Due to problems such as thick details and uneven twist in the yarn, there will be some fragments with less strength in the yarn, causing the potential risk of yarn breakage, which is called “yarn strength weak loop”. The existence of yarn strength weak loop is one of the key factors restricting the speed of spinning machine. The reason why strong weak loops appear on the yarn is mainly due to the existence of detailed and fragmentary weak twists in the yarn.
The strength characteristics of raw yarn include average strength, strength unevenness, average elongation and elongation unevenness. Generally, the average strength of warp yarns is 15cN/tex, and the strength unevenness is about 9% to 10%. The average strength of weft yarns is 12cN/tex, and the strength unevenness is about 9% to 10%. The average elongation at break is generally controlled within 2%.
The hazards of strong and weak loops
Strong and weak loops generally refer to the lowest strength of the yarn. The important strength indicator for the stop of the air-jet loom is the strong weak loop. It is generally believed that when the yarn fineness is only 40% of the normal yarn, this detailed weak loop will inevitably cause breakage and cause the machine to stop. If the strong weak loop is at 4cN/tex , the elongation is less than 2%, which will inevitably cause breakage.
In addition to detailed defects accounting for 61% of other strong and weak links, other strong and weak links such as weak twists, poor joints, and thick joints will also cause stops between longitude and latitude, accounting for about 39% .
In addition to the average strength and uneven strength, the strong factors that cause warp and weft yarns to stop are strong and weak links. Japanese businessmen go to China to buy yarn, especially emphasizing 10 The numbers of Wanwei’s strong and weak links. The possibility of yarn purchase is judged based on the 100,000 weft breakage detected by the high-speed and large-capacity strength machine tensogiet. Therefore, in the strength requirements of yarns in considerable scale knitting and weaving factories, special emphasis should be placed on the level of strength and weak links. Some related enterprises in my country A tensogiet strength tester should be equipped as much as possible to control the quality of raw yarn.
Causes and solutions to strong weak loops
Original There are three main types of details on the yarn: short velvet details, thick details at the knot, and long details or multiple short details connected together will cause breakage.
In order to reduce strong weak links and provide good raw yarn for downstream processes, corresponding measures must be taken, such as using a new roving frame with four-roller drafting with four-unit transmission. On the one hand, it eliminates the details caused by the switch car. On the other hand, it improves the drafting sliver and reduces rough and detailed defects. It also strengthens the coordination of the transmission teeth and keys of the drafting part to prevent them from loosening gaps and ensure the synchronization of the drafting process. One of the most important ways to reduce details.
In addition, reasonable configuration of the process and selection of good drafting components, such as rubber rollers, rubber rings, upper and lower pins, and pressure mechanisms, are also factors that reduce details. </p
