allenby 1996). For each of them, the related information must be effectively managed and organised (Bras 1997). Different approaches have been developed to reduce the environmental impact, and these are known as sustainable development, industrial ecology, green engineering, eco-design, etc. (Brezet and Van Hemel 1997; Coulter et al. 1995). First of all, it is necessary to evaluate the impact on the environment of the materials used, both in terms of raw materials and of the energy needed to produce, recycle, ignite and waste them. Different parameters have been defined to evaluate the environmental risk; one of them is the MET — Materials, Energy, Toxicity — score. About materials, the exhaustion of scarce materials is evaluated, while greenhouse effect, acidification, smog, and eutrophication are considered with respect to the energy associated with all the processes in the product lifecycle. These processes are also evaluated in terms of human toxicity, ecotoxicity and ozone depletion. An interesting activity-based method was proposed to analyse and trace the cost due to energy consumption and waste generation in the lifecycle design (Emblemsvåg and Bras 1997). Products should be designed in order to ease disassembly, so that components with different characteristics can be separated at the end of the product lifecycle (Dowie 1994; Hundal 2000). It could also be highlighted that disassembly and material separation techniques may considerably differ, depending on the kind of products, be they vehicles (Coulter et al. 1996), electronic equipment (Campbell and Asad 2003), or others. The cost of disassembly must be considered too. Components must be designed so that they can be mostly reused or recycled; when they cannot, their degradability must be evaluated. To optimise the end of life value of a product, an

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algorithmic approach for DfE was proposed by Pnueli and Zussman (1997); it identifies weak spots in the product design and proposes possible solutions. The need for considering how a product may impact on the environment while still at the beginning of the design process is underlined by the development of a specific set of standards in the ISO 14000 series. These standards concern the reduction in use of raw materials, resources and energy, the improvement in the efficiency of processes, the reduction in the quantity of waste and the enhancement in the use of recycling. Specifically, ISO 14062 — Design for environment — aims at the improvement of environmental performance of products (ISO/TR 14062:2002). Standards, however, express the requirements in a textual form, and they are often difficult to integrate in the engineering design process. A tool was developed to translate these textual requirements into constraints, in order to verify the compliance of products with the standards (Houe and Grabot 2007). It is not difficult to foresee that DfE concepts could be integrated in the research described in the rest of this book. Thanks to the open structure already mentioned when considering the possible introduction of DfA or DfR concepts, the environmental issues could be introduced as well. For example, product feature formalisation could contain some information for an easy disassembly, and the definition of technological characteristics could include a sort of MET score, as discussed again in Chap. 5. All the DfX methods described here aim at linking the product development process with the whole product lifecycle. Actually, the ideal product should be designed considering all the DfX methods, thus linking the development process with all the phases of the product lifecycle, in a real implementation of the concurrent engineering vision. This is not easy, nor always possible; for example, Design for Assembly and Design for Environment, in its disassembly issues, could imply conflicting activities. Anyway, this is an interesting challenge, leading to the development of design for multi-X methods and tools, where the knowledge of the different domains is integrated and organized (Borg et al. 2000). The next chapters will highlight that the result of the DGLs-CF project may be considered as a design for multi-X method, given that it develops the design process considering both the manufacturing and verification processes; moreover, its structure looks particularly suited to enlarge further its application to the other phases of the product lifecycle.

Summary This chapter has described the state of the art of the scenario where the DGLs-CF project takes place. It opened highlighting that the engineering design process must be considered inside the product lifecycle since its first beginning. Moreover, the effectiveness of the engineering design process is enhanced if it is developed in a collaborative environment, also considering the related standards. In this

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context, the focus is mainly on the design methods, which are developed to formalise, elaborate and make usable all the pieces of information generated and used in this process. Since the DGLs-CF can be regarded as a design for multi-X method, the main characteristics of the DfX methods have been described, so that it will be easier to highlight the specific characteristics of the DGLs-CF in the next chapters.

References Abdel-Malek K, Zou H-L, Wang J-Y, Othman S (1999) Automated Design and Parametrization of Mechanical Part Geometry. Res Eng Des 11:206-217 Akao Y (1990) Quality Function Deployment: Integrating Customer Requirements into Product Design. Productivity Press Alisantoso D, Khoo LP, Ivan Lee BH, Fok SC (2005) A rough set approach to design concept analysis in a design chain. Int J Adv Manuf Technol 26:427-435 Alizon F, Khadke K, Thevenot HJ, Gershenson JK, Marion TJ, Shooter SB, Simpson TW (2007) Frameworks for Product Family Design and Development. Concurr Eng 15(2):187-199 Altshuller GS (1988) Creativity as an Exact Science. Gordon and Breach, New York Altshuller GS, Clarke DW, Shulyak L, Lerner L (2005) 40 Principles: TRIZ Keys to Innovation [Extended Edition]. Technical Innovation Center, Inc. Andersen DM (2004) Design for manufacturability. CIM Press Andreasen M (1988) Design for Assembly. Springer Verlag, New York Antony J (2003) Design of Experiments for Engineers and Scientists. Butterworth-Heinemann Barrentine LB (1999) An Introduction to Design of Experiments: A Simplified Approach. ASQ Quality Press Baumgartner C and Blessing L (2001) Establishing causal links between success characteristics and project outcome. In: Proceedings of the international conference on engineering design, Glasgow Belton V and Stewart TJ (2002) Multiple criteria decision analysis - an integrated approach. Kluwer Academic Publishers Bennett PG (1985) On Linking Approaches to Decision-Aiding: Issues and Prospects. J Oper Res Soc 36(8):659-669 Bennich P (1994) Chains of Standards - A New Concept in GPS Standards. Manuf Rev 7(1):2938 Birmingham R, Cleland G, Driver R, Maffin D (1997) Understanding engineering design. Prentice-Hall, London Blanchard GS, Fabrycky WJ (1981) Systems Engineering and Analysis. Prentice-Hall, New York Boothroyd G, Dewhurst P, Knight WA (2002) Product design for Manufacture & Assembly. Marcel Dekker Borg JC, Yan X, Juster NP (2000) Exploring decisions’ influence on life-cycle performance to aid “design for Multi-X”. AIEDAM 14:91-113 Bralla JG (1998) Design for Manufacturability Handbook. Mc Graw- Hill Bras B (1997) Incorporating Environmental Issues in Product Design and Realization. Ind Environ 20:1-2 Bras B (2006) Design for Environment, Design for Recycling, Part 1-2. Georgia Institute of Technology, Lecture Notes. http://www.srl.gatech.edu/education/ME4171/. Accessed 24 April 2009

24


Brezet H and Van Hemel C (1997) Ecodesign - A Promising Approach to Sustainable Production and Consumption. United Nations Publication. Burr H, Vielhaber M, Deubel T, Weber C, Haasis S (2005) CAx/engineering data management integration: enabler for methodical benefits in the design process. J Eng Des 16(4):385-398 Campbell MI and Asad H (2003) Design Evaluation Method for the Disassembly of Electronic Equipment. In: Proceedings International Conference on Engineering Design - ICED 03 Capasso and Périaux (ed) (2005) Multidisciplinary Methods for Analysis Optimization and Control of Complex Systems. Springer, Berlin Heidelberg Cartwright AJ (1997) Interactive Prototyping - a Challenge for Computer Based Design. Res Eng Des 7:10-19 Chan K, King C, Wright P (1998) COMPASS: Computer Oriented Materials, Processes, and Apparatus Selection System. J Manuf Syst 17(4):275-286 Chang K-H-O, Silva J, Bryant I (1999) Concurrent Design and Manufacturing for Mechanical Systems. Concurr Eng Res Appl 7(4):290-308 Chen W, Allen JK, Mavris DN, Mistree F (1996) A concept exploration method for determining robust top-level specifications. Eng Optim 26(2):137-158 Chiang TA, Trappey AJC, Ku CC (2006) Using a knowledge-based intelligent system to support dynamic design reasoning for a collaborative design community. Int J Adv Manuf Technol 31(5-6):421-433 Choley JY, Riviere A, Clement A, Bourdet P (2007) A New Variational Association Process for the Verification of Geometrical Specifications. Transactions of the ASME J Comp Inf Sci Eng 7:66-71 Clarkson PJ and Hamilton JR (2000) ‘Signposting’, A Parameter-driven Task-based Model of the Design Process. Res Eng Des 12:18-38 Coulter S, Bras B, Foley C (1995) A lexicon of green engineering terms, In: Proceedings ICED’95 Coulter S, Bras R, Winslow G, Yester S (1996) Designing for material separation: lessons from automotive recycling. In: Proceedings of DETC’96, 96-DETC/DFM-1270 Crespo Márquez A (2007) The Maintenance Management Framework Models and Methods for Complex Systems Maintenance. Springer Series in Reliability Engineering Cross N (2000) Engineering Design Methods: Strategies for Product Design. Wiley & Sons Crowe D and Feinberg A (ed) (2001) Design for Reliability. CRC press Deng D, Sheu PC-Y, Wang T, Onoma AK (2004) Model-based Testing and Maintenance. In: Proceedings of the IEEE Sixth International Symposium on Multimedia Software Engineering (ISMSE’04):1-8 Désenfant M, Priel M (2006) Road map for measurement uncertainty evaluation. Meas 39:841848 Dhillon BS (1999) Design Reliability: Fundamentals and Applications. CRC press Diaz M, Azema P (1985) Petri net based models for the specification and validation of protocols. In: Lecture Notes in Computer Science 188, Springer-Verlag, New York Dovmark J (2001) New interesting concepts from ISO/TC 213. In: Proceedings of INTERSEC Dowie T (1994) Design for Disassembly. Technical Report, Manchester Metropolitan University. Duffy AHB and O’Donnell FJ (1997) A Model of Product Development Performance. In: Proceedings Darmstadt Symposium on Designers - The Key to Successful Product Development, Darmstadt, Germany, ISBN 1-85233-031-7: 269-283 Duffy AHB, Andreasen MM, MacCallum KJ, Reijers NL (1993) Design coordination for concurrent engineering. Int J Eng Des 4:251-265 Duffy AHB, Andreasen MM, O’Donnell FJ (1999) Design Co-ordination. In: Proceedings International Conference on Engineering Design (ICED'99), Munich, Germany, (1):113-118 Dwarakanath S and Blessing L (1996) Ingredients of the Design Process. In: Cross N, Christiaans H and Dorst K (ed) Analysing Design Activity, Wiley, Chichester Dym CL and Little P (2003) Engineering Design: A Project-Based Introduction. Wiley and Sons

References

25

Ebeling CE (1997) An Introduction to Reliability and Maintainability Engineering. McGraw-Hill Companies Inc, Boston Eckert C, Clarkson PJ, Zanker W (2004) Change and customisation in complex engineering domains. Res Eng Des 15:1-21 Edwards W and Von Winterefeldt D (ed) (2007) Advances in Decision Analysis: From Foundations to Applications. Cambridge University Press Eide AR (2001) Engineering fundamentals and problem solving. Mac Graw Hill El-Haik B (2005) Axiomatic Quality: Integrating Axiomatic Design with Six-Sigma, Reliability, and Quality Engineering. Wiley-Interscience Emblemsvåg J and Bras B (1997) An activity-based life-cycle assessment method. In: Proceedings of DETC’97, DFM-97-119 Engelhardt F (2000) Improving Systems by Combining Axiomatic Design, Quality Control Tools and Designed Experiments. Res Eng Des 12:204-219 Eppinger SD, Whitney DE, Smith RP, Gebala DA (1994) A model-based method for organizing tasks in product development. Res Eng Des 6(1):1-13 Eppinger S, Nukala M, Whitney D (1997) Generalized models of design iteration using signal flow graphs. Res Eng Des 9:112-123 Figuera J, Greco S, Matthias E (ed) (2005) Multiple Criteria Decision Analysis: State of the Art Surveys. Springer Finkelstein M (2008) Failure Rate Modeling for Reliability and Risk. Springer Series in Reliability Engineering Fischer B (2000) Specification-Based Browsing of Software Component Libraries. J Autom Softw Eng 7(2):179-200 Fleischer M and Liker JK (1997) Concurrent Engineering Effectiveness: Integrating Product Development Across the Organizations. Hanser Gardner, Cincinnati, OH Gamma E, Helm R, Johnson R, Vlissides J (1995) Design Patterns Elements of Reusable ObjectOriented Software. Addison Wesley Gebala DA and Eppinger S (1991) Methods for analyzing design procedures. In: L. Stauffers LA (ed) Design Theory and Methodology. ASME, Miami Geng H (2004) Manufacturing Engineering Handbook. Mc Graw Hill Handbooks Goldberg DE (1989) Genetic Algorithms in Search, Optimization, and Machine Learning. Addison-Wesley Professional Graedel TE and Allenby BR (1996) Design for Environment. Prentice Hall Grewal S and Choi CK (2005) An Integrated Approach to Manufacturing Process Design and Costing. Concurr Eng 13(3):199-207 Gui J and Mäntylä M (1994) Functional understanding of assembly modelling. CAD 26:435-451 Gupta SK, Nau DS (1995) A systematic approach for analyzing the manufacturability of machined parts. CAD 27(5):342-343 Gupta SK, Regli WC, Das D, Nau, DS (1997) Automated Manufacturability Analysis: A Survey. Res Eng Des 9:168-190 Haik Y (2003) Engineering design process. Brooks/Cole Publishing, Pacific Grove Hirtz J, Stone RB, McAdams DA, Szykman S, Wood KL (2002) A functional basis for engineering design: Reconciling and evolving previous efforts. Res Eng Des 13:65-82 Horváth I (2004) A treatise on order in engineering design research. Res Eng Des 15:155-181 Hosaka M (1992) Modeling of curves and surfaces in CAD/CAM. Springer, Berlin Heidelberg New York Houe R and Grabot B (2007) Knowledge Modeling for Eco-design. Concurr Eng 15(1):7-20 Houssin R, Bernard A, Martin P, Ris G, Cherrier F (2006) Information system based on a working situation model for a new design approach in concurrent engineering. J Eng Des 17(1):35-54 Howell SK (2001) Engineering design and problem solving. Prentice Hall Huang H-Z and Gu Y-K (2006) Development Mode Based on Integration of Product Models and Process Models. Concurr Eng 14(1):27-34

26


Hubka V and Eder WE (1992) Engineering Design: General Procedural Model of Engineering Design. Heurista, Zurich Hundal MS (1993) Rules and Models for Low-Cost Design. In: Proceedings Design for Manufacturing Conference, ASME Hundal M (2000) Design for Recycling and Remanufacturing. In: Proceedings International Design Conference -DESIGN 2000, Dubrovnik Hung H, Kao H, Ku K (2007) Evaluation of design alternatives in collaborative development and production of modular products. Int J Adv Manuf Technol 33:1065-1076 Hyde W (1981) Improving Productivity by classification coding and Database Standardization. Marcel Dekker, New York Isaksson O, Keski-Seppälä S, Eppinger S (2000) Evaluation of design process alternatives using signal flow graphs. J Eng Des 11(3):211-224 ISO 14660-1:1999, Geometrical Product Specification (GPS) - Geometrical features - Part 1: General terms and definitions ISO 14660-2:1999, Geometrical Product Specification (GPS) - Geometrical features - Part 2: Extracted median line of a cylinder and a cone, extracted median surface, local size of an extracted feature ISO 5459:1981, Technical drawings - Geometrical Tolerancing - Datums and Datum Systems for geometrical tolerances ISO/TC 213 N355 Annex 1 (2000), Next generation of the Geometrical Product Specifications (GPS) language - The vision for an improved engineering tool ISO/TR 14638:1995, Geometrical product specification (GPS) - Masterplan ISO/TR 14062:2002, Environmental management -- Integrating environmental aspects into product design and development ISO/TS 17450-1:2000, Geometrical Product Specifications (GPS) - General Concepts - Part 1: Model for geometrical specification and verification ISO/TS 17450-2:2002, Geometrical Product Specifications (GPS) - General concepts - Part 2: Basic tenets, specifications, operators and uncertainties Jain VK and Sobek DK II (2006) Linking design process to customer satisfaction through virtual design of experiments. Res Eng Des 17:59-71 Khadilkar DV and Stauffer LA (1996) An experimental evaluation of design information reuse during conceptual design. J Eng Des 7(4):331-339 Kim Y-S, Cochrani DS (2000) Reviewing TRIZ from the perspective of axiomatic design. J Eng Des 11(1):79-94 Kleiner S, Anderl R, Gräb R (2003) A collaborative design system for product data integration. J Eng Des 14(4):421-428 Koh H, Ha S, Kim T, Lee S (2005) A method of accumulation and adaptation of design knowledge. Int J Adv Manuf Technol 26:943-949 Kulon J, Broomhead P, Mynors DJ (2006) Applying knowledge-based engineering to traditional manufacturing design. Int J Adv Manuf Technol 30:945-951 Kurakawa K (2004) A scenario-driven conceptual design information model and its formation. Res Eng Des 15(2):122-137 La Trobe-Bateman J and Wild D (2003) Design for manufacturing: use of a spreadsheet model of manufacturability to optimize product design and development. Res Eng Des 14(2):107-117 Lam WK (2005) Hardware Design Verification: Simulation and Formal Method-Based Approaches. Prentice Hall Lee K-S and Lee K (2004) Evolutionary design and re-design using design parameters and goals. J Eng Des 15(2):155-176 Liang C and Guodong J (2006) Product modeling for multidisciplinary collaborative design. Int J Adv Manuf Technol 30:589-600 Lin M-C, Tai Y-Y, Chen M-S, Chang CA (2007) A Rule Based Assembly Sequence Generation Method for Product Design. Concurr Eng 15(3):291-308 Lumsdaine E, Lumsdaine M, Shelnutt JW (1999) Creative Problem Solving and Engineering Design. Mc Graw-Hill

References

27

Lyons K et al. (1999) The Open Assembly Design Environment: An Architecture for Design Agent Interoperability. In: Proceedings ASME Design Engineering Technical Conf., ASME, New York, (CD-ROM) Maffin D (1998) Engineering design models: context, theory, and practice. J Eng Des 9(4):315327 Maher M, Balachandran B, Zhang D (1995) Case based reasoning in design. Lawrence Erlbaum Publisher Mantripragada R and Whitney DE (1998) The Datum Flow Chain: A Systematic Approach to Assembly Design and Modeling. Res Eng Des 10:150-165 McMahon C and Browne J (1998) CAD/CAM-principles, practice and manufacturing management, 2nd edn. Addison-Wesley, Harlow Mehlitz P and Penix J (2003) Design for Verification - Using Design Patterns to Build Reliable Systems. In: Proceedings of 6th ICSE workshop on component based software engineering, Portland OR Meredith DD, Wong KW, Woodhead RW, Wortman RH (1985) Design Planning of Engineering Systems. Prentice-Hall, Englewood Cliffs, NJ Meyer B (1997) Object Oriented Software Construction. Prentice Hall Molloy O, Warman EA, Tilley S (1998) Design for Manufacturing and Assembly: Concepts, architectures and implementation. Springer Montgomery D.C (2004) Design and Analysis of Experiments, 6th edn. Wiley Nahm Y-E and Ishikawa H (2004) Integrated Product and Process Modeling for Collaborative Design Environment. Concurr Eng 12(1):5-23 Nielsen J (1993) Usability Engineering. Academic Press, Cambridge, MA Nielsen HS (2003) Specifications, operators and uncertainties. In: Proceedings 8th CIRP International Seminar on Computer Aided Tolerancing Nielsen HS (2006) New concepts in specifications, operators and uncertainties and their impact on measurement and instrumentation. Meas Sci Technol 17:541-544 Olewnik A and Lewis K (2005) On Validating Engineering Design Decision Support Tools. Concurr Eng 13(2):111-122 Olewnik A and Lewis K (2006) A decision support framework for flexible system design. J Eng Des 17(1):75-97 Osteras T, Murthy DNP, Rausand M (2006) Product performance and specification in new product development. J Eng Des 17(2):177-192 Otto K and Wood K (2000) Product Design. Prentice Hall Pahl G, Badke-Schaub P, Frankenberger E (1999) Resume of 12 years of interdisciplinary empirical studies of engineering design in Germany. Des Stud 20(5):481-494 Pahl G, Beitz W, Feldhusen J, Grote KH (2007) Engineering Design: A systematic approach, 3rd edn. Springer Park SH (1996) Robust Design and Analysis for Quality Engineering. Springer Park H and Cutkosky MR (1999) Framework for Modeling Dependencies in Collaborative Engineering Processes. Res Eng Des 11:84-102 Phadke MS (1989) Quality Engineering Using Robust Design. Prentice Hall PTR, US edn Pnueli Y and Zussman E (1997) Evaluating the end-of-life value of a product and improving it by redesign. Int J Prod Res 35(4):921-942 Poli C (2001) Design for Manufacturing: A Structured Approach. Butterworth Heinemann Pugh S (1990) Total design. Addison-Wesley, Wokingham Qureshi SM, Shah JJ, Urban SD et al. (1997) Integration model to support archival of design history in databases. In: Proceedings ASME Design Theory and Methodology Conference, DETC97/DTM-3876 Reymen IM, Hammer DK, Kroes PA, van Aken JE, Dorst CH, Bax MFT, Basten T (2006) A domain-independent descriptive design model and its application to structured reflection on design processes. Res Eng Des 16(4):147-173 Riel AJ (1996) Object-Oriented Design Heuristics. Addison-Wesley

28


Ross DT (1977) Structured Analysis (SA): A language for communicating ideas. IEEE Trans Softw Eng 3(1):16-34 Ross PJ (1996) Taguchi Techniques for Quality Engineering. Mac Graw Hill professional Roy RK (2001) Design of Experiments Using The Taguchi Approach: 16 Steps to Product and Process Improvement. Wiley-Interscience, Har/Cdr edition Royce W (1970) Managing the Development of Large Software Systems. In: Proceedings of IEEE WESCON 26:1-9 Salomons OW, van Houten FJ, Kals HJ (1993) Review of research in feature-based design. J Manuf Syst 12(2):113-132 Seif MA (1998) A Concurrent Engineering Approach for Product Design Optimization. Concurr Eng 6(2):101-110 Shah J and Mäntylä M (1995) Parametric and Feature-Based CAD/CAM: Concepts, Techniques, and Applications. Wiley Interscience Shah JJ and Rogers M (1993) Assembly modeling as an extension of feature-based design. Res Eng Des 5:218-237 Shah J and Wright P (2000) Developing theoretical foundations of DfM. In: Proceedings ASME Design for Manufacturing Conference, (CD ROM Paper#DETC2000/DFM-14015) Sharma R and Gao JX (2007) A knowledge-based manufacturing and cost evaluation system for product design/re-design. Int J Adv Manuf Technol 33:856-865 Shehab EM, Abdalla HS (2001) Manufacturing cost modeling for concurrent product development. Robot Comput-Integr Manuf 17(4):341-353 Shehab EM and Abdalla HS (2002) An Intelligent Knowledge-Based System for Product Cost Modelling. Int J Adv Manuf Technol 19:49-65 Smith DR (1996) Toward a Classification Approach to Design. In: Proceedings of the Fifth International Conference on Algebraic Methodology and Software Technology, AMAST'96, LNCS 1101, Springer Verlag Smith LN (2003) A Knowledge-based System for Powder metallurgy Technology. Professional and Engineering Publishing, London & Bury St. Edmunds, UK Smith R and Eppinger S (1997) A predictive model of sequential iteration in engineering design. Manage Sci 43(8):1104-1120 Srinivasan V (2001) An Integrated View of Geometrical Product Specification and Verification. In: Proceedings 7th CIRP International Seminar on Computer Aided Tolerancing Srinivasan V (2008) Standardizing the specification, verification, and exchange of product geometry: Research, status and trends. CAD 40:738-749 Stamatis DH (1995) Failure Mode and Effect Analysis: FMEA from Theory to Execution. American Society for Quality Steward DV (1981a) The design structure system - a method for managing the design of complex systems. IEEE T Eng Manage 28(3):71-74 Steward DV (1981b) Systems Analysis and Management: Structure, Strategy and Design. Petrocelli Books, New York Sturges RH, O’Shaughnessy K, Reed G (1993) A systematic approach to conceptual design. Concurr Eng: Res Appl 1:93-105 Suh NP (1990) The Principles of Design. Oxford University Press Suh NP (1998) Axiomatic Design Theory for Systems. Res Eng Des 10:189-209 Suh NP (1999) A Theory of Complexity, Periodicity and the Design Axioms. Res Eng Des 11:116-131 Suh NP (2001) Axiomatic Design: Advances and Applications. Oxford University Press, USA Suh NP (2005) Complexity: Theory and Applications. Mit-Pappalardo Series in Mechanical Engineering, Oxford University Press, USA Taguchi G (1999) Robust Engineering: Learn How to Boost Quality While Reducing Costs & Time to Market. McGraw-Hill Professional Taguchi G (2004) Taguchi's Quality Engineering Handbook. Wiley-Interscience Thompson G (1999) Improving Maintainability and Reliability through Design. Wiley

References

29

Tor SB, Britton GA, Zhang WY (2005) A knowledge-based blackboard framework for stamping process planning in progressive die design. Int J Adv Manuf Technol 26:774-783 Ullman DG (2002a) The mechanical design process. McGraw-Hill Science/Engineering/Math Ullman DG (2002b) Toward the ideal mechanical engineering design support system. Res Eng Des13:55-64 Ulrich KT and Eppinger SD (2003) Product Design and Development. Mc Graw Hill Veeke HPM, Lodewijks G, Ottjes JA (2006) Conceptual design of industrial systems: an approach to support collaboration. Res Eng Des 17:85-101 Vergeest JSM and Horváth I (1999) Design Model Sharing in Concurrent Engineering: Theory and Practice. Concurr Eng 7(2):105-113 Visser W, Havelund K, Brat G, Park S (2000) Model Checking Programs. In: Proceedings of the 15th International Conference on Automated Software Engineering (ASE), Grenoble, France Wang B, Chen SB, Wang JJ (2005) Rough set based knowledge modeling for the aluminium alloy pulsed GTAW process. Int J Adv Manuf Technol 25:902-908 Wasserman G (2002) Reliability Verification, Testing, and Analysis in Engineering Design. CRC Whitney DE, Mantripragada R, Adams JD, Rhee SJ (1999) Designing Assemblies. Res Eng Des11:229-253 Wiest JD, Levy FK (1977) A Management Guide to PERT/CPM. Prentice-Hall, Englewood Cliffs, NJ Wu Z and Duffy A (2002) Mutual Knowledge Evolution in Team Design. In: Proceedings of 7th International Conference on Artificial Intelligence in Design (AID '02), Cambridge, UK Wu T and O’Grady P (1999) A Concurrent Engineering Approach to Design for Assembly. Concurr Eng 7(3):231-243 Wu Y and Wu A (2000) Taguchi Methods for Robust Design. ASME books Xu QL, Ong SK, Nee AYC (2006) Function-based design synthesis approach to design reuse. Res Eng Des 17:27-44 Xue D (1997) A Multi-level Optimization Approach Considering Product Realization Process Alternatives and Parameters for Improving Manufacturability. J Manuf Syst 16(5):337-351 Xuewen C, Siyu Z, Jun C, Xueyu R (2005) Research of knowledge-based hammer forging design support system. Int J Adv Manuf Technol 27:25-32 Yang G (2007) Life Cycle Reliability Engineering. Wiley Yassine A, Whitney D, Daleiden S, Lavine J (2003) Connectivity maps: modeling and analysing relationships in product development processes. J Eng Des 14(3):377-394 Zhang WY, Tor SY, Britton GA (2006) Managing modularity in product family design with functional modelling. Int J Adv Manuf Technol 30:579-588 Zhao Z and Shah J (2002) A Normative Framework for DfM based on Benefit-Cost Analysi In: Proceedings ASME Design for Manufacturing Conference, (CD ROM Paper#DETC2002/DFM-34176) Zhao Z and Shah J (2004) Modeling and representation of manufacturing knowledge for DFM systems. In: Proceedings ASME Computers and Information in Engineering Conference, (CD ROM Paper#DETC2004/57724)

2 The DGLs-CF — Introduction and Background

The DGLs-CF is a methodological approach for product design and process reconfiguration, aimed at effectively helping and leading the activities of designers, manufacturers and inspectors. The initial consideration is that designers are not necessarily experts in manufacturing and verification processes; likewise, manufacturers and inspectors might not be experts in design. As said in the previous chapter, the birth and evolution of the DGLs-CF took place in a scenario where tools and methods for product development have been analysed from a concurrent engineering point of view, and where the adoption of standards is a key point. Considering the terminology explained in the previous chapter, the DGLs-CF may be considered essentially a design for multi-X method. At the beginning, the former DGLs were developed as a simple DfM method, particularly focused on establishing guidelines for product design considering the characteristics of some manufacturing processes. Subsequent improvements highlighted other interesting peculiarities that started to differentiate the DGLs from the classic DfX methods. According to the ISO GPS vision, it was also considered that the verification process affects the design phase, so that verification aspects have been evaluated together with the manufacturing ones. A sort of Design for Manufacturing and Verification method was the result, to link design, manufacturing and verification in a new way. The study and development of the DGLs-CF as a design for multi-X method, strictly connected with the ISO GPS standards, can be considered the most interesting issue of the whole research. Figure 2.1 shows the role of the DGLs-CF in the product development process. The full-line boxes and arrows represent the knowledge and its flow corresponding to the structure of the former DGLs, while the dashed elements correspond to the new aspects introduced by the DGLs-CF. The contribution of the DGLs-CF, actually representing a differentiation from the classic DfX methods, stands in the fact that knowledge evaluation not only generates guidelines for product development, but also for process reconfiguration. Not only guidelines to redesign the product according with the

32

2 The DGLs-CF – Introduction and Background

manufacturing and verification characteristics are given, but also guidelines to reconfigure the manufacturing/verification processes specifically for the redesigned product. Anyway, the attention is always focused on the product; the process reconfiguration must be intended as a process customisation where the different representations of the product — digital model or physical part — are managed and modified. For now, there is no redefinition of the general parameters of the process. As said before, all of this is shown in Fig. 2.1, where this additional knowledge generation and flow is depicted by the dashed box and arrows.

Fig. 2.1 Role of the DGLs-CF as a design for multi-X method in the product lifecycle

From this new point of view, the specific product is generated by exploiting the specific process characteristics effectively and adequately, since the product is tailored to manufacturing and verification processes, and vice versa.

2.1 Overview of the History of the DGLs Detailed descriptions of the several releases of the DGLs were given by Bandera et al. (2004, 2005, 2006), Cristofolini et al. (2006), Filippi et al. (2001) and Filippi and Cristofolini (2007). Several fundamental aspects are recalled here to make the understanding of what follows easier. The DGLs development started from two main considerations. The redesign activities must remain the responsibility of the designers. Quite often today, manufacturers carry out redesign activities in order to improve the feasibility of products with particular technologies, but this is potentially dangerous; the operators may have little knowledge of the product domain and

2.1 Overview of the History of the DGLs

33

may not take the best decision in the case of multiple choices. Even worse, sometimes they may prejudice the model functions (Kumaran and Chittaro 1998). Moreover, designers need specific knowledge of the manufacturing processes to succeed in redesign (Haffey and Duffy 2000). Design rules and handbooks existing in the literature now represent the only help for designers in modifying the product. Even if constituting a good starting point, they show some limitations that severely reduce their usability (Nielsen 1993) and the consequent effectiveness during the design phase. In fact, they do not have a structure that is helpful in generating, managing and using the rules; there is a lack of application criteria to guide the redesign activities; overall, they impose a scarce autonomy due to the fact that they have not been specifically produced for designers. Three releases of the DGLs exist, corresponding to three important milestones during their development. They are briefly introduced hereafter, and the following paragraphs describe them in detail. The DGLs-CF, representing both the target of the research about a new concept of DfX method and the starting point for further theoretical and applicative research, will be described and applied in the field in the next two chapters of this book. In their first release, the DGLs were based on a set of design rules that completed the existing set in literature and increased the possibilities of their use as an effective guide for the modification of a product during the design phase. Modifications guaranteed not only that the model could be built with particular technology, but also that the building process was advantageous when compared to other technologies, thus exploiting its capabilities and minimising time and costs. This concept is the basis for the definition of the so-called positive rules that will be recalled more than once throughout the book. In the second release of the DGLs, the attention was on the verification phase, following the idea that the product quality could be improved when considering at the design phase not only the manufacturing process, but also the verification one. In this way, the DGLs enlarged their field of application in realising links between design and verification, according to the ISO GPS concepts. Finally, in the third release of the DGLs the impact in terms of process reconfiguration was evaluated in depth; in this way the knowledge sharing among designers, manufacturers and verification experts became biunique. In a true concurrent engineering environment, the DGLs suggested the way to redesign the product and to reconfigure the processes to obtain and maintain the required functionalities. This chapter goes ahead with the description of these three releases of the DGLs. They have been considered in this book because the development of each of them generated new and heterogeneous knowledge about the problem — the product redesign and process reconfiguration — and about the method to solve it — the DGLs-CF. The DGLs-CF answers almost all the questions and hints coming from these previous releases. Moreover, the evolution of the whole development process could be considered for similar situations in different application domains.

34


Each description shows quite the same structure, an introductory paragraph followed by three elements: the conceptual diagram representing the process for gathering and deriving the knowledge, the knowledge matrix that describes the data structure used to encode this knowledge, and the pros and cons at the end of each description that weigh the importance of the results reached and list the directions for the next release. The description of the third release of the DGLs diverges slightly from this structure; the complexity of this release required a sort of roadmap for its application in the field and this new element has been used as a tool to explain the release. Moreover, the descriptions of the three releases contain some case studies to clarify the effects of the DGLs adoption in some real industrial domains.

2.2 First Release of the DGLs. The Beginning The first release of the DGLs was derived directly from the authors’ experience in the field as mechanical designers and Rapid Prototyping — RP — experts. The characteristics of RP technology named Direct Metal Laser Sintering — DMLS — were analysed first, in terms of advantages and drawbacks; then, how these characteristics could affect the product redesign has been investigated (Filippi et al. 2001). The DMLS process was chosen because this is one of the most promising RP technologies currently available. It can build metal objects using the same material as that of the final product. This characteristic widens the field of application of this technology, which can also be used in rapid tooling, i.e. for the generation of inserts for plastic injection moulding (Kuzman et al. 2001; Nelson 2002), and in rapid manufacturing, to build small series of complex mechanical parts (Gatto and Iuliano 1998; Jacobs 1995). On the other hand, the DMLS process shows some critical aspects mainly due to the behaviour of metal powders, such as complex sintering dynamics, residual stress, thermal deformation, etc. (Agarwala et al. 1995), so that more study is needed to solve or avoid current limitations even in early activities, for example during the design phase (Otto and Wood 2000). At the beginning of the development of this release, the attention was mainly focused on collecting knowledge in a spreadsheet as in the work of La TrobeBateman and Wild (2003), and in generating rules to link the design and the manufacturing domains; after that, some software development and concerns about usability issues took place.

2.2.1 Conceptual Diagram The conceptual diagram in Fig. 2.2 shows that this release of the DGLs has been heavily influenced by the considerations about the manufacturing technologies.

2.2 First Release of the DGLs. The Beginning

35

Fig. 2.2 Conceptual diagram of knowledge generation in the first release of the DGLs

Two domains were present, design and manufacturing, and, starting from the manufacturing requirements, a set of design rules was derived. Then the product was characterised in terms of attributes. The match between design rules and attributes gave a configuration, expressed in terms of activities to be performed on the product to make it compatible with the manufacturing technology.

2.2.2 Knowledge Matrix Table 2.1 shows the knowledge matrix of this release of the DGLs. This matrix represents the knowledge structure and contains some examples of pieces of information, expressed in terms of manufacturing requirements, design rules, attributes and redesign solutions. Each row represents a different requirement with an associated design rule. For each rule there is one attribute that allows the characterisation of the product. For each requirement, redesign solutions are suggested to be used when the product does not match the rule. After the definition of the data structure and the collection of some pieces of information, a very simple software prototype was generated using Microsoft Access. This implementation is of interest here because it allowed applying some refinements to the knowledge content of the DGLs. For example, the consequences of the violation of each rule and a coarse evaluation of the required post-process manufacturing cost — using a qualitative low-medium-high ranking — were defined; moreover, each hint — redesign solution — had its redesign cost associated. Finally, a picture explained the meaning of the rule. Figure 2.3 shows the form containing the description of a rule, with some comments about the meaning of the fields used.

36


Table 2.1 Knowledge matrix of the first release of the DGLs Manufacturing requirements Design rules Assure compatibility between workpiece dimensions and workspace of the sintering machine (workspace is 250×250×185 mm) Minimise building time (building time increases with the height) Assure proper building conditions (the recoater may cause bending of parts with high form ratios)

Attributes Descriptions

Keep maximum Maximum Maximum size size below 185 size of the model mm Minimise the height

Height

Redesign solutions Split the model

Height of the model

Split the model Change orientation Minimise the Form ratio Ratio between Change form ratio the height and orientation the horizontal Add reinforcing cross-section of structures the model Minimise post-processing Avoid lower Lower Surfaces Add overhangs operations (lower surfaces surfaces surfaces oriented Change require external support which downward with orientation has to be removed an angle yMmax E2 M2 vs F1 E2=1 IF Zmin>zSmin AND Xmin>xSmin AND Ymin>ySmin ELSE E2=0 IF ZminySmin ELSE E2=0 IF Zmin

The Design Guidelines Collaborative Framework: A Design for Multi-X Method for Product Development

Design for Six Sigma: A Roadmap for Product Development

Engineering Design Methods: Strategies for Product Design

Engineering Design Methods: Strategies for Product Design

Inclusive design guidelines for HCI

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Guidelines for design of wind turbines Copenhagen

Product Design for Manufacture and Assembly

Understanding Product Design For Injection Molding

Product Design for Manufacture and Assembly

System Design Optimization for Product Manufacturing

Computer-aided pattern design and product development

Mechatronics in Engineering Design and Product Development

Guidelines for Design of Structures for Vertical Evacuation from Tsunamis

Guidelines for Design Solutions for Process Equipment Failures

Portable Electronics Product Design & Development

Design for Six Sigma: A Roadmap for Product Development Second Edition

The Method Framework for Engineering System Architectures

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Plastics Engineered Product Design

Plastics Engineered Product Design

Experience Design: A Framework for Integrating Brand, Experience, and Value

Principles of VLSI System Planning:: A Framework for Conceptual Design

New Product Development For Dummies

The Fundamentals of Product Design

A Framework for Complex System Development

Design for a New Europe

Collaborative Product Assembly Design and Assembly Planning: Methodologies and Applications

A framework for complex system development

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Urban Design: Method and Techniques (Urban Design)

The Design Guidelines Collaborative Framework: A Design for Multi-X Method for Product Development

Design for Six Sigma: A Roadmap for Product Development

Engineering Design Methods: Strategies for Product Design

Engineering Design Methods: Strategies for Product Design

Inclusive design guidelines for HCI

Collaborative design and planning for digital manufacturing

Guidelines for design of wind turbines Copenhagen

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Product Design for Manufacture and Assembly

System Design Optimization for Product Manufacturing

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Mechatronics in Engineering Design and Product Development

Guidelines for Design of Structures for Vertical Evacuation from Tsunamis

Guidelines for Design Solutions for Process Equipment Failures

Portable Electronics Product Design & Development

Design for Six Sigma: A Roadmap for Product Development Second Edition

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