What Are the Reasons for the Cracking and Deformation of Metal Stamping Parts?

People who process metal stamping parts have seen metal stamping parts cracking and deforming due to process errors or poor material quality. Why do metal stamping parts crack and deform in the end? There are many reasons for the cracking and deformation of metal stamping parts, mainly as follows.

1. Defects in the mold design of metal stamping parts

The flanging forming die for stamping parts is shared by the left and right parts of a mold with two cavities. In addition to flanging, the process also has shape forming content. In addition to the special complexity of the parts, the curved surface is narrow, and the forming requires a concave die pressing core and the matching of the forming surface results in a large forming stroke and a small blanking area under the conditions of the mold structure. In the initial mold design, the designer only considered the feature of small blanking surface, but ignored the guiding slide stroke of blanking core.

2. The forming process parameters of stamping parts are not in place

In the forming process of stamping parts, the process requires that the die, the blanking core and the parts of the two must be closely attached to each other. When the slide of the machine tool is lowered, the sheet material is plastically deformed to achieve forming. However, due to the shortcomings of the pressed parts such as unstable quality, it shows that the pressure of the machine tool is in a state of unbalanced pressure fluctuation during the production process. The main reason is that the processing technicians did not adjust the pressure of the machine tool at this stage in time according to the requirements of the process regulations, or did not communicate the machine pressure stability information with each other during the handover of each shift, resulting in unstable quality of stamping parts.

3. Errors in the design of metal stamping parts and mold processing parts and drawings

For example, clearly mark the area that needs to be processed. However, because the die core is a complex profile, the guide surface is machined after the casting is formed, resulting in a gap error after the machining surface and the guide surface of the die are slip-fitted, and the blanking core swings to the left/right during the normal operation of the mold. 

Before the stamping part is formed, the positioning is carried out by the positioning pins and holes on the plane of the press core. This requires that the press core must ensure stable, reliable and correct sliding during the forming of the stamping part, otherwise the stamping part will be lost during the forming process. It is stable, so that the pressing core and the die wall collide and squeeze, causing the stamping part to generate tensile stress. When the strength limit of the material is exceeded, the stamping part will be torn and skewed. In addition, if other factors are considered in the mold structure, and the special guide slide is ignored, there is a danger that the guide gap will be instantly destroyed and the guide cannot be correctly guided after the two stamping parts are squeezed and rubbed strongly.

The main reasons for the cracking and deformation of metal stamping parts are the above three aspects. In addition, there are many factors that affect metal stamping parts.