Metal injection molding (MIM) combines fine metal powder and thermoplastic binder feedstock, injection molded into complex green parts, then debound and sintered at 1200–1400°C to over 97% density. It suits high-volume precision components with intricate geometry, achieving tolerances like ±0.3% and properties similar to machined metal parts.
MIM is a revolutionary process that uses a mixture of metal powder and binder to shape solid metal components. This mixture, called feedstock, is solidified through injection molding, enabling high-volume production of complex parts in a single step. After molding, parts undergo debinding and sintering to achieve their final material properties, including density and precision. MIM is ideal for mass-producing precision components with intricate geometries and fine details. The final products find broad applications across industries, making MIM a versatile and efficient manufacturing solution. Discover the potential of MIM for your next project and learn how it enhances production efficiency and product quality.
Raw materialsRaw materials consist of fine metal powder blended with various plastic additives, mixed with thermoplastics in specialized mixers. The compounding process is complete when metal particles in the binder are fully homogeneous. After processing, the material is pelletized. |
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Injection moldingInjection molding machines inject the raw material into molds under high pressure. This allows MIM to combine the design freedom of plastic injection molding with the superior mechanical and thermal properties of metal materials. The result of this process is a "green part," which may be up to 20% larger in dimensions than the final sintered part, depending on the raw material used. |
DebindingDepending on the binder system, debinding can be catalytic, thermal, or solvent-based. The binder is removed from the part, leaving a residual binder content of 2-3% (skeleton). This residual binder ensures the stability of the "brown part" during subsequent processes. |
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SinteringIn the final step, components are sintered at temperatures between 1200°C and 1400°C, depending on the material. During this stage, the remaining binder is completely removed. The component undergoes isotropic shrinkage to its final dimensions. The sintered part is fully metallic with a density >97%, exhibiting properties similar to machined components. |
Post-ProcessingMIM parts can undergo heat treatment and secondary machining like any metal part, e.g., to achieve tighter tolerances on critical dimensions. Precision Tech offers extensive post-processing techniques, including hardening, CNC machining, surface plating, and assembly of complete components. |
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MIM uses a mixture of metal powder and binder, called feedstock, to shape solid metal components via injection molding, followed by debinding and sintering to achieve final material properties including density and precision.
Components are sintered at 1200°C to 1400°C depending on material, the remaining binder is completely removed, and the part undergoes isotropic shrinkage to final dimensions with density greater than 97%.
Debinding leaves a residual binder content of 2–3% (skeleton), which ensures the stability of the brown part during subsequent processes.
MIM parts can undergo heat treatment and secondary machining like any metal part, including hardening, CNC machining, surface plating, and assembly of complete components.
Prototypes start at 500–1,000 pieces. Production economics turn at 10,000+ pieces per year; below that we still quote, and will tell you if CNC or casting is the cheaper route for that part.
It depends on part size, cavity count, slider count and steel grade, so we quote per part after DFM review. The mold is yours, built for 100,000+ shots.
At production volume, typically 40–60% below a machined equivalent on gear-type parts: almost no chip waste, and teeth are molded rather than hobbed. Against investment casting, MIM is competitive from about 10,000 pieces and 30–50% cheaper at 50,000+.
The three processes overlap only in the middle of the size range. Below a few thousand pieces, CNC wins because there is no tooling. Above roughly 10,000 pieces on a small, complex part, MIM usually wins because the mold is amortised and very little material becomes chips. Investment casting sits between them, and is usually the better answer for larger, thicker sections.
| Parameter | MIM | CNC machining | Investment casting |
|---|---|---|---|
| Unit cost at volume | Low — typically 40–60% below a machined equivalent on gear-type parts | High — cycle time scales with every feature | Cheaper than MIM below about 10,000 pcs on a 20 g stainless part |
| Tolerance | ±0.3% as-sintered; ±0.1% on selected features with secondary machining | ±0.005–0.05 mm | ±0.5–1% |
| Minimum wall | 0.3 mm; under 6 mm recommended | Limited by tool rigidity | 1.5 mm |
| Batch threshold | Prototypes from 500–1,000 pcs; economics turn at 10,000+/year | 1 to a few thousand pcs | Under 1,000 pcs; MIM is 30–50% cheaper at 50,000+ |
| Material utilisation | Near-net shape; eliminates most of the machining waste of a cut part | Poor at volume — most of the billet becomes chips | Gating and riser scrap |
| Best fit | Small, complex, high-volume metal parts (0.1–150 g) | Prototypes, low volume, tight tolerances on large parts | Medium-to-large parts with thicker sections |
These crossovers assume a typical 20 g stainless part and are geometry-dependent — treat them as a starting hypothesis and confirm with a DFM review on your drawing.
| Parameter | Capability |
|---|---|
| As-sintered tolerance | ±0.3% of dimension; ±0.5% general guideline on complex net-shape features |
| With secondary machining | ±0.1% on selected features; bores to H7 (±0.01–0.02 mm) |
| Sintered density | >97% typical; 95–100% depending on alloy and HIP |
| Surface finish, as-sintered | Ra 0.8–1.6 µm; below Ra 0.4 µm after electropolishing |
| Minimum wall | 0.3 mm; under 6 mm recommended |
| Part weight | 0.1–150 g typical; up to 250 g demonstrated |
| Typical batch | 10,000+ pcs/year for production economics; 500–1,000 for prototypes |
| Lead time | 5–8 weeks from design release to tooling and samples |
| Mold life | 100,000+ shots |
| Capacity | 50+ million pieces per year |
| Quality system | ISO 9001 |
Anything outside these bands we flag during DFM review rather than quote blind.
Five variables decide the unit price. When two quotes differ sharply, it is almost always one of these:
Send a drawing or STEP file and we will return a DFM review with an indicative piece price — contact us.
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