Determination of textile fabric filter cloth warp and weft density
The number of warp and weft yarns arranged in the unit length of fabric filter fabric is called warp and weft yarn density of the fabric filter cloth.
Fabric density calculation unit metric system, refers to the number of 10cm within the arrangement of the number of warp and weft. The size of the density directly affects the physical and mechanical indicators such as fabric appearance, feel, thickness, strength, bending resistance, air permeability, abrasion resistance and thermal insulation properties. At the same time, it is also related to the cost of the product and the production efficiency.
After the density of the determination of the following two methods.
(A) direct measurement method
Direct measurement method is by virtue of cloth mirror or fabric density analysis to complete. Fabric density analysis mirror scale length of 5cm, in the analysis of the lens below, a piece of long glass strip engraved with a red line in the analysis of fabric density, the lens will move the glass on the red line and the red line at the same time a certain two Root yarn, as a starting point, while moving the lens side of the number of yarn roots, until the 5cm tick for this. The number of output yarns multiplied by 2 is the density value of 10cm fabric.
When the number of yarns is counted, the starting point should be the center between the two yarns. If the number reaches the end, more than 0.5, and if less than one, it should be calculated as 0.75; if it is less than 0.5, By 0.25 root count. Fabric density should generally be measured 3-4 data, and then take the arithmetic mean measurement results.
(B) indirect test method
This method is suitable for high-density, small number of yarns regular organization of the fabric. First, after analyzing the number of circulating warp yarns (the number of weft yarns in the weft) of the weave and its tissue, and multiplying it by the number of weaves in the 10 cm, the resulting product is the warp weft yarn density.
Five: Determination of warp and weft yarn shrinkage
Warp, weft yarn shrinkage is a structural parameter of the fabric. The purpose of measuring warp and weft shrinkage is to calculate the number of yarns and the amount of yarn used for fabric. Since the yarns are staggered in the fabric after the fabric is formed, the length of yarn used in weaving is greater than the length of the fabric being formed. Therefore, we call the ratio of the difference to the original length as the shrinkage rate. To a (%) said.
Shrinkage = 100% * (Straightening Length - Length in Sample) / Straightening Length
The size of warp and weft yarn shrinkage, is an important basis for process design, his dosage of yarn, the physical and mechanical properties of fabrics and fabric appearance have a great impact.
There are many factors that affect the shrinkage rate. The difference of the shrinkage rate will be caused by the difference of the weave, weft and weft yarn material, the weft density and the weft tension in the weaving process.
When analyzing fabrics, the method for determining the shrinkage is generally to take a fabric length of 10 cm along the warp (weft) vector at the edge of the sample. And mark the mark (the sample hour, the length can be measured 5cm), the edge of the tassel cut short (which can reduce the yarn produced when pulled out from the fabric to the outside elongation), and then gently by latitude ) Remove the yarn from the sample, press one end of the yarn with your fingers, and gently straighten the yarn with the other hand (the tension should be correct and there should be no elongation). After measuring the number of the weft yarns between the marks, make ten consecutive numbers for the braised samples, take the average value, and add the above formulas to obtain the shrinkage value of the weft or weft yarn. This method is simple, but less precise. The purpose of determining the yarn shrinkage is to calculate the yarn count and the amount of yarn used for the fabric. In the measurement should pay attention to the following points:
1. When pulling out and straightening the yarn, the yarn can not be untwisted or twisted. For some small twist or poor strength of the yarn, should avoid the amount of accidental elongation.
2. When analyzing scraping and decking fabrics, remove the surface fuzz first with scissors or a match and then pull the yarn carefully out of the fabric.
3. Viscose fiber in the wet state extremely easy to stretch, so in the operation to avoid hand sweat moisten the yarn.
(Addtime：2018-1-4)
