1) The mold device is faulty. If the punch is not perpendicular to the fixed plate or is loose due to wear, or the positioning pin is loose, the correct fixed position of the male and female molds cannot be ensured.
2) Poor guiding accuracy. Excessively large cooperation space of the mold guides causes the center lines of the upper and lower molds to not overlap and affects the uniformity of the punching space.
3) Device fault. When the non-guided mold is installed, the orientation of the upper and lower molds is prohibited to form uneven open space. The surface of the template or bottom plate of the mold is not clean, or the screws of the upper mold are improperly tightened, which will cause the working part to be skewed.
4) Deformation during mold operation. For example, the leakage hole of the punching mattress board is too large, the template under the mold is too thin, and the rigidity of the die is not enough.
5) The open area of the punch guide rail is too large, the parallelism between the bottom surface of the slider and the work surface is not good, or the sliding direction of the slider and the verticality of the work surface are not good.
6) When the maximum resistance of the workpiece during punching exceeds 80% of the nominal pressure of the punch, the open punch will easily deform the “C”-shaped bed, so that the center lines of the upper and lower molds do not coincide.
7) The flatness of the sheet is poor, and the punch with a smaller diameter is skewed during the metal stamping process.
8) Due to improper mold material selection, casting and heat treatment processes, the concave mold deforms during heat treatment or wire EDM, which affects the uniformity of the mold space.