Abstract
BIW (Body in White) plays an important role in automobile business. It is important that the exterior panels are free from surface defects. Defects are caused because of insufficient stretching, wrong material, wrong process, etc. Panels like Roof, Hood outer and Door outers, having shallow depth, retain a lot of insufficient stretching which leads to surface defects like oil canning and wrinklesIn order to perform this study, different shallow depth panels were selected and analyzed for issues related to surface defects. Finally, Roof (Laser brazed) panel was selected for this study to numerically analyze the impact of forming parameters on stretching. The work presented in this paper proposes a new approach to improve stretch in Roof by optimizing the blank holder surface. A comparative study has been performed with conventional blank holder and optimized blank holder with a total of four different cases. Results revealed that the optimized blank holder along with lock beads has a positive impact on stretching.