Ebook Fundamentals of spun yarn technology: Part 1

The yarn technol- ogist has to understand the importance of the various fiber properties used in spec- ifying raw materials, not just with regard to the relation of fiber properties to y[r]

CRC PR E S S

Boca Raton London New York Washington, D.C

Carl A Lawrence, Ph.D.

SPUN YARN TECHNOLOGY

FUNDAMENTALS

of

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Library of Congress Cataloging-in-Publication Data

La wrence, Carl A.

Fundamentals of spun yarn technology / Carl A La wrence.

p cm.

Includes bibliographical references and inde x.

ISBN 1-56676-821-7 (alk paper)

1 Spun yarns 2 Spun yarn industry

3 T e xtile machinery I T itle.

TSI480.L39 2002

CIP

to Mary

Pref ace

The fundamentals of spun-yarn technology are concerned with the production of yarns from fibers of discrete lengths and the structure-property relation of the spun yarns Ever since humans moved from using the skins of hunted animals for clothing

to farming and using farmed animal hairs and fibers from nonfood crops, and eventually to the manufacture of synthetic fibers, the spinning of yarns has been of importance to (initially) the craft and (subsequently) the science, design, and engi-neering of textiles

This book is aimed at giving the reader a good background on the subject of the conversion of fibers into yarns, and an in-depth understanding of the principles

of the various processes involved It has become popular among some textile tech-nologists to view the subject area as yarn engineering, since there are various yarn structures that, with the blending of different fiber types, enable yarns to be con-structed to meet specific end uses It is therefore necessary for the yarn engineer to have knowledge of the principal routes of material preparation and of the various modern spinning techniques These topics are covered in this book A distinction is made between the terms spinning method and spinning technique by referring to a technique as an implementation of a method, and thereby classifying the many techniques according to methods The purpose is to try to get the reader to identify commonality between spinning systems, something that the author has found useful

in carrying out research into new spinning techniques

With any mass-produced product, one essential requirement is consistency of properties For yarns, this starts with the chosen fiber to be spun The yarn technol-ogist has to understand the importance of the various fiber properties used in spec-ifying raw materials, not just with regard to the relation of fiber properties to yarn properties, but especially with respect to the effect of fiber properties on processing performance and yarn quality These aspects are given careful consideration in various chapters throughout the book An understanding of the meaning yarn quality

is seen to be essential; therefore, some effort is devoted to explaining the factors that govern the concept of yarn quality

Textile designers prefer to use the term yarn design rather than yarn engineering,

since the emphasis is often on the aesthetics imparted to the end fabric as opposed

to any technical function Fancy or effect yarns, blends of dyed fibers of different colors, and the plying together of yarns are important topics in yarn design, and the principles and processes employed are described in this book

The material presented is largely that delivered over many years of lecturing and is arranged to be suitable for readers who are new to the subject as well as those who are familiar with the technology and may wish to use this book as a reference source A basic knowledge of physics and mathematics will be helpful to the reader, but is not essential, since a largely descriptive approach has been taken for the

majority of the chapters The few chapters that may be considered more mathemat-ically inclined present a more detailed consideration to a particular topic and should

be easily understood by anyone who has studied physics and mathematics at the intermediate level

Chapter 1 gives a suitable introduction to the subject area by outlining much of the basic concepts and discussing what technically constitutes a spun yarn Chapters

2, 3, 5, 6, 7, and 9 should cover most topics studied by technology students up to graduate level, and Chapter 9 collates material that has been delivered as a module component largely to design students Chapters 4 and 8, and some areas of Chapter

6 that deal with yarn structure-property relation, have been used as topics within a Masters-level module Although, at the advanced level of study, programs are mainly based on current research findings, some areas of the earlier chapters may prove useful for conversion candidates

Throughout the book, definitions are used, where appropriate, in an attempt to give the reader a snapshot of a particular technical point or topic, which is then explained in greater detail It is said that a picture is worth a thousand words, and

in dealing with technical concepts, this is a truism The reader will find, therefore, that effort has been given to fully illustrating the substance of each chapter, and the author hopes that this makes the book a pleasant read for you

A uthor

Carl Lawrence, B.Sc (Applied Physics), Ph.D., is Professor of Textile Engineering

at the University of Leeds and was previously a Senior Lecturer at the University

of Manchester Institute of Science and Technology Before joining academia in 1981,

he worked for 11 years in industrial R&D Many of these years were with the former Shirley Institute, now the British Textile Technology Group (BTTG) In 2002, he was awarded The Textile Institute’s Warner Memorial Medal for his contributions

to investigations in textile technology — in particular, unconventional spinning systems He is the author of many research papers in the field of yarn manufacture and has several patents in the area of open-end spinning

I wish to express my appreciation to the many companies and individuals who gave

me advice, encouragement, and assistance in completing this demanding but enjoy-able project A special “thank you” to my research colleague and friend Dr Moham-med Mahmoudhi for his time and effort in preparing the majority of the diagrams

in this book

The following companies provided me the opportunity to include many of the illustrations depicted, for which I am very grateful:

Andar ADM Group Ltd

Befama S.A

Crosrol Ltd

ECC Ltd

Fehrer AG

Fleissener GmbH & Co

Fratelli Mazoli & Co SpA

Houget Duesberg Bosson

Marzoli

Melliand

Pneumatic Conveyors Ltd

Repco ST

Rieter Machine Works Ltd (Machinenfabrik Rieter)

Rolando Macchine Tessili

Rolando-Beilla

Saurer-Allma GmbH

Savio Macchine Tessili SpA

Spindelfabrik Suessen

The Textile Institute (Journal of the Textile Institute)

TRI (Textile Research Journal)

Trutzschler GmbH & Co KG

W Schlafhorst AG & Co

William Tatham Ltd

Zellweger Uster

Zinser

C A Lawrence

Univer sity of Leeds

T able of Contents

Chapter 1 Fundamentals of Yarns and Yarn Production

1.1 Early History and Developments

1.2 Yarn Classification and Structure

1.2.1 Classification of Yarns

1.2.2 The Importance of Yarns in Fabrics

1.2.3 A Simple Analysis of Yarn Structure

1.2.3.1 The Simple Helix Model 1.3 Yarn Count Systems

1.3.1 Dimensions of a Yarn

1.4 Twist and Twist Factor

1.4.1 Direction and Angle of Twist

1.4.2 Twist Insertion, Real Twist, Twist Level, and False Twist 1.4.2.1 Insertion of Real Twist

1.4.2.2 Twist Level 1.4.2.3 Insertion of False Twist 1.4.3 Twist Multiplier/Twist Factor

1.4.4 Twist Contraction/Retraction

1.5 Fiber Parallelism

1.6 Principles of Yarn Production

1.7 Raw Materials

1.7.1 The Global Fiber Market

1.7.2 The Important Fiber Characteristics and Properties for Yarn Production

1.7.2.1 Cotton Fibers

1.7.2.1.1 Fiber Length (UHM) 1.7.2.1.2 Length Uniformity Index (LUI) 1.7.2.1.3 Fiber Strength

1.7.2.1.4 Micronaire 1.7.2.1.5 Color 1.7.2.1.6 Preparation 1.7.2.1.7 Leaf and Extraneous Matter (Trash) 1.7.2.1.8 Stickiness

1.7.2.1.9 Nep Content 1.7.2.1.10 Short Fiber Content (SFC) 1.7.2.2 Wool Fibers

1.7.2.2.1 Fineness 1.7.2.2.2 Fiber Length Measurements 1.7.2.2.3 Tensile Properties

1.7.2.2.4 Color 1.7.2.2.5 Vegetable Content, Grease, and Yield

1.7.2.2.6 Crimp, Bulk, Lustre, Resilience 1.7.2.2.7 Medullation

1.7.2.3 Speciality Hair Fibers

1.7.2.3.1 Mohair 1.7.2.3.2 Types of Fleeces 1.7.2.3.3 Physical Properties 1.7.2.3.4 Cashmere

1.7.2.3.5 Physical Properties 1.7.2.4 Silk Fibers

1.7.2.4.1 Waste Silk 1.7.2.5 Manufactured Fibers [Man-Made Fibers (MMFs)]

1.7.2.5.1 Viscose Rayon and Lyocell 1.7.2.5.2 Polyamide (Nylon) 1.7.2.5.3 Polyester

1.7.2.5.4 Acrylic 1.7.2.5.5 Polypropylene References

Appendix 1A Derivation of Equation for False-Twist Insertion

1A.1 Twist Equation for Zone AX

1A.2 Twist Equation for Zone XB

Appendix 1B Fiber Length Parameters

1B.1 Staple Length

1B.2 Fiber Length Distributions

1B.3 CFD by Suter-Webb

Chapter 2 Materials Preparation Stage I: Opening, Cleaning, and Scouring 2.1 Introduction

2.2 Stage I: Opening and Cleaning

2.2.1 Mechanical Opening and Cleaning

2.2.2 Striking from a Spike

2.2.3 Beater and Feed Roller

2.2.4 Use of Air Currents

2.2.5 Estimation of the Effectiveness of Opening and Cleaning Systems

2.2.5.1 Intensity of Opening 2.2.5.2 Openness Value 2.2.5.3 Cleaning Efficiency 2.2.6 Wool Scouring

2.2.7 Wool Carbonizing

2.2.8 Tuft Blending

2.2.8.1 Basic Principles of Tuft Blending 2.2.8.2 Tuft Blending Systems

2.2.9 Opening, Cleaning, and Blending Sequence

References

Appendix 2A Lubricants

Reference

Chapter 3 Materials Preparation Stage II: Fundamentals of the Carding

Process 3.1 Introduction

3.2 The Revolving Flat Card

3.2.1 The Chute Feed System

3.2.2 The Taker-in Zone

3.2.3 Cylinder Carding Zone

3.2.4 Cylinder-Doffer Stripping Zone

3.2.5 Sliver Formation

3.2.6 Continuity of Fiber Mass Flow

3.2.7 Drafts Equations

3.2.8 Production Equation

3.2.9 The Tandem Card

3.3 Worsted and Woolen Cards

3.3.1 Hopper Feed

3.3.2 Taker-in and Breast Section

3.3.3 Intermediate Feed Section of the Woolen Card

3.3.3.1 Carding Section 3.3.4 Burr Beater Cleaners and Crush Rollers

3.3.5 Sliver and Slubbing Formation

3.3.5.1 Tape Condenser 3.3.5.2 Ring-Doffer Condenser 3.3.6 Production Equations

3.4 Sliver Quality

3.4.1 Cleaning Efficiency

3.4.1.1 Short-Staple Carding 3.4.1.2 Worsted and Woolen Carding 3.4.2 Nep Formation and Removal

3.4.2.1 Nep Formation 3.4.2.2 The Effect of Fiber Properties 3.4.2.3 Effect of Machine Parameters 3.4.2.4 Short Fiber Content

3.4.3 Sliver and Slubbing Regularity

3.5 Autoleveling

3.6 Backwashing

References

Recommended Readings on the Measurement of Yarn Quality Parameters

Appendix 3A Card Clothing

3A.1 Metallic Wires: Saw-Tooth Wire Clothing

3A.1.1 Tooth Depth

3A.1.2 Tooth Angles

3A.1.3 Point Density

3A.1.4 Tooth Point Dimension

3A.2 Front and Rear Fixed Flats

3A.3 Wear of Card Clothing

Appendix 3B Condenser Tapes and Rub Aprons

3B.1 Tape Threadings

3B.1.1 The Figure 8 Threading

3B.1.2 Series Threading

3B.1.3 Endless Threading

3B.2 Rubbing Aprons

Appendix 3C Minimum Irregularity and Index of Irregularity

Chapter 4 Carding Theory

4.1 Opening of Fiber Mass

4.1.1 Taker-in Action

4.1.2 Feed-Roller, Feed-Plate Systems

4.1.2.1 Feed-Roller Systems 4.2 Carding Actions

4.2.1 Cylinder-Flat Action

4.2.2 Swift-Worker-Stripper Action

4.3 Web Formation and Fiber Configuration

4.3.1 Cylinder-Doffer Action

4.3.1.1 Fiber Configuration and Mechanism of Fiber

Transfer 4.3.1.2 Effect of Machine Variables on Fiber Configuration 4.3.1.3 Recycling Layer and Transfer Coefficient

4.3.1.4 Factors that Determine the Transfer Coefficient, K 4.3.1.5 The Importance of the Recycling Layer

4.3.2 Blending-Leveling Action

4.3.2.1 Evening Actions of a Card

4.3.2.1.1 Step Change in Feed 4.3.2.1.2 General or Random Irregularities 4.3.2.1.3 Periodic Irregularities

4.4 Fiber Breakage

4.4.1 Mechanism of Fiber Breakage

4.4.2 State of Fiber Mass and Fiber Characteristics

4.4.3 Effect Residual Grease and Added Lubrication

4.4.4 Effect of Machine Parameters

4.4.4.1 Tooth Geometry 4.4.4.2 Roller Surface Speed/Setting/Production Rate

4.4.4.2.1 The Taker-in Zone 4.4.4.2.2 Effect of Cylinder-Flats and Swift-Worker

Interaction References

Appendix 4A

Appendix 4B The Opening of a Fibrous Mass

4B.1 Removal of Fibers when Both Ends are Embedded in the Fiber Mass 4B.2 Behavior of a Single Fiber Struck by High-Speed Pins

4B.3 Micro-Damage of Fibers Caused by the Opening Process

References

Chapter 5 Materials Preparation Stage III

5.1 Drawing

5.1.1 Principles of Doubling

5.1.2 Principles of Roller Drafting

5.1.2.1 Ideal Drafting 5.1.2.2 Actual Drafting

5.1.2.2.1 Effect of Input Material Characteristics 5.1.2.2.2 Drafting Wave

5.1.2.2.3 Observations of Floating Fiber Motion 5.1.2.2.4 Drafting Force

5.1.2.3 Factors Influencing Drafting Wave Irregularity

5.1.2.3.1 Size of Draft 5.1.2.3.2 Input Count 5.1.2.3.3 Doubling 5.1.2.3.4 Fiber Straightness, Parallelism, Fineness,

and Length 5.1.2.3.5 Roller Settings 5.1.3 Effect of Machine Defects

5.1.3.1 Roller Eccentricity 5.1.3.2 Roller Slip 5.1.4 The Drawing Operations

5.1.4.1 The Drawframe 5.1.4.2 The Gill Box 5.1.5 Production Equation

5.2 Combing

5.2.1 The Principles of Rectilinear Combing

5.2.1.1 Nasmith Comb

5.2.1.1.1 The Cylinder Comb 5.2.1.1.2 The Feed Roller/Top and Bottom

Nipper Plates/Top Comb 5.2.1.1.3 Detaching Rollers and Delivery Rollers 5.2.1.1.4 The Combing Cycle

5.2.1.2 French Comb 5.2.2 Production Equation

5.2.3 Degrees of Combing

5.2.4 Factors Affecting Noil Extraction

5.2.4.1 Comber Settings 5.2.4.2 Preparation of Input Sliver

5.3 Conversion of Tow to Sliver

5.3.1 Cutting Converters

5.3.2 Stretch-Breaking Converters

5.3.3 Production Equation

5.4 Roving Production

5.4.1 The Speed-Frame (Twisted Rovings)

5.4.1.1 Production Equation 5.4.2 Rub Rovers (Twistless Rovings)

5.4.2.1 Production Equation 5.5 Environmental Processing Conditions

References

Chapter 6 Yarn Formation Structure and Properties

6.1 Spinning Systems

6.1.1 Ring and Traveler Spinning Systems

6.1.1.1 Conventional Ring Spinning 6.1.1.2 Spinning Tensions

6.1.1.3 Twist Insertion and Bobbin Winding

6.1.1.3.1 Spinning End Breaks 6.1.1.4 Compact Spinning and Solo Spinning 6.1.1.5 Spun-Plied Spinning

6.1.1.6 Key Points

6.1.1.6.1 Advantages 6.1.1.6.2 Disadvantages 6.1.2 Open-End Spinning Systems

6.1.2.1 OE Rotor Spinning

6.1.2.1.1 Twist Insertion 6.1.2.1.2 End Breaks during Spinning 6.1.2.2 OE Friction Spinning

6.1.3 Self-Twist Spinning System

6.1.4 Wrap Spinning Systems

6.1.4.1 Surface Fiber Wrapping

6.1.4.1.1 Dref-3 Friction Spinning 6.1.4.1.2 Air-Jet Spinning

6.1.4.1.3 Single- and Twin-Jet Systems: Murata

Vortex, Murata Twin Spinner, Suessen Plyfil

6.1.4.2 Filament Wrapping 6.1.5 Twistless Spinning Systems

6.1.5.1 Continuous Felting: Periloc Process 6.1.5.2 Adhesive Bonding: Bobtex Process 6.1.6 Core Spinning

6.1.7 Doubling Principles

6.1.7.1 Down Twisting 6.1.7.2 Two-for-One Twisting 6.1.8 Economic Considerations