Iyer / Mammel / Schach

Circular Knitting

Technology Process Structures Yarns Quality

FRANK 603U

by Meisenbach Bamberg Contents

01 Knitting Technique ... 1

01.1 Fundamentals of stitch formation ... 1 01.1.1 400 years of mechanical stitch formation ... 1 01.1.2 An outline of knitting machines ... 6 01.1.3 Stitch formation with latch needles ... 9 01.1.4 Structural elements in knitted fabrics ... 10 01.1.4.1 Loop ... 10 01.1.4.2 Stitch ... 10 / Plain stitch / Purl stitch / Needle loop / Sinker-loop-.-- ..' 01.1.4.3 Tuck loop ... 10 • ' . : 01.1.4.4 Float stitch ... 10 : , 01.1.4.5 Weft ... 10 { 01.1.4.6 Filler ... 10 u-" -•-• - • '• .... 01.1.5 Basic knitted structures ... 12 01.1.5.1 Arrangement of structural elements ... 12 01.1.5.2 Plain knitted fabrics ... 12 01.1.5.3 Double knit fabrics (rechts/rechts fabrics) ... 12 Double knit rib fabrics / Double knit interlock fabrics 01.1.5.4 Double knit purl fabrics ... 12

01.2 Processes for large circular knitting machines ... 14 01.2.1 Plain (rechts/links) technique with latch needles ... 14 01.2.1.1 Rest or ground position, Pos. 1 ... 16 01.2.1.2 Tucking-in position, Pos. 2 ... 16 01.2.1.3 Clearing position, Pos. 3 ... 16 01.2.1.4 Yarn presenting position, Pos. 4 ... 16 01.2.1.5 Cast-on position, Pos. 5 ... 17 01.2.1.6 Knock-over position, Pos. 6 ... 17 01.2.2 Relative technology with latch needles ... 18 01.2.3 Compound needle technique ... 20 01.2.3.1 Plain technique with compound needles ... 20 01.2.3.2 Plain relative technique with compound needles ... 24 01.2.4 Rib technique ... 27 01.2.4.1 Coordination between cylinder and dial grooves ... 27 Rib setting of cylinder and dial / Interlock setting of cylinder and dial / Conversion from rib to interlock setting "01.2.4.2 Coordination, between cylinder and dial cams ... 29 Synchronised timing between cylinder and dial cams / Delayed timing between cylinder and dial cams / Conditions for the use of delayed timing for dial and cylinder cams 01.2.5 Purl technique ... 38 01.2.5.1 Rib stitch formation ... 38 01.2.5.2 Purl stitch formation and needle transfer ... 38 Contents V 01.3 Characteristics of circular knitting machines ... 44 01.3.1 Machine pitch and machine gauge ... 44 01.3.1.1 Machine pitch ... 44 01.3.1.2 English machine gauge ... 44 01.3.1.3 Pitch values for circular knitting machines with special pattern devices and for small circular knitting machines ... 44 01.3.1.4 Relation between machine pitch, English gauge, machine nominal diameter and number of needles ... 44 01.3.1.5 Effective machine pitches (machine gauges) ... 44 01 .3.2 Machine nominal diameter ... 45 01 .3.3 Number of feeders / feeder density ... 45 01 .3.4 Production speed, number of machine revolutions ... 45 01 .3.5 Efficiency value / speed factor ... 46

01 .4 Machine elements ... 46 01 .4.1 Frame ... 46 01 .4.2 Machine drive ... 48 01.4.2.1 Motor ... 48 01.4.2.2 Number of revolutions of the machine ...49 01.4.2.3 Brake ... 51 01.4.2.4 Drive arrangement ... 52 01.4.3 Knitting elements ... 52 01.4.3.1 Needles ... 53 01.4.3.2 Holding-down / Knocking-over sinkers ... 58 01.4.3.3 Needle beds on circular knitting machines ... 60 01.4.4 Yarn feeder and its correct setting ... 61 01.4.5 Needle and sinker control units (cams) ... 63 01.4.5.1 Sliding cams ... 65 01.4.5.2 Flexible cams ... 66 01.4.5.3 Changeable cams ... 67 01.4.5.4 Alteration of course density through couliering ... 68 Vertical couliering / Diagonal couliering / Central couliering / Vertical adjustment of needle dial 01.4.6 Fabric take-down ... 72 01.4.6.1 Fabric spreader ... 72 01.4.6.2 Fabric tensioning and winding devices ... 72 Fabric tensioning and winding devices with mechanical drive / Fabric tensioning and winding devices with- electrical drive 01.4.7 Yarn supply ... 79 01.4.7.1 Cone carrier device ... 79 01.4.7.2 Yarn delivery devices (Yarn metering and storage devices on circular knitting machines) ... 84 Yarn delivery devices for constant yarn delivery, yarn metering devices / Devices with constant yarn delivery per unit time, Yarn metering devices with yarn reserve (Positive yarn feeders) / Devices with variable yarn delivery per unit time and yarn reserve (Storage yarn feeders) 01.4.8 Monitoring and maintenance systems ... 94 / Yarn monitoring / Needle monitoring / Fabric monitoring / , Lubricating and oiling systems / Cleaning systems

VI Contents Needle Control and its Equipment ... 97

02.1 Direct needle control ... 97 02.1.1 Control through cam parts ... 97 02.1.2 Control through pattern wheel ... 98

02.2 Indirect needle control ... 101 02.2.1 Indirect needle control with fixed control sinker arrangement ... 101 02.2.2 Indirect needle control through pattern drum ... 103

02.3 Electronically controlled needle selection on circular knitting machines ... 106 02.3.1 Needle control through film tape ... 106 02.3.2 Needle control through machine memory ... 108 02.3.3 Pattern design and production preparation ... 111

03 Additional Equipment Patterning ... 113

03.1 Equipment for fleecy fabrics ... 113 03.1.1 Simple fleecy ... 113 03.1.2 Three-thread fleecy ... 113

03.2 Equipment for plush fabrics ... 118 Quality demands on plush 03.2.1 Unpatterned plush ... 118 03.2.2 Jacquard plush ... 122 The construction of the presentation technique

03.3 Yarn changer devices / stripers ... 126 03.3.1 Yarn changer device with mechanical control ... 126 03.3.2 Yarn changer device with electronical control ... 128

03.4 Wrap finger technique ... 132

Circular Knitting Machines for Garment Length Fabrics ... 135

04.1 Rib and purl techniques ... 136 04.1.1 Fibres and yarns ... 136 04.1.2 Stitch density and quality ... 136 04.1.3 Performance ... 136

04.2 Purl pullover circular knitting machine ... 137 04.2.1 Double selection at the lower cylinder ... 137 04.2.2 Selection at the upper cylinde'r ... 138

04.3 Rib pullover.circular knitting machine ... 140 04.3.1 Free individual needle selection in the knitting feeders ... 141 04.3.2 Means of free selection in the transfer feeders ... 141 04.3.3 Principle of selection ... 142 Contents VII 05 Machine for High-Pile Fabrics ... 144

06 Other Machines ... 146

06.1 Methods for loop transfer ... 146 06.1.1 Transferring of sinker loops ... 146 06.1.2 Transferring of needle loops ... 146

06.2 Machines for the production of transfer patterns ... 147 Cylinder transfer feeder, control sinker cam range / Cylinder transfer feeder, needle cam range ... 150

Knitted and Fabric Structures ... 152

07.1 Pattern analysis of weft knits ... 152 07.1.1 Tools and technical aids ... 152 07.1.2 Methodical pattern analysis ... 152 07.1.3 Representation of weft knitted fabrics ... 154 07.1.3.1 Representation through mesh structure ... 154 07.1.3.2 Representation through technical notation (yarn path) ... 154 07.1.3.3 Symbols used for representation of needles ... 154 07.1.3.4 Representation of structural elements ... 155

07.2 Basic structures ... 156

07.3 Patterned structures ... 156 07.3.1 Patterned structures with one needle type ... 156 07.3.2 Patterned structures with two needle types ... 157 Plain structures / Rib patterned structures / Rib patterned interlock structures

07.3.3 Patterned structures with four needle types ... 161

07.4 Plated structures ... 162

07.5 Speciality structures ... 162 Fleecy/Three-thread fleecy / Interlock fleecy / Plush 07.6 Jacquard structures ... 163 07.6.1 Colour jacquard structures ... 163

Single jersey colour jacquard / Single jersey colour jacquard with t binding-in of floating yarns (three-way technique) / Rib colour jacquard / Horizontal striper backing / Vertical striper backing / Twill backing 07.6.2 Rib relief jacquard structures ... 166 Single relief rib jacquards / Double relief rib jacquard 07.6.3 Rib tuck jacquard ... 170 07.6.4 Rib lock jacquard ... 170 VIII Contens 07.6.5 Rib transfer jacquard ... 170 07.7 Symbolic adjointment between structure and process ... 171 Plain circular knitting machines ... 172 Rib circular knitting machines ... 178

07.8 Transposition of jacquard patterns onto a jacquard circular knitting machine with mechanical indirect needle control ... 182

08 Yarns for Circular Knitting ... 188

08.1 Fibre materials ... 188

08.2 Count ... 190 08.2.1 Direct system and its units... 190 08.2.2 Indirect system and its units ...191 Metric number (Nm) / English number (Ne) 08.2.3 Count calculation and denotion for plies ... 191 08.2.3.1 Ply with yarns of the same count ... 194 Calculation of count on the direct system / Denotion based on the direct system / Calculation of count on the indirect system / Denotion based on the indirect system 08.2.3.2 Ply with yarns of differing counts ... 194 Calculation of count on the direct system / Denotion based on the direct system / Calculation of count based on the indirect system / Denotion based on the indirect system

08.3 Staple fibre yarns ... 195 08.3.1 Spinning systems ... 195 08.3.1.1 Cotton spinning system ... 196 Carded yarn / Combed yarn 08.3.1.2 Worsted spinning system ... 197 08.3.1.3 Semi-worsted spinning system ... 197 08.3.1.4 Woollen spinning system ... 198 08.3.2 Spinning techniques for staple fibre yarns ... 198 08.3.2.1 Ring spinning ... 198 08.3.2.2 Unconventional spinning techniques ... 199 OE rotor spinning / Other spinning techniques: Friction spinning / Air jet spinning / Cover spinning / Yarns with ply resemblance / Self-twist spinning / Ply spinning 08.3.3 Comparison between ring and rotor yarns ...- 201 08.3.3.1 Process-based properties ... 202 08.3.3.2 Fibre-based properties ... 202

08.4 Filament yarns ... 203 08.4.1 The most importaQt raw materials ... 203 08.4.2 Filament yarn types ... 203 08.4.2.1 Monofilament yarn ... 203 08.4.2.2 Multifilament yarns ... 203 08.4.2.3 Minifil yarns ... 203 08.4.2.4 Comingled yarn ... 204 08.4.2.5 Microfilament yarn ... 204 Contents IX 08.4.3 Flat and textured filament yarns ... 204 08.4.3.1 False twist process ... 204 08.4.3.2 Bicomponent process ... 206 08.4.3.3 Knit-de-knit process ... 206 08.4.3.4 Air texturing process ... 207 Single yarn / Parallel yarn / Core-sheath yarn 08.4.3.5 Other texturing processes ... 208 08.4.3.6 Properties of textured yams ... 208 Primary properties: Extension and elasticity / Volume / Secondary properties: Weight / Dyeing behaviour / Handle / Perspiration / Air textured yam

08.5 Fibre blending in yarns and fabrics ... 209 08.5.1 Types of blend ... 210 08.5.1.1 Intimate blending ... 210 08.5.1.2 Core-sheath structures ... 210 Covering / Bicomponent yarns/ Air textured yarns / Open end yarns 08.5.1.3 The real ply ... 211 08.5.1.4 Comingled yarns ... 211 08.5.1.5 Feeder blending ... 211

08.6 Yarn count and machine gauge ... 212

08.7 Knitting demands on yarns ... 216 08.7.1 Tenacity and breaking extension ... 216 08.7.2 Elasticity ... 218 08.7.3 Friction ... 218 08.7.3.1 Waxing of staple fibre yarns ... 219 08.7.3.2 Finishing of filament yarns ... 220 08.7.3.3 Surface of yarn and abradant ... 220 08.7.4 Yarn evenness ... 221 08.7.5 Yarn count deviation ... 222 08.7.6 Take-off behaviour of yarns ... 223

08.8 Yarn supply for circular knitting machines ... 224 08.8.1 Draw twist bobbin ... 224 08.8.2 Draw winder bobbin ... 224 08.8.3 Cross-wound bobbin ... 224 08.8.3.1 Package size ... 225 08.8.3.2 Package shape ... 225 Cylindrical shape / Biconical shape / Conical shape 08.8.4 Winding methods for cross-wound bobbins ... 226 08.8.4.1 Random winding ... 226 08.8.4.2 Precision winding ... 226 08.8.4.3 Digital winding ... 227 08.8.5 Wind-on speed ... 227 " 08.8.6 Package hardness ... 228 08.8.7 Tak.e-off yarn tension ... 228 08.8.8 Friction between yarn and cross-wound package ... 229 08.8.9 Negative yarn withdrawal ... 229 08.8.10 Positive yarn withdrawal ... 229

Contents 08.9 Literature to chapter 08 ... 230 09 Quality and Production Monitoring ... 231

09.1 Faults and its causes in circular knitting ... 231 09.1.1 Pre-requisites for faultless knitwear production ... 231 09.1.1.1 Pre-requisites on the circular knitting machine ... 231 09.1.1.,2 General production conditions for knitting ... 232 '• Selection of proper yarn count / Relation between knitted structures and processing problems / Setting of the knitting machine / Yarn storage / Air conditioning of the knitting plant / Cleaning of knitting machines 09.1.1.3 Yarn pre-requisites ... 234 Influence of dyeing processes / Influence of spinning processes / Influence of the winding process / Factors affecting yarn production / Relationship between yarn properties and knitted fabric qualities 09.1.2 Frequent faults in knitted fabrics, their definition, cause and elimination... 237 09.1.2.1 Definition of faults ... 237 09.1.2.2 Causes of faults and their avoidance ... 238 Cracks or holes / Drop stitches / Cloth fall-out / Snags / Tuck and double stitches / Bunching-up / Vertical stripes / Horizontal stripes / Soil stripes / Colour fly / Distorted stitches

09.1.3 Literature ... 248

09.2 Operational data acquisition ... 248

09.3 Production calculations ... 250

10 Appendage for Tables ... 353

10.1 Machine pitch and machine gauge ... 252

10.2 Nominal machine diameters ... 254

10.3 Number of feeders ... 256

10.4 Yarn counts ... 258

Fluff Blower Devices ... 363 12 Index ... 365

Contents XI