Sewing machine for stitching folding belt

The sewing machine that our company uses now appears to fold the belt in the process of stitching, how is this to return a responsibility? Please give me some advice. I don't understand what it means to fold bags. Reply "zhangkezhang007" is that the bag is stuck in the thread, and the bag skin is broken. I don't know why. I have a headache.-it broke the bag, didn't it? The sewing machine has not been debugged properly, and the stitches may be too dense. -- two possibilities. The quality of the outer skin of the bag is not very good, it is too crisp. The stitches of the sewing machine are too dense and can be adjusted thinly-the crude protein seems to be a little tight, and now the thread is not pressed. It's still being debugged! Thank you for your recovery wawp at 08:46 on 2009-12-1. Thank you for your recovery. Thank you for your recovery. Jumper is for the sewing machine. Just let the repairman or manufacturer repair it. -- the stitches are too dense-- there are all cases of stitches jumping in the sewing machine, as well as in the new sewing machine. Your situation is that the stitches are too dense and the quality of the bag is too poor or the quality of the sewing thread is too poor. -- reply "small farmers thank you ~ ~ wawp at 11:35 on 2009-12-5 11:35, add the following reply" topqiuben OK, thank you for your reply-- learned! ~-1, remove the lid and clean, and press the foot, add lubricating oil ~ 2, jumper, adjust the pins