Metal injection molding (MIM) is a powder metallurgy process used for manufacturing metal parts. Although metal injection molding uses powder metal, it is nothing like conventional powder metal processing. The metal powders used in MIM are 10-100 times smaller than in powder metal processes. Also, the end product of metal injection molding is much higher in density (greater than 95% theoretical density). Unlike powder metal, products manufactured by MIM can be case or through hardened, painted, and drilled and tapped.
Metal injection molding services offer the same benefits and features of plastic and rubber molding, but produce a much stronger end product. Metal injection molding can provide a substantial cost savings over conventional metal machining options. MIM parts have high densities and mechanical properties approaching those of forged or machined components. Applications for metal injection molding parts include surgical tools, automotive locks and actuators, firearm components, computer hard disk drives and electrical connectors.
The metal injection molding process involves five steps, mixing, injection molding, debinding, sintering, and part finishing. In the mixing step, metallic powders, selected for their strengths and inherent abilities (such as impact strength, high and low temperature characteristics, wear resistance characteristics, machinability, and hardness) are mixed, often with a binding agent. By mixing powders, the goal is to create a composite with the strengths and benefits of all the incorporated metals, while offsetting the independent weaknesses. Once the powders are mixed, a “feedstock” is produced. This feedstock is injected into molds in the same way that plastic or rubber injection molding is performed. The part that emerges from the injection molding stage is referred to as a “green” part.
In the debinding stage of metal injection molding, the green part is immersed in a water bath to remove the binder, which has entered into the part matrix. In cross-linking, the debound green part is exposed to ultraviolet light which thermosets the binding agents used with the metal powders. Once this has been completed, the part is placed into a furnace and heated to over 2000? F. This process, called sintering, fuses the metal parts into a solid shape. Finally, the sintered piece is sent to a finished stage where burrs and surface imperfections are removed and the finished part can be shipped.
Sinotech can ensure excellent metal injection molded parts from China, Taiwan and Korea and is very price competitive. Sinotech has audited, qualified and worked with QS-9000 and ISO certified MIM factories in China, Taiwan and Korea for over 12 years. Sinotech is dedicated to managing your project on-site and delivering parts to you at lower prices but the same quality, service and terms as a domestic supplier.