A) When the output shaft diameter of No. 1, No. 2 and No. 3 main bodies is between 018.028, the reducer main bodies are all made of aluminum alloy ad012. When the output shaft diameter of 4, 5 and 6 main bodies is between 032.050, the reducer main bodies are made of cast iron F020. B) The 1/2/3 gear is processed by precision hobbing, and the gear processing accuracy grade is 2.3. The gear is made of 20CrMo and tempered to h4c21., Then it is subject to high frequency heat treatment to hr040.43.