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The determination of the weaving process parameters
The upper machine tension is the basis of all the tensions of the warp yarns in each period of weaving. The proper upper machine tension is a necessary condition for opening the shed, tightening the weft and forming the fabric. The height of the shed of the rapier loom is small, only 26-40mm, which is less than half of the shed height of the shuttle loom, and the speed of the loom is relatively high. In order to quickly open the shed in a short time, a relatively high Large machine tension, otherwise the shed will not be clear, the warp will be cut off by the sword head or triple-jump weaving defects will be formed. However, excessive upper machine tension will cause many warp yarn breaks, and it is also easy to tear the fabric in the warp direction. Therefore, when selecting the tension on the machine, the rate of warp breakage and the clarity of the shed should be considered comprehensively. The size of the machine tension is related to factors such as the type of fabric, the appearance quality requirements, the properties of the original yarn and the quality of the semi-finished products. Generally, for fabrics with large warp density, the warp tension should be appropriately greater for opening the shed and tightening the weft. When weaving plain fabrics with unequal tension sheds, in order to open the upper warp yarns, the machine tension should be high. When weaving viscose fabrics or thin fabrics, the machine tension should not be too large. When weaving twill and satin fabrics, in order to make the weave full, the warp tension can be smaller. However, when weaving thick and dense twill fabrics such as denim, the machine tension should not be too small, so as to tighten the weft yarn and reduce the entanglement and adhesion of the warp yarn, and to clear the shed. If in the previous preparation process, the warp tension is relatively uniform and it is easy to obtain a smooth cloth surface, the upper machine tension can be selected to be smaller.
Rapier looms mostly use spring tension systems. Some rapier looms, such as ST-ERL-808, use a composite system that combines spring and weight. The parameters of the spring tension system to adjust the tension of the upper machine mainly include: spring stiffness, initial spring elongation and spring suspension position, etc. The parameters of the springs on both sides of the loom must be adjusted to be consistent, with easy adjustment of the upper machine tension, stable tension, and adaptable to high speed Features.