Finite Element Simulations of a Hybrid Forming Process: Combined Deep Drawing and Superplastic Forming

It is well established that superplastic forming is limited to low volume production, due to the low deformation rates associated with superplastic deformation. In this work, finite element simulations of a hybrid forming technology that combines superplastic forming with deep drawing are presented. This hybrid process aims at obtaining complex light weight structures without sacrificing the production rate. A two dimensional finite element model is used to simulate the process. The forming process consists of two steps. In the first step, the sheet is drawn into the die, to a preselected level, using a mechanical punch. Thereafter, pressurized gas is applied at a controlled rate in order to force the sheet to acquire the intricate die details. Different aspects of this hybrid process are studied in this paper like the forming time, final thickness distribution and wrinkling possibilities. The ratio between the deformation caused by the first step and that caused by the second step will be varied to investigate its influence on the forming process. The overall objective is to construct deformation maps that describe the optimum forming scheme which guarantees the shortest forming time and best component integrity.