Process modelling for air bending: Equilibrium model and FEM-simulation

A.H. Streppel; D. Lutters; E. ten Brinke; H.H. Pijlman; H.J.J. Kals

University of Twente in Enschede, Netherlands

In small batch part manufacturing of sheet metal products, attention has shifted from closed die bending towards air bending. Consequently, a simulation of the air bending process which can be used in CAPP systems is required. Considerable effort is invested in developing bending models and in simulating the process by means of Finite Element Method.
In this publication, the equilibrium model for sheet bending, called the ABS-model (Air Bending Simulation) is described and the requirements and application of the DiekA FEM-code in air bending simulations are addressed. For both models, the course of the simulations is described, together with parts of their theoretical backgrounds. From the comparison of the simulation processes, distinct aspects and qualities of both models can be identified. The discrepancies caused by approaches applied in both models obviously lead to presumptions on the achievable simulation results and the achievable accuracies.
In this publication, both simulations are elaborated upon. In an accompanying publication, the results of the simulations are compared to experiments.

Keywords: air bending, equilibrium model, FEM, process constraints