Studies on Double-Side Shearing with Parallel and Straight Cutting Edges (Prevention of Tool Breakage by Bevelled Punches with High Slenderness Ratio)

Abstract

In the present investigation the cutting edge of a slender punch was bevelled in an attempt to prevent bending or breakage in use. Tests with Kovar sheet showed that use of a bevelled punch significantly reduces the risk of bending or breakage, a particular problem when clearance on both sides of the punch is unbalanced. This is because the punch guides itself in the later stage of the stroke. Tool life tests shearing Kovar sheet with the bevelled punch produced a smaller burr on the product than with the conventional punch. The application of such punches is found to be most suitable for thin materials such as are used in the manufacture of IC and LSI parts.