Metal Powder Injection Molding (MIM) is an advanced manufacturing technology developed in recent decades. It combines metal powders with organic binders to produce complex, near-net-shape metal components through injection molding techniques. However, despite its numerous advantages such as high production efficiency, material utilization, and product precision, MIM technology still has some limitations and challenges.

1. Material Restrictions

MIM technology is primarily suitable for powder metallurgy materials such as stainless steel, titanium alloys, and cemented carbides. Although some studies have attempted to use other metal powders, such as aluminum and magnesium, for MIM technology, their application remains limited due to their unique properties, such as high chemical reactivity and low sintering temperatures.

2. Complex Structure Limitations

Although MIM technology can produce metal components with many complex shapes, it still has limitations in manufacturing parts with extremely complex structures or micro-features. For example, it may be difficult for the organic binder to completely fill microstructures with high aspect ratios or internal pores during the injection molding process, leading to incomplete structures or degraded performance.

3. Limitations in Dimensional Accuracy and Surface Quality

Although MIM technology can achieve high dimensional accuracy and good surface quality, there are still limitations in certain cases, such as when manufacturing large-sized components or parts with complex surfaces. In addition, post-processing steps such as heat treatment and grinding are often required for MIM-produced parts, which may affect their dimensional accuracy and surface quality.

4. Cost Restrictions

The manufacturing cost of MIM technology is relatively high due to the multiple complex steps involved in the process, including powder mixing, injection molding, debinding, sintering, etc. Furthermore, MIM requires high-precision equipment and skilled technical personnel, which also adds to its manufacturing cost. Therefore, for parts that require mass production, the cost of MIM technology may become a limiting factor.

5. Environmental Restrictions

During the production process, MIM technology generates certain waste and pollution, such as organic binders and debinding wastewater. These waste and pollution need to be properly handled, otherwise they may have a negative impact on the environment. However, there are still challenges and limitations in waste disposal and environmental requirements for MIM technology.

In summary, despite the many advantages of metal powder injection molding technology, it still faces limitations and challenges in terms of materials, structure, precision, cost, and environmental protection. To overcome these limitations, further research and development of new MIM technologies are needed to improve their scope and performance.