What reason causes stamping parts of the coil

General what reason causes stamping parts during the production of coil phenomenon happened? Dongguan city hardware co. , LTD. , the author of the following to simple introduce you to: a, materials with irregular edge breakage, and beyond the qualified material quality standards. 2, because caused by stick slip, when there are foreign bodies fall into the formation of alveolar bulge on the back of three volumes, steel material surface or internal foreign bodies in outside after the foreign body dissection, coil like were revealed the scar, miserably endure to see. Four, when there is a foreign body glue to stick mark on a stick, because of the depth of surface caused by foreign body, and thus the obvious mark. Five, the rod surface caused by a foreign body or scratches, due to the uneven stress of general edges can crushed or deformation, leading to coil edges broken. Our hardware experiment department after a lot of products that caused by foreign body scratches and scar. Simple solution is to make foreign body disappeared.