The size and shape of the process incision depends on the area in which it is located and the requirements for external supplementary materials. Generally, the following principles should be followed:
- 1. The cut should be adapted to the shape and contour of the local protrusions to make the material flow reasonably.
- 2. There should be enough laps between the cuts to make the punch tension the material, ensure clear forming, avoid defects such as corrugation, etc., so as to ensure that good flanging hole edge quality can be obtained after trimming.
- 3. The cut part of the incision (that is, the opening) should be adjacent to the edge of the protruding part, or the area that is easy to break.
- 4. The number of cuts should ensure that the deformation of the material at the protruding part tends to be uniform, otherwise it may not necessarily prevent the occurrence of lines.