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.
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.
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.
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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Knitting Fair is very sorry hear that the epidemic situation has not become clear because of the improvement of China's situation. Slightly turning global trade, or ushering in new challenges again!
Italy: 11 cities in Europe close
According to information compiled by public media reports, the number of confirmed cases in Italy has surged in the past two days. As of 0:00 on the 24th local time, a total of 157 cases of neocoronavirus pneumonia were confirmed in Italy! At present, the Italian region at the center of the epidemic has been called "the Wuhan of Europe" by the media! The severity of the epidemic is evident!
In order to curb the spread of the epidemic, the Italian government has issued an executive order to impose blockades on 11 cities and towns, restrict access, send police to strengthen access control, and if necessary, will dispatch the military. Residents who violate restrictions on the epidemic area will be subject to criminal punishment.
Italy's "Republica" reported on February 22 that the Italian government held a press conference on the country's new crown virus infection pneumonia that night confirmed that as of February 22, the country has confirmed a total of 79 cases of new coronary pneumonia, a surge of 76 cases. Of the 79 cases, two died and one was discharged.
The 76 confirmed diagnoses are mainly concentrated in the northern Lombardy (54 cases) and Veneto (17 cases). In response, the Italian Prime Minister Conte and his cabinet issued an executive order last night to implement epidemic blockade measures on 11 cities and towns in these two regions since February 23. It is expected that about 50,000 residents will be affected. Among them, 10 are in Lombardy, concentrated about 60 kilometers southeast of Milan.
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These include school suspensions, banning all public activities, closing shops and museums, stopping all sporting events, and restricting crowds and logistics.
Italian Prime Minister Conte said that such strict control measures could be applied to other regions depending on the development of the epidemic. He hinted that the possibility of "Italy suspending the issuance of Schengen visas" was not ruled out.
Italy is the first country in Europe to have a new case of death from new coronary pneumonia. On the 23rd, the country's confirmed cases surged from 79 the day before to 132. The spike in infections has spread nervousness. "Global Times" reporters saw that in Milan, the capital of Lombardy, some people began to buy and hoard food and daily necessities.
"This may be just the beginning of the European epidemic," commented German News and TV on the 23rd. Just a few days ago, Europe was still arguing about China's quarantine and epidemic prevention policy, and Italy is now learning from China. The epidemic is spreading in Italy, weakening European defences!
South Korea: Outbreak out of control, 12 countries impose entry controls on South Korea!
South Korea has now become the country with the worst epidemic after China. According to a report by the Central Epidemic Prevention Department of the Republic of Korea on the morning of the 24th, South Korea added 161 new confirmed cases of New Coronavirus infection, and one new death. At present, there are 763 confirmed cases in South Korea!
In addition, South Korea ’s Ministry of Defense reported on the 24th that as of Monday, 11 soldiers had been confirmed as new cases of pneumonia, of which 8 were confirmed by the Army and 1 each by the Navy, Air Force, and Marine Corps. Another 7,700 people were isolated to prevent further transmission of the virus in military camps.
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Data show that just last weekend, South Korea surged 398 new cases of neonatal pneumonia, an increase of 195% in just two days. South Korean President Moon Jae-in announced on Sunday that he would raise the new crown epidemic alert to the highest level, giving the government the right to take comprehensive measures to curb the epidemic in particularly severe cities.
In just 5 days, the number of confirmed diagnoses in South Korea has increased by 20 times. And just the day before yesterday, with the first confirmed case of new crown pneumonia in Ulsan, South Korea ’s last line of defense was also breached, and the national epidemic map turned red without a clear land.
It seems to be realizing that the epidemic is now out of control, and the South Korean authorities hastily announced that the pneumonia epidemic has entered a serious situation. The city of Seoul announced that it would suspend all rally activities in the city, and offenders would be fined 3 million won.
However, there are still Korean citizens who, despite the official ban, hold marches and rallies as scheduled under windy and rainy conditions. Most of the citizens are elderly people, and the people do n’t even wear masks.
According to the Ministry of Foreign Affairs of the Republic of Korea on the 23rd, as of now, there are 12 countries that have banned entry of people from South Korea or strengthened immigration management measures.
Israel and Bahrain prohibit entry of Korean citizens and foreigners from South Korea. Samoa, Brunei, the United Kingdom, Oman, Ethiopia, Uganda and other countries require that people from South Korea be separated from their homes for 14 days or undergo medical observation.
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According to media reports, recently, the CDC of the US Centers for Disease Control and Prevention announced that it is preparing for the new crown virus to become a global pandemic, and US businesses and schools may need to be closed.
From Europe to the Americas, from the Far East to the Middle East, the epidemic has not become clearer with the improvement of China. The closure of Italy and the restrictions on entry to Korea by 12 countries have greatly hindered the pace of global economic recovery.
With the deterioration of the epidemic outside China, global trade may continue to be under pressure! As the most active and largest foreign trade in China's textile industry, it is bound to bear the brunt.
Source: Global Textile Network
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