Fully-Integrated Numerical Analysis of Micro-Injection Molding with Localized Induction Heating

摘要

High-frequency induction is an efficient way to heat mold surface by electromagnetic induction in a noncontact procedure. Due to its capability of rapid heating and cooling of mold surface, it has been recently applied to the injection molding of micro/nano structures. The present study investigates a localized heating method involving the selective use of mold materials to enhance the heating efficiency of high-frequency induction heating. A composite injection mold consisting of ferromagnetic material and paramagnetic material is used for localized induction heating. The feasibility of the localized heating method is investigated through numerical analyses in terms of its heating efficiency for localized mold surfaces and the resulting flow characteristics in a micro-channel. To take into account the effects of thermal boundary conditions of the localized induction heating, a fully-integrated numerical analysis effectively connecting electromagnetic field calculation, heat transfer analysis, thermal stress analysis, and injection molding simulation is carried out. The proposed integrated simulation is applied to the injection molding of a rectangular strip containing micro-channels, and the resulting mold heating capacity and replication characteristics of the micro-channels are compared with experimental findings in order to verify the validity of the proposed simulation.