MIM is a manufacturing technology of small metal parts and a technological means to achieve near net-shape. It has been invented for about half a century (Parmatech applied for the first invention patent of MIM in 1972). Since 2011, it has been inspired by the rise of the mobile phone market in China, and with the favor of Apple in the United States, creating a golden period of more than 10 years. With the efforts of practitioners and scholars, MIM process, together with Metal Addi ‐ tive Manufacturing (MAM), is now known as the top metal parts processing technology. The well-known McKinsey Consulting Company has a very clear description in the 2018 survey report; At the same time, the statistical results of the questionnaire of 100 experts in the survey report evaluated the maturity of MIM technology as 100%, which is very exciting to the MIM peers. This also explains the main reason why MIM has been favored by 3C products, especially the mobile device industry in the past 10 years. Every mobile electronic equipment has at least one MIM part. This technology has changed human civilization with the development of electronic technology.
MIM is applied to metal parts with complex and repetitive characteristics. Only by demonstrating the true technological ability can the parts enter the holy temple of transmission components. Spur gear is a typical representative part. Many of the MIM spur gear products manufactured in the past are mostly used in parts with low rotation speed and low use frequency, such as notebook screen spindles (Hinges), wipers, deployable awnings, etc, Under the conditions of high speed and long-term use, the spur gear with low accuracy will produce transmission noise, low efficiency, tooth surface wear and other problems. Although some articles have published similar discussions and studies [2-4], they cannot put forward more effective countermeasures. In addition, considering the sintering characteristics of metal materials, stainless steel 17-4PH which can be precipitated and hardened at a lower temperature is selected to avoid the deformation after heat treatment and observe the actual situation.
Therefore, with the help of our company’s long-term production experience in the field of machining spur gear products, carry out pilot experiments and take effective measures to improve the distortion of spur gear thickness direction.