20/KNITTING VIEWS/JANUARY-FEBRUARY 2010

K nitting is the second most frequently used method of fabric

construction. The term “Knitting” describes the technique of

constructing textile structures by forming a continuous length of yarn into

columns of vertically intermeshed loops.

Knitted fabrics have been gaining popularity during the past two decades,

thanks to the increased versatility of techniques and adaptability of the

many new manmade fibres. Knitted fabrics are now widely used in the

applications where woven fabrics formerly predominated. Today, the usage

of knitted fabrics ranges from hosiery, underwear, sweaters, slacks, to rugs

and other home furnishings.

Why knits are popular?

Knitted fabrics are popular today because:

• It is usually soft and drapes well

• It molds and moves easily with body movement

• It has good stretch ability

• It resists wrinkles

• Most importantly, knits relate well to contemporary life-styles

History

From the beginning the art of knitting was an occupation for women.

Traditional hand knitting, using knitting needles or pins, has been

practiced for thousands of years. The earliest example of true knitting is

a pair of knitting socks found in Egypt, dating back to 1100 A.D -just over

9 centuries ago! Socks and stockings were knitted because they had to

be shaped to the foot or leg. By the 16th century knitting had advanced

into a craft, the first real evidence of a production knitting machine was

the stocking frame, invented by the Reverend William Lee in 1589. The

invention laid the foundation for the development of knitting technology.

Lee’s invention enabled the knitting of loops at 10 times the speed of

traditional hand pin knitting.

Basics ofBasics ofBasics ofBasics ofBasics ofKNITTINGKNITTINGKNITTINGKNITTINGKNITTING - An introduction - An introduction - An introduction - An introduction - An introduction

VASANT R KOTHARI - has done

Master’s in Textiles Technology

from DKTE’s Textile and

Engineering Institute, Ichalkaranji

(Shivaji University, Kolhapur),

Maharashtra. He has also done

Diploma in Export management

(Apparel Export) from the Indian

Institute of Export Management,

and Garment Export and

Merchandising Management from

NIFT, Bangalore. Presently, he’s

working as an Assistant Professor

in Department of Fashion

Technology, NIFT, Bangalore.

(This is his first input from the

series of articles that will be

published in upcoming issues of

knitting Views)

KNITTING VIEWS/JANUARY-FEBRUARY 2010/21

Weaving KnittingConverting yarn into fabric by Converting yarn into fabric byinterlacement of warp and weft interloping using knitting elements

The capital investment is high Capital investment is usually lower

Not easy as compared with knitting Setting up a machine is easy and faster

Less productivity High productivity

Design modification is difficult Styles and designs can be changedeasily and faster

Woven fabric Knitted fabricLess extensibility High extensibility

High elastic recovery Incomplete elastic recovery

Less crease resistance High crease resistance

Generally fabric is thin Fabric is thicker(For the same yarn count) (For the same yarn count)

Easy to tear Difficult to tear

Requires ironing Ironing not required

High pleat sharpness Less pleat sharpness

Less permeability to air More permeability to air

Stronger fabrics Less stronger fabrics

More rigid as compared Feel of the fabric is softer

No such problems Any small defect occurring in the fabriccan lead to further damage in the clothbecause it cannot be mended easily

Tested by loading or extending Tested by multi-directional fabric fabrics in warp/weft bursting strength test

Difference between knitting and weavingThe major difference between knitted and woven structures lies

in the way the yarns are interconnected geometrically. In weaving,

two sets of parallel yarns are interconnected by interlacing them

at right angles. Different woven structures are produced by

varying this basic principle.

In knitting, the yarns are initially formed into loops, and then

these loops are interconnected in a variety of ways in order to

produce a textile structure. Based on this principle, a textile fabric

is produced by using only one set of yarns.

As a result of this interlooping of yarns, the structure of a weft or

a warp knitted fabric is more open when compared to the structure

of a woven fabric. Because of this interloping of yarns, a knitted

fabric could be stretched more than a woven fabric, even when

only a small force is applied. Once this force is eased the fabric

slowly returns to its original dimensions. In fact, weft and warp

knitted fabrics have higher elongation values than woven fabrics

due to their structure, and their elastic behaviour generally exceeds

the elastic properties of the yarns used to knit the fabric.

22/KNITTING VIEWS/JANUARY-FEBRUARY 2010

Compared with warp knitting, weft knitting is a more versatile method

of fabric production in terms of both the range of fabric structures

that can be produced and the yarn types that can be utilised. Weft

knitting is the simplest method of converting a yarn into a fabric.

In warp knitting, each warp thread is fed more or less in line with the

direction in which the fabric is produced, and each needle in the

knitting width must be fed with at least one thread at each course.

Compared to weaving and weft knitting it is the fastest method of

converting yarn into fabric, though modern developments in weft

knitting machines mean that there is now very little difference in

terms of production between the two forms of knitting

Weft knitting Warp knitting

Course-wise yarn feeding Wale wise yarn feeding

Yarn path horizontal Yarn path either vertical or diagonal

The loops are formed across The loops are formed vertically the widthof fabric down the length of fabric

Needles knit sequentially Needles knit concurrently

Possible to knit with one yarn Need warp yarn sheet

Cone or cheese yarn supply One long beam or a number of smallwarp beams yarn supply

Usually staple fibre yarns Only filament yarns can becan be worked successfully worked

Normally latch needles are used Latch, beard or compound needles are used

Less versatility More versatility

Changing design affect the speed Changing design does not affect the speed

Relatively not consistent and Consistent and uniform quality productuniform quality product

Loops are not uniform Loops are uniform

Stretch in both direction Stretch in widthwise direction

Dimensionally less stable Dimensionally more stable

Weft knitting machines are Warp knitting machines are more expensiveless expensive

Running costs is less Running costs is high

Softer yarn is required (less twist) Stronger yarn is required (more twist)

Short production runs For mass scale production

Small floor space requirements Need more space

E.g. Circular Knitting machine E.g. Tricot and Raschel machine

Due to the structure and good elastic behaviour of knitted fabrics,

knitted garments are comfortable to wear. The air trapped in the

loops of a knitted garment insulates the human body against cold.

At the same time the relatively loose and open structure aids in

the perspiration process of the human body, especially when the

knitted fabric is made of yarns spun from natural fibres. Due to the

interlooping of yarns, the knitted fabrics also have better crease

recovering properties compared to fabrics woven from similar yarns.

Classification of knitted fabrics

The knitting industry is divided into two distinct sectors, weft

knitting and warp knitting.

Weft knittingIn weft knitting, the loops are formed across the width of the

fabric, and each weft thread is fed more or less at a right angle to

the direction in which

the fabric is produced. It

is possible to knit with

only one thread or cone

of yarn, though

production demands

have resulted in circular

weft knitting machines

being manufactured with

up to 192 threads.

Warp knittingWarp Knitting is a method of producing a fabric by using needles

similar to those used in weft knitting, but with the knitted loops

made from each warp

thread being formed

down the length of the

fabric; the loops are

formed vertically down

the length of the fabric

from one thread as

opposed to across the

width of the fabric, as in

case of weft knitting.