Study of multi-point forming for polycarbonate sheet

The multi-point forming (MPF) process of polycarbonate (PC) sheet is introduced briefly, geometrical relationship between objective surface and punch element is determined, and a simple calculation scheme of punch height is developed. Numerical simulations of spherical and saddle-shaped parts are carried out by dynamic explicit finite element analysis; the effects of forming temperature, forming pressure, punch matrix, and punch radius on the forming quality are investigated, and the suitable forming parameters are determined. Then, the MPF experiments of PC sheet for spherical and saddle-shaped parts based on the forming parameters are done, and the comparisons of shape error between experimental parts and object surfaces are carried out. Consequently, the PC products have good shape accuracy, which confirms that MPF used for forming PC sheet is feasible and the forming parameters obtained by numerical simulation are sensible.