On Improving Sheet Metal Formability in Hydrodynamic Deep Drawing Process through a Solid-Oil-Type Mineral Grease Pressure Medium

In this research, the improvement in sheet metal formability obtained through the utilization of a mineral grease in solid-oil-type (SMG) pressure medium in the hydrodynamic deep drawing process assisted by radial pressure is investigated by experiments and finite-element method (FEM) simulations on flat-bottom cups realized with pure copper and DIN 1.0338 steel. To determine the process parameters ranges, an FEM model is developed in ABAQUS/Explicit and validated against experimental results. Afterward, experiments are carried out using two pressure mediums with different viscosities, i.e., water and SMG. Considering the results relevant for both sheet materials, the SMG medium allows an average reduction of the sheet metal thinning of 15% and 10% on the corner edges while also granting a negligible thickness variation on the cup walls. In contrast, the higher viscosity of the SMG, in comparison to the water medium, also results in an average 16% increase in the forming force when compared to the water pressure medium.