Introduction to Metal Injection Molding Parts Process

Metal Injection Molding parts refer to metal components manufactured by the metal Injection Molding (MIM) process. It is a near-net-shape forming technology that combines metal powder with a binder and injects it into a mold. Here is a detailed introduction:

Manufacturing Process

Feedstock Preparation: Mix fine metal powders with a thermoplastic and wax binder to form a paste-like material, which is then made into pellets for use in Injection Molding machines.

Injection Molding Phase: The feedstock pellets are injected into a mold under high pressure and heated to form a "green part", which cools and hardens quickly.

Binder Removal: Remove the wax and polymer binders in the green part to form a "brown part" with small, controlled pores for subsequent sintering.

Sintering Process: Sinter the brown part at a high temperature (usually around 1550°C) to make the metal powder particles bond and densify, improving the strength and density of the parts.

Final Densification: Some parts may require additional processes such as hot isostatic pressing to further improve density and performance.

Material Used

Stainless Steel: Such as 316L, 17-4PH, etc., which have good corrosion resistance and mechanical properties and are widely used in medical, food and other industries.

Tool Steel: Such as 42CrMo4, M2, etc., with high hardness and wear resistance, suitable for manufacturing parts that require high strength and wear resistance.

Tungsten Alloys: Have high density, high melting point and excellent mechanical properties, and are often used in the aerospace, military and other fields.

Copper and Titanium: Copper has good electrical and thermal conductivity, and titanium has high strength, low density and good biocompatibility, which are used in corresponding application scenarios.

Specialty Metals: Including some rare metal alloys and special-purpose metals, which can meet the special requirements of specific industries.

Advantages

High Dimensional Accuracy: The dimensional accuracy can reach ±0.3% - ±0.1%, and the shape accuracy can reach ±0.5°, which can meet the requirements of high-precision parts.

Complex Part Production: It can produce parts with complex shapes, such as parts with inner holes, grooves, threads, etc., which are difficult to be realized by traditional processing methods.

Material Utilization Rate: The material utilization rate can reach More than 95%, which is much higher than the 30% - 50% of traditional processing methods, saving materials and costs.

Good Surface Quality: The surface roughness can reach Ra1μm, and generally does not require secondary processing.

High Production Efficiency: It can realize mass production, has high production efficiency, and is suitable for large-scale manufacturing of parts.

Application Fields

Consumer Electronics: Used to manufacture mobile phone card trays, volume keys, smart watch cases, laptop hinges and other parts.

Automotive: Such as turbocharger impellers, engine valves, interior and exterior trim parts, etc.

Medical Devices: Including orthopedic implants, dental implants, surgical instruments, etc.

Aerospace: Used to make engine blades, turbine discs, satellite structural parts and other high-performance parts.

Limitations

Size Constraints: Generally suitable for manufacturing small parts, and there are limitations on part size, usually with a maximum wall thickness of about 10mm.

Tooling Costs: The initial mold manufacturing cost is high, which is not suitable for small-batch production.

Shrinkage Control: Parts will shrink by 15% - 20% during the sintering process, and strict control and compensation are required for shrinkage.