Gas-assisted mold temperature control for improving the quality of injection molded parts with fiber additives

A rapid heating cycle has the advantage of improving product quality in injection molding. In this study, gas-assisted mold temperature control (GMTC) was combined with cool water to achieve dynamic mold surface temperature control. By applying the GMTC system on the mold of a rectangular plate, the advantages of using GMTC for injection molding were evaluated and compared with the traditional injection molding process using different gas gap sizes and gas flow capacities. The effect of GMTC on the quality of the part was also studied. Results showed that when GMTC was used, the heating rate can reach 28 °C/s. For an initial mold temperature of 60 °C, and an air gap size of 8 mm, after 6 s heating, the mold surface temperature can reach 147.8 °C, 167.2 °C, and 229 °C with gas flow capacities of 100, 200, and 300 l/min, respectively. When the gas gap size is changed from 4 mm to 8 mm, the uniformity of temperature distribution shows a clear improvement. When GMTC was used for injection molding of parts with fiber additives, the part surface was clearly improved.