| For the last 25 years, the metal injection molding | | | | for the metal injection molding process? The answer |
| industry has grown at a steady rate. In the 70s it | | | | to that is it depends upon the configuration of the |
| was predicted that the MIM process would grow at | | | | part. But in general terms, if a part can be plastic |
| the rate of 18 to 22% per year. But because of | | | | injection molded, it can be metal injection molded (as |
| some challenges with the materials, known as | | | | long as the part does not have any undercuts). |
| feedstocks in the industry, the initial growth was | | | | A wide variety of materials can be molded. Carbon, |
| slow. Typically feedstocks were mixed by the | | | | alloy and stainless steels are molded day in and day |
| individual companies involved in making metal injection | | | | out with titanium catching up quick. Lots of |
| molded components. The inconsistency in the mixing | | | | development is being done with titanium for medical |
| of the feed stocks led to part variation that was | | | | devices. |
| unacceptable in a wide variety of precision | | | | The industries using a lot of MIM components are |
| applications. | | | | firearms, medical device, dental equipment and |
| As more and more components were designed using | | | | electronics. Most of the parts are relatively small, less |
| the metal injection molding process, larger | | | | than 1 1/2" in length. But we have molded parts 7" |
| manufacturers became interested in developing feed | | | | long. |
| stocks. Two major players were Allied Bendix and | | | | Even though most materials have 18% shrink, |
| BASF. This enabled companies without metallurgists | | | | dimensions are very consistent. Tolerances can be |
| and large technical staffs to become involved in the | | | | held to plus or minus .001 for small critical dimensions. |
| process. The number of companies producing metal | | | | Remember, tooling for this process is virtually the |
| injection molded parts grew. | | | | same as plastic injection molding. So small precise |
| Then with the advancement in digital process | | | | parts are good candidates for the MIM process. MIM |
| controls, processing equipment became more | | | | tools cost the same as plastic molding - $15,000 - |
| exacting with greater process control. Now, plastic | | | | $50,000 and up. But if you are looking at components |
| injection molding machines and furnaces are able to | | | | that get machined and you can eliminate machining |
| produce complex shapes with greater consistency. | | | | costs, you can pay for tooling very quickly. |
| So what types of components are good candidates | | | | |