A variotherm mold for micro metal injection molding

In this paper, a variotherm mold was designed and fabricated for the production of 316L stainless steel microstructures by micro metal injection molding (μMIM). The variotherm mold incorporated a rapid heating/cooling system, vacuum unit, hot sprue and cavity pressure transducer. The design of the variotherm mold and the process cycle of μMIM using the variotherm mold were described. Experiments were conducted to evaluate the molded microstructures produced using variotherm mold and conventional mold. The experiments showed that microstructures of higher aspect ratio such as φ60 μm × height 191 μm and φ40 μm × height 174 μm microstructures could be injection molded with complete filling and demolded successfully using the variotherm mold. Molded microstructures with dimensions of φ60 μm × height 191 μm were successfully debound and sintered without visual defects.