What is Spinning?
Spinning is the first step to produce a textile product such as yarn, fabric, garments, home textiles etc. At present, the short-staple or cotton spinning process is the most common spinning method worldwide. Yarn spinning is a process of converting fibres into yarn. It consists of different processes. Spinning is the initial step in the textile manufacturing process and is essential for producing the raw material necessary for the creation of fabrics and textiles.
Process Flow Chart of Yarn Spinning Technology:
Flow chart of yarn spinning technology is given below:
Mixing and Blending
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Opening
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Carding
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Doubling
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Combing
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Drawing
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Roving
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Spinning
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Winding
Flow chart of yarn spinning technology are described given below:
1. Mixing and Blending:
Mixing and blending are the first steps in yarn spinning operation. Blending cotton fibers of different lengths to produce a more consistent and smoother yarn. 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. Mixing and blending are used to achieve uniformity, enhance yarn performance, and create unique yarn blends tailored to different textile applications.
The objective of mixing is to optimize the homogeneity of the material mixture by combining several bales. Further objectives of mixing are
- Decrease in irregularities in bales of different origins,
- Economic processing,
- Recycling of comber waste and other offal,
- Improved properties of the final product, and
- Reduction of raw material costs.
Blending is the adjustment of defined mass percentages of several raw material components. It is achieved by the following processes:
- Manual layup of the various mixture components,
- Automated bale-reduction systems,
- Hopper feeder, and
- Continuous metering hopper.
2. Opening:
Opening is the breaking up of the fiber mass into tuft. The main objectives of the opening are the further separation of the fibre flocks and the removal of contamination particles and dust from the cotton. Opening means to increase the specific volume (cc/g) of the feed material and is adjudged from the tuft size. 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. It is necessary in order to loosen hard lumps of fibre 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 fibres from each of a predetermined number of bales in turn and deposit them into a opening machine where the fibres are loosened) hopper. The fibre is mixed and passed to an opener. As the mass of fibre 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.
Increase in the opening/cleaning intensity increases waste removal but also leads to fibre damage, fibre loss, and an increase in neps level. Choice of beaters and sequence of opening depend on the nature of fibre and the process requirements. Fibre opening is the key to good yarn spinning. Good, gentle opening ensures maximum retention of fibre strength by minimizing fibre rupture, reducing the level of neps, effective thrash removal, and minimal amounts of microdust and lint.
3. Carding Process:
The final stage in the blowroom process is carding. It is considered as the heart of the spinning process. Carding process is a crucial step in spinning that prepares raw fibres for further processing and spinning into yarn. In this stage, the cleaned and blended short tufts are converted into individual fibres. For the first time in the blowroom, fibre orientation is important. Before the raw stock can be made into yarn, the remaining impurities must be removed, the fibres must be disentangles, and they must be straightened. The straightening process puts the fibres 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 fibres, 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 fibre 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 fibre or directly to drawing.
4. Doubling Process:
After carding, several slivers are combined. This results in a relatively narrow lap of compactly placed staple fibres. The compactness of these fibres permits this cotton stock to be attenuated, or drawn out, to a sliver of smaller diameter without falling apart.
5. Combing Process:
Combing is an optional step in fibre production and is used when a smoother, finer yarn is required. Combing allows the production of very fine, high-quality spun yarns. In this operation, fine-toothed combs continue straightening the fibres until they are arranged with such a high degree of parallelism that the short fibres, called noils, are combed out and completely separated out from the longer fibres. The combing process also removes short fibres (<0.5 in), fibre hooks and any neps or impurities that might remain. The combing process forms a comb sliver made of the longest fibres, 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.
Combed yarns have a superior appearance compared to carded yarns, having smoother surfaces and finer diameters. The removal of short fibres means that fewer short ends show on the surface of the fabric, and the lustre of the fabric is also increased.
6. Drawing Process:
Drawing refers to the attenuation (lengthening) and straightening of the slivers. However, the terms ‘drafting’ and ‘drawing’ are often used interchangeably. Again, blending can take place at this stage, and in fact this is where cotton is usually blended with a man-made fiber. The drawing process also removes fibres with hooked ends from the carded sliver. The drawing process is repeated twice for carded slivers, while combed slivers are drawn once before combing and twice after combing – hence the improved quality of fibers that have undergone both carding and combing operations.
The combining of several fibres 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 fibres much more nearly parallel. The sliver is now ready for roving frames.
7. Roving:
Roving process is an intermediate step in textile spinning that follows the carding process and precedes the final spinning of fibres into yarn. This process is important for further refining and preparing the fibres for spinning.
The drawn sliver is fed into a machine called a roving frame, the final step before spinning. In the roving frame, the strands of the fibre are lengthened still further by a series of rollers. As the fibres are wound onto the bobbins they are twisted slightly, and this twisted strand is called the roving. The twist results in improved cohesion of the strand and also condenses it so that the strand can be handled effectively in the subsequent spinning process.
8. Spinning Process:
It is the last step of yarn manufacturing. 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.
9. Winding Process:
Yarn winding is the final stage of the yarn-forming process and the starting point for various subsequent processes, from weaving or knitting to textile finishing. Yarns manufactured and packaged from ring spinning are not in the optimum condition to be used to form fabrics. Package size, build, and other factors make it necessary for the yarn to be further processed to prepare it to be handled efficiently during fabric formation. Yarn winding can be viewed as a packaging process, forming a link between the last few elements of yarn manufacturing and the first element of fabric manufacturing process. This interface function of winding is what makes the winding process so important. The ring spinning operation produces a ring bobbin containing just a few grams of yarn, which is unsuitable for the efficiency of further processing, such as warping, weaving, and knitting. The winding process converts the ring bobbin of several grams into dense yarn package of several kilograms, which can unwind in the subsequent operations without interruptions.
Conclusion:
Process flow chart of yarn spinning technology illustrates the systematic transformation of raw fibers into usable yarn. Starting with raw material selection and preparation, it proceeds through cleaning, mixing, blending, carding, roving formation, spinning, and winding, culminating in yarn inspection and packaging.
References:
- Textiles and Fashion: Materials, Design and Technology Edited by Rose Sinclair
- Process Management in Spinning by R. Senthil Kumar
- Textile Technology: An Introduction, Second Edition by Thomas Gries, Dieter Veit, and Burkhard Wulfhorst
- Textile Engineering – An Introduction Edited by Yasir Nawab
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- Basic Concept of Yarn Manufacturing Process (Machine Flowchart)
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- Cotton Yarn Spinning Process Step by Step
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
