Punching die reasonable gap: Generally stamping the thickness of the material within 2mm punching die gap value can be taken less than 10%, if the burr is required to be small, you can take about 5% (bilateral gap).
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When the clearance of punching die is reasonable, the upper and lower cracks produced by the material in the cavity and die can coincide with each other in the same position. In this way, the bright zone of the punching surface is large, while the collapse surface and burr are small, the fracture taper is moderate, and the surface of the part is relatively flat. Blanking parts can be of satisfactory quality. The mold life is smaller when the gap is small, but the quality of the obtained parts is better. When the gap is larger, the mold life is also larger, but the quality of the obtained parts is poor.