What is the cause of scratches on the bending surface of precision stamping parts

Precision focuses on the production and processing of precision stamping parts, metal shrapnel and precision terminals. Surface scratches sometimes appear during processing of bent parts. Where does the scratches come from? The author found the following reasons in his daily work. When the processed material is bent, metal particles or dust particles stick to the surface of the working part, causing scratches on the precision stamping parts. The bending direction is parallel to the rolling direction of the material, which will cause cracks on the surface of the workpiece and reduce the surface quality. If the corner radius of the concave and convex mold is too small, cracks will appear in the bending part of the workpiece. The gap between the concave and convex molds should not be too small, too small gap will cause scratches. If the depth of the punch into the concave mold is too large, the surface of the precision metal stamping parts will be scratched. The springs on the pressing plate, positioning pin holes, pallets, and ejection holes will all be pressed into indentations.