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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.