Woollen and Worsted Woven Fabric Design

Woollen and worsted woven fabric design

Woollen and worsted woven

E. Grant Gilligan

Thek t i l e Institute

CRC Press Boca Raton Boston New York Washington, D.C.

WOODHEAD PUBLISHING LIMITED Cambridge England

Published by Woodhead Publishing Limited in association with The Textile Institute Woodhead Publishing Limited, Abington Hall, Atington Cambridge CB 1 6AH, England www.woodhead-publishing.com Published in North America by CRC Press LLC, 2000 Corporate Blvd, NW Boca Raton FL 33431, USA First published 2004, Woodhead Publishing Ltd and CRC Press LLC 0 2004, Woodhead Publishing Ltd The author has asserted his moral rights. This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. Reasonable efforts have been made to publish reliable data and information, but the author and the publishers cannot assume responsibility for the validity of all materials. Neither the author nor the publishers, nor anyone else associated with this publication, shall be liable for any loss, damage or liability directly or indirectly caused or alleged to be caused by this book. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming and recording, or by any information storage or retrieval system, without permission in writing from the publisher. The consent of Woodhead Publishing Limited and CRC Press LLC does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Specific permission must be obtained in writing from Woodhead Publishing Limited or CRC Press LLC for such copying. Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation, without intent to infringe. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Library of Congress Cataloging in Publication Data A catalog record for this book is available from the Library of Congress. Woodhead Publishing ISBN 1 85573 743 4 CRC Press ISBN 0-8493-2587-0 CRC Press order number: WP2587 Printed by Antony Rowe Ltd, Chippenham, Wiltshire, UK

Contents Preface ....................................................................................................... List of figures ................................................................................................ List of tables ...............................................................................................................................

.

1 Woollen and worsted weaving yarns 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20

.

...........................................................................

Introduction............................................................................................................ Woollen and worsted systems................................................................................ The woollen process .............................................................................................. The worsted process ............................................................................................... Micron suitability for woollen apparel end use ..................................................... Number of fibres in yarn cross-section .................................................................. Twist in single and folded worsted yams .............................................................. Direct yarn numbering system ............................................................................... Calculate Direct count from a given length and weight of yarn ............................ Convert Direct (Tex) to Direct (Denier) ................................................................ Convert Direct (Tex) to Indirect ............................................................................ Calculate average yarn counts in the Direct system .............................................. Resultant yam counts in the Direct system ............................................................ Indirect yarn numbering system........................................................................... Calculate Indirect count from a given length and weight of yam ........................ Convert Indirect to Indirect .................................................................................. Calculate average yarn counts in the Indirect system .......................................... Resultant yam counts in the Indirect system ....................................................... Yarn twist calculations......................................................................................... Yarn testing ..........................................................................................................

.........................................................................................

vii ix xi

1 1 1 1 3

4 5 6 6 7 7 7 8 9 10 10 11 11 12 13 14

15 2 Woven fabric construction 2.1 Introduction.......................................................................................................... 15 15 2.2 Relationship between yarn count and thickness .................................................. 2.3 Relationship between frequency of interlacings and density of fabric ................18 2.4 Diameter reciprocal. weave value and percentage reduction below maximum 18 setting ................................................................................................................... 2.5 Ashenhurst’s cloth setting formula ...................................................................... 19 2.6 Angle of curvature theory .................................................................................... 20 2.7 Law’s cloth setting formulae ............................................................................... 22 2.8 Different fabric weights. densities and in-loom particulars using woollen yarns ..................................................................................................................... 23 2.9 Suggested in-loom making particulars for menswear worsted fabrics ................33 2.10 Changing cloth weights and settings.................................................................... 39 2.1 1 Similar cloths formulae ........................................................................................ 41 2.12 How to calculate warp and weft weights for piece and sample length production ............................................................................................................ 46

vi Contents

2.13 2.14 2.15 2.16

Influences on both weight and dimensional changes in woven fabrics ...............47 Finished cloth analysis ......................................................................................... 48 How to calculate in-loom particulars from finished state .................................... 50 How to determine finished fabric weight in grammes per linear metre at standard finished width ........................................................................................ 51

.

...................................................................................................

.

..................................................................................

53 3 Woven fabric design .......................................................................................................... 3.1 Introduction 53 3.2 The weaving process ............................................................................................ 53 3.3 Basic weaves ........................................................................................................ 55 77 3.4 Simple warp and weft colour effects ................................................................... Drafting and pegging (English system) ............................................................... 85 3.5 94 3.6 Sleying (or Denting) ............................................................................................ 4 Design and fabric development 95 4.1 Introduction .......................................................................................................... 95 The role of the woven fabric designer ................................................................. 95 4.2 4.3 Section blanket making ........................................................................................ 98 4.4 Section blanket design and colour layouts ......................................................... 104 4.5 Common warps .................................................................................................. 110 4.6 Common drafts................................................................................................... 117 References ............................................................................................................................... 135 Index ....................................................................................................................................... 137

Preface After a working lifetime of more than forty years in various woollen and worsted weaving mills in Scotland and Yorkshire, plus five years with the International Wool Secretariat, I felt in retirement a desire to make some of that experience available to others. My work in the weaving mills consisted of marketing, designing, manufacturing and selling womenswear and menswear apparel fabrics for the markets of the UK, Europe and the United States. During my five years with IWS based at the Development Centre in Ilkley I was employed as Fabric Manager in the developing countries area, travelling extensively to work with the larger woollen and worsted weaving mills in India, Turkey, Algeria, Egypt and Morocco. It had been my experience in the weaving industry that many students on completion of their studies in design and technology were ill prepared in the practicalities of woven fabric construction, design and development. I found that when they came into industry for the first time, they had to rely heavily on the practical experience of an older generation of fastdisappearing, woven fabric designers and manufacturers to compensate for their shortcomings. Training of this older generation had always concentrated on the technical and practical side of cloth making rather than the aesthetic which appears to be the case today. If not addressed, this situation worldwide could only escalate. This book is my attempt to improve matters by providing explanations and answers to some of the technical and practical problems encountered in the development, design and manufacture of woven fabrics. E. Grant Gilligan

Figures Yarns A and B have the same weight and volume but different yarn counts ................. 15 Yarn A with a relative diameter of six. assume the yarn count is unknown ................... 16 Yarn B with a relative diameter of three. assume the yarn count is 25 Tex ..................17 Yarn A with a relative diameter of six. assume the yarn count is unknown ...................17 Yarn B with a relative diameter of three. assume yarn count is 16 sks Yorkshire woollen ........................................................................................................................... 17 2.6 Cross-section of 24 threads side by side just touching in the space of one inch ............18 2.7 Plain we.ave interlacing allows only 12 threads in the space of one inch ....................... 18 2.8 In 2/2 twill there is sufficient space to allow 16 threads in the space of one inch ..........18 2.9 In 3/3 twill only six interlacings provides space for 18 threads in the space of one inch .................................................................................................................................. 18 2.10 The square of the hypotenuse on a right-angled triangle is equivalent to the sum of the sauares of the other two sides ............................................................................... 21 2.1 la Yarn diameter takes up 4 squares on point paper ........................................................... 39 2.1 1b Yarn diameter takes up 3 squares on point paper ........................................................... 39 39 2.1 lc Yarn diameter takes up 6 squares on point paper ...........................................................

2.1 2.2 2.3 2.4 2.5

3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.1 1 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22 3.23 3.24 3.25 3.26

The basic requirements and principles of the weaving process ...................................... Terms used to describe fabric interlacings...................................................................... Plain weave as represented on point paper ..................................................................... Plain weave and derivatives ............................................................................................ Commoin twill as represented on point paper ................................................................. Twill weaves ................................................................................................................... Twill weaves (continued)................................................................................................ A sateen weave as represented on point paper ................................................................ Sateen weaves ................................................................................................................. Secondary weaves ........................................................................................................... Secondary weaves (continued) ....................................................................................... Basket weaves (or entwining twills) ............................................................................... Whipcords ....................................................................................................................... Backed cloths .................................................................................................................. Extra warp figuring ......................................................................................................... Double plains .................................................................................................................. Double plains (continued)............................................................................................... Double plains (continued)............................................................................................... Double plains (continued)............................................................................................... Double plains (continued)............................................................................................... Cramme.dline stripes ...................................................................................................... Extra warp stitched double cloths ................................................................................... Plain we.ave colouring arrangements .............................................................................. Plain weave colouring arrangements (continued)........................................................... Plain weave colouring arrangements (continued)........................................................... 2/2 twill colouring arrangements ....................................................................................

53 55 55 56 57 58 59 60 61 62 63 64 65 67 68 69 70 71 72 74 75 76 78 79 80 81

x Figures

3.27 3.28 3.29 3.30 3.3 1 3.32 3.33 3.34

2/2 twill colouring arrangements (continued)................................................................. 82 83 2/2 twill colouring arrangements (continued)................................................................. 84 Colouring arrangements for other weaves ...................................................................... Elementary example of design. draft and peg plan ......................................................... 86 Designs. drafts and peg plans for two simple herringbone effects ................................. 88 90 Example of a slightly more complex draft ...................................................................... Various types of drafts .................................................................................................... 92 Design. draft and peg plan for a herringbone design combined with another ................93

4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26 4.27 4.28 4.29 4.30 4.3 1 4.32

Five shades of grey fabric from three shades of grey yarn ............................................. 97 ‘In-loom’ dimensions for a three warp, three weft section blanket ................................ 99 ‘Finished’ dimensions of a three warp, three weft section blanket ............................... 100 Pattern material available from one section of a three warp, three weft blanket .......... 101 Unavoidable wastage in section blanket making .......................................................... 103 105 Contrasting warp and weft showing herringbone design effect.................................... 106 Only three colourways show the herringbone design effect ......................................... Dogtooth design with classic 4 & 4 colquring .............................................................. 107 Dogtooth design in 4 & 4 gunclub colouring................................................................ 108 Glen check (or Prince of Wales check) with a gunclub colouring arrangement...........109 Three different warp and weft set-in arrangements ...................................................... 111 Three colours moved up one place in each colourway ................................................. 112 113 Single warp section blanket .......................................................................................... 114 Single multicoloured warp section blanket ................................................................... 115 Four different designs from a single warp .................................................................... Four designs in white, grey and black combination on a single warp .......................... 116 Selection of designs which will weave on an 8 shaft straight draft .............................. 118 Selection of designs which will weave on a 16 shaft straight draft .............................. 119 Weaves using 2/2 twill standard interlacings in warp and woven from same draft ..... 120 Respective peg plans for designs in figure 4.19 ........................................................... 121 Designs which can be woven from the same 10 shaft draft .......................................... 122 Designs which can be woven from the same 10 shaft draft (continued) ...................... 123 Designs which can be woven from the same 10 shaft draft (continued) ...................... 124 Designs which can be woven from the same 10 shaft draft (continued) ...................... 125 Peg plans for previous eighteen designs ....................................................................... 126 Peg plans for previous eighteen designs (continued).................................................... 127 Different stripe designs from same 12 shaft draft ......................................................... 129 Different stripe designs from same 12 shaft draft (continued) ..................................... 130 Different check designs from same 16 shaft draft ........................................................ 131 Different check designs from same 16 shaft draft (continued)..................................... 132 Different check designs from same 16 shaft draft (continued)..................................... 133 Different check designs from same 16 shaft draft (continued)..................................... 134

Tables 1.1 1.2 1.3 1.4

Micron suitability for woollen apparel end use .................................................................. 4 Worsted yarn fibres per cross-section................................................................................. 5 Twist classification ............................................................................................................. 6 Indirect yarn numbering systems ...................................................................................... 10

2.1 ‘In-loom’ making particulars for different menswear jacketings made from the same single lambswool yarn ...................................................................................................... 25 2.2 ‘In-loom’ making particulars for different fabrics made fram the same single Shetland yarn ................................................................................................................................... 26 2.3 ‘In-loom’ making particulars for two different fabrics using the same two-ply Shetland yarn .................................................................................................................... 27 28 2.4 ‘In-loom’ making particulars for traditional Donegal cloths ............................................ 2.5 ‘In-loom’ making particulars for two Cheviot cloths, one with a single yarn and the other with a two-ply version of the same yarn .................................................................. 29 2.6 ‘In-loom’ making particulars for two lightweight worsted cloths .................................... 30 2.7 ‘In-loom’ making particulars for four novelty tweed jacketings and coatings for womenswear ..................................................................................................................... 32 2.8 ‘In-loom’ making particulars for four menswear worsted suiting cloths in plain weave ................................................................................................................................ 34 2.9 ‘In-loom’ making particulars for another four menswear worsted suiting cloths but this time in 212 twill .......................................................................................................... 37 4.1 Menswear fabrics in 2/52 nm worsted yarn ...................................................................... 96 4.2 Womenswear fabrics using 8.5 nm Shetland yarn ............................................................ 96

References Denton, M. J. and Daniels, P. N. (eds.) Textile Terms and Definitions, 10' edition, Manchester: The Textile Institute, 1995 1

1. Woollen and worsted weaving yarns 1.1 Introduction Some knowledge of yarns and yarn counts would appear to be a prerequisite in any study of woven fabric design and manufacture and this first section starts with a brief account of the yarn manufacturing processes of both woollen and worsted systems. There are two yarn numbering systems, the Indirect system which is seldom used now and the Direct system. Very few spinners today will be familiar with the Indirect Galashiels and Yorkshire woollen yarn systems, but it is quite likely that in many mills in Scotland and Yorkshire, records still exist of past successful cloths containing yarn details in these old systems. So if for no other reason, an ability to convert these yarn counts to the present day Direct system would be useful. Methods of calculating the average yarn count (where more than one count is used), and the resultant yarn count (when different yarn counts are twisted together) are provided in this section. Examples are given in both Direct and Indirect yarn numbering systems.

1.2 Woollen and worsted systems The basic difference between the two is that in the Worsted system all short fibres are removed and the remaining long ones are aligned parallel. In the Woollen system there is no removal of short fibres, so some fibres lie parallel and others randomly. The following from Textile Terms and Definitions (lothedition)’ describe differences between the two systems: Woollen, woollen yarn or woollen fabric is descriptive of the fibre - that is wool fibre spun on the woollen system. Woollen spun, woollen type fabric or condenser spun is descriptive of the system that is any fibre spun on the woollen system. Worsted, worsted yam or worstedfabric is descriptive of the fibre - that is wool fibre spun on the worsted system. Worsted spun or worsted type fabric is descriptive of the system. Some would say that the terms ‘woollen’ and ‘worsted’ have become system descriptive, with ‘wool’ being added to describe content - for example, ‘wool worsted’. Woollen yarns being so rarely 100% wool, a description of the blend is usually used if required - for example, 100%wool woollen spun or 100%wool woollen.

1.3 The woollen process A woollen fabric (as distinct from a worsted one) is made from yarns comprising of wool fibres of variable length, which have been spun on the condenser or woollen spun system. The fibres are allowed to lie haphazardly in spinning and the resultant yarns have a roughish appearance and full handle. Although the raw material for both woollen and worsted yarns is wool fibre, there are important differences. In woollen spinning a wide range of shorter wool types can be used in varying proportions in a blend, together with a limited amount of reprocessed or re-used wool in order to reduce the cost. In worsted spinning only pure new

2 Woollen and worsted woven fabric design

wool fibres of the longer type are used. Certain man-made fibres such as polyester can be blended in varying proportions with pure new wool and spun on either woollen or worsted systems, but such yarns will be neither ‘woollen’ nor ‘worsted’. The main processes in woollen yarn production are described briefly as follows:

Sorting: This was at one time a highly-skilled manual operation to select and divide the fleece into different qualities. It is now rarely used for that purpose, but occasionally to remove heavily contaminated, matted or weathered wool and heavily stained or pigmented patches. Scouring: Wool in its raw or greasy state is cleaned by mechanically passing it through a series of scouring bowls containing hot water and detergent, then rinsing and drying. The main contaminates removed during this process are wool grease (lanolin), animal sweat (suint), animal wastes and mineral dirt picked up from the grazing area. Depending on the country of origin, sheep wool type, fibre length and fineness, a minimum of 20% of the greasy wool weight will be lost during scouring. In extreme cases only 20% of the greasy wool weight might be wool fibre. The average Australian wool yields 65% clean, but this figure is slowly rising as farming methods improve. Carbonising: After scouring some wools contain seeds previously picked up by the sheep and these are removed by carbonising. This is a process that carefully treats the scoured wool with acid, dries it and then crushes the seeds or burrs into a powder that falls from the wool. As carbonising tends to weaken and discolour wool, it is processed as a small percentage of a blend. Blending: This describes the mixing of different fibre lots, which will provide the required quality and performance characteristics of the end product, at a specific price. Fibre lubricants are added at this time to improve processing performance. Depending on blend and end product, between 2% and 15% oil and anti-static additives may be applied. Carding and Condensing: The blended wool fibres are disentangled and mixed by passing through a series of large cylinders and rollers clothed with wire teeth. As the fibres pass along the card, spacing between the rollers is reduced, the wire teeth become finer and roller speeds increase. The material is transformed into an even web of fibres which is split lengthways into strands of untwisted slubbing, then wound onto spools in preparation for spinning. Spinning: Twist is added to the untwisted slubbings to convert them into strong, single yarns on the spinning machine. The mule spinning machine has a complex working action and is now more or less obsolete after the arrival of the more productive ring spinning frame. The mule consists of a carriage that travels backwards and forwards across the floor, drawing out the slubbing to the required thickness of yarn, whilst rotating spindles twist and wind the yarn onto tubes. Ring spinning frames have a higher production rate and larger take-up packages and perform the same functions as the mule, but on a faster and continuous basis. However, the mule produces a better yarn than the ring frame for a given raw material and quality requirement. Improved production speeds gained from more sophisticated engineering methods and computer control has resulted in a renaissance for mule spinning. Twisting: The resultant spun yarn can be used in single form, or folded with itself (or other yarns) for increased thickness, strength or effect.

Woollen and worsted weaving yarns 3

Dyeing:

This may be carried out on loose fibre, spun yarn or woven cloth, depending on the type of fabric required.

1.4 The worsted process A worsted fabric is an all wool cloth made from yarns produced on the worsted spinning system. This system for producing yarns from staple fibres has many more operational stages than those required for woollen yarn spinning. In worsted yarn spinning the drawing out operation to f6rm yarn employs several stages of drafting, together with a combing operation. This produces a yarn in which the fibres lie as parallel to each other as possible, after removal of the shorter fibres. The resultant yarn has a smooth, slick handle and appearance as well as good strength. Worsted yam spinning produces lighter and finer yarns and fabrics than woollen yarn spinning from the same fibre micron. Wool can be blended with selected manmade fibres and the resultant yarns combine the desirable properties of the components. For example, in a blend of wool and polyester, the fabric would have the superb handle and drape of wool, plus the easy care properties of the polyester. The early processes in the manufacture of worsted yarns are basically the same as for woollen yarns, namely blending, scouring and carding. There is however one difference in the blending process. The components in a worsted blend are combined in their greasy state and are usually of a similar quality, unlike a woollen blend, so no special blending is necessary since adequate: mixing takes place in subsequent processing. The extra processes in worsted yarn spinning after carding are described briefly as follows:

Preparatory Gilling:

The carded slivers are prepared for combing by drawing out a group of them between two pairs of rollers, to straighten the fibres. Between the pairs of rollers are pinned bars known as fallers, which control the fibre during drafting and improve the parallelism of the fibre.

Combing: This process is critical in the production of worsted yams. Between 20 and 30 slivers are fed into a combing mechanism, which removes most of the short fibres (noils) and further straightens the fibres, making them lie parallel to each other. The combed slivers are thereafter referred to as ‘tops’. Finisher Gilling:

By using further gill stages, the tops are blended and arrive at a specified and uniform linear density. They can then be sold to spinners for drawing and twisting into yarn.

Dyeing:

If coloured tops are required, they must be dyed before drawing and spinning, by forcing a dyeing solution through them. After further gilling and combing they are ready to be drawn and spun into yarn.

Drawing: The main objective in the drawing process is to gradually reduce the thickness of the top in three or four stages, to a roving from which yarn is spun. This is done by gill box drawing. The roving frame, the intermediate stage between gilling and spinning, drafts a fine sliver to a thickness which is suitable for the spinning frame and either adds a few turns of twist, or lightly rubs the sliver with a rolling action before winding the fibre onto a large bobbin. The twisting or rubbing action gives the fine fibre assembly some cohesion so that it can be pulled from the bobbin as it feeds into the spinning machine.

4 Woollen and worsted woven fabric design

Spinning:

The last processing stage where drafting is used to reduce the thickness of the fibre strand. In worsted spinning the material will be drafted at a ratio of 20 - that is, the fibre assembly will be 20 times longer at 20 times thinner when it leaves the delivery rollers, than it was when it entered the feed rollers. This is the highest draft the fibre will experience. Gill boxes usually have a draft of about 8 and roving frames 12. It is also much higher than woollen spinning where the draft is often less than 2, the final count being fixed at the card. The final count has some bearing on the spinning draft used, as will the type of fibre used for example, coarse counts spun from synthetic fibre may be drafted at 35 or more. Once the fibre has been drafted, the strand is then twisted and wound onto a package by the ring and traveller unit.

Final yarn processing: Winding machnes are fitted with devices for detecting and removing faults in the yarn, such as thick and thin places and this operation is known as clearing. Nearly all single worsted yarns are subsequently two-folded and this gives excellent performance in cloth production. The folding of single yarns of different colours can add to the aesthetic features of the yarn.

Microns

20

22

Lambswool fabrics

x x x x

x x x x x

Flannels Meltons Blankets Velour coats and jackets Heavy coatings Sports jackets Trousers and slacks Scottish tweeds Donegal tweeds Cheviots Harris tweeds

24

x x x x x x x x

26

28

30

32

34

36

x x x x x x x x x x x x x x x x x x x x x x

x x x

x x x x x x

Woollen and worsted weaving yams 5

Wool fibre diameter is usually expressed in microns (one micron = 1/1000 mm) and is expressed by the Greek letter p e.g. 20 p

:= 20 microns = 20/1000 mm or 1/50 mm fibre diameter.

Table 1.1 shows that low micron number wools are used for the finer and lighter weight types of fabrics and the medium to higher numbers for the coarser and heavier types.

1.6 Number of fibres in yarn cross-section In drafting and spinning, the number of fibres in the cross-section of a yarn is a factor of great importance. Table 1.2 shows typical numbers of fibres per cross-section in worsted yarns and how they are calculated. It is rare to see wool worsted single yarns with more than 42 fibres in the yarn crosssection due to the high cost of finer wool fibres. Only at microns greater than about 24, where the differential between microns is small, would more than 42 be used. In synthetic yarn production, where the raw material is relatively cheap and finer fibres have a smaller price ratio, then higher numbers of fibres in yam cross-section may be seen. 9 16.9 x Tex

Number of fibres per cross-section =

micron2

Table 1.2 Worsted yam fibres per cross-section

Fibre diameter (microns)

22

25

Yarn count (Tex)

Average number of wool fibres

30 35 20 25 30 35 40 25 30 35 40 45 50

35.6 50.8 63.5 76.2 88.9 37.9 47.4 56.8 66.3 75.8 36.7 44.0 51.3 58.7 66.0 73.4

I ,

6 Woollen and worsted woven fabric design

1.7 Twist in single and folded worsted yarns Table 1.3 Twist classification

Classification

Approximate folding twist in relation to single twist

Balanced twist

0.67 x single spinning twist

Hosierv yams

0.50 x single stinning twist

Suiting yams

1.00 x single spinning twist

Marl yarns

1S O x single spinning twist

The following formula is used to calculate the number of turns per metre to be inserted in a single or two-fold worsted yarn. Turns per metre =

0~

JResultant yam count (nm)

Single yarn = = 85 to 95 2 fold yarn = = 100 to 130

for plain yarns

I in pure new wool

Single yarn turns per metre = 95

J60

e.g.

2/60nm

= 735

2 fold yam turns per metre = 120 430 = 657 Most two-fold worsted yarns have the folding twist inserted in the opposite direction to single spinning twist. Although there are many exceptions, table 1.3 gives a guide to the twist classification of various yarn types.

1.8 Direct yarn numbering system In the Direct system, the yarn count number refers to ‘the weight in grammes of a given length of yarn’. This means the higher the yarn count number, the heavier or thicker the yarn. In the Direct universal Tex system, yam count number indicates ‘the weight in grammes of 1000 metres of yarn’.

e.g. 30 Tex indicates that 1000 metres of yam weigh 30 grammes, e.g. 50 Tex indicates that 1000 metres of yam weigh 50 grammes, e.g. 70 Tex indicates that 1000 metres of yam weigh 70 grammes. In the Direct denier system, the yarn count number indicates ‘the weight in grammes of 9 000 metres of yarn ’. Decitex (or Dtex) yarn count number indicates ‘the weight in grammes of 10 000 metres of yarn ’.

Woollen and worsted weaving yarns 7

1.9 Calculate Direct count from a given length and weight of yarn C L Wt L1

= yarncoiint = length of yarn sample (metres) = weight of yam in units of the system at official regain = unit of length of the system

C =

Wt x 1.1 L

Example 1

C =

1.67 x 9000 100 = 150.3 = 150Denier

Example 2

c =

?weightof yarn sample = 1.67 grammes length of yarn sample = 100 metres unit of length (Denier) = 9000 metres

>weightof yarn sample = 1.75 grammes length of yam sample = 90 metres unit of length (Tex) = loo0 metres

1.75 x 1000 90 = 19.44Tex

1.10 Convert Direct (Tex) to Direct Denier Multiply Tex count by 9

Example 1

:30 Tex = 30 x 9 = 270 Denier

Example2

40Tex = 40 x 9 = 360Denier

Example3

60Tex = 60 x 9 = 540Denier

Conversely, to (convertDirect (Denier) to Direct (Tex), divide Denier count by 9

Example 4

180 Denier = 180 / 9 = 20 Tex

Example5

450Denier = 45019 = 50Tcx

Example 6

225 Denier = 225 / 9 = 25 Tex

1.11 Convert Direct (Tex) to Indirect To convert Tex to any in the Indirect system, the following constants may be used: 1000 x 12 x 454 Tex x 11 x 840 = 590Cottonconstant

8 Woollen and worsted woven fabric design

1000 x 12 x 454 Tex x 11 x 560 = 884 Worsted constant 1000 x 12 x 454 Tex x 11 x 496 = 1OOOMetricconstant 1000 x 12 x 454 Tex x 11 x 256 = 1935 Yorkshire woollen constant

590 = Tex

Tex to Cotton

590 e.g. 45 Tex

884 Tex to Worsted = Tex 1000 = Tex

Tex to Metric

= 13.1 Cotton

884 = 17.7 Worsted

e.g. 50Tex

50

e.g. 20Tex

1000 20 = 50 nm Metric

1935 Tex to Yorkshire = Tex

45

1935 e.g. 100Tex

100 = 19 sks Yorkshire

Tex (2ply) to Worsted (2ply)

884 R38Texl2 =

38 = 23.26 = 2/46 worsted

884 R42 Tex I 2 =

42 = 21.05 = 2/42 worsted

884 R48 Tex I 2 = R52Texl2 =

48 = 18.42 = 2/36 worsted 884 -

52 = 17.00 = 2/34 worsted

884 R56Texl2 =

56 = 15.78 = 2/32 worsted

1.12 Calculate average yarn counts in the Direct system To determine the average yarn count of two or more yams, calculate the arithmetical mean as follows:

Example 1

1 thread of 30 Tex 1 thread of 60 Tex 2 threads = 90 Tex

90 Average yarncount = 2 = 45Tex

Woollen and worsted weaving yarns 9

Example 2

1 thread of 17 Tex 1 thread of 20 Tex 1 thread of 50 Tex 3 threads = 87 Tex

87 Average yarncount = 3 = 29Tex

Example 3

2 threads of 20 Tex 1 thread of 30 Tex ,1 thread of 35 Tex ,4 threads = 105 Tex

105 Average yarncount = 4

Example 4

= 26.25Tex

1 thread of 40 Tex :2 threads of 25 Tex 3 threads of 30 Tex 6 threads = 180 Tex

180 Average yarncount = 6 = 30Tex 1.13 Resultant yarn counts in the Direct system Example 1

'75 Tex / 45 Tex

--

R120 Tex / 2

Example 2

60 Tex / 30 Tex

-

R90 Tex / 2

Example 3

60 Tex / 40 Tex / 30 Tex

=

R130 Tex / 3

Example 4

20 Tex / 20 Tex / 40 Tex

=

R80 Tex / 3

Example 5

30 Tex / 30 Tex / 30 Tex

=

R90 Tex / 3

Example 6

SO Tex / 25 Tex

-

R75 Tex / 2

Percentage take-up has not been allowed for in the above samples 2

threads of 30 Tex are written as R60 Tex / 2

2

threads of ;!O Tex are written as R40 Tex / 2

3

threads of 100 Tex are written as R300 Tex / 3

2

threads of 300 Denier are written as R600 Denier / 2

10 Woollen and worsted woven fabric design

1.14 Indirect yarn numbering system Table 1.4 Indirect yarn numbering systems ~~

Name

Area

Length unit

Weight unit Standard no.

Worsted

Universal

Hanks of 560 yards Per 1 Ib.

560

Cotton

Universal

Hanks of 840 yards Per 1 lb.

840

Galashiels

Scotland

Cuts of 300 yards

Per 1.5 lbs.

200

Yorkshire

Yorkshire

Skeins of 256 yds.

Per 1 lb.

256

Metric

Europe

Metres

Per gramme

496

Table 1.4 shows the various Indirect systems, most of which (with the exception of Metric) are hardly ever used today. The number given to a yarn is an indication of its thickness and is referred to as the yarn count. In the Indirect system, yarn count number refers to ‘the number of length units in a given weight of yam’. The higher the yam count number, the finer or thinner the yam. 1/20 worsted indicates 20 x 560 yards of yam weigh 1 pound. 1/40 worsted indicates 40 x 560 yards of yarn weigh 1 pound. 1/30 cotton indicates 30 x 840 yards of yarn weigh 1 pound. 1/48 cotton indicates 48 x 840 yards of yarn weigh 1 pound.

15 cut Galashiels indicates 15 x 200 yards of yarn weigh 1 pound. 28 cut Galashiels indicates 28 x 200 yards of yarn weigh 1 pound. 16 skeins Yorkshire indicates 16 x 256 yards of yarn weigh 1 pound. 24 skeins Yorkshire indicates 24 x 256 yards of yarn weigh 1 pound. 30 nm Metric indicates that 30 x 496 yards of yam weigh 1 pound. 50 nm Metric indicates that 50 x 496 yards of yam weigh 1 pound.

1.15 Calculate Indirect count from a given length and weight of yarn C L W Wt S

= = =

= =

c =

yarncount length of yarn sample (yards) unit of weight of the system weight of yarn sample in units of the system at official regain standard number of the yarn system LXW WtxS

Woollen and worsted weaving yarns 11

Example 1

Weight of yam sample Length of yarn sample Standard no. (worsted) Unit of weight (llb.)

120 x7000' C =

50 x 560

Example 2

= =

50 grains 120 yards = 560 yards = 7000 grains

= 30 = 2160worsted

Weight of yarn sample = 90 grains Length of yarn sample = 75 yards Standard no. (Yorkshire) = 256 yards Unit of weight (llb.) = 7000 grains

75 x7000 C =

90 x 256

= 22.79 = 23 sks Yorkshire woollen

1.16 Convert Indirect to Indirect Example 1

.Convert 2/48 worsted to Metric 48 x 560 496 = 54.19 = 2/54 nm

Example 2

Convert 24 sks Yorkshire woollen to Worsted 24 x 256 560 = 10.97 = 2/22 worsted

Example 3

Convert 2/40 cotton to Metric 20 x 840 496 = 33.87 = 2/68nm

Example 4

Convert 15 cut Galashiels to Yorkshire woollen 15 x 200 256 = 1 1.7 = 11.7 sks Yorkshire woollen

Example 5

Convert 16 sks Yorkshire woollen to Metric 16 x 256 496 = 8.3 = 8.3 nmMetric

Example 6

Convert 2/20 cotton to Galashiels woollen 10 x 840 200 = 42.0 = 42cut Galashiels

1.17 Calculate! average yarn counts in the Indirect system Example 1

1 end of 2/40 worsted (20s) 1 end of 2/30 worsted (15s)

12 Woollen and worsted woven fabric design

60 units of 20s = 3 x 1 = 3.0 60 units of 15s = 4 x 1 = 4.0 2 = 7.0 60 x 2 7.0 = 17.14 = 2/34 worsted

Average count =

Example 2

1 end of 20 sks Yorkshire woollen 1 end of 30 sks Yorkshire woollen 2 ends of 18 sks Yorkshire woollen

30 units of 20 sks = 1.50 x 1 = 1.50 30 units of 30 sks = 1.00 x 1 = 1.00 30 units of 18 sks = 1.67 x 2 = 3.34 4 = 5.84 30 x 4 5.84 = 20.55 = 20.5 sks Yorkshire woollen

Average count =

Example 3

1 end of 40s cotton 1 end of 16s worsted

1/16 worsted to Cotton = 16units of 10.67 16 units of 40

Average count =

16 x 560 840 = 10.67s Cotton

= 1.50 x 1 = 1.50 = 0.40 x 1 = 0.40 2 = 1.90

16 x 2 1.90 = 16.84 = 16.8 Cotton

1.18 Resultant yarn counts in the Indirect system The resultant yarn count is the count of two or more yarns twisted together.

Example 1

24 sks Yorkshire / 16 sks Ysrkshire 24 units of 24 sks = 1.00 24 units of 16 sks = 1.50 24 units of ‘x’ = 2.50 24.00 Resultant count = 2.50 = 9.6 sks Yorkshire

Example 2

24 worsted / 32 cotton First convert 32 cotton to worsted =

32 x 840 = 48 worsted 560

Woollen and worsted weaving yarns 13

48 units of 24s = 2.00 48 units of 48s = 1.00 48 units of ‘x’ = 3.00 48.00 Resultantcount = 3.00 = 16 worsted

Example 3

56 worsted / 48 worsted / 2/80 cotton 40 x 840 Convert 2/80 cotton to worsted = 560 = 60 worsted

60 units of 56 60 units of 48 60 units of 60 60 units of ‘x’

= = = =

1.07 1.25 1.00 3.32

60.00 Resultant count = 3.32 = 18.07 = 18 worsted Percentage take-up means extra length of single yarns per unit length of folded but has not been included in the foregoing examples. However it must be allowed for in any such calculations, in order to give an accurate resultant count. Take-up is variable and depends on the thickness of the component yams and the number of turns per inch inserted in the twisting operation. The more turns per inch inserted, the greater percentage take-up and thicker resultant count.

1.19 Yarn twist calculations A much used calculation is the one to determine the unknown component yarn count in a two ply twist yam, when the other single component yarn count and the resultant count are both known. Indirect systein:

Example 1 A two ply twist yarn of 8 metric resultant count is composed of one thread of 24 metric count and one thread of an unknown count. What is the unknown yarn count? 24 units of 24 metric = 1 24 units of ‘x’ metric = ? 24units of 8 metric = 3

so 24units of ‘x’ metric = 3 - 1 = 2

Therefore the unknown yarn count is equal to 24 divided by 2 = 12 metric

Example 2 A resultant two ply yarn count of 16 worsted has one component yam of 36 worsted. Wha.t is the count of the other component? 144 units of 36 worsted = 4 144 units of ‘x’ worsted = ? 144 units of 16 worsted = 9 so 144 units of ‘x’ worsted = 9 - 4 = 5

14 Woollen and worsted woven fabric design

Therefore the unknown yarn count is equal to 144 divided by 5 = 28.8 worsted. Direct system:

Example 1 A two ply yarn in Tex (Direct system) is composed of one thread of 40 Tex, one thread unknown count and has a resultant count of 100 Tex. What is the count of the other component yarn? The simple answer to this one is 100 minus 40 which is 60 Tex, the count of the unknown yarn. Example 2 A three ply yarn in Tex (Direct system) is made up of one thread 50 Tex, one thread of 70 Tex and one unknown Tex count. The resultant count is 150 Tex. The unknown yarn count this time is 150 minus 50, minus 70 which gives the count of the third component as 30 Tex. 1.20 Yarn testing In industry today, sophisticated apparatus and methods are used to test and assess the various properties of yarns. Whilst it is not within the scope of this publication to deal with such apparatus and test results, it is relevant to list the properties: Yarn count Count variation between bobbins Mean breaking strength Mean elongation at break Breaking strength variation Elongation at break variation Evenness Number of thick and thin places and neps Faults (slubs, fly, piecings etc.) Hairiness Twist Twist variation between bobbins.

This chapter has fulfilled the need for knowledge of yarns, yarn counts and yarn manufacturing processes mentioned in the introduction. It has presented a general understanding of the subject without an in-depth study as woven fabric designers are unlikely to be asked to solve carding and spinning problems as there are others better qualified to do so. The study of both Direct and Indirect yarn numbering systems has concluded that the Direct system is the simpler and more straightforward of the two to use. Calculations for average yam count, resultant yarn count and yarn twist are much easier to determine in the Direct system.

2. Woven fabric construction 2.1 Introduction The basics of' woven cloth construction are explained in thisBchapter as well as cloth setting rules and formulae. There are also various tables that show full making particulars for different fabrics using the same yarn count for womenswear and menswear woven apparel fabrics. They are all commercially acceptable fabrics and provide accurate guides when developing cloths in other yarn counts. A very important part of a woven fabric designer's job is that of cloth adjuster and modifier; where existing fabrics are sometimes required to be made in a different weight, weave, yarn (,orall three), whilst preserving the firmness of the original cloths. These changes are almost impossible to carry out correctly without a sound understanding of the necessary formulae. This chapter contains several examples of how to use these formulae. At various stages throughout the weaving and finishing processes, changes in fabric weight and dimension take place. These changes have to be anticipated and allowed for, so that the finished fabric is delivered to the customer at the standard finished width and within the originally quoted weight in grammes per running metre. Finished cloth analysis is another important subject dealt with here. Fabrics obtained from customers and elsewhere are often copied for all sorts of reasons and accurate determination of the finished properties of such cloths is essential. These results are then adjusted to give the necessary in-loom making particulars to accurately reproduce the cloths. The topics in this section address the practical cloth-making responsibilities of the woven fabric designer, rather than the creative and aesthetic ones.

2.2 Relationship between yarn count and thickness Before considering cloth setting formulae it is important to fully understand the relationship between the count of a yarn and its thickness, see figure 2.1. Assuming it is possible to draw out yarn A to four times its original length, resultant yarn B will be thinner with a reduced radius and both yarns will have the same weight and volume but different yarn counts. The weight of 20 crns of yarn B will be the same as 5 crns of yarn A, so 5 crns of yarn B will weigh one quarter of 5 crns of yarn A. If yarn A is say 100 Tex, then drawing it out to four times its original length makes resultant yam B equal to 25 Tex.

2.1 Yarns A and B have the same weight and volume but different yarn counts.

16 Woollen and worsted woven fabric design

Volumes of yams A and B are the same, both being equal to the area of cross-section multiplied by length.

z A 2 x 1 = ITB’ x 4 A2 = B2x4 A = B X2 As A = B x 2, the radius of yarn A is twice the radius of yarn B, therefore yam A is twice the thickness of yarn B. In the Direct Tex yarn numbering system, by quartering the yarn count the thickness is halved. The example below shows that 25 Tex is half the thickness of 100 Tex. From this it can be established that the thickness or diameter of a yarn is directly proportional to the square root of its count. Diameter of 25 Tex : diameter of 100 Tex = --

fi

: 5 : 10

1 :

2

Therefore 25 Tex is half the diameter or thickness of 100 Tex Having just proved that in the Direct Tex yam numbering system the thickness or diameter of a yarn is directly proportional to the square root of the count, figures 2.2 and 2.3 and the following equations may explain this more clearly in another way.

-4

-

JCount A

Diameter B Diameter A

6

Jcount A

JcountA = (&EX6 ) / 3 = Count A =

10

100 Tex

2.2 Yarn A with a relative diameter of six, assume the yarn count is unknown.

Woven fabric construction 17

2.3 Yarn B with a relative diameter of three, assume the yarn count is 25 Tex.

2.4 Yarn A with a relative diameter of six, assume the yarn count is unknown.

2.5 Yarn B with a relative diameter of three, assume yarn count is 16 sks Yorkshire woollen.

In the Indirect yarn numbering system the yarn thickness or diameter is inversely proportional to the square root of the count. Figures 2.4 and 2.5 explain how using Yorkshire skeins woollen yarn counts.

Diameter B

JCount A

3

JCount A

= Count A =

2 4 skeins Yorkshire woollen

Diameter of :16 sks YSW : diameter of 4 sks YSW = = =

fi : & 2 : 1 :

Therefore 16 sks YSW is half the diameter of 4 sks YSW.

4 2

18 Woollen and worsted woven fabric design

2.3 Relationship between frequency of interlacings and density of fabric

---2.6 Cross-section of 24 threads side by side just touching in the space of one inch.

2.7 Plain weave interlacing allows only 12 threads in the space of one inch.

~~

2.8 In 2/2 twill there is sufficient space to allow 16 threads in the space of one inch.

--

2.9 In 3/3 twill only six interlacings provides space for 18 threads in the space of one inch. Figures 2.6 to 2.9 inclusive show clearly that if the same thickness of yarn is used in different weaves, for example, plain weave, 2/2 twill and 3/3 twill, the fewer interlacings there are in the weave, the greater the number of threads that can be packed into the same space. In order to make the examples as simple as possible, Ashenhurst’s original theory that one interlacing takes up the same space as one thread has been applied. This theory was subsequently found to be somewhat inaccurate and replaced by the angle of curvature theory which is dealt with in a later section.

2.4 Diameter reciprocal, weave value and percentage reduction below maximum setting Cloth setting indicates the number of ends and picks per inch (or centimetre), to be inserted during the weaving process. It is influenced by the density and thickness of the yarn used and the firmness of the weave. A cloth setting formula comprises three parts: 1) Diameter reciprocal: The first part of the setting formula determines the maximum number of threads in a particular yarn count that can be laid side by side just touching in the space of one inch. Attempts to establish a relationship between yarn count and diameter reciprocal were made by Thomas Ashenhurst in the early 1880’s when he provided the following formula for worsted yarns: Diameter reciprocal = 0.9 JYarn Count xStandard number This can be applied to any Indirect yarn numbering system, using the appropriate yarn counts and standard numbers.

Woven fabric construction 19

2) Weave value: After the diameter reciprocal has provided the number of threads in a particular yarn count that can be laid side by side in one inch, an allowance is made for the spaces required for warp and weft interlacings in the particular weave to be used. This value for any given weave can be determined as follows: Weave value = F/(F+l), where F = average float e.g. Plain weave = l/(l+l) = 1/2 2/1 twill = 1.5/(1.5+1) = 1 3 2 . 5 212 twill = 2/(2+1) = 2/3

3) Percentage reduction below maximum setting: By using the diameter reciprocal and weave value parts of the formulae, theoretical maximum setting is determined. The figure however is further reduced to give the actual number of ends and picks per inch to be inserted during weaving. This percentage figure is based on experience and comparison with other commercially acceptable fabrics. This final reduction influences firmness, drape, handle, weight and suitability of the fabric for its intended end use.

2.5 Ashenhurst’s cloth setting formula Maximum sett = k ,/Yards per pound x F/(F+l) = ends, picks per inch.

k value for woollens = 0.84 k value for worsteds = 0.90 k value for cottons = 0.95

and F = average float.

Diameter reciprocal (woollens)

= 0.84 Jcount x standard number

Diameter reciprocal (worsteds)

= 0.90 Jcount x standard number

Diameter reciprocal (cottons)

= 0.95 Jcount xstandard number

Maximum setting (plain weave)

= k ,/yards/lb x YZ

Maximum setting (2/1 twill)

=k

Maximum setting (2/2 twill)

= k ,/yards/lb x 2/3

Jyardsnb x

132.5

Ashenhurst arrived at a weave value of F/(F+l) by allowing the equivalent of one thread space for each intersection in the weave. This was later proved to be inaccurate on two points: 1)

The angle of curvature theory showed geometrically that the space occupied by one intersection in a weave was less than the diameter of one thread - actually 0.732 of a diameter. See section 2.6.

20 Woollen and worsted woven fabric design

In floats longer than two it was likely that threads would bunch together and roll over each other to a certain extent, rather than lie conveniently side by side as Ashenhurst had originally assumed, thereby making more ‘space’ than that required for exactly one thread. Later setting theories (such as Law’s) take these points into consideration but Ashenhurst’s original theory, though on the low side for determining maximum ends and picks per inch, remains reasonably accurate for plain weave, 2/1 twill and 2/2 twill. Ashenhurst’s formula for determining diameter reciprocal used the Indirect yarn numbering system, but adjustments can be made to accommodate Direct yam numbering systems such as Tex. 2)

Yards per pound of any Tex yarn count can be calculated as follows:

lo00 x 39.37 x 454 Tex x 36

-

496 499 Tex

For example, diameter reciprocal for worsted yarn in Tex count is: 0.9 -/,

= 0.9

4

G /Tex

= 6341

6

Bearing in mind that Ashenhurst’s settings are lower than those of his successors a more accurate value might be: 660 / &. Cloth setting is not an exact science so determination of maximum setting using diameter reciprocal and weave value should only be accepted as an accurate starting point. The actual number of ends and picks per inch (or centimetre) to be inserted during weaving is decided after deliberation on what percentage reduction is made to the calculated maximum setting. The following are examples using the original Ashenhurst setting formula:

Example 1 Calculate setting for a fabric using 20 sks Yorkshire woollen yarn in plain weave, 20%below maximum setting. Sett = 0.84

Jyardsnb x F/(F+l)

x percentage reduction.

= 0.84 420x256 x 95 x 80/100 = 24.04 ends and 24.04 picks per inch.

Example 2 Calculate setting for a 2/2 twill fabric, 10% below maximum setting using 2/56 worsted yarn. Sett = 0.90 428x560 x 2/3 x 90/100 = 67.6 ends and 67.6 picks per inch. If ends and picks per centimetre are preferred, calculated ends and picks per inch are simply divided by 2.54.

2.6 Angle of curvature theory In figure 2.10 the angle between adjacent threads at an intersection is assumed to be 30” in a balanced, square woven cloth.

Woven fabric construction 21

2.10 The square of the hypotenuse on a right-angled triangle is equivalent to the sum of the squares of the other two sides.

AB = 2 diameters (or 1 diameter plus 2 x ‘/2 diameters) = 2 AC = 2 x!hdiameters = 1 CB is unknown

= 1.73:2

Therefore, if CB equals one diameter plus one interlacing, then one intersection is equal to 1.732 - 1 =: 0.732 After the angle of curvature theory Ashenhurst’s new formula for maximum setting became: DR x F/(F+I) where DR = diameter reciprocal F = average float in weave I = intersection = 0.732 Weave value for plain weave = 1/(M.732) = U1.732 = 1 S/(1.5+0.732) = 1.Y2.232 Weave value for 211 twill Weave value for 212 twill = 2/(2+0.732) = 2/2.732 Comparing the original Ashenhurst formula with the later one based on the angle of curvature theory for a 2/2 twill fabric with a DR of 63 below: Old formulil = 63 X 2/(2+1) = 63 X 2/3 = 42 ends, picks per inch. Later formula = 63 X 2/(2+0.732) = 63 X 212.732 = 46 ends, picks per inch. Ashenhurst’s original formula (diameter intersection theory) gives firm cloth settings for plain weave, 2/1 twill and 212 twill but is not used much when the average float is more than two. Law experimented to increase the maximum setting of square sett cloths and came up with the formula J500X yarn count to find the DR for a yarn. He also added 5% for each float above two. Below is a comparison between the two theories for an imaginary setting in a 3/3 twill cloth made with 2/18 worsted yarn count:

22 Woollen and worsted woven fabric design

Ashenhurst for 3/3 twill = 0.9 49x560 x 3/4 Law for 3/3 twill

=

9500x9 x

= 48 ends, picks per inch.

3/4 x 1.05 = 53 ends, picks per inch.

2.7 Law's cloth setting formulae Maximum sett = 4500 x C x F/(F+ 1) + 5% for every end in the average float above 2. This is the setting rule generally used in the Worsted industry. Maximum sett =

JG x F/(F+l) + 5% for every end in the average float above 2.

This is the setting rule generally used in the Yorkshire woollen industry. Law's rules for maximum settings in the following weaves: 2/2 hopsack: DR x F/(F+l) + 4.5% = DR x 2/3 x 1.045 3/3 hopsack: DR x F/(F+l) + 9.5% = DR x 3/4 x 1.095 4/4 hopsack: DR x F/(F+l) + 19% = DR x 4/5 x 1.190 Sateens:

DR x F/(F+l) + 5.5% for every end in the average float.

Backed cloths: 2/2 twill lFace, lBack warp or weft backed fabric, sateen stitched, reduce face setting by 6.75%. 2/2 twill lFace, lBack warp or weft backed fabric, twill or crow stitched, reduce face setting by 13.5%. Self-stitched double cloths: 2/2 twill lFace, lBack double cloth, sateen stitched, reduce face setting by 10%. Twill or crow stitched, reduce face setting by 20%. Double sateen stitched, reduce face setting by 20%. Double twill stitched, reduce face setting by 25%. Double crow stitched, reduce face setting by 25%. Non-square cloths: Sometimes it is desirable to construct a cloth with a steeper twill than the normal 45" of a square sett cloth and this can be simply done by increasing the number of warp ends per inch. However, the difficult part is to determine the reduced number of weft picks per inch which will maintain the same degree of firmness in the cloth. For example, a square sett 2/2 twill cloth which might normally have 64 ends and picks per inch can be made instead with 120 ends per inch in order to give a much steeper twill effect. The reduced number of weft picks per inch is calculated as follows: If X is the increase in ends per inch above square sett, the decrease in picks per inch is = 1.8 .$56 = 13.5 decrease in picks per inch. 1.8 1 . 8 z

-4

Woven fabric construction 23

So the setting required to preserve the firmness of the original square sett cloth will be 120 ends and 50 (64-14) picks per inch. Alternatively, the same square sett 2/2 twill fabric with 64 ends and 64 picks per inch can be adjusted to say, 96 picks per inch to give a flat twill effect. In this case the reduced number of ends per inch is calculated as follows:

If X is the increase in picks per inch above square sett, then the decrease in ends per inch 3.6 = 3.6 = 20.36 decrease in ends per inch. is 3.6 f i

4

s

a

Therefore, the setting required to preserve the firmness of the original square sett cloth is 96 picks and 44 (64-20) ends per inch.

2.8 Different fabric weights, densities and in-loom particulars using woollen yarns One yarn count can be used to make at least three different, basic cloths:

1) 2) 3)

Plain weave 2/1 twill 2/2 twill.

They will be different to each other in weight, density, drape, handle, price and end use. Each of the three cloths can be made in lighter and heavier versions - the lighter ones with fewer ends and picks per centimetre, heavier ones with more ends and picks per centimetre. In determining cloth setting, care must be taken to ensure that lighter weight versions are not too loosely sett below maximum; otherwise seam slippage might become a problem in garments. At the other end of the scale, cloths which are too firmly sett might be difficult to weave owing to excessive warp end breakages. So before actually using cloth setting formulae it is advisable to consult ‘in house’ fabric making records.kept by all woven cloth manufacturers, in order to find a starting point by comparing weight and firmness of commercially acceptable cloths. As there is no formula to calculate the required total number of warp threads in loom to give a standard finished fabric width of 150 crns, the same ‘in house’ records will provide guidance. Cloth setting is more than just calculating the number of warp ends and weft picks per centimetre to be inserted during weaving using a particular yam count and weave structure. Desired weight in grammes per linear metre has to be considered, as well as the aforementioned total number of warp ends to produce a cloth of 150 crns finished width. Pieces that finish under the standard width will cause problems for the garment maker and might well be rejected. Finished widths that are two or three centimetres over 150 crns will probably be acceptable to the customer, but the cloth manufacturer will be giving cloth away as costings are (calculatedfor 150 crns finished width. The following series of tables (2.1 to 2.7 inclusive) are given as accurate guides to ‘inloom’ making particulars. As well as recommended warp and weft details, they show resultant weights in grammes per linear metre and total number of threads required to produce fabrics at standard finished width. They also show percentage width shrinkage from ‘in-loom’ width, as well acs finished length yield from a standard 70 metre warp length. The cloth setting formula shows how loom ends and picks per centimetre are calculated and then rounded up or down to give the appropriate metric reed and picks per 10 crns to be inserted in loom.

24 Woollen and worsted woven fabric design

The data provided in the tables is from commercially acceptable fabrics and serves as an accurate guide for developing other pure new wool woven fabrics. Table 2.1 shows full ‘in-loom’ making particulars for three different menswear jacketing cloths made from the same single lambswool yarn in 2/2 twill weave. They are different in weight, firmness, drape, handle and price. From the same calculated maximum number of ends and picks per centimetre in loom, Cloth 1 is reduced by 45%,Cloth 2 by 35% and Cloth 3 by 25%. Each is then rounded up or down to give the appropriate metric reed required and number of picks per 10 crns to be inserted during weaving. Note that as percentage reduction below maximum becomes less, settings are firmer and width shrinkages decrease. As previously stated no formula exists with which to calculate the total number of ends required in the warp to give 150 crns standard finished width of cloth. Experience of and comparison with existing commercially acceptable fabrics is essential. Cloths 4, 5, 6 and 7 in table 2.2 are made from the same single Shetland yarn. Two of the cloths are made in plain weave, the other two in 2/2 twill. The cloths in plain weave are sett firmer (see column 14 showing percentage reduction below maximum setting) and are suitable for womenswear lightweight jackets and skirts. The fabrics in 2/2 twill are sett looser and wider in loom and make excellent jacketings for both womenswear and menswear. Two-ply versions of the above Shetland yarn, one in plain weave the other in 2/2 twill are featured in table 2.3. Plain weave Cloth 8 is sett 25%below maximum but there is no technical reason why a reduction of 20% or 30% cannot be used as it is entirely a question of personal preference and experience. Heavier Cloth 9 in 2/2 twill is sett wider in loom to allow greater width shrinkage in finishing and ensure the desirable fuller handle in a womenswear coating. Table 2.4 features four traditional Donegal cloths suitable for both womenswear and menswear garments. Cloths 10 and 11 are made from the same Donegal yarn in plain weave and 2/2 twill respectively. Both are ideally suitable for jacketings in the characteristic homespun look. Cloths 12 and 13 are also in plain weave and 2/2 twill respectively, but this time made from a typical Donegal yarn twice the thickness of the one used in Cloths 10 and 1 1 . Notice how percentage reduction below maximum setting in both plain weave fabrics is fairly similar, as is also the case with the twills. Two Cheviot wool cloths are featured in table 2.5, one of which, Cloth 15, is made in 2/2 twill from a single Cheviot yarn of 7 nm count warp and weft. It is sett 45%below maximum and gives a finished cloth weight of 385 grammes per linear metre 150 crns finished width. This is an ideal jacketing cloth for both men and women. Plain weave Cloth 14 is made with a two-ply version of the same Cheviot yarn, sett firmly in loom (only 10%below maximum) to give a substantial coating fabric for womenswear. Two lightweight worsted cloths are shown in table 2.6, one in plain weave the other 2/2 twill and both made with the same 2/48 nm worsted yarn. Plain weave Cloth 16 is firmly sett 5% below maximum whilst 2/2 twill Cloth 17 is sett looser at 15% below. These firmer settings give the sleek, smooth yet firm handle associated with worsted fabrics and both fabrics are suitable for lightweight menswear jacketings.

Total

175.0

185.1

186.8

(ems)

Loom width

150

150

150

Std.fin. width (crns)

x 213 x 751100 x U2.54 = 12.49 ends, pickskm = 3014 reed (120ends/lOcrn), 125 picks/lOcm.

0.84

25%

63.5

Cloth 3

35%

45%

Sett below max.

63.5

63.6

Std.fin. length (metres)

x 2/3 x 651100 x 1/2.54 = 10.82 ends, picks/cm = 51/2 reed (102ends/10cm), 110 picks/lOcm.

70

70

70

Std.wp. length (metres)

0.84 -/I

14.3

18.9

19.7

%

Width shkge

Cloth 2

x % below maximum x U2.54 = ends, picks per cm.

2100

1888

1756

ends

x 2/3 x 55/100 x V2.54 = 9.16 ends, picks/cm = 47/2 reed (94ends/lkrn), 95 picks/l&m.

Jyardsnbx F/(F+l)

11.5

11.5

11.5

(nm)

Weft yarn

0.84 -/I

k

11.5

11.5

11.5

Warp yarn (m)

Cloth 1

To calculate in loom

2/2twill

125

375

3

30/4

2/2 twill

110

5112

345

2

U2twill

95

47/2

3 10

Weave

1

Picks/ 10 crns

Metric reed

Weight grm/lm

Cloth No.

Table 2.1 ‘In-loom’making particulars for different menswear jacketings made from the same single lambswool yarn

85

85

90

95

40/2

45/2

40/2

45/2

212 twill

2/2 twill

PC

PC

Weave

8.5 8.5

8.5 8.5 8.5 8.5

8.5

8.5

(W

Weft yarn (nm)

Warp yarn

1644

1476

1552

1380

Total ends

182.7

184.5

172.4

172.5

Loom width (crns)

150

150

150

150

Std.fin. width (crns)

17.9

18.7

13.0

13.0

Width shkge 9%

70

70

70

70

Std. wp. length (metres)

0.84 - \ 1 8 5 ~496 x 2/3 x 60/100 x 112.54 = 8.59 ends, pickskm = 40/2 reed (80ends/lOcms), 90 picks/lOcm.

0.84 a . 5 X 496 x 2/3 x 65/100 x U2.54 = 9.30 ends, picks/cm = 45/2 reed (90ends/lOcms), 95 picks/lOcm.

Cloth 6

Cloth 7

1/2 x 89100 x U2.54 = 9.13 ends, picks/cm = 45/2 reed (90ends/lOcms), 85 picks/lOcm.

63.5

63.5

63.9

63.9

Std.fin. length (metres)

0.84

$8.5x496 x

0.84 a . 5 496 ~ x 1/2 x 75/100 x U2.54 = 8.05 ends, picks/cm = 40/2 (80ends/lOcms), 85 picks/lOcm.

k ,/yards/lb x F/(F+l) x % below maximum x U2.54 = ends, picks per cm.

Picks/ 10 crns

Metric reed

Cloth 5

Cloth 4

To calculate in loom

No.

Table 2.2 ‘In-loom’ malung particulars for different fabrics made from the same single Shetland yam.

35%

40%

15%

25 %

Sett below max.

475

9

Cloth 9

Cloth 8

k

60

55

Picks/ 10 crns

218.5

218.5

932 1052

218.5

Total ends

U8.5

Warp Weft yarn yarn (nm) (nm)

202.3

166.4

(ems)

Loom width

150

150

Std.fin. width (crns)

96 below maximum x 112.54 = ends, picks per cm.

212 twill

PC

Weave

Jyardsflb x F/(F+l) x

2612

2812

~

Metric reed

25.8

9.8

%

Width shkge

70

70

Std. wp. length (metres)

0.84

4 4.25x 496

x 213 x 551100 x 112.54 = 5.57 ends, pickslcm = 2612 reed (52endsIlOcm), 60 picksll0cm.

25% 45%

66.4

Sett below max.

64.4

Std.fin. length (metres)

0.84 J 4.25 x 496 x 112 x 751100 x 112.54 = 5.69 ends, pickslcm = 2812 reed (56ends/lOcm),55 picksIl0cm.

To calculate in loom

385

Weight grm/lm

8

Cloth No.

365

435

500

11

12

13

PC 2/2 twill PC 2/2 twill

80

85

50

55

26/2

2812

4.0

4.0

8.0

8.0

Warp yarn (nm)

1032

4.0

184.3

175.4

184.2

1400 912

180.0

Loom width (ems)

1368

Total ends

4.0

8.O

8.0

Weft yarn (nm)

150

150

150

150

Std. fin. width (ems)

70

14.5

70

70

18.6

18.6

70

Std. wp. length (metres)

16.7

%

Width shkge

0.84 d 4 . 0 X 4 9 6 x 2/3 x 55/100 x 1/2.54 = 5.40 ends, pickskm = 28/2 reed (56ends/lOcm), 55 picks/lOcm.

. 0 ~ 4 9 6x 112 x 701100 x 112.54 = 5.16 ends, pickskm = 2612 reed (52ends/lOcm), 50 picksIl0cm.

Cloth 13

I/ 4

0.84

x 213 x 601100 x 112.54 = 8.33 ends, pickslcm = 3812 reed (76ends/lOcm), 85 picks1lOcm.

Cloth 12

8.0;-496

0.84

I/

0.84 J 8 . 0 ~ 4 9 6 x 1/2 x 75/100 x U2.54 = 7.81 ends, picks/cm = 38/2 reed (76ends/lOcm), 80 picks/lOcm.

k ,/yarddlb x F/(F+l) x % below maximum x U2.54 = ends, picks per cm.

38/2

38/2

Weave

Picks/ 10 cms

Metric reed

Cloth 11

Cloth 10

To calculate in loom

330

Weight grm/lm

10

Cloth No.

64.4

63.9

63.3

63.9

Std. fin. length (metres)

a

4.

1

6

0