1. Stamping material properties

There are automobile stampings with different strengths on the automobile body. From ordinary plates to high-strength plates, different plates have different yield strengths. The higher the yield strength of the plate, the easier it is to spring back. For example, S500MC, DP780 are high-strength steel plates with good cold forming properties.

2. Stamping material thickness

In the metal stamping process, the thickness of the sheet has a great influence on the bending performance. As the thickness of the sheet increases, the springback phenomenon will gradually decrease. This is because as the thickness of the sheet increases, the materials involved in plastic deformation increase. Furthermore, the elastic recovery deformation increases, and therefore, the springback becomes smaller.

3. Shape of stamping parts

The springback of parts with different shapes is very different. For parts with complex shapes, a sequence of reshaping is generally added to prevent springback when forming is not in place. Some parts with special shapes are more prone to springback, such as U-shaped parts. In the analysis of the forming process, the springback compensation of the stamping die must be considered. At present, European and American customers generally require that the springback compensation should be handled in the process design stage of the stamping die, and the springback should be within the product tolerance range.

4. Blank holder force of auto mould blank holder

Blank holder force The stamping process is an important technological measure. By continuously optimizing the blank holder force, the flow direction of the material can be adjusted and the internal stress distribution of the material can be improved. The increase in blank holder force can make the part drawing more fully, especially the part side wall and the R angle position. If the forming is sufficient, the internal and external stress difference will be reduced, thereby reducing the springback.

5. Drawing bead of automobile mould

Drawbeads are widely used in today's processes. The reasonable setting of the drawing position can effectively change the direction of material flow and effectively distribute the feed resistance on the pressing surface, thereby improving the formability of the material. The drawing bead set on the part will make the part more fully formed, the stress distribution will be more uniform, and the springback will be reduced.

Based on the above factors, in order to save the time of auto mold adjustment and reduce the subsequent cost of mold modification, before the stamping process of auto mold is determined, it is generally necessary to use CAE simulation software for springback analysis, and for springback compensation and continuous correction. Commonly used software includes Autoform, Dynaform and JStamp etc.