Metal Injection MoldingOne Step at a Time
Parmatech works closely with customers to ensure the best production at the minimum cost. While PIM generally consists of a few main steps, we will optimize the material, binder system, and processing path for your application.
PIM tooling is very much like that used in plastic injection molding. These tools can range from simple prototype to multi-cavity production tools. Please see our Tooling Philosophy section for more information.
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.
After compounding, the feedstock is injected into a mold to form a "green" part.
The binders are removed through thermal processing. In some cases, depending on the application, a solvent bath is used as an initial step.
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 PIM process can be batch or continuous.
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.
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 PIM 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 PIM 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.