Yarn Formation Systems

There are various commonly used popular Yarn Formation Systems.Some of them are Cotton woolen or worsted, staple, Filament yarn formation systems. Also some of the common types of yarns like mercerized, dyed, grindle or twisted, yarns are discussed in this page.

Dyed 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).

Popular Yarn Formation Systems

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 is 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.

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Subsequent drawing and high-speed twisting are carried out by ring spinning in which the drafted, lightly twisted sliver (roving) is fed from the drafting unit onto a high-speed spindle via a traveler 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 carbonization.

After washing and drying, the cleaned wool is blended and carded to form a sliver. The sliver 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 doubling of the sliver 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.

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Grindle/Twisted Yarns

These yarns are also called ‘Twisted Yarns’. Two yarns of same counts but in different colors are twisted together. Among these 2 colors, one color will be in the lighter shade and the other will be in the darker shade. After the twisting, the yarn will be in a different mixing shade. We must be sure of these yarns are in same counts and have same yarn strength. Also when they are being twisted together, the number of twists per inch (usually 14) should be even for the full length of yarn. If the twisting is not done properly, then we will face problems during knitting.

Mercerised Yarn

After combing and twisting, the yarn will be signed (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 mercerizing, the yarn will have great strength and greater brightness. Also, the yarn will capture 20% more humidity without getting wet. Further, this mercerizing process increases the resistance of yarn and reduces it’s becoming dirty. (Now the yarn is called Gassed Mercerised Yarn).

For more news, please pay attention to Yarn Fair.

Source: textileschool

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This year's severe epidemic made people smell "virus" discoloration and made people aware of the importance of personal hygiene. What we usually overlook is the hygiene of underwear. Although not as immediate as the virus, long-term inattention can also cause certain harm to women's health.

The healthy wearing of underwear and panties mainly needs to pay attention to two aspects, the first is the time for replacement and cleaning, and the second is the time for service life.

Observe changes in underwear

There will be a lot of garbage left on the changed underwear. In general, it is dirty, which is very disgusting for many people.

In addition to menstruation and leucorrhea, women can observe physical and gynecological health problems, and the other is that the underwear is dirty and more comprehensive. Simple judgments of leucorrhea abnormalities and irregular menstruation will have limitations. For example, under normal circumstances, these conditions will appear.

The garbage left on the changed underwear can include various secretions, including leucorrhea abnormalities, irregular menstruation, comprehensive observation and judgment, the amount of secretion, secretion color, secretion color, secretion type, etc. The real existence of gynecological diseases and severity.

Replacement and cleaning of underwear

For women, it is recommended that you change and clean your underwear at least 2 days in winter. If you can change it every day, it is recommended to change it every day in summer. Because the chest sweats more, it will be on the underwear, and it will increase the bacteria and cause the risk of gynecological diseases.

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Underpants are recommended to be washed every day. After all, there are too many dirty things in the privacy area. Accompanying the residue of urine and feces, it is easy to cause an increase in E. coli and affect health.

At the same time, when the underwear is not replaced or washed, the odor of the lower body will continue to increase. Even if the girls are busy again, it is essential to change and clean their underwear every day.

As far as cleaning of underwear and underwear is concerned, there are many women who directly save trouble and put underwear and underwear together with other clothes in the washing machine for cleaning, which is definitely wrong.

For washing underwear, use a basin alone, simple and gentle. Should not be too hard, this will easily cause underwear deformation.

When washing underwear, underwear fair recommends rubbing with running water, and the crotch part should be washed carefully. After washing with hot water, it can effectively sterilize. In addition, it can be effectively sterilized by exposure to the sun and using a special underwear sterilizer.

Underwear life

Entering adolescence, women's breasts begin to develop. At this time, the choice of underwear requires parents to keep more in mind. It is best to keep them for two months and then repurchase and replace them. It is in the growth stage. If it is not replaced in time, it will affect the development of the chest.

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For adult women, the best time to change underwear is not more than six months, and the longest should not exceed one year. Especially if the steel ring is deformed, it should be replaced in time.

As for the service life of underwear, it should be paid more attention. Don't try to save money. Only change the underwear until it is completely deformed.

Generally speaking, women's underwear is worn for a long time, cleaned daily, and during the menstrual period, the penetration of menstrual blood will cause a lot of bacteria on the underwear. These will affect the life of the underwear. It is best to keep it replaced for three months. Once, if it is not replaced in a timely manner, it will lead to increased bacteria and easily cause gynecological diseases.

Disposable underwear

Disposable underwear is indeed a good invention. When it is not convenient to change underwear during business trips, travel, etc., when women's menstruation comes, when postpartum activities are inconvenient, or when some vaginitis patients are being treated, it helps a lot.

However, wearing it everyday is not recommended. Most disposable underwear has poor moisture absorption and breathability. Long-term wearing has created a beautiful life paradise for various germs. Especially for women, prone to urethritis and vaginitis.

When will underwear be changed

Some people say that underwear must be changed every six months. What if I do n’t wear it for half a year?

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Lost or not?

In fact, the direct basis for judging whether it should be discarded is not time, but whether it is colored or deformed.

The underpants are stained and cannot be washed off; they become deformed and lose their elasticity when they are worn; the moisture absorption effect and breathability have become worse ... These indicate that your underwear should be changed.

Underwear is a small piece of clothing that is relevant to everyone. After this epidemic, underwear fair felt that every knowledge point related to health should be taken seriously.

Source: International Underwear Website

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The commonly used, time-tested spinning technique, ring spinning is one of oldest machine oriented spinning techniques used for staple fiber spinning. The staple fiber such as cotton and wool has to go through a series of processes until reaching the finished product or the yarn package.

Ring Spinning Process

² Roving bobbins are creeled in appropriate holders

² Guide rods leave the roving into the drafting arrangements

² Drafting arrangements attenuate the roving to the final count

² The drafting arrangements are inclined at an angle of 45 degrees to 60 degrees.

² Upon leaving the front rollers the fiber strand is twisted to impart strength

² Each rotation of the spindle imparts one twist to the strand

² The twist is generated by the spindle which is rotating at high speed

² The directions of the twist are either “S” or “Z”

² This completes the spinning of the yarn

² The amount of twist inserted in the yarn is controlled by the front roll or the delivery speed and traveler rational speed

² In practice, spindle speed(n spindle) is used instead of traveler speed in the above equation, the spindle speed is slightly higher than traveler speed

² Yarn Winding is performed simultaneously with Twisting

² The difference in the speed between traveler and spindle causes the yarn to wind on the package

² The size of the yarn package is limited by the ring diameter, which has to be small to increase the spindle rotation at the same traveler speed

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The traveller speed in a ring frame is the main limitation in achieving higher spindle speed because of the frictional resistance of traveller over the ring flange. The design, metallurgy, surface finish and breaking-in of the rings decide the speed at which a ring frame can be run without excessive end breaks. It is important to understand the schematics of the ring travellers in order to achieve maximum productivity from the ring spinning machines.

For minimizing friction so as to attain higher traveller speed, many surface finishes have been suggested and larger area of contact is provided by the ring and traveller manufacturers. During ring spinning, both yarn tension and ring/ traveller friction play an important role from the wear point of view and depend mainly upon ring diameter, spindle speed, count and frictional resistance of traveller with the ring.

Arrangements in Ring Spinning

Drafting arrangement:

It is the most important part of the machine. It mainly influences evenness and strength. All modern Ring Spinning machines are fitted with 3/3 double-apron drafting arrangements.

The drive is applied to the lower fluted steel rollers

Top rollers are carried in pivoted weighting arms.

Top rollers are arranged over fluted rollers and pressed against them.

As the drafted strands contain few fibres in the main drafting field, aprons are used to guide the fibres.

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Spindle arrangement:

The spindle consists of two clearly separate parts namely the upper part and the bolster part. The upper part is made of aluminium alloy and is slightly tapered. Near its upper ends and in larger spindles, also near the lower end, it has a tube gripping device that ensures firm seating of the tube on the upper part.

Mechanically the spindle is capable of speeds up to 28000 rev/min. This maximum speed cannot be exploited commercially because the traveller speed is limited. The centring of the spindles relative to the rings should be as accurate as possible.

Ring and Traveler arrangement

Basic forms of rings can be classified into:

1.Lubricated rings(in woollen and worsted spinning

2.Unlubricated runs (in short staple spinning)

It is the standard ring of the short staple spinning mills. It can be of two types

1.Single sided rings

2.Double-sided rings.

For rings used in short staple spinning mill, two dimensions are of prime importance:

1.internal diameter and

2.the Flange width

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Materials for Ring and Traveler

Required properties for Ring materials:

1.The ring should always be hard and tough on its exteriors

2.The traveller hardness should be lower so that wear occurs mainly on travellers, which is easier and cheaper to replace

3.Surface smoothness is also important

The traveler

1.The traveller imparts twist to the yarn

2.It enables winding of the yarn on the cop

3.Its speed is somewhat less than that of a spindle

4.The traveller does not have a drive of its own but is dragged along behind the spindle

The traveller mass

The traveller mass determines the winding and the balloon tension. If the traveller is too small the balloon will be too big and the cop too soft, material take-up in the cop will be too low. An unduly high traveller mass leads to high yarn tensions and many end breaks.

For more news, please pay attention to Yarn Fair.

Source: textileschool

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