High Speed Spinning of Polyester and Its Blends with Viscose

Contents

Preface
Early in 2000 AD, the two major manufacturers of ring frames in Indiaviz. Lakshmi Machine Works and Kirloskar Toyota Textile Machinery Manufacturers Ltd – offered their latest ring frames – LR6 and RXI 240 respectively to the Indian spinning industry. Both these ring frames are designed to run at spindle speeds of 25000 rpm.

It was in 2001, that I got involved with high speed spinning of polyester blends when I worked with the technical team of Priyadarshini Spinning Mills, Hyderabad to run their 14 Lakshmi’s LR 6 ring frames at a maximum speed of 24500 rpm. Since then, I have worked with other mills to speed up their LR 6 ring frames.

Since then, several spinning mills have installed these ring frames. But currently most of them run these ring frames at the speed of 16000-18000 rpm under utilising them. Spinners, who use these ring frames, have several fears – that at speeds above 18 000 rpm, the traveler temperature could reach 290 “C-well above the melting point of polyester which is 260 “C; and could lead to fusion of protruding fibres creating dark spots in fabric on dyeing; that hairiness will be so high that it will be difficult to weave these yarns especially on an air jet loom; and that power cost will go up too high which will make spinning uneconomic.

However, some of the adventurous spinners, whose number may be about 8 or 10, are running these ring frames at spindle speeds ranging from 20 500 to 24500 rpm on both grey and dyed fibre spinning. They have found-to their relief-that the fears expressed by other spinners were not true. No fusing of fibres was found while hairiness increased only marginally. The power cost did go up, but not as high as they feared. Making a success of high speed spinning involves several factors -right from selecting bales to be fed to the blow room to controlling U% and CV% of wrapping at finisher drawing, to ensuring almost zero breaks at roving. I have been personally involved in helping a few mills to run their ring frames at 22000-24500 rpm and so have built up a knowledge base on how to go about making a success of high speed spinning. This practical knowledge has a strong theoretical basis, Hence it can be applied successfully under varying industrial conditions. Therefore, I felt the urge to write this book as a practical guide to the spinners, not only of polyester viscose blends, but also of other fibres at the mechanically designed maximum spindle speed at ring frames.

This book includes four live case studies of spinning mills in India (Chapter 7) that are running their ring frames successfully on both grey and dyed fibre spinning at speeds varying from 20500 rpm to 24500 rpm. The book concludes by saluting the pioneers (Chapter 8) of ‘High Speed Spinning of Polyester Blends’, who had vision and took great risks to run their ring frames at real high speeds.

Since high speed spinning of polyester blends (Chapterl) is mostly an Indian phenomenon (Chapter 2), it is apposite that this book is written by an Indian and is produced in India. However, it charts out a path that a spinning mill any where in the world could take to run their ring frames at super high speeds. Right from blowroom till winding, one needs to ensure quality in such a way that at high ring frame speeds, end breaks at ring frame, vital yarn properties, and winding cuts remain more or less at the same level (Chapters 3 and 4) as obtained at slower ring frame speeds. The book examines economics of high-speed spinning (Chapter 5) and ends up predicting the future of high speed spinning technology (Chapter 6). The book would prove eminently useful to spinning mills, which buy modern high-speed ring frames, to run them successfully at speeds 20 500-24 500 rpm depending upon the count spun. By doing so, the spinning mill will ensure that their conversion cost is lowered substantially and the ‘bottom line’ is improved considerably.

It must be clarified here that this book could also be useful to all those mills that run their ring frames at speeds lower than the designed highest mechanical spindle speed, irrespective of the fibre material they process. To give an example: a spinning mill with Laksmi’s G 5/1 ring frames runs them at say 16000 rpm for a PC blend or for 100% cotton in the range of 30-40s.

This machine is designed to run at a maximum speed of 20000 rpm. If this spinning mill wants to speed up their G 5/1 frame to 20000 rpm, it will find ways to do so in this book. Of course, the norms of quality given in this book, which apply only to polyester and its blends with viscose, would need to be adapted to the material being processed. In fact, the financial returns from high speed spinning are so high that it is worth replacing the spindles, rings and the drive motors by high speed versions to raise the mechanically achievable upper limit of spindle speed. (Appendix 1)

The ideas given in this book can definitely be applied to high speed spinning of other fibre/blends such as polyester/cotton, viscose, cotton and others.

This book should prove eminently useful to:

• The top management of spinning mills who should compare the highest spindle speed at their ring frames with those employed by high speed spinners, look closely at the economics given and then check if their ring frames can be speeded up so as to increase substantially their mill’s profits. Also if the mill does not posses high speed ring frames, then top management should take inspiration from RSWM Ltd. which runs their Lakshmi’s G 5/1 ring frames at 22000 rpm against the designed speed of 20000 rpm in a very cost effective way as given in Chapter 7, and supported in Appendix 1.
• Senior spinning technologists can check if they can speed up their ring frames and make a success of high speed spinning as suggested in this book, so as to add to their unit’s profits.
• Quality control heads who would need to help the production personnel in taking trials to finally reach the goal of high speed spinning.
• Maintenance personnel will know what mechanical conditions of the machines are expected to make a success of high speed spinning and could plan their activities accordingly.
• Teachers in textile institutes would find this book useful to explain to their students the inter relations of various actions starting from fibre properties to breakage rates in ring spinning and winding. The way in which knowledge gained as different subjects gets used in controlling the processes will become clear to the students. A good study of the ides in this book will prepare them to become better technicians when they join the industry.

I hope that my efforts of putting the ideas used in consultation in a book form become fruitful, and all these groups use this book on a large scale and benefit from it.

S. Y. Nanal