Study on the drawbead setting of the large deformation area in a trunk lid

In the stamping forming process of an automotive panel, some defects such as wrinkles and fractures can be eliminated by setting a proper drawbead, such that a successful forming operation can be obtained. The effect of the structure, the geometrical shape and the parameters of a drawbead on the draw restraining force has been analyzed, as also the effect of the draw restraining force on the metal flow in the panel forming process. Some principal guidelines of drawbead setting are summarized for the die-tool design of a panel. The drawing process of a trunk lid is simulated numerically using non-linear finite elements. Referencing the simulation results and the principal guidelines, the geometric shape of the drawbead is adjusted partly, and the material flow is controlled effectively during the drawing process. It is shown that the principal guidelines of drawbead design and the numerical simulation method of the cover panel forming process are reliable.