Metal Injection Molding (MIM) is a metal working process that draws on two technologies — plastic injection molding and powdered metallurgy. Finely powdered metal (typically less than 20 micrometers) is mixed with a binder material to create a feedstock that is then fed into the cavities of a regular injection molding machine. After cooling and solidification, this ‘green part’ is removed from the machine and the binder extracted by thermal or solvent processing, resulting in the ‘brown part.’
Lastly, the metal is condensed through the sintering process, where the part is heated to near melting temperatures (as high as 1450 Celsius), causing the metal particle surfaces to bind together into a final, 96-99% solid density.
MIM can produce intricate, near-net shape parts in a short time, with mechanical properties that are superior to castings due to their fine particle size and high sintered density. MIM parts can also be produced at a lower cost than other processes such as machining, investment casting or stamping, making it ideal for the production of high volume, highly complex small parts.
Finally, MIM is considered a ‘green’ technology due to the significant reduction in wastage compared to other traditional manufacturing methods.