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Yarn is continous strand which is made up of filaments or fibers. It is used to make fabric/textiles of different kinds.

Yarn formation methods were originally developed for spinning of natural fibers including cotton, linen, wool and silk. Since the overall physical characteristics of the fibers and processing factors needed differed from fiber to fiber, separate processing systems were developed. As synthetic fibers were introduced, synthetic spinning systems for texturized and untexturized cut staple were developed as modifications of existing staple systems, whereas spinning systems for texturized and untexturized filament were developed separately.

The thickness of yarn is measured as Counts. Yarns are made in different counts like 2’s, 4’s, 10’s, 16’s, 20’s, 24’s, 25’s, 30’s, 34’s, 36’s, 38’s, 40’s, 60’s, 80’s, 100’s, etc. We can consider like this. 0’s counts are cotton fiber. 20’s counts yarn is thicker than 24’s yarn. Likewise 30’s yarn is thicker than 34’s. So when the yarn counts are increasing, the thickness becomes lesser. We can see, the higher the counts, the lesser the thickness.

Yarn prices based on the thickness. Price of 20’s yarn is lesser than 24’s. Price of 30’s yarn is lesser than 34’s yarn. We must know, higher the counts, higher the prices. There are 2 qualities of yarn. Combed and Carded.

Combed is superior quality. The cotton fibers are in different lengths from 0.25 inches to 2.5 inches. According to the technical parameters, the fibers with more length are considered to be better. These long fibers give more evenness and more strength for yarns. Also the short fibers are increasing hairiness whereas the long fibers are decreasing hairiness in yarns. Hence in order to get uniformity in fiber lengths, the short length fibers are to be eliminated from the long length fibers. For this purpose, a special process is being done. This process is called ‘Combing’. Because of the same longer length of fibers, the yarn will be very even with lesser hairiness. Hence after knitting or weaving, the fabric will have very even look.

Carded yarn is inferior in quality. As the above said ‘combing’ process is not being done, the carded yarn will be made of the fibers in different lengths. Hence the yarn strength will be lesser than combed yarn. Also carded yarn will have more hairiness and due to this, the fabric made with carded yarns will have more unevenness. Because of this extra process, the Combed yarn price is higher than Carded yarn. Also Combed yarn quality is superior to Carded yarn.

Cotton Yarn Formation

On removing the cotton from the bales, the cotton is opened up, blended and mixed with cotton from other bales. Finally the fibers are formed into a thin partially oriented continuous web of intertwined fibers called a picker lap. The picker lap in turn undergoes carding to remove short fibers and remaining trash and to provide additional orientation to the fibers.

The cotton sliver from carded machines are combed before feeding to drawing in order to further straighten and orient the fibers and to remove additional short tangled fibers. The drawing portion of the operation is referred to as the drafting process.

Subsequent drawing and high speed twisting is carried out by ring spinning in which the drafted, lightly twi sted sliver (roving) is fed from the drafting unit onto a high speed spindle via a traveller holding the spun yarn to a ring surrounding the reciprocating spindle.

Woolen and Worsted Yarn Formation

The wool is washed in successive baths of detergent solution to remove the impurities. The process is called scouring, and the weight of the raw wool can be reduced by as much as 50% by the scouring process.

Vegetable matter remaining in the wool can be removed by passing the wool through concentrated sulfuric acid to chemically destroy the cellulosic matter, a process called carborization.

After washing and drying, the cleaned wool is blended and carded to form a sliver. The sl iver must undergo additional straightening, orientation, and removal of short fibers to be used in the worsted system. The process involves several successive steps including gilling (a form of pin orientation) and combing to give wool top. The wool top is drawn and slightly twisted in several stages to form a roving which is finally spun into a highly twisted worsted yarn.

Other Staple Yarn Formation

Cut staple manmade fibers arrive in boxes at the mill and are ready for carding and processing into yarn. When two or more different staple fibers are mixed, it is critical to provide extensive blending before carding and repeated doubl ing of the sl iver to assure intimate blending prior to roving and spinning.

Filament Yarn Formation

Filament spinning systems are much less complex because the fibers are continuous and do not need to be highly twisted to give a cohesive strong yarn. Filament yarn spinning usually involves man-made fibers and only the portion of the ring spinning system that involves twisting and winding onto spindles is used.

After combing and twisting, the yarn will be singed (gassed). By this process, the yarn will pass rapidly through flames and the superficial hair around the yarn would be eliminated. Due to more heat, the hairy particles of the yarn will be burnt out. (Now this is called Gassed Yarn).

Then the yarn is treated with caustic soda under perfectly controlled tension. This process is called Mercerising. Mercerising is done to strengthen the yarn and to improve luster of yarn. After mercerising, the yarn will have great strength and greater brightness. Also the yarn will capture 20% more humidity without getting wet. Further, this mercerising process increases the resistance of yarn and reduces its becoming dirty. (Now the yarn is called Gassed Mercerised Yarn).

For making the stripes and jacquard design fabrics, the dyed yarns are used. Yarns are dyed by manually and by sophisticated machines. In manual yarn dyeing, we can not expect the consistency of shades, yarn strength and better quality. Hence it is always advised to dye the yarns with the latest machines only.

For yarn dyeing, only combed yarns are used. Also the yarn should have more yarn strength. It is called Count Strength Product (CSP).

GSM is the short form of Grams per Square Metre. GSM is the very most important thing which defines the weight of the fabrics of knit garments.

Garment price and quality based on many things like GSM, fabric quality, colours, finishing, prints, embroidery, style, etc. But GSM is the most important thing to be decided when confirming the prices between the sellers and buyers.

GSM is the weight of 1mtr x 1mtr fabric. It means 100cm x 100cm = 10,000 sq.cms. It can be found out by any one of the below ways.

• By the weight of 100cm x 100cm fabric bit.
• By the weight of 50cm x 50cm fabric bit multiplied by 4.
• By the weight of 25cm x 25cm fabric bit multiplied by 16.
• By the weight of 10cm x 10cm fabric bit multiplied by 100.

We must be aware that if we use the smaller size bit, accurate GSM can not be achieved. The bigger size of fabric bit is better used to get exact or closer GSM.

If we have fabrics, then we don’t have any problem in finding GSM, as we can cut any dimension to find GSM. But most of the times, we will have only the garments to find GSM. And we will have to keep the garment for style, making and other references. So we will be allowed to cut a small bit from the garments. Hence nowadays, round cutters are used. This system is used worldwide. With the help of this round cutter, the fabric will be cut into a small bit.

Then the GSM of the fabric can be found out by multiplying the weight of this round bit by 100. This round bit is to be weighed in an electronic scale with milligram accuracy. As this bit is very small and as the weight has to be multiplied by 100, the fabric has to be cut very sharply to get the exact GSM. Hence the blades of this round cutter are to be  sharp and new to get the exact GSM.