4, continuous jumper or a needle can not be sewn.

       Analysis: Poor quality of the needle or bending of the needle does not produce a loop. The needle is too high, the wire loop can not be hooked, and the stitching needle is not properly matched. Long-term use of the shuttle, swinging bed and other components are severely worn or folded.

       Treatment: Replace the qualified needle or straightening needle. Adjust the needle bar or needle height. In general, the shuttle or shuttle bed can be replaced and overhauled if necessary.

       5, the seam is thin, no jumper, seam thick jumper.

       Analysis: The presser foot pressure is not enough, the needle is too thin, and the hook line mechanism and other parts are seriously worn.

       Treatment method: adjust the pressure of the presser foot, change the needle, replace the parts, and repair.

       6, seam thick jumper, seam thin jumper.

       Analysis: The pinhole of the needle plate is too worn, the needle is too thick, the bottom of the presser is worn, or the presser foot pressure is too small.

       Treatment method: replace the needle plate, change the needle, change the pressure foot, change the pressure foot, or adjust the pressure of the presser foot.