MIM tooling is very much like that used in plastic injection molding. These tools can range from simple prototype to multi-cavity production tools. mp 3 na mmf
Compounding
We start with a fine metal or ceramic powder (particle size approximately 1-20 microns) and mix this with a proprietary blend of plastics that we call "binders". The powders are incorporated into the fluid binder and pelletized to form a feedstock for an injection molding machine. mp 3 na mmf
Molding
After compounding, the feedstock is injected into a mold to form a "green" part. mp 3 na mmf
Debinding
The binders are removed through thermal processing. In some cases, depending on the application, a solvent bath is used as an initial step. mp 3 na mmf
Sintering
Finally, the parts
are put through a high-temperature sintering furnace where the remaining
binders are removed. The powder particles fuse together to reach 96-99% of
theoretical density.
During this critical step, the parts shrink approximately 20%. We utilize
special techniques that result in exceptional metallurgical and dimensional
controls, resulting in very repeatable and stable parts.
Depending on the annual volume of your project, the MIM process can be batch
or continuous. mp 3 na mmf
Inspection and Secondary Operations
After sintering, the parts are inspected against high quality standards. At this point, additional operations - such as machining, heat treating or plating - may be undertaken to achieve tighter tolerances or enhanced properties. mp 3 na mmf
D2M and Tolerances
Part design greatly
impacts process capability. From uneven wall sections to features that need
support through sintering, there are specific factors that determine the
tolerances possible on a part.
By working with you as early as possible in the MIM process, our sales and
engineering staff can help you to match the process’ capability to the
tolerances needed to achieve required design function.
Without secondary operations, the general rule of thumb in MIM is that the
process is capable of ± 0.3% to ± 0.5% of a given dimension; for example,
1.000 ± 0.005 inches or 25 ± 0.125mm. mp 3 na mmf
Download a free PDF of the MIM Design Guide.mp 3 na mmf