Metal injection molding

Metal injection molding or (MIM) is a manufacturing process which combines the versatility of plastic injection molding with the strength and integrity of machined, pressed or otherwise manufactured small, complex, metal parts. Competing processes include pressed powder, investment casting, turning and machining.

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The process involves combining fine metal powders with a plastic binders which allow the metal to be injected into a mold using standard plastic injection molding machines. After the part is molded and before the binders are removed, the part is referred to as a 'green part'. The next step is to remove the binders with solvents and thermal processes. The resultant metal part is sintered at temperatures great enough to bind the particles but not melt the metal. The products of metal injection molding are up to 98% as dense as wrought iron and used in a broad range of applications (including medical, dental, firearms, aerospace, and automotive just to name a few.)

The window of economic advantage in metal injection molded parts lies in the complexity and small size of the part. Tolerances as small as +/-.003" per linear inch can be usually be held without secondary processes. The difficulty of fabrication through other means may make it cost inefficient or even impossible to manufacture otherwise. Increasing complexity for traditional manufacturing methods typically does not increase cost in a metal injection molding operation due to the wide range of features possible through injection molding (threads (both internal and external), miniaturization, branding).

External resources

• http://www.basf.com/catamold - BASF markets granulates, including the unique technology of catalytic debinding for the manufacture of complex metallic or ceramic parts by Powder Injection Molding under the trade name Catamold.

• Powder Injection Moulding International Powder Injection Moulding International (ISSN 1753-1497) is a combined business-to-business magazine and scientific journal offering in-depth coverage of the metal, ceramic and carbide injection moulding industries. Each issue includes news, sectorial and regional reports, and technical features with three industry-relevant technical papers. Editorial content is supplemented by invited industry expert comment and analysis.

• European Powder Metallurgy Association A comprehensive website on powder metallurgy, including MIM. Contains details of PM processes, products and companies.

• PIM Research at the Powder Technology Center of Austrian Research Centers, The development of new materials and feedstocks, micro-PIM, process simulation and innovative tooling concepts are the main basic research topics of the center, while demand in industrial R&D projects is mainly for feasibility studies and small series production. In cooperation with material suppliers and equipment manufacturers, the Powder Technology Center offers a pilot-scale facility for PIM R&D.
• GKN Sinter Metals - Global manufacturer of MIM components- Engineering and Design
• http://www.mimtech-alfa.com Spanish company specialized in MIM parts manufacturing
• http://www.mimitalia.com Italian company specialized in MIM parts manufacturing
• http://www.parmaco.com a Swiss producer of MIM and MicroMIM components for a wide range of applications including medical and automotive.
• http://www.megamet.com St. Louis, MO based company specializing in MIM using the BASF Catamold system.
• http://www.ryerinc.com Temecula, CA Manufacturer, Supplier and Developer of MIM / PIM Feedstock.
• http://www.associatedcontent.com/article/505745/a_description_of_metal_injection_molding.html - A breif overview of metal injection molding.