Arrangement and Schemtics of Ring Spinning

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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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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At present, cotton masks, paper masks, activated carbon masks, sponge masks, medical surgical masks and N95 masks are available in the market. But only medical surgical masks and N95 masks can play a role in preventing infectious diseases.

The N95 mask is one of nine anti-particulate masks certified by NIOSH (National Institute of Occupational Safety and Health). "N" means unsuitable for oily particles (oil fume produced by cooking is oily particles, and droplets produced by people speaking or coughing are not oily); "95" means filtering under the test conditions specified by the NIOSH standard The efficiency reaches 95%. N95 is not a specific product name. As long as the product meets the N95 standard and passes the NIOSH review, it can be called a "N95 mask".

N95 mask: powerful 95% filtration efficiency

The N95 mask can filter most of the influenza virus, dust, pollen, smog, smoke and soot in automobile exhaust, and the filtering efficiency must be at least 95%.

N stands for not resistant to oil, and 95 stands for the level of filtration efficiency when tested with 0.3 micron particles. For the selection of masks, and the principle of protection, you can refer to this article: the types of masks, the principle of protection, and the method of distinguishing true and false

100x magnification to see mask meltblown cloth

After cutting the N95 mask, it can be seen that its internal structure mainly has three layers, and the key layer that plays a barrier role is the melt-blown cloth that has been fried on the market at 290,000 / ton.

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After magnifying the meltblown layer by 100 times, we observe the meltblown cloth, and we can see that the meltblown cloth is intersected by countless ultra-fine fibers to overlap into a dense network.

Among them, the thickness of each fiber is about 1 to 5 microns, and the fibers are intricately complex, which can prevent the entry of dust, viruses, and bacterial micro-foam, while maintaining the holes through which the breath passes. Meet the requirements of respiratory resistance.

There is no harm if there is no contrast. Take another non-woven fabric for comparison. Under the microscope, although the fibers look more uniform and beautiful, the diameter of the fibers is more than 20 microns, and the gap is much larger. Non-woven fabric effectively blocks viruses, bacteria and small particles of dust.

N95 Mask Cloth: Static Additive (Electret Treatment)

N95 mask melt-blown layer, the fiber density is not enough, but also need to increase static electricity, by performing an electret discharge treatment. In a certain range, the applied voltage (electret voltage), the larger the voltage, the more secure the charge is bound, and the higher the filtering efficiency.

The surface charge of the meltblown cloth will decay with time. After the electret masterbatch is added, the decay time is greatly prolonged. As the amount of the electret masterbatch is appropriately increased, the charge retention rate is also longer. Different formula decay rates.

The electret masterbatch (usually added 2-3%) separates the positive and negative charges of polypropylene ultrafine fibers and fixes them, so that the charges are stored for a longer time.

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Polarized fiber

There are very few electret masterbatch manufacturers, most of which are masterbatch plants for meltblown cloth, and their scale is usually not large.

Accumulated experience in long-term production. The formula has undergone a lot of exploratory tests from additives, base resin selection, granulation temperature, screw combination, melt index control, and additive content, etc., combined with electret treatment, optimized filtration performance, filtration resistance, etc. Index, the meltblown cloth is also placed for half a year, one year, two years or even longer and then test the filtration performance and other indicators.

Through the meltblown cloth factory and customer channels, we have collected electret masterbatch manufacturers with good feedback in the market for reference only. The specific application is also related to the manufacturer's meltblown equipment, process and formula.

Maintenance of N95 masks-natural enemies of static electricity

After the electret, the binding force weakens with the passage of time, the charges will migrate, and the polarization effect will weaken. As time goes by, static electricity will slowly disappear, which is why N95 masks have a shelf life. The general shelf life is about five years. N95 mask is most afraid of water, the secret of maintenance is to stay away from water.

In the process of N95 masks, particles are adsorbed and static electricity is consumed. Therefore, after a period of time, a large number of particles are adsorbed, and the static electricity is consumed. There is no additional static electricity to adsorb particles. This is why the used N95 masks cannot be reused.

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Finally, Yarn Fair reminds: It is precisely because of the intricacies of meltblown cloth fibers that N95 masks and medical surgical masks can block viruses and dust! Some criminals, in order to make huge profits, use extremely inferior, cheap, and substandard raw materials, and some even directly eliminate the most important meltblown filter layer in the middle and use ordinary non-woven fabrics instead.

Such a mask does not play a role in filtering viruses at all and may be harmful to the body. Therefore, when we purchase masks, we must pay attention to whether there are melt-blown cloths in the masks.

Source: Global Textile Network

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