Medical MIM

As labor costs for medical manufacturing continue to rise, reductions in component manufacturing costs become ever more important for controlling overall costs. Many medical devices, especially instruments and implants, are produced from difficult-to-machine materials such as stainless steels, cobalt-chromium alloys, and titanium alloys. A relatively new process to reduce the costs of fabricating components from these materials is metal injection molding. This is a net-shaping process in which metal powder is mixed with a thermoplastic binder and molded into a cavity. The molded part is then thermally processed, or sintered, to remove the binder and produce a high-density metal component.

Metal injection molding can be used to form complex parts as easily as simple ones. The process is generally best suited to parts measuring less than 6 mm thick and weighing less than 100 g. Newer binder removal techniques, however, have enabled the processing of cross sections above 12.5 mm and up to 400 g. For all size ranges the process can usually achieve tolerances within 0.3 to 0.5%. Higher tolerances are best met by machining critical dimensions after sintering.

Medical MIM (Medical Metal Injection Molding) is used increasingly within the medical device industry to produce a variety of components. The technology has matured to the point where quality and delivery can be assured through the ISO 9001 and TS 16949 certification of metal injection molding suppliers. These companies can make components from many of the alloys used for medical devices with properties comparable to those of wrought and cast materials. Surgical instruments and implants are two types of medical devices for which this process is particularly well suited. As can be seen, there are now a large number of materials with a variety of desirable properties for these applications that can be used in medical metal injection molding.