Reasonable clearance of blanking die: Generally, the clearance value of blanking die with the thickness of stamping material within 2mm can be below 10%, and the required burr can be about 5% (bilateral clearance).

When the clearance of the blanking die is reasonable, the upper and lower cracks produced by the material at the population of the punch die can overlap at the same position. In this way, the bright area of the blanking section is larger, but the collapse surface and burr are smaller, the fracture taper is moderate and the surface of the part is smoother. Satisfactory quality can be obtained by stamping parts. When the gap is small, the service life of the die is shorter, but the quality of the parts obtained is better. When the gap is large, the service life of the die is longer, but the quality of the parts obtained is poor.