What is MIM

Metal injection molding or MIM is a manufacturing process that combines the versatility of plastic injection molding with the strength and integrity of machined, pressed or otherwise manufactured small and complex metal parts.

Competing processes include pressed powder, investment casting, turning and machining.

The window of economic advantage in MIM parts lies in the complexity and miniature. The smaller and the more complex a part is, the more cost savings can be made by MIM compared to conventional manufacturing processes.

The difficulty of fabrication through other means may make it cost inefficient or even impossible to manufacture otherwise, while increasing complexity typically does not increase cost in a metal injection molding operation.

Tolerances as critical as +/-.003" per linear inch can usually be accomplished without secondary processes. MIM components are used in a broad range of applications e.g. medical, dental, firearms, aerospace, and automotive just to name a few.

The process starts from blending fine metal powders with plastic binders to prepare feedstock and then inject the heated feedstock into a mold using refitted plastic injection molding machines.After the part is molded and before the binders are removed, the part is referred to as a 'green part'.

The next step is to remove the binders with solvents and thermal processes. The resultant metal part is sintered at temperatures great enough to bind the particles but not melt the metal.After sintering process, a brittle 'green part' becomes a solid piece of metal with desirable dimensions and strength.