Failure Causes of overlock sewing machine and the Countermeasures(Ⅲ)

Broken looper of an overlock sewing machine

1. The expenditure of the upper looper is large, and the needle is broken when the height is too low; replace the looper with a new one and adjust it according to the standard;

2. The upper and lower loopers and the fixing screws of the chain crochet are loose; replace the loopers with new ones and install them according to the standard;

3. The position of the lower looper is incorrect; replace it with a new needle and adjust it according to the standard;

Broken needle thread of an overlock sewing machine 

1. The pressure of the needle thread clamping plate is too tight; loosen the needle thread clamping nut;

2. Needle tip hair; replace the needle;

3. Lower looper needle tip hair; grinding the lower looper tip or replacing the lower looper ;

4. The feeding dog has a sharp edge; grinding or polishing the feeding dog surface;

5. There are burrs on the edge of the small needle plate; trim or polish the edge of the small needle plate;

6. The thread quality is poor; use a good quality needle thread instead ;

7. The thickness of the thread is uneven or thicker than that of the needle; change the appropriate needle and thread.

8. Wrong threading; re-threading correctly;

9. The control line pressure is too strong; adjust the control line strength;

10. The needle is installed incorrectly; re-install the needle correctly ;

11. The wire rack is wrong; re-install the wire rack so that the wire can pass freely;

12. Needle temperature is too high: (1) There is no cooling oil for needle cooling; (2) Needle guide plate is installed incorrectly; (1) Refueling and cooling; (2) Adjust needle guide plate;

13. The line control sheet has been rough; it is polished with abrasive cloth;

14. The relationship between needle and crochet is wrong; adjust the relationship between needle and crochet ;

Break the looper thread of an overlock sewing machine 

1. The suture is threaded incorrectly or the pressure on the upper looper thread clamp is too large; thread the thread correctly or loosen the upper looper thread clamp nut;

2. The eye of the upper looper needle burr; apply the polishing paste with thread, thread it into the eye of the upper looper needle and pull it lightly ;

Break the looper thread 

1. The suture is threaded incorrectly or the pressure of the lower looper thread clamping plate is too large; thread correctly or loosen the lower looper thread clamping nut;

2. The lower looper touches the small needle plate, causing thread breakage; when grinding the small needle plate, adjust the height of the lower looper appropriately as required;

3. The eye of the lower burr; apply the polishing paste with the string, penetrate into the eye of the lower looper, and pull the hole smoothly ；