An early developer of the process during the 1970s was Dr. Raymond E. Wiech Jr., who refined MIM technology as co-founder of a California company named Parmatech; the name being condensed from the phrase ‘particle materials technology’. Dr. Wiech later patented his process, and it was widely adopted for manufacturing use in the 1980s. Competing processes included pressed powder sintering, investment casting, and machining. MIM gained recognition throughout the 1990s as improvements to subsequent conditioning processes resulted in an end product that performs similar or better than those made through competing processes. MIM technology improved cost efficiency through high volume production to ‘near-net-shape’, negated costly, additional operations left unrealized in competing processes, and met rigid dimensional and metallurgical specifications.
The process steps involve combining metal powders with wax and plastic binders to produce the ‘feedstock’ mix that is injected as a liquid into a hollow mold using plastic injection molding machines. The ‘green part’ is cooled and de-molded in the plastic molding machine. Next, a portion of the binder material is removed using solvent, thermal furnaces, catalytic process, or a combination of methods. The resulting, fragile and porous (2-4% “air”) part, in a condition called “brown” stage, requires the metal to be condensed in a furnace process called Sintering. MIM parts are sintered at temperatures nearly high enough to melt the entire metal part outright (up to 1450 degrees Celsius), at which the metal particle surfaces bind together to result in a final, 96-99% solid density. The end-product MIM metal has comparable mechanical and physical properties with parts made using classic metalworking methods, and MIM materials are compatible with the same subsequent metal conditioning treatments such as plating, passivating, annealing, carburizing, nitriding, and precipitation hardening.
Therefore, powder injection molding technology is especially suitable for manufacturing of small precise metal injection molding components with complex shape and special requirements on performance on a large scale. sofine is a professional powder metal components manufacturer, we supply powdered metal parts, and other metal powder products for wholesale, OEM is welcomed.
In order to meet the capacity demand from customers of powder metal components & parts, sofine sets an independent mold department which is operating by a high-specialized engineer team. The mold workshop insists on attaching importance to 5S management and is configured with high-precision inspection equipments.