Local microwave heating of sand molds as a means to overcome design limitations in sand mold casting

摘要

Microwave induced selective heating outmatches conventional mold heating byconvective heat transfer in means of energy efficiency and cycle time.Moreover, it provides the opportunity of a local manipulation ofsolidification and cooling processes within the sand casting mold. In thispaper, we investigate the suitability of different highly absorbing materialsto indirectly heat up the mostly microwave transparent sand mold. Thetemperature-dependent permittivity of the involved materials is determined byresonator experiments and subsequently used to simulate the electromagneticfield and the thermodynamic response of the sand mold prior to a metalcasting process. Experimental results are presented and compared with theoutcome of the coupled electromagnetic-thermodynamic simulations and theinfluence of local microwave heating on the solidification and cooling of thecast is studied.