Experimental study of surface defects on automotive doors during flanging and their numerical prediction

Surface defects can develop on automotive exterior panels after drawing and flanging steps, during springback and may alter significantly the vehicle quality. These defects are characterized by a depth below 0.5 mm and are then difficult to detect or predict numerically. This study focuses on a L-shaped part designed on purpose to reproduce at a small scale surface defects that occur after flanging. Dimensions of these defects are measured from profiles obtained with a tridimensional measuring machine. The investigation of the influence of the flanging height and flanging speed shows than neither of these parameters have impact on the surface defect . The numerical simulation of the flanging process predict the surface defect but with a lower depth than the experimental defect.