The seam slippage of the fabric is also known as the degree of cracking in China. It refers to the ability of the yarn at the seam to resist external pulling force after the fabric is seamed. It is an important indicator to measure the seam performance of the fabric.
Test process
Sample humidity adjustment → sampling → sample preparation → equipment adjustment → test → result analysis
Test direction
The test directions are mainly divided into the following two types:
1. Warp slip refers to the slip of weft yarn on warp yarn, and the corresponding standards are: ASTM D434, ASTM D1683
2. Warp slip refers to the slip of warp yarns on weft yarns, the corresponding standards are: GB/T 13772.1, ISO 13936.1
The two are opposite, so when we get the test report, we must see clearly which direction of yarn slip is worse. In order to let customers know at a glance, each test center now uses the following representation method: //Warp direction (//to warp), which means that the suture is parallel to the warp; //Weft direction (//to weft), which means that the suture is parallel Yu Wei.
During the seam slip test, the following phenomena often occur, and one or several types may appear. Different fabrics have different phenomena.
Reasons and criteria
1. The fabric breaks at the seams
The test result is expressed as: //Warp (warp direction) 25.7 lbf (pounds) FTS (fabric breaks at the seam).
When the fabric breaks at the seam, the tensile strength of the fabric is the same as or slightly lower than the sewing strength of the sewing thread; when the fabric is sewing, the sewing needle will stab part of the yarn of the fabric, causing the seam strength value to decrease The degree is a parameter that we can only hear occasionally, sewing damage rate. There is also a case where the fabric is coated or resin-free. This kind of fabric is relatively fixed due to the external force and cannot move. When it is strongly stretched, the suture forms a cutting force on the yarn to make the fabric A tear occurred.
When the fabric breaks, it indicates that the strength value of the fabric itself is not very high, and the test results need to look at the specific opening and slippage: if the opening degree is ≥6.4mm and the slippage value meets the customer's requirements, it is judged to be qualified; otherwise it is not qualified;
If the opening degree is less than 6.4mm, and the slip value meets the customer's requirements, it is judged to be qualified; otherwise it is not qualified;
2. Suture break
The test result is expressed as //Weft (weft direction) N/F lbf (pound) STB (broken thread).
Note: N/F indicates that the 6.4mm open suture has not been found and has been broken.
The occurrence of suture breakage generally indicates that the slip between the fabric yarns is small, and the tensile strength of the fabric is significantly greater than the suture strength. Most of this phenomenon can be concluded that the seam slip performance of the fabric is very large; and most of them are unable to find the standard prescribed opening degree (indicated by N/F). At this time, you need to refer to the value of the seam strength. If the seam strength value is greater than the customer's requirements, it is determined that the slippage is qualified. What needs to be mentioned is that if there is STB phenomenon and the seam strength value is very low, then 100% is a problem in the sewing of the sample.
3. The fabric breaks:
The test results are expressed as //Weft (weft) N/F lbf (pound) FR (fabric break).
Note: N/F indicates that the 6.4mm open fabric has not been found and has been broken.
The occurrence of fabric breakage indicates that the tensile strength of the fabric is too low, but the seam performance of the fabric is still very good. When the test report is issued, it is basically expressed as N/F, and at the same time, the seam strength value (theoretically the same as the tensile strength) is noted; for this type of fabric, we need to solve the fabric strength problem from improving the fabric strength. Take into account the slip performance. If the seam strength value meets the customer's requirements, it is judged as qualified.
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