When the punching material in precision stamping is soft and magnetically absorbing material, the larger the size of the blanking step hole of the punching die is, the easier it is to induce lateral frictional resistance, which eventually leads to the blockage of the blanking hole.

 

When punching copper, aluminum and other soft thin materials with low melting point, punching will cause high-speed separation and rapid stacking of the punching waste, and the fusion phenomenon occurs on the punching surface, and the punching waste is no longer a piece The state can be separated, but the state of melting into a strip is discharged downward. When the cutting edge is designed to have a hollow stepped hole, the strip waste that is free of the effective edge wall constraint has a bending space in the enlarged stepped hole, and the bending is induced by the different friction coefficients around the edge wall However, the different friction coefficients are caused by problems such as uneven punch and die assembly gaps, and inconsistent finish on the periphery of the die edge wall. When the curved head of the strip scrap contacts the wall of the enlarged stepped hole , One-sided frictional resistance will cause the lateral deformation of the strip-shaped waste, which will further cause the upset deformation of the strip-shaped waste in the stepped hole until the entire blanking hole is filled.

 

When the punching object is a magnetic adsorption material, the die enlarges the size of the blanking stepped hole, and the punching scrap under high-speed punching is affected by the magnetic adsorption force of the magnetic die that does not dissipate the magnet after the sharpening of the die. It is absorbed to the wall of the hole when it rolls and falls, and gradually piles up to form a mutual shelving phenomenon that overlaps and overlaps in the stepped hole, continuously increasing the lateral force of the punching waste, accumulating the friction between the hole wall of the stepped hole, and finally It affects the normal fall of the punching waste and causes the entire blanking hole to be blocked.