1. The edge of the machine needle hole has sharp angle or groove hair; after polishing the needle hole, use or replace the new machine needle.

 

2. The part of the thread-crossing holes of the surface line is furred to prevent the seam from moving; polishing and polishing can be done by sanding or applying polishing paste to the thread.

 

3. Sewing thin thread for thick material; Replacing sewing thread accordingly

 

4. The stitching strength is too poor; changing the stitching

 

5. The pressure of pressing thread is too tight, so that the suture is bruised or the yarn is broken. Mule mothers with thread clamps should be properly loosened by spinning.

 

6. The inner groove of the spindle has sharp angles, which may cause the seam to be damaged or the yarn to be broken. The inside of the spindle should be polished, then tested, or a new spindle should be replaced.

 

7. Improper matching between the hook and the recess of the shuttle frame; Adjusting the matching of the hook to make the surface line pass smoothly

 

8. Fuse chemical fibre threads by needle overheating; Needle or sewing should be cold and accurate (silicone oil)

 

9. There are burrs and sharp angles on the edge of the pinhole of the needle plate so as to damage the sewing thread; it can be polished with yarn rope and polishing paste, but it can not be pulled too large, which will cause jumping thread.

 

10. The position of the machine needle is wrong; adjust the machine needle to the correct position

 

11. Bending needle; Replacing new needle

 

12. The upper and lower stroke of the needle rod is not right. The thread-lifting and crank-positioning mule nails on the needle rod crank are not positioned in the groove of the thread-lifting crank or the positioning direction is wrong. The wrong positioning direction should be corrected after repositioning.