Computer aided analysis and design of sheet metal forming processes:: Part III: Stamping die-face design

The finite element simulations of a sheet metal forming process help the methods and tooling engineer designing the forming interface for a stamping part by shifting the costly press shop try-outs to the computer aided design environment. The finite element models used in the sheet metal formability and stamping feasibility assessment studies are commonly based on the ideally rigid die-face design. This hypothesis is in general consistent with the present industrial experience even for large draw-dies of conventional steels. Nevertheless, it may not be practicable in the case of the forming high strength steels of moderate thickness because of the comparable higher press loads required to shape the blank. Consequently, an estimation of the die-face deformations during the forming process may be necessary during the evaluation of potential formability and springback problems and possible compensations should be considered in connection with the usual stamping die design and construction routines before submitting to the production. In this part of the study, an engineering methodology is presented for the structural assessment of the stamping tooling and the die-face designs during the sheet metal forming processes. Using the computer aided analysis and design concepts given previously in Part I and in Part II of this study, the proposed approach is employed in the forming interface design of an automotive stamping part including the complete die construction. The results have indicated the relative merits of the die-face distortions on the formability and springback deformations.