Textile Yarns

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Textile YarnsProcess of Yarn Manufacturing

Classification of YarnsYarn Numbering

Sewing Threads

Prepared byP.Lakshmana kanthSenior Faculty IFTK


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Process of YarnFormation

Yarn is continuous strand which is made up offilaments or fibers. It is used to makefabric/textiles of different kinds.

Yarn formation methods were originally

developed for spinning of natural fibersincluding cotton, linen, wool and silk.

Yarn is defined by the American Society for

Testing and Materials (ASTM) as A genericterm for a continuous strand of textile fiber,filament, or material suitable for knitting,weaving to form a textile fabric. Yarn occursin the following forms.


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Yarn forms

A number of fibers twisted together.

A number of filaments laid together

without twist. A number of filaments laid together

with more or less twist.

A single mono filament. e.g. Silk


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Yarn ManufacturingSystem Yarn is defined as a linear assemblage of the

fibers twisted together. The process ofmaking the yarn from a textile fiber is calledSpinning.

Spinning is the art of producing continuous,twisted Strands, of a desire size, from fibrousmaterials.

In a broad sense, the term is used to includeall the operations through which cotton fibersare passed until they become yarn.

Spinning includes all the processes requiredto prepare and clean the fibers from the


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Process of YarnManufacturing


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The basic process sequence involved in themanufacturing of the cotton yarn is shown

above in the chart. Some of the process like combing can be

skipped when some low quality yarn isrequired.

The final end product of the spinning mill willbe yarn which can be delivered in differentforms of packages like cones, cheeses, hanks

etc. The package may be selected according to

the convenience and for easy transportationas the weaving or knitting mill will be away

from the spinning mill in normal.


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Bale Opener


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Bale Opener

The cotton tufts are opened in thisprocess.

As the cotton arrives in an extremely

compressed condition the first operation isto loosen the matted fibers

The cotton fiber is loosened by means of

rotating spiked rollers of the bale opener.


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Mixing


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Mixing

This is a process of mixing thesame/different category of fibers toget desired properties and cost

effectiveness. Mixing is done after the study of the

essential properties of fiber like

staple length, Tensile strength,fineness, uniformity etc.


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Blow room


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Blow room

In this process the cleaning andopening of the cotton is done bybeaters and openers.

The foreign materials like dustparticles, seeds of cotton and otherimpurities are partially removed in

this process.The cotton tufts are opened and

cleaned in this process and the

cotton lap is made out.


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Carding


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Carding

Carding is the heart of spinning inthis process the minute impuritieslike small seed particles, immature

fibers etc. are removed.The straightening and aligning of

fibers are done in this process.

In carding the Blow room lap isattenuated to the card sliver.


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Drawing


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Drawing

Through drafting fibers get paralleled

Up to Eight Carded Slivers are fed into theDraw-Frame and they are

stretched/Straightened and made into asingle sliver.

Also fiber blending can be done at this

stage.


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Simplex (Speed Frame)


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Simplex (Roving)

Further drafting is done here to getthe fibers more aligned/paralleled.

The Sliver from Draw-Frame is thickerand will be difficult to be fed into theRing-frame as is, hence here theSlivers are stretched and were made

thinner by Drafting and mild twisting(so as to strengthen the Roving).

The End-Product from the Simplex is

called as Roving


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Ring Spinning

The roving is fed into the Ring-frameand is made into yarn by furtherDrafting & Twisting.

Basic Functions of Ring Frame are

to draft the roving until the requiredfineness is achieved

To impart strength to the fiber, byinserting twist.

Depending upon the yarn count


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Ring Spinning


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Lap Formation - Diagram


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Sliver Formation-Diagram


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Roving Formation Diagram


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Spinning Ring Frame (Yarn Formation)- Diagram


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Yarn Twist

When fibers are twisted to make a yarn, they aretwisted to the right or left.

This twisting is called S or Z twist. Most yarns aremade with a Z twist.

The direction of twist does not usually affect thecharacteristics of the yarn or fabric.


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Twist per Inch (TPI)

The number of twists per inch can, inplied yarns, be determined bycounting the number of bumps in

one inch, and divide by the numberof singles (the strands plied togetherto make the yarn).


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Amount of Twist

Twist is needed in yarn to hold thefibers together, and is added in boththe spinning and plying processes.

The amount of twist varies on thefiber, thickness of yarn, preparationof fiber, manner of spinning, and thedesired result.

Fine wool and silk generally use moretwist than coarse wool, short staplesmore than long, thin more than thick,

and short drawn more than long

Generally higher twist creates


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Generally, higher twist createsyarns that are

Stronger

More firm

Smaller in Diameter Smoother

Resistant to snagging and

abrasion

Resilient

Good Conductors of heat

Generally lower twist creates


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Generally, lower twist createsyarns that are

Weaker

Softer

Larger in Diameter

Fuzzy

Prone to Snag & abrade

Crush Easily Resistant to heat transfer.


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Structure of Textile Yarns

Basically there are three types ofyarn. They are

(1) Spun yarn,(2) Filament yarn &

(3) Textured Yarn


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pun Yarns Spun yarn is made by twisting or otherwise

bonding staple fibers together to make a cohesivethread.

Twisting fibers into yarn in the process calledspinning. Spinning was one of the very first

processes to be industrialized.

Spun yarns may contain a single type of fiber, orbe a blend of various types.

Combining synthetic fibers (which can have highstrength, luster, and fire retardant qualities) withnatural fibers (which have good water absorbencyand skin comforting qualities) is very common.

The most widely used blends are cotton-polyester-


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Yarns are made up of a number of plies,each ply being a single spun yarn.

These single plies of yarn are twistedtogether (plied) in the opposite directionto make a thicker yarn.

Depending on the direction of this finaltwist, the yarn will be known as s-twist orz-twist.

For a single ply, the direction of the finaltwist is the same as its original twist.


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Filament Yarns &Textured Yarns

Filament yarn consists of filament fibers(very long continuous fibers) either twistedtogether or only grouped together.

Thicker monofilaments are typically usedfor industrial purposes rather than fabricproduction or decoration.

Silk is a natural filament, and syntheticfilament yarns are used to produce silk-likeeffects.

Textured Yarns -Texturized yarns are

made by a process of air texturizing which


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Classification of Yarns

Classification of yarns can bedone

(1) Based on the number ofstrands &

(2) Based on the end use

Classification of yarns


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Classification of yarnsbased on number of

Strands Based on the number of strandsyarns can be classified into

- Single Yarns

- Ply Yarns

- Cord Yarns

- Textured Yarns

- Metallic Yarns

- Stretch Yarns


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Single Yarns

A yarn which is smooth and uniform andevenly twisted is called a simple singleyarn.

It is commonly used for making fabric likepoplin and cambric.

A simple single yarn is an assemblage offibres evenly twisted together.


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Ply Yarns

A Simple Ply yarn is made of two or more singlesevenly twisted together.

If the ply has two singles it is called a 2-ply and soon.

This type of yarn is found in a 2 by 2 rubia fabric.

It has 2 ply yarns in both directions of the fabric.Similarly 3 Ply and 4 ply yarns are available.


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Cord Yarns

A simple cord yarn is made of two or moreply yarns twisted together.

To make a cord yarns, take two or more ply

yarns and twist it together


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Complex / Novelty Yarns

Complex yarns are the uneven yarnswhich may be thick and thin or have curls,loops, twists and even differently coloured

areas along their length. Due to this fancy look of the yarns they

are used to add interesting effects infabrics. Like simple yarns, the complex

yarns may also be single or ply. A single complex yarn is usually unevenly

twisted to make it thick and thin in places.

This is the type of yarn which is found in

Types of Complex /


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Types of Complex /Novelty YarnsS.No Type of Yarn Figure

01 SLUB yarn with thick and thin

places

02 SPIRA or GIMP- combination

of soft, thick yarns twisted

with fine, hard yarns03 BOUCLE- two different yarns

are fed into the loom at

different speeds for a varied

effect04 LOOP stiff fibres form loops

which spring out of the core

yarn

05 SNARL very highly twisted

yarn

06 KNOP ground yarn is held

under tension as knops are

built up a fast speed07 CHENILLE a woven cut

fabric yarn


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Textured Yarns

When you unravel a sweater, you find thatthe yarn which was straight when youknitted has now become curly. This yarncan now be called a textured yarn.

Texturizing is a treatment usually given toa manmade filament, after which itbecomes curly or acquires some forms of

loops, coils or crimp.

Diff t t f t t d


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Different types of texturedEffect is shown below


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Metallic Yarns

Metalized yarns can take manyforms.

Some examples: Metal wirecombined with textile. Metalizedstrip, consisting of a core of metal foilor of plastic (often polyester) film

coated with metal dust, sandwichedby means of adhesive between twolayers of plastic film (e.g., Lurex).

Gimped (supported) yarn,


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Stretch Yarns

Stretch yarns are frequentlycontinuous-filament man-made yarnsthat are very tightly twisted, heat-

set, and then untwisted, producing aspiral crimp giving a springycharacter.

Although bulk is imparted in theprocess, a very high amount of twistis required to produce yarn that has

not only bulk, but also stretch.


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Yarn Numbering

Count:Yarn number varies and itdiffers according to the kind of fibre.

Many weaving yarns and sewingthread are numbered by the cottonsystem (count).

Spun yarn size is referred to asnumber and is expressed in terms oflength per unit of weight. It is anindirect system; the finer the yarn,

the larger the number.


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Denier

The size of filament yarns is determined asdenier, which is expressed in terms ofweight per unit of length. If 9000 metes ofyarn weigh 1 gram, it is then 1 denier. Inthis system, the unit of length remainsconstant. The finer the yarn, the smaller isthe number.

Denier = weight of yarn in gms/ 9000meters

1 denier - 9,000 meters weigh 1 gram

i.e,


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Tex System

The International Organization forStandardization has adopted the Texsystem, which determines yarn count

or number in the same way for allfibre yarns and uses metric units(weight in grams of 1 thousands

meters of yarn Tex = weight in gms / 1000

meters of yarn


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Sewing Threads

The seam performances of thegarment are influenced by sewingthread and sewing techniques and

the end use desired.These yarns are differing from other

threads. We are taking more care to

construct the sewing thread, becausesewing threads are having somespecial character.

Almost all type fibres can be used as


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Sewing thread are special kinds of yarns.They are engineered and designed to pass

through a sewing machine rapidly. To forma stitch efficiently and to function while ina sewn products without breaking orbecoming distorted for at least the usefullife of the product.

Classification of Sewing


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Classification of SewingThreads Sewing Threads

Spun Core Spun ContinuousFilament

Cotton- Glazed- Soft- Mercerized

Linen

PolyesterBlendedPolyester / CottonPolyester / Viscose

Cotton

Wrappedcorepolyester

Polyester

wrapped CoreCotton

Monofilament

- Nylon

- Polyester

Silk

Multi filament- Bonded- False twisted

- Air jet texturized

Properties of Sewing


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Properties of SewingThreadsThe performance of textile fabrics

and clothing is strongly influenced bythe properties of the yarns from

which they are made. Sewing threads require certain yarn

properties.


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Regularity Smooth fabrics should be sewn only with very

regular yarns. In spun yarns, this is achieved by

repeated doubling and drafting, and bycombing out the short fibers.

Strength Yarn strength depends on the quality of the

fibres, the yarn regularity and the twist. Folding

increases the strength.

Hardness/Twist

The twist density affects the hardness of a yarn

and hence the handle and the appearance of

textiles.

Extensibility/Elasticity

Extensibility and elasticity are very important

during yarn processing and utilization. They are

determined mainly by the fibre type and the

spinning system.

Textile Yarns

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