With the improper replacement and suture between a machine needle, stitching and sewing materials, sewing pin compatible. Bending machine needle, blunt or wear replacement needle Needle installed wrong. the correct re-installed needle rotary hook hook line at the wrong time or gap between the needle 4. the correct position of the needle and rotary hook Gou Jian to re-adjust the needle 5. rotary hook Gou Jian bad grinding rotating spindle hook tip or a new rotary hook 6. movement around the needle stroke height is not equal to 6. re-adjust the machine needle to the coordination position. presser foot slot too wide, foot pressure is not enough 7. presser foot to replace the narrow groove, and increase pressure. needle plate slot too wide. replace needle plate slot. pressed the soles of the feet flat and needle plate plane is not parallel. adjust the presser foot, it parallel to the needle plate 10. needle bar and the upper and lower sets of the gap is too large 10. replacement of worn over large sets of cross-section line (1) threading the correct order to a correct order to re-threading. noodles adjustment too tight 2. slowly unscrew folder pileare poison, and accordingly adjusted the bottom line is elastic. Needle improper selection Replacement and stitching, sewing needle Needle bending 4. a new machine needle. Needle collision presser foot to adjust the location of the presser foot. rotating spindle rotation is unfavorable, or the position filled not . good rotary hook correct position adjustment position, and tighten the 7 rotary hook hook injured. light repair rotary hook hook or a new rotary spindle 8. eye of a needle rough or needle plate needle slot by injury repair light eye of a needle hole or the groove of the needle, such as the needle groove serious injury should be renewed. noodles Pythium or too brittle nine. exchange good line 10. rotary hook hook line too fast or too slow 10. adjust the hook hook line off the bottom line. Bobbin wound too full or uneven. re around the bottom line. bottom line moldy two exchange a good line. bottom line adjustment too tight. appropriate Loosen the shuttle skin screws, and accordingly adjusted the noodles elastic. bobbin sets Inlet sharp or rough. oil stone or fine emery cloth to polish, to the acute angle. send dog position is too low to cause the bottom of the feed dog fast mouth, the bottom line qualifying distance is too small, the bottom line and the teeth at the bottom of the mouth occur faster friction. rationally adjust the feed dog position Duanzhen opportunity to work with sewing mis-match replacement and machine needle sewing compatible machine needles are not equipped with the collision of the presser foot or needle plate according to the correct location. re-installed needle. needle bending. replace the needle swing needle body modification 4 agency position adjustment put the needle in the correct position and tighten the machine not working. motor belt is too loose or too tight an adjustment with rolled cable head or fouling of the length of the two hook and remove the hook, remove lint or fouling, and add a small amount of sewing machine oil