1. There is no air hole on the punch.
During the stamping process, the air in the workpiece is compressed by the punch and cannot be discharged, which makes the shape of the drawn part uneven, which is often ignored by many people. The solution is to add air vents on the punch.
Second, the blank is uneven.
The rough surface is uneven, resulting in an uneven surface of the drawn part. The solution is to replace the material with a better surface quality.
Third, the material rebounds greatly.
The material has a large springback, resulting in an uneven appearance of the drawn part. The solution is to increase the annealing or shaping process.
Fourth, the gap between the punch and the die is too large.
If the gap is too large, the working surface of the mold will lose its straightening effect on the wall of the workpiece, making the shape of the workpiece uneven. Therefore, the die gap should be trimmed or replaced with new parts.
5. The negative deviation of material thickness is too large.
If the material thickness is too small, the gap between the molds will be larger, making the appearance uneven. The material needs to be replaced with a suitable thickness.
6. Improper use of stretching oil.
Select the correct stamping and drawing oil to ensure effective lubrication during the drawing process. Deep drawing processes require extreme pressure lubricants and highly effective antiwear agents. Mineral oil is generally not suitable. Stamping and drawing oil is prepared by adding oily agent, extreme pressure agent, anti-wear agent and synthetic ester. The products are widely used in calendering forming processes such as automobile panels, doors and trunks, and calendering forming processes such as carbon steel and sheet metal. It can effectively reduce the friction between the workpiece and the mold, reduce wear and tear, and the oil film is firm. It can effectively reduce the occurrence of marks, scratches, sintering welding, cracking and other phenomena. It helps the metal to slide, is conducive to forming, has no jamming, and ensures that the edge of the workpiece is smooth and free of burrs. It has good thermal stability at high temperature. Good smooth function, improve machining accuracy, protect mold, prolong mold life.
When processing metal stamping and drawing parts, if there is an uneven appearance, you may first find out the reasons from the above aspects.Read More →