Abstract: In this paper, the characteristics of water and gasassisted injection molding technologies were analyzed. The formation mechanism and sizes of residual wall thickness of water and gasassisted injection molded parts were proposed based a plenty of experiments. It showed that the wall thickness of waterassisted injection molded parts was more uniform compared with that of gasassisted, which was produced by the mold with deflection runner. Waterassisted injection molding technology was more suitable for the parts with circle sections.

Key words: water-assisted injection molding, gas-assisted injection molding, medium-assisted injection molding, residual wall thickness