Insufficient fabric weight is not a big problem and has little impact in regular trade, but when it comes to export orders or specific trades, weight is often a key issue. Ring, often because a company finally receives a large order, but later encounters a chargeback or claim due to insufficient weight. The following explains the reasons for insufficient weight.
1. Weight
Analyze whether the yarn count and density are correct. Cut the two warp yarns and two weft yarns along the four sides of the sample into a rectangle or square. Use a steel ruler to measure its length and width (cm), and then find out the cut of the gray fabric sample. The area of the back (square centimeters), and put it on the balance to weigh the weight (milligrams)
Gram weight of the sample cloth per square meter = weight ÷ 1000 ÷(area÷10000)=weight÷area×10;
1. Use calculation methods and tools together
For example: a piece of sample fabric is 7 cm long, 8 cm wide, and weighs 772 mg, then the gram weight per square meter of the finished sample fabric = 772 ÷ (7 × 8) ×10=138 grams
2. Tool method
Use a round disk to cut the sampling knife, Place the fabric sample below, rotate it clockwise a few times, take three circular-shaped sample fabrics on the gray fabric (take them 20cm away from the edge or tail of the fabric), and weigh them on an electronic balance to measure the specific data.
2. Calculate the weight of color cloth
The weight of gray fabric refers to the weight per unit area of the fabric, generally expressed in grams per square meter (g/m2) or ounces per square yard (oz/Y2). The actual gram weight is closely related to the cotton distribution, yarn count thickness, finished product width, and finishing process. Simple calculation of gram weight:
1. Non-woven fabric Calculation of weight of elastic cloth:
(grey cloth warp density/warp count + gray cloth weft density/weft count)*24.3
For example: Calculate the gram weight of 20*16 / 128*60/63〞.
（128/20 + 60/16)*24.3≈246.6(g/m2)
Its weight is about 242-248g/m2.
2. The weight of the finished elastic fabric
Reed width on the machine/finished door width*(density on the machine/warp count*22.17 + gray fabric weft density/ Weft count*21.4)
For example: Calculate variety C78〞 20*16+70D / 226*48 Gram weight
78/58* (226/20*22.17+48/16*21.4)≈259 (g/m2)
Its actual gram weight is about is 260-265g/m2.
Note: 78″ is the reed width on the machine, and the finished door width is 58″
3. Simple calculation and weighing
Simple calculation formula compares the weight of the gray cloth with the weight of the weighed finished cloth sample. Under normal circumstances, the difference within ±5 grams is within the normal range. Large differences require careful analysis. Based on our many years of experience, we have summarized a few rules:
Generally, differences within ±5 grams are more normal.
If the difference is large, analysis is required. The principle is as follows: the difference between combed compact yarn is slightly smaller.
(1) Because the conversion constants of polyester-cotton or polyester-nylon blended yarn and chemical fiber yarn are greater than 583.1 of pure cotton, the same yarn count, number If the number is larger, the calculated weight is smaller than the actual weight;
(2) Strands are made of two or more single yarns twisted together. Due to twist shrinkage, the actual yarn count is thicker and the calculated weight is smaller than the actual weight. When the warp and weft yarns are both strands, the difference is large;
(3) Open-end spinning is a short fiber yarn, which loses more during pre-treatment and scouring during printing and dyeing, and its calculated weight is heavier than the actual weighing;
(4) Washing The final weight is about 5-6.5% larger;
(5) When dyeing dark colors, due to the weight of the dye, the calculated weight is slightly larger than the actual weighing;
(6) The calculated weight of bleached blanks and light-colored blanks is slightly larger than the actual weight;
(7) Coating The weight after grinding is 3-7% heavier;
(8) The weight after grinding is 3.5-6% lighter;
4. Reasons for the reduction in finished product weight
① Excessive pre-processing stretching will result in a reduction in weft density.
② The finished door width is too wide.
③ Excessive alkali concentration and excessive post-processing temperature will cause damage to the yarn fibers
④ When purchasing raw yarn, the yarn is too thin, such as 40S. The actual measurement is only 41S
⑤ The raw yarn is greatly worn during the weaving process, which will cause excessive hairiness to fall off, resulting in thinning of the yarn and low weight.
⑥ Repeat during the dyeing process. Color change and stripping will cause yarn loss and make the yarn thinner.
⑦ During the singeing process, excessive singeing fire will cause the cloth surface to be too dry, and the yarn will be damaged during desizing, resulting in thinning. ⑧ In the catching process. , damage to the cloth surface during the sanding process.
Extended reading: https://www.tpu- ptfe.com/post/10.html
Extended reading: https://www.alltextile.cn/product/product-83-321.html
Extended reading: https://www.alltextile.cn/product/product-45-825.html
Extended reading:https://www.tpu-ptfe.com/post/7738.html
Extended reading:https://www.alltextile.cn/product/product-11-389.html
Extended reading:https://www.tpu-ptfe.com/post/3295.html
