When weaving the warp yarns, the machine tension not only directly affects the production operation, but also seriously affects the quality of the product. Ribbed files, a few skid files, and single-sided files formed by human pressing on the warp threads are all due to warp yarns. Caused by improper machine tension. Specifically, the effect of machine tension on warp threads on product quality is roughly as follows:
1
Impact on decapitation
The warp yarn comes out of the warp beam to be woven into the fabric. It must pass thousands of times of stretching and friction through guide rollers, healds, and reeds. The machine tension on the yarn increases, which easily causes fatigue and breaks at the weak links of the warp. Therefore, excessive machine tension is the main cause of warp breakage. Some people have conducted tests on a certain fabric, and adjusted the relevant factors such as the machine tension, overall flatness, and warp position on the warp to reduce the breakage rate of the warp from 0.839 pieces / set · hour to 0.175 pieces / set · hour. . Can you think that the lower the tension on the machine, the lower the head break rate? After analysis, the beating-up on a general fabric is not 90 °, so its beating-up force can be decomposed into a force F along the fabric direction and a force f perpendicular to the fabric direction. When the beating-up force is constant, if the warp tension decreases, The beating force F in the direction of the silk surface will inevitably decrease, so both the fabric formation area and the beating area will increase. In this way, not only the friction between the warp threads between the reed and the heald is increased, but also the warp threads have a "congestion" phenomenon in front of the steel reed, which leads to an increase in the number of broken ends. Weaving is also disadvantageous.
2
Effect on fabric shrinkage
If the warp tension is large, when the warp and weft are intertwined, the warp threads press the weft threads, which causes the buckling of the weft threads to increase, thereby increasing the internal stress of the weft threads. When the fabric is wound into the take-up roll, especially after the machine is removed, the tension of the warp yarns disappears. Due to the "resistance" of the internal stress of the weft yarns, there will be a large back pressure on the warp yarns, which will increase the warp shrinkage. When the zonal shrinkage is reduced.
3
Effect on fabric feel and appearance
The amount of tension on the warp threads has a large impact on the feel and appearance of the fabric. If the tension on the warp threads is properly controlled, the silk surface of the fabric is flat, the texture is clear, and the hand feels good; If it is stretched too much, the silk surface is not full, and the tension on the warp yarn is too large, and the fabric is likely to have a "thin mouth".
