Abstract: In the paper, the problem of nonuniform filling in a multicavity mold was explored by numerical simulation with a simplified model. It was found that it was the difference in the heat generated in different runners that caused the difference in flow fields, and resulted in that the cavities could not be filled simultaneously. Based on this argument, different geometries grooves were designed in the site of runner cross in order to change the temperature field of subrunner entrance. The simulation showed that two cavities could be almost simultaneously filled.

Key words: injection molding, filling imbalance, runner improvement, numerical simulation, multi-cavity