Application of viscous pressure forming (VPF) to low volume stamping of difficult-to-form alloys - Results of preliminary FEM simulations

Viscous Pressure Forming (VPF), a recently developed process, offers a versatile approach to forming of sheet metal parts in small quantities. The process entails the use of a highly viscous medium typically applied to both sides of the sheet. In its simplest implementation, the viscous medium is pumped under pressure into the cavity on one side of the sheet to be formed and controllably released through a single or multiple ports from the other side. Thus, the VPF process is a combination of the bulk (viscous media) and sheet metal forming processes. The finite element-based code, DEFORM, which was specifically designed for analysis of the bulk forming operations, has been chosen to simulate the axisymmetrical viscous pressure forming of sheet metals, i.e., stretching and drawing. The simulation results show that (a) properties of the viscous medium, especially, viscosity, has a great effect an the process; (b) the sheet can be stretched more uniformly when the viscous medium is introduced on both sides of the sheet; (c) the location of the outlet port in the die influences the forming processes and can be used to control the deformation of the sheet metal.