Role of yarn tension in weaving

288 Pages·2016·8.02 MB·english

by  Neogi

Role of Yarn Tension in Weaving
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Role of Yarn Tension in
Weaving
Samir Kumar Neogi
WOODHEAD PUBLISHING INDIA PVT LTD
New Del hi, India
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Published by Woodhead Publishing India Pvt. Ltd.
Woodhead Publishing India Pvt. Ltd., 303, Vardaan House, 7/28, Ansari Road,
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www.woodheadpublishingindia.com
First published 2015, Woodhead Publishing India Pvt. Ltd.
© Woodhead Publishing India Pvt. Ltd., 2015
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Woodhead Publishing India Pvt. Ltd. ISBN: 978-9-38030-825-8
Woodhead Publishing Ltd. e-ISBN: 978-9-38030-827-2
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Contents
Preface xi
Foreword xiii
1 Fundamentals of yarn tension 1
1.1 Introduction 1
1.2 Defi nition of yarn tension 1
1.3 Necessity of tension in textile processing 2
1.3.1 Tension at weaving preparatory 2
1.3.2 Tension at weaving 3
1.4 Yarn tension and yarn breakage 4
1.5 Tensioning system 4
1.6 Tensioner (or Tension device) 10
1.6.1 Disc tensioner 10
1.6.2 Gate-type tensioner 11
1.6.3 Roller tensioner 11
1.6.4 Capstan tensioner 11
1.6.5 Tensioner with automatic control system 11
1.7 Tension measurement 12
2 Yarn tension at the weaving preparatory process 17
2.2 Weaving preparatory processes 18
2.3 Winding process 19
2.3.1 Unwinding 20
2.3.2 Tensioning (and clearing) 26
2.3.3 Winding 27
2.3.4 Pirn winding 28
2.4 Warping process 30
2.5 Slashing (or sizing) process 32
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vi Contents
3 Warp tension measurement 37
3.1 Introduction 37
3.2 Passage of warp yarns through the loom 37
3.3 Stretch and strain of warp yarns due to shedding 38
3.4 Warp tension control by let-off motion 42
3.5 Measurement techniques of warp tension 44
3.5.1 Tension measurement of the whole warp sheet 44
3.5.2 Tension measurement of the bunch of warp yarns 47
3.5.3 Tension measurement of single warp yarn 49
4 General form of warp tension variation 59
4.2 Warp tension variation 60
4.2.1 Tension variation of the whole warp sheet 60
4.2.2 Tension variation of the bunch of warp yarns 62
4.2.3 Tension variation of single warp yarn in shuttle
loom 63
4.2.4 Tension variation of single warp yarn in shuttleless
loom 69
5 Weft tension measurement 73
5.1 Introduction 73
5.2 Weft tension measurement in shuttle loom 74
5.2.1 Measurement during unwinding from pirn 74
5.2.2 Measurement during insertion of a pick 76
5.3 Weft tension measurement in shuttleless loom 79
6 General form of weft tension variation 81
6.1 Introduction 81
6.2 Weft tension variation in shuttle loom 82
6.2.1 Tension variation during unwinding from pirn 82
6.2.2 Tension variation during insertion of a pick 83
6.3 Weft tension variation in shuttleless looms 86
6.3.1 Tension variation in projectile picking 87
6.3.2 Tension variation in rapier picking 88
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Contents vii
6.3.3 Tension variation in air-jet picking 90
6.3.4 Comparison of weft tensions in different shuttleless
picking systems 92
7 Effects of loom settings and other factors on warp tension 97
7.1 Introduction 97
7.2 Effects of warp beam and let-off motion 98
7.2.1 Warp tension control in negative let-off motion 99
7.2.2 Warp tension control in positive let-off motion 102
7.3 Effects of back-rest 105
7.3.1 Back-rest setting 105
7.3.2 Back-rest movement 108
7.3.3 Back-rest mounting 112
7.3.4 Back-rest type 118
7.4 Effects of warp stop motion setting and warp leasing
pattern 119
7.4.1 Warp stop motion setting 119
7.4.2 Warp leasing pattern 120
7.5 Effects of shedding 123
7.5.1 Front shed geometry 123
7.5.2 Heald movement 124
7.5.3 Heald position 128
7.5.4 Warp drafting pattern 129
7.5.5 Shed timing 130
7.6 Formation of clean warp shed 132
7.7 Effects of warp denting pattern 138
7.8 Effects of beat-up 139
7.9 Effects of temple 148
7.10 Effects of looming-in lengths of warp and cloth 151
7.11 Effects of other factors 155
7.11.1 Weave 155
7.11.2 Loom speed 156
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viii Contents
7.11.3 Yarn join 157
7.11.4 Weft tension 160
8 Effects of loom settings and yarn characteristics on
weft tension 167
8.1 Introduction 167
8.2 Shuttle picking 168
8.2.1 Effects of pirn and shuttle modifi cations 168
8.2.2 Effects of shed timing 171
8.2.3 Effects of shuttle checking 172
8.3 Shuttleless picking 172
8.4 Effects of weft package 173
8.5 Weft storage system (weft accumulator or weft feeder) 175
8.5.1 Forces acting on the yarn at weft accumulator 177
8.5.2 Effects of weft accumulator 180
8.5.3 Effects of type and setting of weft accumulator 184
8.6 Effects of other loom mechanisms 189
8.7 Effects of loom speed 193
8.8 Effects of weft yarn characteristics 197
9 Effects of yarn tensions on loom performance 207
9.1 Introduction 207
9.2 Loom performance 208
9.2.1 Warp break 209
9.2.2 Weft break 215
10 Effects of yarn tensions on fabric properties 221
10.1 Introduction 221
10.2 Mechanics of cloth formation in relation to yarn tensions 222
10.3 Beat-up force 225
10.4 Cloth properties 233
10.4.1 Structural and dimensional properties 233
10.4.2 Physical properties 242
10.4.3 Comfort properties 249
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Contents ix
10.5 Weave prominence 250
10.6 Roll of yarn tensions on the remedy of some cloth defects 251
10.6.1 Starting mark or setting-on place 251
10.6.2 Repping 258
10.6.3 Reed mark or reediness 260
10.6.5 Selvedge distortion 268
Index 273
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