Traditional precision casting with sand core removal is an extremely effective technique for producing complex-shaped products. In recent years, the use of ceramic cores has enabled the completion of finished products with narrow slots and deep cavities. However, due to limitations in the strength of ceramic cores and the fluidity of molten metal, this process still faces certain technical challenges. Generally, this process is more suitable for manufacturing large and medium-sized parts, while the MIM process is more appropriate for small, complex-shaped components.
Comparison of MIM Process and Traditional Powder Metallurgy Die casting is used for materials with low melting points and good casting fluidity, such as aluminum and zinc alloys. Due to material limitations, the strength, wear resistance, and corrosion resistance of products made by this process are limited. The MIM process can process a wider range of raw materials.
Precision casting, though improving in part accuracy and complexity in recent years, still falls short of investment casting and MIM. Powder forging represents a significant development and is now applied to mass-producing connecting rods. However, heat treatment costs and mold life remain challenges in forging processes, requiring further resolution. Impact of MIM on the Machining Industry。
Traditional machining methods have recently enhanced their processing capabilities through automation, achieving significant improvements in effectiveness and precision. However, their fundamental procedures remain rooted in sequential machining (turning, planing, milling, grinding, drilling, polishing, etc.) to achieve part geometry. While machining offers superior precision compared to other fabrication methods, it suffers from low material utilization and geometric limitations imposed by equipment and tooling, rendering certain components unfeasible to produce. Conversely, MIM enables efficient material utilization without such constraints. For manufacturing small, complex-geometry precision parts, the MIM process demonstrates lower costs and higher efficiency than machining, making it highly competitive.
MIM technology does not compete with traditional machining methods but rather complements their technical limitations or inability to produce certain parts. MIM excels in applications where traditional machining falls short. Its technical advantages in component manufacturing enable the formation of highly complex structural parts.
The injection molding process utilizes injection molding machines to form product blanks, ensuring material fully fills the mold cavity and thereby enabling the realization of highly complex part structures. In traditional machining techniques, individual components were previously manufactured separately before assembly into assemblies. With MIM technology, these can be integrated into a single complete part, significantly reducing steps and simplifying the manufacturing process. Compared to other metal processing methods, MIM offers high dimensional accuracy, eliminating the need for secondary machining or requiring only minimal finishing.
The injection molding process can directly form thin-walled, complex structural components. The shape of the product is already close to the final product requirements, with part dimensional tolerances generally maintained at around ±0.1 to ±0.3. This is particularly significant for reducing the processing costs of hard alloys that are difficult to machine and minimizing processing losses of precious metals. The products feature uniform micro-structure, high density, and excellent performance.
The metal molds used in MIM technology have a service life comparable to that of engineering plastic injection molding tools. Due to the use of metal molds, MIM is suitable for high-volume production of parts. By utilizing injection molding machines to form product blanks, production efficiency is significantly enhanced and production costs are reduced. Furthermore, the consistency and repeatability of injection-molded products provide assurance for large-scale and mass industrial production. The process accommodates a broad range of materials and offers extensive application potential (ferrous alloys, low-alloy steels, high-speed steels, stainless steels, cobalt-based alloys, cemented carbides).
The range of materials suitable for injection molding is exceptionally broad. In principle, any powder material capable of high-temperature sintering can be processed into parts via the MIM process, including materials that are difficult to machine using traditional manufacturing methods and those with high melting points. Furthermore, MIM allows for material formulation research tailored to user requirements, enabling the production of alloy materials with arbitrary compositions and the molding of composite materials into parts. Applications for injection-molded products now span all sectors of the national economy, presenting vast market potential.
