Woodhead Publishing Series in Textiles: Number 131 Process control in textile manufacturing Edited by Abhijit Majumdar, Apurba Das, R. Alagirusamy andv.k.kothari The Textile Institute WP WOODHEAD PUBLISHING ppshr- ^ > ±M Oxford Cambridge Philadelphia New Delhi
Contents Contributor contact details Woodhead Publishing Series in Textiles Foreword xi xiv xix Part I General issues 1 1 Basics of process control in textile manufacturing 3 Vedpal and V. Jain, Indian Institute oftechnology Delhi, India 1.1 Introduction 3 1.2 Process mapping, analysis and control 5 1.3 Statistical process control (SPC) and improving processes 9 1.4 Future trends 11 1.5 References 13 2 Basic principles of control systems in textile manufacturing 14 S. S. Saha, Government College of Engineering & Textile Technology, Berhampore, India 2.1 Introduction 14 2.2 Components of control systems 18 2.3 The control system design process 28 2.4 Digital control systems 34 2.5 Intelligent control systems using soft computing 36 2.6 Application of control systems in textile processing 39 2.7 References 39 3 Testing and statistical quality control in textile manufacturing 41 A. Das, Indian Institute oftechnology Delhi, India 3.1 Introduction: statistical quality control 41 3.2 Basic measurement concepts in statistical quality control 42 v
vi Contents 3.3 Interpretations: critical difference 48 3.4 Interpretations: 'f' tests, 'F' tests and the chi-square method 53 3.5 Decision-making using control charts 57 3.6 Decision-making: hypothesis testing 59 3.7 Decision-making: significance testing 61 3.8 Testing fibre and yarn properties 72 3.9 Testing fabric properties 75 3.10 References 78 Part II Process control in fibre production and yarn manufacture 79 4 Process and quality control in cultivating natural textile fibres 81 M. Zimniewska, Institute of Natural Fibres and Medicinal Plants, Poland, I. Frydrych, Technical University of Lodz, Poland, J. Mankowski, Institute of Natural Fibres and Medicinal Plants, Poland, and W. TkYWiANSKA, Gdynia Cotton Association, Poland 4.1 Introduction 81 4.2 Control of cotton fibre quality 81 4.3 Indexes for cotton fibre quality 85 4.4 Process control in harvesting 89 4.5 Control of natural lignocellulosic/bast fibre quality: climatic conditions 96 4.6 Process control in production 100 4.7 Evaluating fibre quality 105 4.8 Future trends 107 4.9 References 107 5 Process control in the manufacturing of synthetic textile fibres 109 B. L. Deopura, Indian Institute oftechnology Delhi, India, A. Chatterjee, Dr B R Ambedkar National Institute of Technology Jalandhar, India and N. V. Padaki, CSTRI Central Silk Board, India 5.1 Introduction 109 5.2 Process control in polymerisation and fibre spinning 111 5.3 Post-spinning process control: drawing and heat setting 122 5.4 Key control points in synthetic fibre manufacture 127 5.5 Future trends 130 5.6 References 131
Contents vii 6 Process control in blowroom and carding operations 132 R. Alagirusamy, Indian Institute oftechnology Delhi, India 6.1 Introduction to blowroom operations 132 6.2 General process control in the blowroom 135 6.3 Process control in blowroom processes 137 6.4 Process control in carding: control of process parameters 142 6.5 Process control in carding: control of card clothing, wire maintenance and card waste 147 6.6 Yarn count issues and other common process control problems for blowroom and carding operations 153 6.7 Bibliography 157 7 Process control in drawing, combing and speed frame operations 158 A. Ghosh, Government College of Engineering & Textile Technology, Berhampore, India, and A. Majumdar, Indian Institute oftechnology Delhi, India 7.1 Introduction 158 7.2 Process control in drawing: key elements 159 7.3 The impact of drawing on yarn quality 164 7.4 Process control in drawing: common problems 166 7.5 Process control in combing: key elements 171 7.6 Process control in combing: the impact of combing on yarn quality and common problems arising from the process 178 7.7 Process control in speed frame operations: key elements 181 7.8 Process control in speed frame operations: the impact of speed frame operations on yarn quality and common defects related to the process 185 7.9 Conclusions and future trends 189 7.10 Acknowledgement 189 7.11 References 189 8 Process control in ring and rotor spinning 191 P. K. Majumdar, Government College of Engineering & Textile Technology, Serampore, India 8.1 Introduction 191 8.2 Factors affecting spinning tension in ring spinning 195 8.3 Control of end breakage rate in ring spinning 202
viii Contents 8.4 Factors affecting end breakage rates in ring spinning 205 8.5 Control of fly generation and twist variations in ring spinning 208 8.6 Process control in rotor spinning 213 8.7 Control of end breakage rate and twist loss in rotor spinning 217 8.8 Future trends 220 8.9 References 221 9 Maintenance of yarn spinning machines 225 A. Basu, Central Silk Board, India 9.1 Introduction 225 9.2 Maintenance of spinning preparatory machines 231 9.3 Maintenance of ring and rotor spinning machines 235 9.4 Future trends 236 9.5 Sources for further information and advice 239 9.6 References 240 Part III Process control in fabric manufacture, coloration and finishing 241 10 Process control in knitting 243 S. C. Ray, University of Calcutta, India 10.1 Introduction 243 10.2 Key control points in knitting 244 10.3 Quality control of knitted fabrics 248 10.4 Control of knitted loop length 251 10.5 Common faults in knitted fabrics 253 10.6 Other process control factors in knitting 259 10.7 Future trends: online quality control 262 10.8 References 264 11 Process control in weaving 265 V. K. Kothari, Indian Institute of Technology Delhi, India 11.1 Introduction 265 11.2 Controlling loom productivity, efficiency and fabric quality 267 11.3 Online process control, quality control and monitoring in weaving 269 11.4 Cost control in weaving 276 11.5 References 278
Contents ix 12 Process control in nonwovens production 279 D. Moyo, A. Patanaik and R. D.Anandjiwala, CSIR Materials Science and Manufacturing, South Africa, and Department of Textile Science, Nelson Mandela Metropolitan University, South Africa 12.1 Introduction 279 12.2 Needle punching: process variables and process control 280 12.3 Hydroentanglement: process variables and process control 285 12.4 Melt blowing: process variables and process control 288 12.5 Spunbonding: process variables and process control 292 12.6 Future trends 295 12.7 Sources of further information 296 12.8 Acknowledgement 296 12.9 References 296 13 Process control in dyeing of textiles 300 S. M. Shang, The Hong Kong Polytechnic University, China 13.1 Introduction 300 13.2 Dyeing of cotton 302 13.3 Dyeing of synthetic materials 315 13.4 Dyeing of blends 322 13.5 Process control in batchwise dyeing machines 326 13.6 Process control in continuous dyeing machines 334 13.7 References 338 14 Process control in printing of textiles 339 S. M. Shang,The Hong Kong Polytechnic University, China 14.1 Introduction 339 14.2 Direct printing 339 14.3 Discharge, resist and heat transfer printing 345 14.4 Process control in roller and screen printing machines 348 14.5 Inkjet printing and its process control 353 14.6 Product safety and low-carbon production 360 14.7 Sources of further information 361 14.8 References 362 15 Process control in finishing of textiles 363 A. K. Roy Choudhury, Government College of Engineering and Textile Technology, Serampore, India 15.1 Introduction 363 15.2 Instrumental process control 365
x Contents 15.3 Textile finishing processes and process control in finishing 369 15.4 Process control in basic finishing machines 373 15.5 Process control in stenter machines 376 15.6 Calendering process 380 15.7 Surface raising and pre-shrinking finishes 385 15.8 Finishing with alkali 389 15.9 Softeners 393 15.10 Resin finishes 396 15.11 Protection from fire damage and water penetration 401 15.12 Anti-pilling finish 405 15.13 Other types of finishing: antistatic, soil release, antimicrobial and UV protection 407 15.14 Wool treatment and enzyme finishes 413 15.15 Low-liquor finishing 417 15.16 Plasma treatments 421 15.17 Future trends 425 15.18 References 425 16 Process control in apparel manufacturing 428 G.Thilagavathi and S.Vuu, PSG College of Technology, India 16.1 Introduction 428 16.2 Process control in spreading, pattern making and cutting 428 16.3 Process control in sewing 432 16.4 Causes of damage to the fabric during sewing 441 16.5 Control of fusing and pressing operations, storage and packaging 449 16.6 Quality evaluation of apparel: testing for tailorability 454 16.7 Quality evaluation of apparel: testing for sewability 463 16.8 Quality evaluation of accessories 465 16.9 References 471 Index 475