High-frequency induction heating for increase of flow length in polymer/metal hybrid molding

Recent trends of miniaturization and multi-functionality in electrical parts have driven development of molded interconnect devices (MIDs) that contain conductive tracks on a nonconductive base. This study aims to develop polymer/metal hybrid molding technology to fabricate MIDs in a single manufacturing process, without an additional assembly procedure. For this purpose, injection molding was performed to fabricate a thermoplastic carrier that contained negative circuit channels, and die casting was used to fill the circuit channels with metal alloy of low melting point. To increase the flow length of the molten metal through the narrow circuit channel, high-frequency induction heating was used prior to the die casting stage. The effect of heating conditions on the mold temperature was investigated numerically, and the relevant induction heating conditions were determined accordingly. Induction heating was then applied to the die casting process to increase the flow length enough to be used as a circuit path for fabrication of MIDs.