Abstract: the warpage, residual stress, molding pressure, and temperature field in microcellular injection molding were compared with those in conventional process. Based on rheology theory, the microcellular injection molding mechanism was disclosed. It showed all the warpage, residual stress, molding pressure, and molding time of the microcellular injection molding were obviously smaller than those of conventional molding. The warpage and residual stress decreased with decreasing initial filling volume fraction of the foaming melt. For microcellular injection molding, a lower melt temperature near the gate and a higher melt temperature were needed than those for conventional injection molding.

Key words: microcellular injection molding, numerical simulation, warpage, mechanism