On the importance of selvage
During the entire process of gray fabric production, the edges of the fabric extremely important role. During the weaving process, the edges of the fabric must be fastened to both ends of the weft yarns to withstand the strong force of the temple braces, so that the fabric surface does not produce excessive weft shrinkage, reduce the bending of the edge warp yarns, improve the friction between the edge warp yarns and the reed teeth, and reduce the friction between the edge warp yarns and the reed teeth. The edge warp yarn breakage rate increases the edge strength, keeps the cloth surface flat and consistent in width, and is easy to wind and form well, which facilitates subsequent processing.
During the dyeing and finishing process, the edge of the cloth is also subject to the tension of cloth clips or needle punching, especially cellulose fiber fabrics such as cotton and linen. During the final shaping and tentering process, it has to withstand a lot of tension. Therefore, a strong, flat, and appropriately tight edge structure is a necessary condition for finishing. Unreasonable fabric edge design will cause the fabric to have loose edges, broken edges, tight edges, curled edges, etc. In severe cases, a large number of broken edges will occur, and even post-finishing processing will be impossible, causing huge losses.
In shuttle looms, the weft yarn is alternately inserted on both sides through the shuttle to form a smooth edge; while on rapier looms and air-jet looms, the weft yarn is inserted through The package is unwound at high speed, and the weft is inserted in one direction. Both sides of the weft yarn are free ends, and then burrs are formed. In the middle part of the fabric, the weft yarns have a greater degree of buckling and are relatively uniform, while the two sides of the fabric are free ends and are mainly held by the seams and false edges. If the edge design is unreasonable, the tension of the weft yarns at the edges will be greater than that of the fabric body. The tension of the weft yarn is much smaller and the weft yarn is loose, which will cause weft shrinkage, and the shrinkage rate of the warp yarns at the edge and the warp yarn of the cloth body will be quite different, which will bring hidden dangers to the subsequent processes.
Twill weave and forged weave generally use borrowed edges, that is, a single heddle and ground are woven into one piece. The pattern plates must be opposite, such as 4/1 edge and ground. 1/4 of the organization is matched, and the organization points are opposite. Jacquard organization, joint organization, etc. are accustomed to use heavy flat and square flat edges. Consider the following four aspects:
1) Width
The edge tissue is too narrow and not strong enough to withstand the pulling force. It is easy to tear the edge and cannot protect it. If it is too wide, it increases the cost of the fabric and affects the cutting area of the fabric under a certain width. Generally speaking, a simple weave fabric only needs a smaller width, but the edge width of some same-face, different-face weaves and elastic fabrics with longer floating lines should be appropriately increased according to the situation.
2) Thickness
The edge thickness should be as consistent as possible with the fabric body, so that it is easy to keep the fabric flat, winding, beautiful, and evenly stressed.
3) Tightness
The edge of the fabric is usually slightly tighter than the body of the fabric, but it must not be too tight. Too tight will affect the finishing, because the edge of the fabric cannot withstand large deformation in a short period of time, and may even tear the edge of the fabric, making the entire batch of fabric useless. It won’t work if it’s too loose. On the one hand, it will cause weft shrinkage and ruffles, which will easily break during finishing. Therefore, the density of edge tissue is greater than that of ground tissue.
4) Heald threading and reed threading
The number of healds used for the edge should be as small as possible, so that the heald frames can be easily organized to make the edge. Usually, two more pages of healds are added, otherwise it will increase the difficulty and difficulty of weaving. Cost, reeding and reeding are mainly designed based on the organizational structure of the edge and its required functions to achieve the requirements and functions of the edge. The number of reeding for the edge tissue should usually not be less than the number of reeding for the ground tissue. For varieties with more than 8 pages, it is best to place the edges on the first two pages to ensure clear edge openings and reduce the number of weft stops.
5) Suggestions
Make 4/1 elastic fabric. If you use a dobby machine, it is recommended to use 2/2 square. For stability, it is recommended to use 2/3 when using a pedal. +3/2 is worn alone, which is less easy to curl than 1/4+4/1. You can also add keel ribs to the 2/3+3/2 selvage, which is also helpful in overcoming the large difference in warp and weft texture points on both sides. of curling edges.
AAAFGNHIYIYO
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