MIM Glossary

A forming technology where the part leaves the mold very close to its final dimensions, minimizing secondary machining. MIM is a typical near-net-shape process.

The moldable mixture of fine metal powder and polymer binder used in MIM injection molding, prepared by mixing and granulating.

The polymer system (approx. 40 vol%) blended with metal powder to give the feedstock flowability during injection; it is completely removed during debinding.

The first MIM process step: metal powders are uniformly blended together with the binder.

Kneading and extruding the powder–binder mixture into homogeneous feedstock granules ready for the injection molding machine.

Feedstock is heated to approx. 190 °C and injected into the mold cavity like plastic injection molding — the part geometry is formed here.

Removing the binder from the molded part by catalytic or thermal debinding, leaving a pure metal-powder brown part.

The porous, fragile part after debinding: metal powder in the final shape, but not yet densified. It goes into the sintering furnace next.

High-temperature densification in vacuum or atmosphere-protected furnaces; the particles bond, the part shrinks uniformly and reaches a relative density of ≥95%.

The dimensional shrinkage of the brown part as it densifies during sintering; molds are scaled up in advance to compensate for it.

The ratio of the sintered part density to the theoretical density of the material. MIM parts typically reach 98% or higher.

A secondary pressing operation in a sizing mold that corrects sintering distortion and improves dimensional accuracy.

Materials Standards for Metal Injection Molded Parts, published by the Metal Powder Industries Federation; it defines standard MIM material grades and their properties.

A continuous atmosphere-protected sintering furnace in which parts are pushed through the heating zones on plates — the workhorse of high-volume MIM sintering.