Geometric compensation for automotive stamping die design integrating structure deflection and blank thinning

Abstract

Targeting to improve dimensional accuracy of automotive body panels, elastic deformation of stamping die structure and blank thinning are considered for compensation on the die surfaces. The thinning distribution on the deformed blank is extracted from stamping process simulation results and converted into first quantitative compensation. The boundary load required for die structural FEM analysis can be automatically mapped from process simulation results by using an updated load mapping algorithm, and the die deflection is then calculated and the deflection of die surfaces is transferred into second quantitative compensation. These two quantitative contributions are referred together for the compensation on the die surface model. The proposed methodologies have been programmed and can be integrated with LS-Dyna and HyperWorks or with Autoform and CATIA. Additionally, a software toolkit used to calculate the contacting ratio between the formed blank and die face has also been developed to automatically evaluate the effectiveness of die face compensation rather than virtually check the contacting ratio. The proposed methodologies and developed software have been verified by a case study of process and die design for an automotive panel part, showing the benefit in improving the contacting ratio.