Causes and countermeasures of pulling marks on the surface of metal drawing parts

The use of metal drawing parts is becoming more and more widespread, and our quality requirements are getting higher and higher. If there are pull marks on the surface of the stretched part, it will greatly affect the quality of the product. Therefore, the metal stamping parts processing plant should avoid this problem through reasonable production control. So what causes this surface pull mark? The following is introduced by the author. 1. There are sharp crush marks on the surface of the convex or concave mold, which causes the corresponding stretch marks on the surface of the stretched part. At this time, the crushed surface should be ground or polished; 2. The gap between the convex and concave molds is too small or the gap is not Evenly, so that the surface of the workpiece is scratched during deep drawing. At this time, the gap between the convex and concave die should be trimmed until it is suitable; 3. The rounded surface of the concave die is rough, and the surface of the workpiece is scratched during deep drawing. At this time, the concave die should be rounded. The corner radius is polished; 4. The surface of the workpiece is crushed due to the impurity of the working surface of the die or the surface of the material during stamping. Therefore, the surface of the convex and concave die must always be kept clean when the blank is drawn. Wipe before deepening; 5. When the hardness of the convex and concave mold is low, the surface of the convex and concave mold is attached with metal scraps, which will also cause the drawing marks on the surface of the workpiece. Therefore, in addition to increasing the hardness of the convex and concave mold surface, it is necessary to often draw Check the surface of the convex and concave mold even if the metal scraps left behind are cleaned; 6. Poor lubricant quality will increase the surface roughness of the drawn part. At this time, use a lubricant suitable for the deep drawing process. Use the lubricant after filtering to prevent impurities from mixing in and damaging the surface of the workpiece. [Related recommendation] Learn more: What are the methods for polishing the surface of stainless steel? Learn more: Manufacturing characteristics of automobile stamping parts molds Learn more: Points to note in the design of continuous stamping dies (2)