Simulation-based automatic tool clearance to reduce the tryout efforts of car body stamping tools

Abstract

In addition to material and process parameters, their scatter, and the elasticity of the mechanical system, the real geometry of the die active surfaces is important for the resulting part geometry. Besides the fact that those surfaces can be modified to compensate elastic springback and the press and tool deflection, they mostly are designed with experience-based clearances to simplify the subsequent manual tool tryout process. In this process the tool is adjusted to create a homogeneous contact pressure which shall resemble the simulated pressure distribution. It is only when the actual pressure is sufficiently like the simulated one that the desired level of predictability can be attained. The final tool quality depends on the workers’ experience. In the tool shop the adjustment efforts can be significantly reduced by reducing the tool surface to process relevant areas. To minimize the die surface modelling and tryout efforts, a new method for the semi-automatic generation of the die clearance is presented. It identifies the belonging surfaces based on the previously simulated pressure distribution. Depending on the chosen pressure threshold, the die surfaces can be reduced by up to 60%.