Due to the existence of coarse details, irregular twist and other problems on the yarn, there will be some small pieces of yarn strength and form the yarn broken potential, called "weak yarn strength loop". The existence of yarn strength and weak loop is one of the key factors restricting the speed of spinning frame. Strong weak loops in yarns are mainly caused by weak twisting of details and fragments.
The strength characteristics of raw yarn include average strength, unevenness of strength, average elongation and unevenness of elongation. The average warp strength is 15cN/ Tex, strong unevenness is about 9% ~ 10%, the average weft strength is 12cN/ Tex, strong unevenness is about 9% ~ 10%. The average breaking elongation is generally controlled within 2%.
Hazard of strong weak ring
It is generally believed that when the yarn fineness is only 40% of the normal yarn, this kind of detail weak loop will inevitably cause end break, resulting in stop. If the strong weak loop is 4cN/ Tex and the elongation is lower than 2%, it will inevitably cause end break.
Other strong weak ring in addition to detail defects accounted for 61%, other such as weak twist, poor joint, including miscellaneous rough joints will also cause the stop between warp and weft, accounting for about 39%.
In addition to average strength and strong unevenness, strong weak ring is an important factor that causes warp and weft yarns to stop. When Japanese businessmen go to China to buy yarns, they emphasize the number of strong and weak ring of 100,000 weft. The possibility of yarn purchase can be judged according to the condition of 100,000 weft broken by high speed and large capacity strength machine TensogiET. Therefore, the requirement of yarn strength in large-scale knitting and weaving factories should emphasize the strength and weak loop level. Some relevant enterprises in China should be equipped with Tensogiet strength meter as far as possible to control the quality of original yarn.
The cause of strong weak ring and its solution
There are three main types of details on the original yarn: one is short velvet details, one is the knot of thick details, and the other is long details or multiple short details connected together will cause broken ends.
In order to reduce the strong weak link, to provide good raw yarn to the downstream process, must adopt corresponding measures, such as using four units in the form of transmission of the four rollers drafting new type roving frame, the details of the car on the one hand, eliminates the switch, on the other hand to improve draft article dry, reduce coarse details defect, such as the transmission gear keys with drafting part should be strengthened, not make its loose clearance, Ensuring the synchronization of drafting process is also one of the important ways to reduce details.
In addition, reasonable configuration of the process, the selection of good drafting components, such as cots, rubber rings, upper and lower pins, pressure mechanism, is one of the factors to reduce details.