The warp tension during weaving will not only directly affect the operation of production, but also seriously affect the quality of products. Some products' rib files, a few pry files, unilateral files formed by man pressing warp surface, etc. are all caused by improper warp tension. Specifically, the warp tension has the following effects on the quality of products:
The influence of 1 on the rate of broken head
When the warp comes out of the warp shaft and weaves into the fabric, it needs thousands of times of stretching and friction from the guide roller, heald and reed. The tension on the thread increases, which is easy to cause fatigue and fracture in the weak link of the warp. Therefore, the excessive tension on the thread is the main cause of the broken end of the warp. Some people have done experiments on a certain fabric to adjust the tension, healthful degree, warp position and other relevant factors of warp, so as to reduce the breaking rate of warp from 0.839 per unit hour to 0.175 per unit hour. Can we think that the lower the tension is, the lower the rate of breaking? Through analysis, the beating up force of general fabric is not 90 °, so the beating up force can be divided into the force along the fabric direction F and the force perpendicular to the fabric direction F. when the beating up force is constant, if the warp tension decreases, the beating up force F in the silk surface direction will decrease, so the fabric forming area and beating up area will increase. In this way, it not only increases the friction between the reed and the heald, but also causes the "bloated" phenomenon in front of the reed, which leads to the increase of the broken ends. Therefore, too small tension on the warp is also detrimental to weaving.
2 Effect on fabric shrinkage
If the warp tension is large, when the warp and weft are interwoven, the warp will compress the weft, which will increase the flexion of the weft and the internal stress of the weft. When the fabric is drawn into the take-up roll, especially after the machine is off, the tension of the warp disappears. Because of the "resistance" effect of the internal stress, the weft will produce a large counter pressure on the warp, thus forming the situation of the increase of the warp shrinkage and the decrease of the weft shrinkage.
3. Influence on the feel and appearance of fabrics
The size of warp tension has a great influence on the hand feel and appearance effect of the fabric. If the warp tension is properly controlled, the silk surface of the fabric will be flat, the texture will be clear, and the hand feel will be good. If the warp tension is too large, the silk surface will not be full due to excessive elongation, and the warp tension is too large, the fabric is likely to produce a "thin mouth stop".
