Metal Injection Molding Produces Precise, Complex Components

For the last 25 years, the metal injection molding industry has grown at a steady rate. In the 70s it was predicted that the MIM process would grow at the rate of 18 to 22% per year. But because of some challenges with the materials, known as feedstocks in the industry, the initial growth was slow. Typically feedstocks were mixed by the individual companies involved in making metal injection molded components. The inconsistency in the mixing of the feed stocks led to part variation that was unacceptable in a wide variety of precision applications. cap mould

As more and more components were designed using the metal injection molding process, larger manufacturers became interested in developing feed stocks. Two major players were Allied Bendix and BASF. This enabled companies without metallurgists and large technical staffs to become involved in the process. The number of companies producing metal injection molded parts grew.

Then with the advancement in digital process controls, processing equipment became more exacting with greater process control. Now, plastic injection molding machines and furnaces are able to produce complex shapes with greater consistency.

So what types of components are good candidates for the metal injection molding process? The answer to that is it depends upon the configuration of the part. But in general terms, if a part can be plastic injection molded, it can be metal injection molded (as long as the part does not have any undercuts).

A wide variety of materials can be molded. Carbon, alloy and stainless steels are molded day in and day out with titanium catching up quick. Lots of development is being done with titanium for medical devices.

The industries using a lot of MIM components are firearms, medical device, dental equipment and electronics. Most of the parts are relatively small, less than 1 1/2″ in length. But we have molded parts 7″ long.

Even though most materials have 18% shrink, dimensions are very consistent. Tolerances can be held to plus or minus .001 for small critical dimensions.

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