SPINNING
The cotton fiber grows in the seedpod or boll, of the cotton plant. Each fiber is a single elongated cell that is flat, twisted, and ribbon like with a wide inner hollow (lumen).It is composed of about 90 percent cellulose and about 6 percent moisture; the remainder consists of natural impurities.
The outer surface of the fiber is covered with a protective wax like coating which gives the fiber a somewhat adhesive quality. After this hydraulic pressing is done and cotton is been tested for the quality control. And then it has been sent for even moisture distribution. After all these processes this bale cotton gone to traders and textile mills receives these bale cotton from traders. As soon as the cotton arrives at the mill after ginning process in large bales weighing about 500 pounds (225 kg) each it is been kept for 24 hours.
1. BLENDING STEPS: Cotton is passed from bales and then to apron. Apron moves cotton to blending apron. Blending apron has sharp spikes the raise cotton until part of it is knocked off by the roll. Some of the cotton stays on apron. The cotton knocked back by roll and continues to chum and blend until picked up again by apron. Another roll strips off cotton that was not knocked back by previous roll. Cotton falls on conveyor belt and is carried to next process. WHY ITвАЩS BEEN DONE?It is necessary so as to obtain uniformity of fiber quality.
2. OPENING STEPS: Lint cotton falls on apron and passes between feeder rolls to beater cylinder. The rapidly whirling beater blades take off small tufts of cotton, knock out trash, and loosen up the mass. The two screen rolls are made of screen material and air is sucked out of them by fan. This draws the cotton from beater and condenses it on the surface of the screen rolls from which it is taken and passed on by the small rolls. Air suction through cotton takes out dirt and trash. Conveyor belt passes cotton to another type of beater. From beater the cotton passes to a conveyor and is carried to (Cotton going through the picker. WHY ITвАЩS BEEN DONE?It is necessary in order to loosen hard lumps of fiber and disentangle them; cleaning is required to remove trash such as dirt, leaves, burrs, and any remaining seeds. Mechanical bale pickers pluck thin, even layers of the matted fibers from each of a predetermined number of bales in turn and deposit them into a opening machine where the fibers are loosened) hopper. The fiber is mixed and passed to an opener. As the mass of fiber passes through the opener, cylinders with protruding fingers open up the limp and free the trash. The kind and number of cylinders or beaters, employed depend upon the type of cotton that is being processed. The commonly used porcupine beater revolves about 1000 revolutions per minute. As the cotton is opened, trash falls through a series of grid bars. When the cotton emerges from the opener, it still contains small tufts with about two-thirds of the trash. It may be conveyed as lap. GBR- Here the cottons are fed for homogenous mixtures and for removing dirts.MPM-8 вАУ it has got 8 chambers. Generally used for homogenous mixture of fibers like while harvesting some cotton are from matured plants and some are not. So that it will affect the fabric. So, after homogeneous mixing all will be the same.
3. CARDING PROCESS: Before the raw stock can be made into yarn, the remaining impurities must be removed, the fibers must be disentangles, and they must be straightened. The straightening process puts the fibers into somewhat parallel CARDING. The work is done by carding machine. The lap is passed through a beater section and drawn o rapidly revolving cylinder covered with very fine hooks or wire brushes slowly moves concentrically above this cylinder. As the cylinder rotates, the cotton is pulled by the cylinder through the small gap under the brushes; the teasing action removes the remaining trashes, disentangles the fibers , and arranges them in a relatively parallel manner in form of a thin web. This web is drawn through a funnel shaped device that molds it into a round rope like mass called card sliver. Card sliver produces carded yarns or carded cottons serviceable for inexpensive cotton fabrics.
STEPS: The lap from pucker unrolls and feed roll passes cotton licker in roll (covered with saw toothed wire).The licker in roll passes fiber against cleaner bars and gives it up to large cylinder which passes between the thousands of fine wires on surface of cylinder and on flats. The cotton follows large cylinder to doffer cylinder, which remove lint from large cylinder. The doffer comb vibrates against doffer cylinder and takes lint off in a filmy web that passes through condenser rolls, coiler head, and then into can. The sliver may be passed from one can to combing for further removal of foreign matter and parallelization of fiber or directly to drawing.
4. DOUBLING PROCESS: After carding, several slivers are combined. This results in a relatively narrow lap of compactly placed staple fibers. The compactness of these fibers permits this cotton stock to be attenuated, or drawn out, to a sliver of smaller diameter without falling apart.
5. COMBING PROCESS: When the fiber is intended for fine yarns, the sliver is put through an additional straightening called COMBING. In this operation, fine-toothed combs continue straightening the fibers until they are arranged with such a high degree of parallelism that the short fibers, called noils, are combed out and completely separated out from the longer fibers. The combing process forms a comb sliver made of the longest fibers, which, in turn, produces a smoother and more even yarn. This operation as much as 25% of the original card sliver; thus almost one fourth of the raw cotton becomes waste. The combing process, therefore, is identified with consumer goods of better quality. Since long-staple yarns produce stronger, smoother, and more serviceable fabrics, quality cotton goods carry labels indicating that they are made from combed yarns or combed yarns.
6. DRAWING PROCESS: The combining of several fibers for the drawing, or drafting, process eliminates irregularities that would cause too much variation if the slivers were pulling through singly. The draw frame has several pairs of rollers, each advanced set of which revolves at a progressively faster speed. This action pulls the staple lengthwise over each other, thereby producing longer and thinner slivers. After several stages of drawing out, the condensed sliver is taken to the slubber, where rollers similar to those in the drawing frame draw out the cotton further. Here the slubbing is passed to the spindles, where it is given its first twist and is then wound on bobbins. STEPS: Her six cans that were filled at cards feed each drawing from delivery. The spoons are connected so that if any one of the six slivers from can should break, the machine automatically stops. This prevents making uneven yarn later. Each of four set of rolls runs successively faster than preceding set. The last set runs approximately six times as the first set; consequently, sliver coming out is the same size as each one of six going in. but is attenuated to six times the length per minute. The sliver is neatly coiled again in roving can by coiler head. The sliver is now much more uniform and fibers much more nearly parallel. The sliver is now ready for roving frames.
8. SPINNING PROCESS: The roving, on bobbins, is placed in the spinning frame, where it passes through several sets of rollers running at successively higher rates of speed and is finally drawn out to yarn of the size desired. Spinning machines are of two types; ring frame and mule frame. The ring frame is faster process, but produces a relatively coarse yarn. for very fine yarns, such as worsted, the mule frame is required because of its slow, intermittent operation. The ring frame, which is general in use, is more suitable for the manufacture of cotton yarns in mass production. Its hundreds of spindles, whirling thousands of revolutions per minute, and its constant spinning action provide a fast operation. The ring spinning frame completes the manufacture of yarn (1) by drawing out the roving (2) by inserting twist, and (3) by winding the yarn on bobbins-all in one operation. The bobbins of yarn are removed for such processing as may be desired; for example, the yarn may be reeled into skeins for bleaching or may be wound on cheeses, or spools, for ultimate weaving. STEPS: The principle of spinning is same as that used in roving except that the operation is more refined and a ring and traveler are used instead of the flyer. From bobbin roving is fed between set of drafting rolls to draw strand down to its final desired size. The spindle turns bobbin at a constant speed. The front set of rolls is adjusted to deliver yarn at a speed sufficient to insert desired mount of twist as strand moves along. The traveler glides freely around ring. The tension caused by drag of traveler causes yarn to wind on bobbin at same rate of speed as it delivered by rolls.
