Metal Injection Molding (MIM): Breaking the Precision and Batch Production Bottlenecks of Traditional Machining

In the field of precision metal parts manufacturing, traditional machining processes have long faced a dilemma: sufficient precision comes at the cost of insufficient batch production, while increased batch output leads to reduced precision. Although cutting processes such as turning and milling can ensure precision, their single-process efficiency is low, making them difficult to adapt to large-scale production. Casting processes, while suitable for mass production, are limited by their forming principles—precision errors often exceed 0.5 millimeters, requiring extensive subsequent corrections. The emergence of Metal Injection Molding (MIM) technology has provided a revolutionary solution to this bottleneck.

MIM combines the batch production advantages of plastic injection molding with the metallic properties of powder metallurgy, and its core process can be described as "micro-precision casting." First, metal powder is mixed with binders to form a uniform feedstock, which is then injected into precision molds via injection machines to produce green parts consistent with the final product. After the binder is removed through a debinding process, the green parts are placed in high-temperature sintering furnaces for densification at temperatures near the melting point, ultimately yielding high-density, high-precision metal parts. This process achieves the breakthrough of "one-step forming to finished product," fundamentally resolving the contradiction between precision and batch production.

Precision breakthrough is MIM’s core competitiveness. Traditional machining struggles to accurately control complex internal cavities, micro-apertures, and other structures, while MIM—using micron-level precision molds—can form precision structures with minimum apertures of 0.1 millimeters and tolerances of ±0.01 millimeters. In the medical field, orthopedic implants manufactured by MIM not only meet dimensional precision requirements but also achieve a density close to that of human bone through powder ratio optimization. In the electronics industry, micro connectors for 5G base stations, after MIM forming, can meet plug-in precision requirements without secondary polishing.

MIM’s batch production capability further highlights its advantages. A single mold injection can produce dozens of green parts, with the production line’s automation level exceeding 90%—daily output is 5-10 times higher than that of traditional machining. For high-volume demand products such as turbocharger blades in the automotive industry and metal camera brackets in the mobile phone industry, MIM technology achieves the balance of "high precision + million-level annual output," reducing production costs by more than 30% compared to traditional processes.

Today, MIM has penetrated high-end fields such as aerospace, medical devices, and consumer electronics. From micro-transmission gears in satellites to precision cases for smart watches, this technology is redefining the boundaries of precision metal manufacturing. With the continuous upgrading of metal powder preparation and mold precision, MIM will surely drive the manufacturing industry toward "higher precision, larger batch production, and lower costs."