Pre-Sintered MIM Brown Parts Obtained by Microwave-Assisted Binder Remova

Microwave assisted thermal debinding of parts obtained by Metal InjectionMoulding (MIM) was studied using Design of Experiment techniques to reducethe number of virtual experiments needed to gather information regardingbinder removal. The optimization, in terms of speed, heating homogeneityand energy efficiency of the early stages of this process in an existing2-feeds multimode applicator operating at 2.45 GHz has been reached withnumerical simulation used to perform the virtual experiments. The obtainedmodel was used to determine the optimum debinding conditions, which wereexperimentally tested in a laboratory multimode applicator. Samplecharacterization, before and after sintering, in terms of strength andfinal density, with respect to an equivalent industrial production, wasused to assess the optimized process. A process time reduction of morethan 6 times was achieved. In case of MIM parts made of 430L steel,material not prone to high temperature oxidation, the preferentialmicrowave absorption by the metallic powders resulted also in apre-sintering treatment which improves the brown parts strength and favorstheir handling during the subsequent sintering stage.