Abstract
The effect of clearance on tool wear was examined during the blanking of a high-tensile-strength steel sheet. When the clearance was small, at approximately 2%t (relative to sheet thickness), the tool expectedly became more worn during the blanking of the high-tensile-strength steel sheet than during the blanking of a stainless-steel sheet, which is generally considered to induce severe tool wear. However, tool wear was greatly reduced to lower than that for the blanking of a mild steel sheet when the clearance was increased to 10%t or more. This was because the percentage of the shear surface relative to the cut surface decreased with increasing clearance, resulting in a decreased distance over which the sheet slid on the tool surface. For the high-tensile-strength steel sheet, the inner diameter of a hole on the sheet and the outer diameter of the blanked piece also changed greatly as the clearance increased. This prevented the sheet from adhering to the tool surface and suppressed the increase in shearing energy during blanking.
