Conversion of fiber into yarn:

Presented by:ELFA RAJA

Fibers: A fiber can be described as any substance natural or manufactured that is

suitable for being processed into a fabric. Fibers are units of matter having length at least 100 times their diameter or

width. Fibers suitable for textile use possess adequate length, fineness, strength, and flexibility for yarn formation and fabric construction and for withstanding the intended use of the completed fabric.

Other properties affecting textile fiber performance include elasticity, crimp (waviness), moisture absorption, reaction to heat and sunlight, reaction to the various chemicals applied during processing and in the dry cleaning or laundering of the completed fabric, and resistance to insects and microorganisms. The wide variation of such properties among textile fibres determines their suitability for various uses.

To create a fabric, fibers are spun into yarns and then woven into fabric.

YARN:YARN is a strand composed of fibers, filaments (individual

fibers of extreme length), or other materials, either natural or man-made, suitable for use in the construction of interlaced fabrics, such as woven or knitted types.

The strand may consist of a number of fibers twisted together; a number of filaments grouped together but not twisted; a number of filaments twisted together.

 The properties of the yarn employed greatly influence the appearance, texture, and performance of the completed fabric.

Yarn manufacturing process:

Spinning Yarns:The process of converting cotton fibres from ginned

lint into a yarn involves a number of processes that aim to clean, remove short fibres, align fibres and ultimately spin the yarn and prepare it for delivery.

Depending on the setup and machinery present in a spinning mill and the desired quality of the yarn needed to be produced will determine which processes are undertaken.

Ginned lint Carded sliver Combed sliver Drawn sliver Roving Yarn

The results of various spinning mill processes that help to clean, remove short fibres, align fibres and ultimately produce yarn.

Opening, Blending and Cleaning:Opening, blending and cleaning of the fibre are

the first processes in the spinning mill.The opening and blending processes ensure a

consistent and homogeneous blend of fibres.Blended fibre is then passed through more

machines to further open (loosen) the fibre tufts and to clean and remove contaminants which may create serious quality issues if contained within the fibre to the final product.

Purposes of Blending: Blending of different fibers is done to enhance the performance

and improve the aesthetic qualities of fabric. Fibers are selected and blended in certain proportions so the fabric will retain the best characteristics of each fiber. Blending can be done with either natural or manufactured fibers, but is usually done using various combinations of manufactured fibers or manufactured and natural fibers.

For example, polyester is the most blended manufactured fiber. Polyester fiber is strong, resists shrinkage, stretching and wrinkles, is abrasion resistent and is easily washable.

Blends of 50 to 65% polyester with cotton provides a minimum care fabric used in a variety of shirts, slacks, dresses, blouses, sportswear and many home fashion items A 50/50 polyester/acrylic blend is used for slacks, sportswear and dresses. And, blends of polyester (45 to 55%) and worsted wool creates a fabric which retains the beautiful drape and feel of 100% wool, while the polyester adds durability and resistance to wrinkles.

Carding:This is for good reason as the carding machine

individualizes, aligns and further cleans the fibres, before condensing them into a single continuous strand of overlapping fibres called a ‘sliver’.

Importantly, a large proportion of short fibres and neps are also removed during carding.

The quality of the sliver assembly from the card determines both the quality and processing efficiency of products further up the processing chain.

Carding:

Drawing:Drawing is the process where the fibers are

blended, straightened and the number of fibers in the sliver reduced in order to achieve the desired linear density in the spinning process.

The drawing process also improves the uniformity or evenness of the sliver.

The number of drawing passages utilized depends on the spinning system used and the end products.

Combing:Combing is the process that removes the final proportion

of short fiber, neps and other impurities.The waste material, which is predominantly made up of

short fiber, is referred to as noil or comber waste and commonly makes up between 15 and 20% by weight of the fiber into the comber.

Combed yarns are superior in quality when compared to carded yarns as they are generally finer, stronger, smoother and more uniform due to the removal of short fibers and the alignment of fibers.

Combed yarns are however more expensive than carded yarns (approximately 10%) as combing involves additional processing stages and produces more waste.

Carded yarn Combed yarn

Roving:In preparation for ring spinning, the sliver

needs to be condensed into a finer strand known as a roving before it can be spun into a yarn

The roving frame draws out the sliver to a thickness of a few millimeters and inserts a small amount of twist to keep the fibers together.

Spinning Process - The Spinneret:Before being formed into fibers, the fiber-producing

substance for all manufactured fibers is in a thick liquid state.

In the spinning process this liquid is forced through a spinneret, which resembles a large shower head. A spinneret can have from one to literally hundreds of tiny holes.

The size of the holes varies according to the size and type of the fiber being produced.

Spinning:There are three main spinning systems used

commercially to produce yarns from fibres typically with lengths up to 50 mm.

1) Ring spinning2) Rotor spinning (also known as open-end

spinning )3) Air-jet spinning (including Vortex spinning)

Ring Spinning:Ring spinning is the process of further

drawing out roving to the final yarn count needed, inserting twist to the fibres by means of a rotating spindle and winding the yarn on a bobbin.

These three stages take place simultaneously and continuously.

Ring spinning is a comparatively expensive process because of its slower production speeds and the additional processes (roving and winding) required for producing ring spun yarns.

Ring Spinning:Ring spun yarns produce high quality

and are mainly produced in the fine (60 Ne, 10 tex) to medium count (30 Ne, 20 tex) range, with a small amount produced in the coarse count (10 Ne, 60 tex) range.

End uses include shirting, towels.Tex is a unit of measure for the linear mass

density of fibers and is defined as the mass in grams per 1000 meters. 

Ring Spinning:

Rotor spinning (open –end spinning):Sliver is fed into the machine and combed and

individualized by the opening roller. The fibres are then deposited into the rotor

where air current and centrifugal force deposits them along the groove of the rotor where they are evenly distributed.

The fibres are twisted together by the spinning action of the rotor, and the yarn is continuously drawn from the centre of the rotor.

The resultant yarn is cleared of any defects and wound onto packages.

Rotor spinning (open –end spinning):The production rates of rotor spinning is 6-8 times

higher than that of ring spinning and as the machines are fed directly by sliver and yarn is wound onto packages ready for use in fabric formation the yarn is a lot cheaper to produce.

Rotor spun yarns are more even, somewhat weaker and have a harsher feel than ring spun yarns.

Rotor spun yarns are mainly produced in the medium count (30 Ne, 20 tex) to coarse count (10 Ne, 60 tex) range.

End uses include denim, towels, blankets socks, t-shirts, shirts and pants.

Rotor spinning (open –end spinning):

Air jet spinning (vortex): Sliver is fed into the

machine and is further drawn out to the final count and twist is inserted by means of a rotating vortex of high pressured air.

The resultant yarn is cleared of any defects and wound onto packages ready for use in fabric formation.

Air jet spinning (vortex):The production rate of air jet/vortex spinning is 3-5

times higher than rotor spinning and 10-20 times that of ring spinning and, like rotor spinning, air-jet spun yarn is a lot cheaper to produce as it also uses fewer production stages.

As is the case with rotor spun yarns, air jet yarns are more even, but weaker and have a harsher feel than ring spun yarns.

Air jet spun yarns are mainly produced in the medium count (30 Ne, 20 tex) range and are mainly polyester/cotton blended yarns.

End uses include woven sheeting and knitted lightweight shirting.

Winding:Winding process can be defined as the

transfer of spinning yarn from one package to another large package(cone, spool, pirn, etc).

The other objective of winding process is to:To improve quality of yarn.To get suitable yarn package.To remove dust and clean yarn.To reduce labor cost.To store yarn.To improve the efficiency of yarn for next

process.

YARN FINENESS OR COUNT: yarn fineness is typically described by terms such as yarn

count, yarn number, or yarn size. The linear density or mass per unit length is commonly used

as an alternative measure of actual fineness or thickness. In general, two yarn count systems are commonly used: (i) the direct system, and (ii) the indirect system.

Direct Count SystemIn a direct system, yarn count is the mass of a unit length of

yarn. One of the universally used direct systems is known as the "tex". This is defined by the mass in grams of 1 km of yarn.

Indirect Count SystemIn an indirect system, the yarn number or count is expressed

in "units of length" per "unit of weight".

http://www.britannica.com/EBchecked/topic/589392/textile/15720/Conversion-to-yarn

http://www.fabriclink.com/university/production.cfm

http://www.textileschool.com/articles/108/ring-spinning

http://www.textileschool.com/articles/112/open-end-spinning

http://fr.slideshare.net/kir123/yarn-manufacturing-processes

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