Metal Injection Molding (MIM) can create components for a wide variety of industrial applications. The MIM process combines injection molding technology with powder metallurgy to achieve near-net-shape, high-volume production of complex mechanical components.
Parmatech works closely with customers to ensure the best production at the minimum cost. While MIM generally consists of a few main steps, we optimize the material, binder system, and processing path for your application.
Powder injection molding was pioneered by Parmatech founder Karl Zueger in 1973, after he identified a need for precisely manufactured ceramic capillary tubes used in wire-bonding integrated circuits. Since 1979, Parmatech has won six Grand Prize awards, five Awards of Distinction, and two Awards of Achievement from the Metal Powder Industry Federation (MPIF).
MIM tooling is similar to tooling used in plastic injection molding. These tools can range from simple prototype tools to high-volume, multi-cavity production tools. Built from premium tool steels and backed by Parmatech’s in-house maintenance program, production tools routinely exceed 750,000 shots, with some tools surpassing 1 million.
We start with a fine metal powder (particle size approximately 10–20 microns) and mix this with a proprietary blend of plastics we call “binders.” The powders are incorporated, or compounded, into the fluid binder and granulated to form a feedstock for an injection molding machine.
After compounding, the feedstock is injected into a mold to form a “green” part. The injection molding machine, similar to that used in the plastic injection molding industry, heats the feedstock and injects the viscous fluid into the mold. The MIM part in this molded state is often referred to as a ‘green’ part.
The binders are removed through solvent and thermal processing. This step is called debinding, and it helps separate the binder materials from the powder metal. Debinding can be done in two or three process steps, depending on the equipment capability.
Finally, the parts are put through a high-temperature sintering furnace where the remaining binders are removed. The powder particles fuse together to reach 98%+ of theoretical density. During this critical step, the parts shrink approximately 20%. We use special techniques that result in exceptional metallurgical and dimensional control, producing very repeatable and stable parts.
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, specific factors 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 match the process’s capability to the tolerances needed to achieve your required design function. Without secondary operations, the MIM process is capable of ±0.3% to ±0.5% of a given dimension — for example, 1.000 ± 0.003 inches or 25 ± 0.075mm.
MIM excels when part usage is large, complexity is high, and part size is small to moderate. As a general guide:
| Characteristic | Minimum | Optimum | Maximum |
|---|---|---|---|
| Mass | 0.01 g (0.0004 oz) | <50 g (<1.75 oz) | 250 g (8.82 oz) |
| Wall Thickness | 0.125 mm (0.005 in) | 2.03 mm (0.080 in) | 7.62 mm (0.300 in) |
| Annual Usage | 25,000 | >100,000 | Millions |
We work with an extensive range of metal and ceramic materials, and develop custom alloys when your application calls for something beyond our standard offering, including:
