Multi-objective optimization of heating system for rapid thermal cycling molding mold with internal induction heating

A rapid thermal cycling molding (RTCM) with novel internal induction heating mode is proposed in this work. The induction coils are directly inserted in the corresponding mounting holes of mold with an annular gap in between. During mold heating, eddy current losses confined at the walls of the mounting holes act as thermal sources to rapidly heat the mold cavity surface. Water passed through the annular gaps can be utilized to cool the mold in the cooling stage. Moreover, a design framework of the internal induction heating system in the RTCM mold is also developed. Firstly, a unit cell model of the mold was established to evaluate mold thermal response via numerical simulations, in which the effect of frequency and magnitude of coil current, the layout of induction coils and the annular gap size were examined. Then, a hybrid multi-objective optimization method was applied to optimize the induction heating system for the unit cell model. Finally, based on the obtained optimal parameters, a novel design strategy was adopted to conformally arrange the induction coils for the industrial RTCM molds. The blow mold of automotive spoiler was taken as an example to validate the effectiveness of the proposed approach. The results show that the present approach cannot only improve the mold thermal response performance, but also facilitate the mold heating system design process. This work may provide an effective method to realize RTCM of industrial plastics parts with free-form shape.