Knitting and Technical Textile

An introduction of knitting technology and its applications in Technical Textiles by Dr. Muhammad Mushtaq Mangat Dec 9, 2012

Lecture 4 Contents Knitting technology explanations Knitting types Warp and weft knitting Application of knitted fabrics in Technical Textile

Knitting A type of fabric formation by using loop insertion into other loop.

Weft Knitting One major kind of knitting

Knitting   Weft knitting

  Only weft yarn is used to make loops,

  Needles and sinkers are used to make loops and insert loops

  Yarn is fed around right angle

  No yarn sheet is made

  Individual yarns are uses

  Warp knitting

  Yarn sheet (warp ) is made

  Loops are made from warp and inserted along the warp length

  Needles are used to make loops and insert loops across the warp

  Warp knitted fabric is more rigid and many types are possible

  More share in Technical Textile

[1]

Weft Knitting

  Most common

  More elastic fabric

  Used for general clothing

  Lot of variation in GSM and width is possible

  Available in flat and circular shape

Weft Knitting Loop Description [1]

Knitting is one of several ways to turn thread or yarn into cloth. Unlike woven fabric, knitted fabric consists entirely of horizontal parallel courses of yarn. The courses are joined to each other by interlocking loops in which a short loop of one course of yarn is wrapped over the bight of another course. Knitting can be done either by hand, described below, or by machine. In practice, hand knitting is usually begun (or "cast on") by forming a base series of twisted loops

  Knitting is a process in which one thread is used to make loops and then newly formed loops are passed through previously formed loops and top and bottom loops are joined with the help of head and feet

Knitting Fundamentals Basic Elements in knitting is Stitch or Course

Stitch Details

  loop

  Loop insertion through loop

  Joining of two loops

  Knitted fabric flexibility depends upon loop structure

  Loops have many shapes and types

Loop

  An extended portion of a regular string

  Has no end

  It is part of main string

  Have balance shape

  Is made with the help of any tool which is able to pull the string from a certain point

Loop Insertion

  Loop is inserted through an other previously held loop with the help of needle

  Needle should have the ability to hold fresh loop during insertion period

  Needle is responsible to make new loops and hold the previous sloop

Loop insertion Animation

Knitting Cycle

Knitting Classification Based upon Knitting Procedure

Warp and Weft

  Warp Knitting

  Weft Knitting

Warp Knitting

  In this process yarn sheet is developed (warp sheet) and then with the help of needles stitches are formed by insertion new loop into old loop.

Warp Knitting Machine

Warp Knitted Fabric

Weft Knitting

In weft knitting single yarn is fed to knitting needles. Needle with the help of cams, sinker make a new loop and passed it into previously held loops.

Types of Weft Knitting

Circular Knitting and Flat Knitting

Circular Knitting Machines

  In circular knitting machines needles are fixed on a cylinder or dial in a circular shape.

  There are more than one feeders to feed yarn to needles at different places.

  In most of the cases needle bed (cylinder or dial) moves while feeders remain stationary.

  Diameter of cylinder and dial is fixed but in case of sock knitting machines it is changeable due to structure of socks

Circular Knitting Machine

Flat Knitting Machines

  In flat knitting machines needles are fixed on a straight plate. On this machine needle bed remains stationary while yarn feeding system called carriage moves from one end to other end

  This machine is used to knit collars, arm bands and sweaters

Flat Knitting

Types of Circular Knitting Machines

  Single Knitting

  Double Knitting

Single Knit Machine

  In these machines needles are fixed on cylinder and sinker are fixed on sinker ring. Needles knit with the help of sinkers.

Single Knit Machine

Double Knit Machine

  In double knit machine needles are fixed on dial as well as on cylinders. There is no sinkers on this machine.

  This machine is used to knit interlock, rib and double jerseys

Double Knitting

Double Knit Fabric   Interlock--- Two sides are fully knitted, highly

flexible used for under garments. Front and back wales are exactly at same point

  Rib--- two sides are fully knitted. Less flexible but have strong grip, used for neck, cuff opening and waist band. Front and back wales are not at same point

  Double Jersey

Double side knitted, can have different designs on both sides

Interlock Machine

Double Knit Jacquard Knitting Machine

Types of Single Knitting Machines

  Plain knitting

  Loop knitting

Single Knit Plain Knitting Machines

  Mostly called jersey machines. On this machines, there is a set of needles and sinkers. These machines may be single track of multi track. From one track to six track machines are available.

  These machine can knit jersey, pique, honey comb, mini jacquard

Single Plain Knitting Machines

  Single Track

  Multi Track

Single Track Single Knit

  Track means number of cams vertically fitted

  In single track machine there is only one track

  This machine can knit only full knit fabric (single jersey)

Multi Track Knitting Machine

  In this machine there are 2-6 tracks

  More number of tracks means that variety of designs can be produced

  On these machine many types of fabric can be produced, like, pique, pique fleece, two thread fleece and mini jacquard

Loop Knitting Machines

  In these machines we can make loop on one or on both sides of fabric.

  By introducing loops we can increase the weight and bulkiness of fabric

Types of Loop Knitting Machines

  Terry

  Fleece

Terry Fabric

  This fabric has loops on the surface, like towel but the length of loops is smaller than towels. Normally used to make shirts of kids or for people working under high temperature to absorb the moisture

Terry Knitting Machine

Terry Knitting Machine

Single Jersey Double Face Fabric

Three Thread Knitting Machine

  This machine is used to produce fleece fabric. This fabric is plain from one side. Mostly front side is of single jersey and on back loop is inserted across various number of wales (normally two to three wales are covered).

  Back side is brushed with the help of raising machine to make it more comfortable and bulky as well as warm

  Two types of threads are used; fine for the top and course for back ( 30/16, 28/12 etc)

Three Thread Fleece Machine

Fleece Fabric

Striper

  In stripe knitting machines we can produce horizontal stripes with the help of scissors which cuts the yarn and a new yarn is fed

  There are two types of:

  Mechanical

  Electronic

  Note: in current era there is no fresh production of mechanical strip machines

Stripe Knitting Machine

Jacquard Knitting Machines

  These machine are available in single and double knit technology

  Normally more than one colored yarns are used.

  Different patterns are made

  Normally 4-6 color machines are available

  All types of machines can be converted into jacquard machines

Jacquard Machines

  Mechanical Jacquard

  Electronic Jacquard

Jacquard Fabric

Flat Knitting

  Single bed

  Double bed

Full Garment Flat Knitting Machines

  These are latest machines and are used to make full length of garment

  Quite expensive

  Not in Pakistan

  Required in countries where labour is expensive

Gloves Knitting Machine

Gloves Knitting machines

  In this machine bed rotates and carriage moves from one side to other

Warp Knitting

Types of Flat Knitting

  Raschel, made with latch needles,

  Tricot, using bearded needles.

Warp-Knitting

  When producing warp-knits, a yarn sheet is linked by stitches in longitudinal direction. Thus, each individual thread in the sheet (warp) forms a wale.

Warp Knitting

  Main products   Nets

  Curtains   Technical fabrics

  Covers   Covering sheets

Working Principle

  Warp sheet

  Loops development with the help of needles

  Loops insertion with the help of needles

  Needle movement controls mechanically and electronically

Properties of Warp Knitted Fabric

  More stable than knitted

  Big and small holes are possible

  Many designs are possible

  Highly course yarn can be used

  Technical fabric can be produced

Use of Warp Knitted Fabric

  Use to fulfill technical demands, like, filters, seat covers etc

  Used as curtains, table covers

  Used as Chadar in Pakistan

  Not used for clothing

References   [1] Anand, S.C., Technical fabric structures – 2. Knitted fabrics, in Handbook

of Technical Textiles A.R. Horrocks, Anand, S. C., Editor 2000, Woodhead Publishing Ltd Cambridge.