Metal Injection Molding

What is Metal Injection Molding (MIM)? MIM is the world's most advanced near-net-shape metal forming technology. It combines the design freedom of plastic injection molding with the material performance of wrought metals. Fine metal powders (typically <20μm) are homogeneously mixed with a polymer binder system to create a moldable feedstock, which is injected into precision molds under high pressure. The resulting "green" parts then undergo a controlled debinding process (binder removal) followed by sintering at high temperature — transforming loose powder into a fully dense (95–99% theoretical density), high-strength metal component with mechanical properties nearly equivalent to wrought materials. At HY-HK, our core MIM technology covers parts from 0.5g to 100g, with dimensional accuracy of ±0.3% and wall thicknesses as thin as 0.5mm — geometries that CNC cannot reach, die casting cannot hold, and stamping cannot form. And because it's under the HY-HK roof, every MIM part can be seamlessly passed to our CNC trimming line or PVD coating chamber — one factory, one quality standard, zero handoff.

Technical Principle

How It Works — 5 Steps, Atom by Atom:

① Feedstock Preparation: Fine metal powders (<20μm) are blended with a proprietary binder system (thermoplastics + waxes) and granulated into pellets — ensuring uniform flow and consistent density.

② Injection Molding: The feedstock is heated to ~170°C and injected under high pressure (100–200 MPa) into a precision multi-cavity mold — filling every corner, every detail. The result is a "green part" with the exact geometry but not yet the strength.

③ Debinding: The green part undergoes a two-stage binder removal — catalytic debinding (fuming nitric acid removes bulk binder) followed by solvent debinding (bath soaking removes residual binder). This step is critical: too fast = cracking, too slow = cost. Our core technology controls the rate precisely.

④ Sintering: The "brown part" is sintered in a controlled-atmosphere furnace (vacuum or protective gas) at 1300–1500°C — well below the melting point. Metal particles bond via solid-state diffusion, achieving 95–99% density. Linear shrinkage: 15–20%.

⑤ Secondary Operations: Heat treatment, CNC trimming, surface treatment (PVD coating), or plating — as needed.