Like powder metallurgy, MIM relies on shaping metal particles and subsequently sintering those particles. The final product is nearly full density, unlike press-sinter powder metallurgy. Hence MIM products are competitive with most other metal component fabrication routes, and especially are successful in delivering higher strength compared with die casting, improved tolerances compared with investment casting or sand casting and more shape complexity compared with most other forming routes. Injection molding enables shape complexity, high production quantities, and excellent performances, often is lower in cost with respect to the competition.
Metal Injection Molding is a process by which powder is shaped into complex components using tooling and injection molding machines that are similar to those used in plastic injection molding. Therefore, the component’s complexity is of the same magnitude as those seen in plastic injection molding. The artifacts associated with the injection molding process (gates, ejector pins, parting line) are also similar to those seen in plastic injection molding and must be accounted for in design. The main advantages of MIM process are
- Complex Shapes and features such as cross-drilled holes and fins.
- High Production
- Low Cost
- Thin Section
- Better surface finish – better than 30 RMS
- Less Time consuming – a MIM component can be produced within 10 seconds whereas other processes can take 10 to 20 minutes
- Density > 97% similar to that of investment casting
- Better resistance against corrosion
- Since the basic manufacturing process is high pressure injection molding, exact shapes can be produced (without runner and sprues or overflows), resulting in Minimal material waste
- Wide range of alloys available