Due to the problems of coarse details and uneven twist […]
Due to the problems of coarse details and uneven twist on the polyester color yarn, there will be some fragments with less strength on the yarn and the hidden danger of broken yarn is formed, which is called "yarn strength weak loop". The existence of polyester color yarn strength and weak loops is one of the key factors restricting the spinning machine speed. The reason why strong and weak loops appear on the yarn is mainly because of the details and fragmentary weak twist on the yarn.
The strength characteristics of the original draw texturing yarn include average strength, strength unevenness, average elongation and elongation unevenness. Generally, the average strength of warp yarn is 15cN / tex, and the unevenness of strength is about 9% -10%. The average strength of weft yarn is 12cN / tex, and the unevenness of strength is about 9% -10%. The average elongation at break is generally controlled within 2%.
The danger of a strong weak loop
Strong weak loop generally refers to the minimum strength of the draw texturing yarn. The important strength index of the air jet loom is the strong weak loop. It is generally believed that when the fineness of the yarn is only 40% of the normal yarn, this detail weak loop will inevitably cause breakage. If it is stopped, if the strong weak ring is at 4cN / tex and the elongation is less than 2%, it will inevitably cause a break.
In addition to the detail defects accounting for 61% of other strong and weak loops, others such as weak twists, poor joints, and thick knots, etc., can also cause stoppages between warp and weft, accounting for about 39%.
In addition to the average strength and unevenness, the strong weak loop is an important factor that causes the warp and weft yarn to stop. The Japanese merchants went to China to buy yarn, with particular emphasis on the number of 100,000 weft strong weak loops. Judging the possibility of yarn purchase according to the 100,000 weft breakage detected by the high-speed large-capacity strength machine tensogiet, therefore, the strength requirements of the yarn in a large-scale knitting and weaving factory should particularly emphasize the level of strength and weak loops. Some relevant enterprises in China It should be equipped with a tensogiet tenacity tester as much as possible to control the quality of the original yarn.
Causes and solutions of strong weak loops
There are three main types of details on the original polyester raw material: a short-pile detail, one is the knot at the thick detail, and another long detail or multiple short details connected together will cause a broken end.
In order to reduce the strength and weak loops and provide good raw yarn for downstream processes, corresponding measures must be taken, such as the new roving machine in the form of a four-roller four-roller draft, which on the one hand eliminates the details caused by the switch car and improves The drafting is dry, reducing the defects of coarse details, etc. It is also necessary to strengthen the coordination of the transmission tooth key of the drafting part, so as not to make it loose, and ensure the synchronization of the drafting process, which is also one of the important methods to reduce details.
In addition, the reasonable configuration of the process and the selection of good drafting components, such as rubber rollers, rubber rings, upper and lower pins, and pressure mechanisms are also one of the factors that reduce details.