MIM Process
Metal Injection Molding Process
Metal injection molding (MIM) offers a manufacturing capability for producing complex shapes in large quantities. The process utilizes fine metal powders which are custom formulated with a binder into a feedstock which is granulated and then fed into multiple cavities of a conventional injection molding machine. After the “green” component is removed, most of the binder is extracted by thermal or solvent processing and the rest is removed as the Metal injection moldingcomponent is sintered (solid-state diffused) in a controlled atmosphere furnace. The MIM process is very similar to plastic injection molding and high-pressure die casting, and it can produce much the same shapes and configuration features. However, it is limited to relatively small, highly complex parts that otherwise would require extensive finish machining or assembly operations if made by any other metal forming process.
Mixing
Mix <20 µm typical powder with polymer (binder) system to produce the MIM feedstock. Theoretically speaking, the smaller the particle is, the bigger its specific surface will be, which is good for molding and sintering.
Granulation
The evenness of the mixture directly influences its fluidity and further influences the technical parameter of the injection molding, and the density and other performances of the final material.
Molding
Mold complex components from the feedstock using standard plastic injection molding equipment & techniques.During injection molding, the mixture is heated in the injection molding machine into plastic material with rheology, and then injected into the mold under certain pressure to mold a blank.
Sintering
Remove the plastic binder by sintering parts in a high temperature H2/N2 pusher furnace. The high density of MIM component is achieved through high sintering temperature and long sintering time, which greatly improves the mechanical property of the component.
Secondary Operations
Parts can be machined, coined, heat treated, plated, and black-oxided and so on.