Metal Injection Molding (MIM)
Injection-molded complexity with full metal density and strength.
MIM combines plastic injection molding with powder metallurgy to produce small, complex, high-density metal parts in volume - with fine detail and properties close to wrought metal.
Overview
In MIM, metal powder is mixed with a binder and injection moulded, then debound and sintered at high temperature to full density, giving mechanical properties close to those of forged material. It combines the complex-shape capability of plastic injection moulding with the mechanical performance of metal, making it ideal for high-volume production of small precision parts in 3C, medical and automotive applications.
How the Process Works
Mixing - metal powder and binder are kneaded and pelletized into feedstock; the ratio determines sintering shrinkage and final density;
Injection - the feedstock is heated and injected into the mould in one shot to form the green part; complex micro-structures can be formed;
Debinding - the binder is removed to leave the brown part; the porous, fragile part must be handled with care;
Sintering - high-temperature sintering densifies the part, which shrinks to its final dimensions; controlling sintering shrinkage is central to MIM precision;
Sizing, finishing and surface treatment as required by the product;
Density and dimensional inspection, then packing and shipping.
Key Advantages
- Sintering densification - density close to forged material with good mechanical properties.
- Complex, fine detail - using plastic injection moulding capability, micro complex structures are formed in one shot with excellent detail reproduction.
- Dimensionally stable - good batch consistency, high repeatable accuracy and efficiency.
- Fast injection cycles and a high degree of automation suit high-volume production of micro parts.
- Near-net shape and high material utilization - one-shot forming close to final shape minimizes machining and material waste.
- Wide material choice - stainless steel, alloy steel, titanium alloys and more.
- Good surface quality - the polished mould cavity reproduces detail clearly.
Materials We Process
Stainless steels: 316L, 17-4PH and similar grades
Low-alloy steels and tool steels
Soft magnetic alloys
Copper and other MIM-compatible alloys
Typical Applications
- Medical and surgical instruments and implants-adjacent hardware
- Firearms, defense and security components
- Automotive and powertrain components
- Consumer electronics and mobile device parts
- Connectors, gears and precision mechanisms
- Watch, jewelry and fine hardware components
Capability at a Glance
|
Parameter |
Details |
|
Typical part weight |
0.1–100 g, part-dependent |
|
Typical wall thickness |
0.5–5 mm, geometry-dependent |
|
Sintered density |
Typically ≥95% of theoretical density |
|
Typical tolerance |
±0.3% of nominal dimension, part-dependent |
|
Materials |
316L, 17-4PH stainless, low-alloy steels, soft magnetic and copper alloys |
|
Post-processing |
Machining, heat treatment, plating and passivation available |
Frequently Asked Questions
Q: What products is MIM suitable for?
A: Miniature, complex, high-volume precision parts: 3C components, medical device parts, small automotive precision parts, lock hardware, etc.
Q: What materials can be moulded?
A: Commonly: stainless steel (304/316, etc.), alloy steel, titanium alloys and more.
Q: How do I choose between MIM and CNC machining?
A: For complex micro parts with internal features in high volumes, MIM forms them in one shot and saves machining; for simple, low-volume parts, CNC is more flexible with no mould investment.
Work With Us
Send your part drawing and target annual volume for a MIM feasibility and cost study. Our engineers will confirm density, tolerance and tooling strategy for your component.