High‐Thermal Conductivity Aluminum Alloy Mold Inserts: Improving Injection Efficiency and Mechanical Properties of <scp>ABS</scp> Molded Parts

ABSTRACT In plastic injection molding industry, aluminum alloy mold (abbreviated as Al mold) surpasses traditional steel mold in terms of weight, heat transfer and production efficiency. However, different heat transfer of molds may lead to variations in the mechanical properties of the molded parts. To investigate the impact of Al mold on the filling capability of polymers and the mechanical properties of the molded parts, this paper adopts the central composite experimental design and Box–Behnken response surface analysis for the design of injection process parameters. The effects of Al and steel mold on the filling capacity of ABS polymer and mechanical properties of ABS injection molded parts were analyzed. The results show that the heat transfer efficiency and cavity temperature uniformity of the Al mold are higher than those of the steel mold. The high cooling rate of the Al mold induces rapid freezing of the polymer melt surface, enhancing the molecular chain orientation of the polymer along the flow direction, thus improving the mechanical properties of the molded parts. The optimal ranges of melt filling rate and melt temperature for ABS injection molding using Al mold are 55–60 cm 3 /s and 220°C–240°C, respectively. In this parameter range, the filling capacity of ABS melt in Al mold is not only comparable to that in steel mold, but also the tensile strength of the parts molded by Al mold is up to about 10.5% higher than that of the parts molded by steel mold.