Design of a Stamping Test for Investigating Surface Distortion in Sheet Metal Parts

Surface distortions/deflections are frequently introduced into the Class “A” surfaces during sheet metal stamping processes. However, the origins of the draw die related surface distortion/deflection have not been well understood. This paper presents our design of a stamping test for the investigation of the distortion phenomenon. Five geometric parameters are first identified to represent basic geometry of typical automobile outer panel depression features around the surface distortions. Experimental stamping dies are then designed to reflect various combinations of these five geometric parameters with the assistance of numerical simulations to ensure that the designed dies are able to replicate the surface distortion phenomenon. Also, real-time dynamic measurement techniques are designed to collect historical data of strains and deflection on the stamping panels. Our preliminary tryouts show that the designed stamping test successfully replicates the distortion phenomenon observed in production stamping processes. It provides a platform for the investigation of the root-cause of the draw die related surface distortions.