Effect of punch clearance in the high-speed blanking of thick metals using an accelerator designed for a mechanical press

Abstract

This paper examines the effects of varying (a) the punch-die clearance and (b) the hardness of the specimen, on the surface finish and quality of blanked specimens for a variety of metals. The blanking speeds used were both low (0.13 m/s) and high (10 m/s). To achieve the high speed required, an accelerator has been developed to convert the low speed of a mechanical press into the fast movement of a piston, using the compression of air through a differential piston system. Features of the sheared surfaces of both low- and high-speed blanks were observed using an optical and a Scanning Electron Microscope, details of which are also reported in the paper.