Moving Beyond The Limitations of Machining And Casting: The Innovative Path of Metal Injection Molding

Throughout the long history of manufacturing development, machining and casting processes have long occupied a core position. However, their inherent limitations have always restricted the R&D and production of precision metal components. Machining processes have a material utilization rate of less than 50%, and face great difficulties and high costs when processing complex structures. Casting processes, on the other hand, are plagued by low precision, numerous internal defects, and challenges in forming complex internal cavities. 

The emergence of Metal Injection Molding (MIM) technology has broken this deadlock, opening up an innovative path in the field of metal forming with its unique process advantages. MIM technology integrates the convenience of plastic injection molding and the material adaptability of powder metallurgy, with its core process consisting of four key steps: feedstock preparation, injection molding, debinding and sintering. Compared with traditional machining processes, MIM technology has achieved a leap-forward improvement in material utilization. A large amount of metal is turned into waste during machining, while MIM boasts a material utilization rate of nearly 100%, making it particularly suitable for processing precious metals and significantly reducing raw material costs. For components with complex structures, machining requires multiple processing steps for assembly, which makes it difficult to ensure precision. In contrast, MIM can realize one-step forming of components with complex internal cavities and special-shaped structures, eliminating the need for extensive subsequent finishing. Compared with casting processes, MIM technology has achieved a qualitative breakthrough in forming precision and product consistency. Castings are often affected by defects such as shrinkage cavities and gas porosity, which impair their performance, and their dimensional accuracy is usually above ±0.5%, requiring additional machining for correction. After sintering, MIM products can achieve a dimensional accuracy controlled within the range of ±0.1% to ±0.3%, with low surface roughness, and can meet precision requirements with little to no subsequent processing. In the production of miniaturized and lightweight components, casting processes struggle to meet the forming challenges of thin-walled and micro-sized structures, while MIM can easily manufacture micro-components with a wall thickness of over 0.2 mm, which are widely applicable to high-end fields such as electronics and medical devices. The innovative value of MIM technology is further reflected in material adaptability and industry expansion. Traditional processes are severely restricted in processing refractory metals and rare alloys, while MIM is compatible with a variety of metal materials including stainless steel, titanium alloy and tungsten alloy, and can even produce metal matrix composites. Today, MIM products have penetrated into fields such as automotive, aerospace, electronic communication and medical devices—from precision metal middle frames of mobile phones, to micro-blades of aero-engines, and then to implantable components of medical devices, all bear the mark of MIM technology. With continuous technological iteration, MIM has made steady breakthroughs in feedstock formula optimization and debinding-sintering equipment upgrading, leading to steady improvement in production efficiency and gradual reduction in costs. It not only makes up for the shortcomings of machining and casting processes, but also drives the transformation of the precision manufacturing industry towards the direction of "high efficiency, energy conservation and precision". In the future, with the in-depth integration of MIM with digital and intelligent technologies, it will unleash innovative vitality in broader fields and inject strong impetus into the high-quality development of the manufacturing industry.