Hydromechanical deep drawing of cups with stepped geometries

This paper deals with the hydromechanical deep drawing of metal cups with complex stepped geometries. Two materials, a low-carbon steel (DC04) and stainless steel (DIN 1.4301), have been researched. A die set with a maximum possible deep drawing ratio β0,max = 3.0 for a punch diameter ∅ 100 mm has been designed and constructed. The die set is designed to withstand fluid counter pressures up to 200 MPa. Pressure control is achieved using a micro-metering pressure control valve. The process is initially simulated using the FEM solver LS-DYNA. Experiments have been conducted with two punch geometries. The punch geometries consist of cylindrical and conical wall segments. Complex positive and negative features are manufactured in the punch bottom face. The ability of transferring complex features from the punch onto the blank surface with high deep drawing ratios is investigated. Extended limiting deep drawing ratios of β0,max = 3.0 for DC04 and β0,max = 2.875 for DIN 1.4301 have been achieved.