Experimental study on cold press workability of aluminum‐polyethylene sandwich laminates

Abstract

The cold press workability of aluminum-polyethylene sandwich laminates is experimentally investigated by a deep drawing process with a conical die. "Planium" of 2 mm thickness, in which the core layer, high density polyethylene, is sandwich-laminated between two aluminum sheets, is used as a test specimen. Soybean oil is employed as a lubricant. The dimensions of the drawing die set are determined for a circular blank so that the tensile fracture of the drawn cup occurs at the top corner of the punch. The limiting draw ratio (LDR) is experimentally explored by using many blanks of various initial diameters. In general the maximum punch load in successful drawing increases linearly with increasing draw ratio. Because of the sandwich structure, the fracture of the drawn cup occurs twice. The initial fracture (LDR,,) corresponds to a fine bending fracture at the aluminum surface. The second fracture (LDR,,) is the complete fracture of the whole laminate. The effect of punch corner radius, working velocity and thickness fraction of aluminum and polyethylene on LDF& and LDR,, are studied. The strain distributions of deep drawn cup in three orthogonal directions are analyzed experimentally.