Knitting Introduction

Dr. Danish Mahmood baitab

 Interlooping

oSecond most popular technique

of fabric formation
oFabric formation by interlooping
of yarns
o Straight continuous length of
yarn is bent into loops and
those loops are interlooped for
fabric formation
oContinuous length of yarn is
converted vertically into
intermeshed loop either by hand
or machine

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Classification of Knitting
• Knitting is primarily classified as weft knitting and warp knitting.
• This classification is based on the direction of movement of yarn with
respect to the direction of fabric formation.

Knitted
fabrics

Weft Warp
Knitting knitting

Tricot Raschel

Single
Purl Rib Interlock
jersey

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Knitting Status
oKnitted fabrics
o World Exports : US$ 33.6 billion
o Pakistan exports: US$ 35.9 million
o Pakistan Share: 0.11 %

oKnitted apparel
o World exports: US$ 237.7 billion
o Pakistan exports: US$ 2.4 billion
o Bangladesh exports: US$ 14.35 billion
o Vietnam exports: US$ 9.5 billion
o Pakistan Share: 1.01 %
o China No. 1; Bangladesh No. 2; Vietnam No. 5;
Pakistan No. 19

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 Knitting Status of Pakistan
o12,000 knitting machines

oThe main export destinations are

oEuropean,
oAmerican and
oUAE markets.

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 Major Knitting Industry
Interloop
Hosiery

Leisure
Masood Textiles
Knitwear

Anwar Textiles Hasni Textiles

Three Star
Globe Textiles
Hosiery

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Knitting Major Exports Apparel

Men's &
ladies T-
shirts

Night shirts
Boxer sets
for ladies

Major Exports

Men's
Jogging suit
pyjama

Sportswear

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Technical Textile (Knitting)

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Basic Terminologies

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 Basic Terminologies
Loop
oBasic unit of knitted
structure
oThree Parts
oHead (H)
o2 side limbs or legs (L).
oA foot (F), at the base
of each leg
oYarn passes through the
head of the loop formed
at the previous knitting
cycle.

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Loop Types
oOpen loop
o The open loop is one in which
loop forming yarn does not
cross at bottom of loop.

oClosed loop
o In closed loop, legs of loop
cross so loop closing takes
place

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 Loop Types New Loop

oFace loop
o In face loop legs of new loop
pass over the head of old Old Loop
loop
o (Legs are appeared)

New Loop o Back loop

o In back loop head of
old loop pass over the
Old Loop legs of new loop
o (Head and Feet are
appeared)
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 Basic Terminologies
Courses Wales
• A horizontal row of loops • A vertical column of loops
across the width of flat fabric along the length of fabric
• Series of loops, connected
horizontally (Feet to Feet) • Series of loops
intermeshing vertically
• Courses per unit length is
(Head to Head)
course density,
• measured in cpi (course/inch) • Wales per unit length is
or cpcm(course/cm) wale density,
• measured in
wpi(wales/inch) or
wpcm(wales/cm)

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 Basic Terminologies
Technical Face
• The side of the knitted
fabric consist of Face
Knit Loops

Technical Back
• The side of knitted
fabric consist of
Back Knit Loops

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 Basic Terminologies
oTechnical Upright
o A knitted fabric is technically upright when its courses run horizontally and
its wales run vertically,
o with the heads of the needle loops facing towards the top of the fabric
o and the course knitted first situated at the bottom of the fabric.

Welt
Secure edge of knitted fabric or garment made during/after knitting
process
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 Basic Terminologies
oStitch length
olength of the yarn in the knitted loop.
omeasured in millimetre
ocontrol properties of knitted fabrics
ogenerally longer the stitch length, the more open and
lighter the fabric.
oStitch density
oTotal number of loops in a given area.
oIs the product of Courses and Wales per unit length
omeasured in units of loops per square centimetre or
loops per square inch.
oCPC x WPC = Loops/Sq. cm
oCPI x WPI = Loops/Sq. in

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 Knitting
oFirst hand knitting machine was developed
in 5th century.
oActual Knitting machine was made in 1589
by Willian Lee.
Needle
oInstrument used for intermeshing of loops
Gauge
oNumber of needles per unit length of
knitting machine is called gauge

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 Single jersy Purl
Weft Knitted
Knitted Fabrics Double jersy Rib

Tricot Interlock

Milanese

Simplex

Warp Knitted Raschel

Ketten Raschel

Corchet

Weft Insertion
warp 18
 Weft Knitting
oMethod of constructing the knitted fabric where loops
made from each yarn run along the width or crosswise
direction (courses) with reference to the direction of
fabric formation during knitting, then the process of
knitting is called weft knitting

Fabric Formation

Yarn run in width

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 Weft knitting machine

oFlat ( gloves and fully fashioned machine )

oCircular ( socks , single and double jersey machine)

Circular Knitting m/c Flat Knitting m/c 20

Weft knitting machine

Socks m/c Gloves m/c

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 Flow process

oWeft knitting

Yarn / Weft
Cone knitting
Package m/c

oWarp Knitting

Yarn / Warping Warp

Cone / Beam knitting
Package formation m/c

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Woven vs knitted

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 Weaving Knitting
Produced by interlacement of yarn Produce by interlooping of yarn
Minimum Two Sets of yarn is Minimum one yarn is required
required for warp and weft
Sizing is required Don't require sizing

Production is lower Production is higher

Production cost is higher Production cost is less

Elasticity and stretch ability is poor Good elasticity and stretch ability
Dimensional stability is higher Dimensional stability is lower

Thick and wind resistant Cool and breathable

Holds a crease well Wrinkle resistant

More durability Less durability

Harsher Softer

less moisture absorption More moisture absorption

Less air permeability More air permeability
Lengthy processing route(singeing, Short processing route( scouring,
desizing, scouring , bleaching) bleaching)
Less Shrinkage, Ironing is required More Shrinkage, Not necessary 24
Properties & Applications

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Properties

oKnitted Fabric are popular for

their
o Shape fitting property,
o Soft handle,
o Bulkier nature and
o High extension at low tension.

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 Clothing’s
• Vests , Sweaters and pullover Cardigan (we)
• Gloves(we), Socks(we), Tights(wa,we)
• Seamless garments (wa, we)
• Undergarments (Wa,we)

Home and furnishing

• Curtain(wa)
• Uphostery (we)
• Blanket(we)
• Terry towel (wa,we)

Technical
Medical(stocking, compression bandages)
(wa,we)
Automotive(seat upholstery, roofing, filtration,
composites)(wa,we)
Packaging and mosquito nets, filtration
(wa,we)
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 Loop Formation
oRest Position
o The old loop is in the closed hook
o Needle moves to next feeder without rising.
oClearing
o As needle reaches the top of the cam (Maximum height), old
loop is cleared from the hook and latch spoon on to the stem.
oFeeding
o Needle starts to descend, with the old loop moving under the latch.
o New yarn is fed through feeder guide to the descending needle hook.
o Knocking-over
o As the head of the needle descends below, the old loop slides off the
needle and the new loop is drawn through it.

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Warp Knitting

In case the yarns run in length direction, i.e. the

direction of fabric formation during knitting, the
process is called warp knitting.

Types are
• Tricot
• Raschel

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Warp knitting machine

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Guide BarMovements

Guide Bas
Motions

Swing Shog

Vibration
Forward Backward
(Over/Under
(Overlap) (Underlap) lap) 9
 Weft Knitting Warp Knitting
1. Loop formation takes place course 1. Loop formation takes place wale wise in
wise in horizontal direction vertical direction
2. Yarn runs in horizontal or course 2. Yarns runs in vertical or wale direction
direction during knitting during knitting
3. Needles knit sequentially in a knitting 3. Needles knit altogether in a knitting cycle.
cycle. Yarn is supplied generally in the form of
4. Yarn is supplied generally in the form warp beam (number of beams may be 2
of cone hold in a creel or more)
5. Only one or a few yarn(s) (152 4. Large number of yarns are needed for
maximum) is/are needed during knitting a fabric
knitting a fabric 5. Filament yarns are mostly used
6. Staple yarns are preferably used 6. More preparatory processes are required
7. Less preparatory processes are before knitting
required before knitting

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