LINKWIN PRECISIONHONGKONG LINKWIN PRECISION PARTS CO., LTD.
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METAL INJECTION MOLDING PROCESS
Metal powders (such as 316L, 17-4PH, TC4, etc.) are mixed with organic binder (mainly polyoxymethylene, POM) in precise proportions and heated and stirred in a mixer to form uniform feedstock. The binder bonds the metal powder and provides flowability during injection.
The uniformly mixed feedstock is extruded, cooled, and cut into granules approximately 3-5mm in diameter for easy feeding and storage in injection molding machines. Granulated feedstock has excellent flowability and filling performance.
Feedstock granules are fed into an injection molding machine, heated to the specified temperature for flowability, and injected into the mold cavity under high pressure. After cooling, a green part in the desired shape is obtained. This process is similar to plastic injection molding but fundamentally different in materials and process parameters.
Organic binder is removed from the green part. The process consists of solvent debinding (dissolving surface binder) and catalytic debinding (using nitric acid gas to catalytically decompose binder at high temperature). The resulting porous brown part maintains its original shape but has low strength.
Debound parts are heated in a vacuum or inert atmosphere furnace to near the metal melting point (typically 80-90% of the material's melting point). At this temperature, particles densify through diffusion and migration, forming metal parts close to theoretical density. Parts shrink approximately 20% in volume after sintering.
Per customer requirements, surface treatments such as precision finishing, coining, grinding, polishing, PVD coating, laser marking, painting, and electroplating are performed, followed by final inspection and packaging for shipment. Post-processing gives parts the required appearance, dimensional accuracy, and functional performance.
MIM ADVANTAGES
Can form extremely complex geometric shapes in a single step, reducing secondary machining. Ideal for internal cavities, thin walls, and fine features.
Near-net-shape process with material efficiency above 95%, significantly reducing raw material waste and cost compared to traditional machining.
Precision up to ±0.3% (equivalent to ISO IT8), excellent surface finish with Ra below 0.8μm, greatly reducing the need for secondary finishing.
Processes stainless steel, titanium alloy, tungsten carbide, soft magnetic alloy, copper alloy, ceramics, and more, meeting diverse performance requirements.
Suitable for batch production from thousands to millions of parts, with unit cost decreasing significantly as volume increases — delivering strong economies of scale.
Near 100% material utilization with no chip waste; sintering conducted in vacuum or inert atmosphere — eco-friendly, efficient, and aligned with sustainable manufacturing principles.
MATERIALS CAPABILITIES
| Grade | Material Type | Key Properties | Typical Applications |
|---|---|---|---|
| 316L | Austenitic Stainless Steel | Excellent corrosion resistance, ductility and weldability | 3C Parts, Medical Devices, Food Contact |
| 17-4PH / 17-4PHN | Precipitation Hardening SS | High strength and hardness, corrosion resistant, heat-treatable | Aerospace, Structural Parts, Gears |
| 304L / 303 | Austenitic Stainless Steel | Easy Machining, Corrosion Resistant | Hardware, Connectors |
| TC4 (Ti-6Al-4V) | Titanium Alloy | High Strength-to-Weight Ratio, Excellent Biocompatibility | Aerospace, Medical Implants |
| WC (YG8/YG15) | Tungsten Carbide | Extremely High Hardness, Wear Resistant, Red-Hard | Cutting Tools, Dies, Wear Parts |
| Fe-50Ni | Soft Magnetic Alloy | High Permeability, Low Coercivity | Electromagnetic Parts, Magnetic Cores |
| Cu-Cr-Zr | Copper Alloy | High Conductivity, High Thermal Conductivity, Wear Resistant | Electronic Connectors, Electrodes |
| ZrO₂ (白/黑) | Zirconia Ceramic | High Hardness, High Wear Resistance, Biocompatible | Cutting Tools, Watch Cases, Grinding Parts |
| 100Cr6 | Bearing Steel | High Hardness, High Wear Resistance, Good Hardenability | Precision Bearings, Rollers |
| Inconel 718 | Nickel-Based Superalloy | Excellent High-Temperature Strength & Corrosion Resistance | Aero Engine, High-Temperature Environments |