2. 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.
3.
4. 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.
6. 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.
8. The results of various spinning mill processes that help to clean, remove
short fibres, align fibres and ultimately produce yarn.
9. 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.
10. 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.
11. 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 โsliverโ.
๏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.
13. 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.
14. 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.
16. 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.
17. 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.
18. Spinning:
There are three main spinning systems used
commercially to produce yarns from fibres typically
with lengths up to 50 mm.
1) Ring spinning
2) Rotor spinning (also known as open-end spinning )
3) Air-jet spinning (including Vortex spinning)
19. 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.
20. 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.
22. Rotor spinning (open โ
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.
23. Rotor spinning (open โend
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.
25. 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.
26. 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.
27. 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:
๏ผ To improve quality of yarn.
๏ผ To get suitable yarn package.
๏ผ To remove dust and clean yarn.
๏ผ To reduce labor cost.
๏ผ To store yarn.
๏ผ To improve the efficiency of yarn for next process.
28. 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 System
In 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 System
In an indirect system, the yarn number or count is expressed in
"units of length" per "unit of weight".
