1. Needle broken when sewing thick material
　　Analysis: The needle of the sewing machine is too thin or bent, the thickness of the sewing material is uneven, and the needle bar moves too much. Treatment method: replace the thick needle with a new one, adapt to slow down the sewing speed and use the hand to help feed the material, replace with a new needle bar or needle bar cover.
　　 2. Short stitch length keeps the needle, long stitch length breaks the needle
　　Analysis: the action of the feed dog is lagging, the feed dog is unqualified, the needle of the sewing machine hits the rear end of the feed dog and the needle breaks. Solution: Adjust the positioning of the feeding cam, appropriately shorten the stitch length or replace the feeding dog with a new one.
　　 3. The needle of the sewing machine is broken under the needle plate
Analysis: The needle position of the sewing machine is low, the needle of the sewing machine touches the shuttle, the shuttle bed is not installed properly, the tip of the shuttle touches the needle of the sewing machine, the gap between the shuttle holder and the needle end of the sewing machine is too small or too large, and the shuttle holder touches the needle or loses protection. Needle effect. Treatment method: adjust the needle bar or the position of the sewing machine needle, reinstall the shuttle, and adjust the gap between the shuttle holder and the end face of the sewing machine needle.
　　 4. The needle of the sewing machine is broken on the needle plate
Analysis: The sewing material is pulled too hard, causing the sewing machine needle to bend, the presser foot screw is loose, causing the presser foot to touch the sewing machine needle obliquely, and the displacement of the cloth feeding cam causes the sewing material to break the sewing machine needle, and there is a hard object in the sewing material to break the sewing machine needle. Treatment method: strengthen the operation practice, adjust the presser foot to tighten the screw, and adjust the position of the cloth feeding cam screw.

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