Blow room is the initial stage in spinning process. Where the fiber is opened, cleaned, mixed and evened.
Carding is a mechanical process that disentangles, cleans and intermixes fibers to produce a continuous web or sliver suitable for subsequent processing.
Drawing is the operation by which slivers are blended, doubled and leveled. In short staple spinning the term is only applied to the process at a draw frame. In drawing slivers are elongated when passing through a group of pair rollers, each pair is moving faster than previous one. This permits combing, drawing and elongating of several slivers to make them strong and uniform.
Combing is a process which is introduced into the spinning of finer and high quality yarns from cotton. The carded materials (sliver) contain certain amount of short fibres, neps, fine kitty and leaf particles. Short fibres are a hindrance to spinning of finer counts where the number of fibre in the cross section of the yarn is less. The short fibres cause thick and uneven places in the yarn length and the yarn looks hairy. Apart from this, very short fibres do not contribute any thing to yarn strength.
Simplex is an intermediate process in which fibers are converted into low twist lea called roving. The sliver which is taken from draw frame is thicker so it is not suitable for manufacturing of yarn. Its purpose is to prepare input package for next process. This package is to prepare on a small compact package called bobbins. Roving machine is complicated, liable to fault, causes defect adds to the production costs and deliver the product.
The ring spinning machine is used to draft the roving and impart strength to the fibers by inserting twist.
Electronic magnetic tension will control the tension of individual spindle and the whole cheese winding process, and improves the quality of packages. The straight path to get the good conditions of winding and it will reduce the hairiness of the threads. With yarn broke sensor to detect individual spindle.
After spinning the yarn through various processes in the preparatory process and ring frame department, it is ready to be formed into a regular shaped package called cone to make it suitable for shipment for end use.
During the winding process, the following objectives are met:
a) Scanning and removing the faults,
b) Splicing of broken / cut yarn, and
c)Making of big packages as per customer requirement
As single yarn will be used in major fabrics, doubling yarn will be preferred in terry towels. The purpose of producing doubled yarn is to improve yarn uniformity, abrasion resistance, tenacity and flexural endurance. This is also an essential process for the production of balanced yarn. It is a two-stage process.
A) Doubling / Plying
“Two for One Twister” (TFO)
The method of twisting two or more single yarns is called doubling or twisting. “Two for One Twister” means, in one revolution of the spindle two turns of twist will be inserted in the yarn. The yarn will be unwound from a stationary feed package, guided through twisting spindle, twisted and finally wound on the take up package.
TFO have following advantages:
1. Production of long lengths of knot free yarn
2. Higher productivity
3. Fewer pre & post – twisting operations
4. Low manpower.
Regular yarns are twisted to impart strength in the terry towel fabric. “Twist less” or “Zero twist” yarn will be having maximum softness and absorbency. For producing zero twist yarn, cotton yarn will be wound with a water-soluble PVA filament yarn in a parallel winding machine. The wound yarn will be twisted in TFO machine. The direction of double yarn twist will be opposite to that of the single spun yarn twist, and the amount of twist will be equal to the twist in the spun yarns. By this process, the PVA filament will be wrapped around the cotton yarn and the yarn will be sufficiently strong due to the cohesion given by the filament. The twisting the yarn will open the cotton fibers so that they can trap air and moisture between them, this will ultimately increase softness and absorbency. The PVA will get dissolved during dyeing, leaving the extremely low-twist cotton behind.
High speed spinning machines generate more friction thus giving additional heat to the yarn and as a result of such heat transfer the yarn moisture content is vaporized. Rising speeds in spinning result in decreased yarn quality for other processes and it is well known that dry yarns have worse properties. For quality reasons it is absolutely important to have even distribution of this recuperated moisture throughout the entire yarn package. Only the vacuum technology provides the conditions for the required moisture regain.