Metal Injection Molding (MIM) Technology
MIM combines plastic molding, polymer chemistry, powder metallurgy and metal materials science. Feedstock is injection molded and sintered to rapidly produce high-density, high-precision, complex 3D structural parts in volume — a new revolution in manufacturing technology.
Complete Process
Full MIM flow: powders + binders → mixing → extruding → feedstock → injection moulding → green samples → solvent / thermal debinding → brown samples → sintering → final products.
Key Advantages
- Near-net-shape precision — maximum dimensional accuracy without machining; overcomes low density and inhomogeneity of conventional PM.
- High alloy flexibility — works with materials too hard or brittle to machine; uniform density above 95% with wrought-like dynamic properties.
- High efficiency — multi-cavity tooling makes MIM ideal for volume production of small, complex parts.
MIM forms complex 3D structures with tolerance ±0.3%–±0.1% in one shot, sintered density up to 98%, with strength, hardness, elongation and fatigue resistance approaching wrought materials, ideal for continuous mass production.
Process Comparison
Compared with powder metallurgy (press-sinter), precision casting and CNC machining , MIM combines the advantages of powder metallurgy and injection molding: complex internal & external 3D geometries in one shot, high dimensional accuracy, high material utilization, and mass-production efficiency — while achieving higher density and finer surfaces than precision casting and far less machining than CNC, especially for small complex parts.
Key Equipment
| Equipment | Purpose |
|---|---|
| Mixers | Compounding powder & binder into feedstock |
| Injection molding machines (small-flight metal feedstock) | Molding complex green parts |
| Debinding furnaces | Solvent / thermal binder removal |
| Hengpu vacuum debinding-sintering furnaces | Vacuum sintering densification |
| Continuous sintering lines | Continuous mass sintering |
| Post-processing equipment | Quenching, tempering, hardness & wear-resistance enhancement |
R&D and QC Instruments
- R&D inspection equipment: complete laboratory capability for material development, process validation and product inspection;
- QC control equipment: full-process quality inspection covering incoming, in-process and outgoing testing.
Material Systems
| Category | Representative Grades | Features / Applications |
|---|---|---|
| Low-alloy steel | Fe-2Ni, Fe-8Ni, 2200, 2700, 4605, 100Cr6, 8620, 8740, 42CrMo4, 1010 | High-strength structural, automotive & hardware parts |
| Stainless steel | 17-4PH, 304L, 310N, 316L, 420, 430, 440, high-nitrogen nickel-free | Corrosion-resistant, medical & precision equipment |
| Soft magnetic | Fe-50Ni, Fe-3Si; copper alloys (Copper / Bronze) | Electromagnetic & inductive components |
| Low thermal-expansion | Invar, Kovar | Electronic packaging, precision instruments |
| Titanium | CP-Ti, Ti-6Al-4V (TC4) | Medical implants, wearables, lightweight parts |
| Tungsten | W-Ni-Fe, W-Ni-Cu, W-Cu | Counterweights, shielding, electronic packaging |
| Ceramics | 99%Al₂O₃, 3Y-TZP, Si₃N₄, SiC, ZTA, Super-ZrO₂ | Wear-resistant, insulating, high-temperature parts |
Key Materials & Technologies
Low-Alloy Steel & Stainless Steel
Five key properties: corrosion resistance, high strength, wear resistance, good ductility and cost-effectiveness, covering 316L austenitic, 17-4PH precipitation-hardening, 304L austenitic and 430L ferritic stainless steels for medical, IT electronics and corrosion-resistant applications.
High-Nitrogen Nickel-Free Austenitic Stainless Steel
Properties: non-magnetic, high strength, good ductility, biocompatibility, high corrosion resistance and fine appearance; an upgrade path over traditional 316L — higher hardness, better ductility, suitable for wearables, jewelry, smart devices, medical devices and bio-implants.
High-Polish 316L Stainless Steel
Key practices: fine powder size, dedicated binder system (residual carbon control), reducing (H₂ or dissociated NH₃) or vacuum sintering atmosphere, strict impurity control (O, C, N); applications: wearables, bag hardware, phones, earphones, brand logos, jewelry.
Titanium Alloy (TC4)
| Item | Value |
|---|---|
| Chemistry | Al 5.5–6.75%, V 3.5–4.5%, O <0.3%, N <0.05%, C 0.06–0.08%, Ti balance |
| Density | ≥4.2 g/cm³ |
| Yield strength | ≥800 MPa |
| Tensile strength | ≥890 MPa |
| Elastic modulus | 100–120 GPa |
| Elongation | ≥4% |
| Micro hardness | ≥300 HV10 |
Titanium alloys feature low density, high specific strength, biocompatibility, corrosion resistance and high-temperature performance for electronics, medical, aerospace and defense industries. North Haitai holds low-cost titanium MIM technology; a success case is the world's first AR smart glasses with titanium alloy temple arms — complex curved surfaces difficult to machine.
Tungsten Alloys
Properties: high density, low thermal expansion, high thermal conductivity, non-magnetic, high strength, high elastic modulus; injection-molded W-Ni-Cu / W-Ni-Fe density ≥18 g/cm³; applications: armor-piercing projectiles, electronic packaging, vibration motors.
Tungsten-Copper Alloys
| Grade | Density g/cm³ | Thermal cond. W/(m·K) | CTE ×10⁻⁶/℃ |
|---|---|---|---|
| 90W-10Cu | >16.7 | >160 | 6.9 |
| 85W-15Cu | >15.9 | >170 | 7.2 |
| 80W-20Cu | >15.2 | >180 | 8.4 |
Advantages: high strength, high density, high-temperature resistance, arc-erosion resistance, excellent electrical & thermal conductivity; uses: military high-temperature materials, switchgear alloys, EDM electrodes, microelectronics.
Kovar Alloy
For electronic packaging: CTE close to hard glass over 20–450℃, high Curie point, stable low-temperature microstructure; applications: vacuum electronic components, transmitter tubes, hermetic plugs, relay housings.
Ceramic Materials
| Property | Unit | 99%Al₂O₃ | 3Y-TZP | Si₃N₄ | SiC | ZTA | Super-ZrO₂ |
|---|---|---|---|---|---|---|---|
| Density | g/cm³ | >3.5 | >5.8 | >3.0 | >3.0 | >4.7 | >6.09 |
| Hardness | HRA | 91 | 88~99 | 92~93 | 92~94 | 91 | 93 |
| Flexural strength | MPa | 350 | 700 | 700 | 500 | 550 | >1600 |
| Compressive strength | MPa | 3000 | 2100 | 3500 | 2800~3000 | 2100 | 3000 |
| Fracture toughness | MPa·M⁻³/₂ | 2~4 | 10 | 7 | 5 | 6.7 | ≥18 |
| CTE | ×10⁻⁶/℃ | 6.5~8.4 | 10.2 | 3.2~4 | 4.3 | 7 | 10.2 |
| Resistivity | Ω·cm | 10¹⁴~10¹⁶ | >10¹⁰ | >10¹⁴ | <200 | >10¹⁴ | 10¹⁴ |
| Elastic modulus | GPa | 260 | 300 | 410 | – | 300 | 500 |
New Product Introduction (NPI) Flow
| Phase | Lead time | Goal | Sample build |
|---|---|---|---|
| Planning | 1–2 wks | Customer confirms project, kick-off | — |
| EVT | 2–4 wks | Customer confirms product spec | EVT1, EVT2… |
| DVT | 4–8 wks | Customer approves samples, release to mass production | DVT1, DVT2… |
| PVT | 2–4 wks | Capacity assessment passed | PVT1, PVT2… |
| MP | — | Yield / first-pass yield targets met | — |
Each phase has OK/NG review gates (NG returns to previous phase); key activities include DFM, PFMEA, Control Plan, SOP/SIP.
Quality Assurance System
Quality policy: Quality first, Customer first, Continuous improvement. Quality management forms five closed-loop modules around "Quality": Product development (quality planning & validation), Manufacturing (process improvement, yield control, SPC), Supplier management (development, audit & coaching, delivery control), Quality control (incoming / in-process / outgoing testing), Customer service (customer requirement contact, feedback, analysis, improvement).
Scope of Service
We accept stainless steel, ceramic, iron-based, copper-based, tungsten-based and titanium powder injection molded products — complex, precision metal parts for consumer electronics (phones, tablets, wearables, earphones), medical devices, automotive, hardware tools, machinery, transformers and power supply equipment.