A set of shaft and hinge assembly is made up of a number of key components that closely cooperate with each other, which involves various performances such as torsion, life test, seismic test, floor test, material performance, selection of component manufacturing process, etc. Claim. Among the above items, the selection of the material and manufacturing process of the components is particularly important. The material can ensure certain mechanical properties, and the appropriate manufacturing process can not only economically carry out mass production, but also ensure the high precision of the parts. The manufacturing process of the core parts of precision rotating shafts-Metal Injection Molding ("MIM"), has developed into an important part of powder metallurgy in recent years and has grown rapidly. It is a combination of plastic injection and powder metallurgy. Advantageous molding technology. This process mixes fine metal powder with polymer binder and heats it to obtain a fluid injection material, which is then injected and molded by an injection machine. The obtained molded body is sintered and densified after degreasing treatment. The final product can be automated and mass-produced small workpieces with precise dimensions and complex three-dimensional shapes; this process greatly reduces the complicated procedures and costs of traditional metal processing, so it has certain competitive advantages in certain industrial applications , Has been widely used in machinery, electronics, communications, automobiles, clocks, optoelectronics, weapons, medical equipment. The mature application of MIM technology greatly expands the design space for precision rotating shafts.