Experimental and Numerical Investigation of Thinning Behavior in Deep Drawing of AISI 1008, CuZn30, and Aluminum 1100

Abstract

This study investigates the thickness distribution behavior of deep drawing cup products under the influence of various forming parameters, die radius, punch velocity, blank holder force, sheet thickness, and sheet metal type. Three types of sheet metal were used: low carbon steel (AISI 1008), aluminum (1100), and brass (CuZn30), in sheets of 80 mm diameter circular blanks with thicknesses of 0.7 and 1 mm, formed by a tooling set (die, punch, and blank holder). The die radius profile at R4 and R6 was used, where the punch velocities were 100, 150, and 200 mm/min. ABAQUS/CAE was used for numerical simulation, and a dynamic explicit solver was employed to form cylindrical cup products. The results show that for three metals, higher punch speeds tend to increase strain localization, and maximum thinning occurs at the punch nose radius; the maximum thickening in the sidewall region and thinning are increased with the decrease of die radius. It was also found that the r-value of the Lankford coefficients plays a significant role in thinning behavior in relation to rolling (r-value direction). The results also indicate that aluminum alloys are relatively formable, but they are highly sensitive to process variables, specifically blank holder pressure and sheet thickness. Wrinkles are reduced by increased blank holder force, but higher values cause tearing near the punch corners. All of the materials showed a similar thinning behavior during the deep drawing process, in spite of the variations in their mechanical properties. The results have shown a strong agreement between experimental and numerical work with a maximum discrepancy of 5 %.