A check valve is a valve that normally allows fluid, be it liquid or gas, to flow through it in only one direction. In some check valves a spherical ball is used to block or release the flow. Japanese Metal Injection Moulding (MIM) producer Taisei Kogyo Co. Ltd., based in Neyagawa City, Osaka Prefecture, recently introduced what the company claims is the world’s smallest MIM-made metal check valve at the 6th Medical Equipment Exhibition held in Tokyo, June 24-26, 2015, using its MicroMIM technology. The check valve has a diameter of just 2.4 mm and wall thickness of 0.2 mm, which is considered to be the limit of conventional MIM technology.
The function of this MicroMIM check valve component is to control the flow of blood to the heart, however the design is not limited to just medical applications but also to other industries. Fig. 1 shows the internal structure of the check valve and its operation in the ‘stopped’ and ‘flowing’ states. Fig. 2 shows the MicroMIM check valve and its inner structure.
Taisei Kogyo reports that it has been successful in the series production of the small part having such a highly complex internal shape thanks to its expertise in MicroMIM. The company states that such a complex shape would be impossible to machine, and some of the internal features would also be impossible without Metal Injection Moulding.