What are the hazards of the strong and weak loops of the yarn and how to avoid them?

Due to the problems of thick details and uneven twist on the yarn, there will be some fragments with less strength on the yarn, which will cause the hidden danger of spun yarn breakage, which is called "the weak loop of yarn strength". The existence of the yarn strength and weak loop is one of the key factors restricting the speed-up of the spinning frame. Strong weak loops appear on the yarn mainly due to the presence of small details and fragmented weak twists in the yarn.

The strength characteristics of the raw yarn include average strength, strength unevenness, average elongation and elongation unevenness. Generally, the average strength of warp yarn is 15cN/tex, and the uneven strength is about 9% to 10%. The average strength of weft yarn is 12cN/tex, and the uneven strength is about 9% to 10%. The average elongation at break is generally controlled within 2%.

The danger of strong and weak links

The strength weak ring generally refers to the minimum strength of the yarn. The important strength index of the air-jet loom is the strong weak ring. It is generally believed that when the yarn fineness is only 40% of the normal yarn, this kind of detail weak ring will inevitably cause end breakage. If the strength and weak ring is 4cN/tex and the elongation is less than 2%, it will inevitably lead to breakage.

In addition to detail defects accounting for 61% of other strong and weak rings, others such as weak twists, poor joints, and miscellaneous thick knots will also cause stoppage between warp and weft, accounting for about 39%.

In addition to the average strength and uneven strength, the strength factor that causes the warp and weft yarns to stop is an important factor. Japanese merchants buy yarn in China, especially the number of 100,000 weft strength and weakness rings. The possibility of yarn purchase is judged according to the 100,000 weft breakage detected by the high-speed and large-capacity strength machine tensogiet. Therefore, the strength requirements for yarns in knitting and weaving factories of considerable scale should emphasize the level of strength and weak links. Some related enterprises in my country It should be equipped with a tensogiet strength tester as much as possible to control the quality of the original yarn.

Causes and solutions of strong and weak rings

There are mainly three types of details on the original yarn: one kind of short pile details, one is the knot of thick details, and the other is long details or multiple short details connected together will cause end breakage.

In order to reduce strong and weak loops and provide good raw yarns for downstream processes, corresponding measures must be taken, such as the use of a new type of roving frame in the form of four-roller drafting with four-unit drive. It is also one of the important methods to reduce the details to ensure the drafting process is synchronous, and to strengthen the transmission gear key coordination of the drafting part, so as not to make it have a loose gap, and to ensure the synchronization of the drafting process.

In addition, reasonable configuration of the process and selection of good drafting components, such as rubber rollers, aprons, upper and lower pins, and pressure mechanisms, are also one of the factors that reduce details.