Optimization of Process Parameters in Sheet Metal Forming

Figure 1 shows a simplified CAD representation of the tools and initial blank in the stamping process. During stamping, the metal sheet is submitted to large displacements and large elasto-plastic strains; rupture and wrinkles must be avoided, (Figures 2 and 3). The resulting part must also satisfy quality requirements regarding its geometry: after tools removing, the springback effect (Figure 4) can produce a non admissible final shape. The definition of the tools (punch, die, blankholders), choice of material (anisotropy, hardening) and process parameters (number of forming stages, forces to apply) must be performed for every new part to manufacture (there are several hundred parts obtained by stamping in a compact car). Improvement of the design and tryout procedures using numerical simulations may have a significant impact on the cost of the tools and on the reduction of the total time from design to manufacture, with also the possibility to provide better solutions than those determined from purely experimental tryout procedures.