Reasons:
1. Use the wrong sewing thread, such as the material or sewing requirements are not clear, the bottom line is not properly matched.
2. The pinhole of the needle car is damaged or defective.
3. The needle eye is hot, the sewing thread does not have enough lubrication, that is, the oiling rate is not enough.
4. The quality of the sewing thread itself is flawed, such as: fluffing, insufficient strength, lack of strands and less strands.
5. No anti-static, anti-friction, high-temperature treatment in the production process.
Solution:
1. Choose to use the correct sewing thread.
2. Choose high quality sewing thread.
3. Increase the proportion of sewing thread lubricant.
4. Improve product quality inspection requirements.
5. Increase anti-static, anti-friction, high temperature treatment.