Dimensional accuracy is out of tolerance:

1. The mold cutting edge size is manufactured out of tolerance.

2. Springback during the punching process, the shape of the workpiece in the previous process is inconsistent with the shape of the supporting surface of the working part of the mold in the next process, causing the workpiece to deform during the punching process and produce elastic recovery after the punching is completed, thus Affects dimensional accuracy.

3. The shape of the board is not good.

4. For multi-process parts, due to improper adjustment or fillet wear in the previous process, the principle of equal volume during deformation is destroyed, causing dimensional changes after punching.

5. Due to poor positioning during operation or poor design of the positioning mechanism, the blank moved during the blanking process. Or positioning inaccuracies due to defects in the sheared parts (prismaticity, missing edges, etc) can cause dimensional deviations.

6. The punching sequence is wrong.