Product quality analysis of stamping die drawing parts During the product drawing process, the drawing parts will mainly have these kinds of problems: wrinkling, cracking, uneven thickness, surface scratches, shape distortion, springback, etc. Among these phenomena, wrinkling and cracking have the greatest impact on product quality. Products with these two problems must not be delivered and must be adjusted. Products with these two problems generally can only be scrapped, and customers will not need.
The first problem is tearing, which is often encountered in the stretching process. When the tensile stress on the wall of the cylinder exceeds the strength limit of the material, the product will crack, and the crack generally appears at the wall of the cylinder slightly above the round corner of the punch.
The factors that affect the product’s cracking are: the tensile properties of the material, the diameter and thickness of the material, the drawing coefficient, the fillet radius of the concave and convex mold, the blank holder force, the friction coefficient, etc. The radius of the rounded corners of the concave and convex molds is too small and too sharp, and the product is easy to crack. The general method of repairing the mold is to find a way to enlarge the rounded corners, make the rounded corners a little smoother, and polish them. It is also possible to add oil during production, especially the special oil for stretching, which is very effective.
When designing a stamping die, you can increase the fillet as far as possible if the customer’s product requirements allow it. Great, I want to exhaust the fitter! It’s annoying to repair molds.
When stretching, necessary lubrication is used, which is conducive to the smooth progress of the stretching process, and the thinning of the cylinder wall is improved. However, it must be noted that the lubricant can only be applied to the working surface of the concave mold, and the surface of the convex mold and the material must not be lubricated, because there is a favorable friction between the convex mold and the surface of the blank, which can prevent the material from sliding and pulling. Cracking and thinning.