Cup-drawing from a Flat Blank: Part I. Experimental Investigation

Abstract

Part I gives an account of an experimental investigation of the forces, work and strains involved, and the conditions for successful drawing of a cylindrical shell from a flat circular blank. It is claimed that the results are sufficiently accurate to provide a basis of reference for theoretical treatments of cup-drawing, as well as an empirical basis of comparison between different drawing conditions. The work was carried out in an experimental crank-press of 50 tons nominal capacity, and was based on a cup diameter of 4 inches. Blank thicknesses from 0·025 to 0·060 inch were used, and although most of the work was carried out on a low-carbon rimming steel, comparative tests were made with aluminium, brass, and copper, of different tempers. The conditions examined included methods of blank-holding, drawing ratio, punch and die profile radii, punch-die clearance, and blank thickness. Although this part has no theoretical pretensions, it includes a descriptive account of stresses and strains in the deep-drawing process, based on plastic theory.