2006 年 2006 巻 51 号 p. 55-62
Micro metal powder injection molding (μ-MIM) has some technical problems such as hard full-filling to narrow cavity and difficult de-molding in molding process in addition to careful operations of handling in sintering process. Sacrificial plastic mold was used to solve such several specific problems in μ-MIM process. The production method of micro plastic sacrificial mold inserted MIM (μ-SPiMIM) process was applied to manufacture advanced springs in this study. The sacrificial molds made of Polymethylmethacrylate were fabricated by injection moldings, and zigzag-type springs made of stainless steel were obtained after debinding and sintering. The dimensional accuracy and density of molded and sintered parts were evaluated with various injection molding conditions.