Y3150 gear hobbing machine is selected as the experimental equipment, 6542 tungsten molybdenum high-speed steel, class a gear hob with modulus of 2 and pressure angle of 20 ° is selected as the cutting tool, and 20CrMnTi material with good impact toughness and high hardenability is selected as the gear blank. In order to ensure the unity of processing parameters, nine 20CrMnTi gear hobbing specimens are selected and divided into three groups. The rake face roughness Ra is 3.2 μ m、1． 6 μ m、0． 8 μ M, the hobbing speed VC is 35 m / min and the feed rate f is 2.0mm/r. The hobbing experiment is carried out, as shown in Fig. 1. After machining, measure the tooth surface roughness value.

Draw the box line through the experimental data, as shown in Figure 2. It can be seen from the figure that the quality of hob rake face has a great impact on the surface roughness of gear hobbing, and the rake face roughness Ra is 0.8 μ The surface quality of gear hobbing machined with hob of M is better than that of rake face, and the roughness Ra is 3.2 μ M hob. According to the measurement results, the smaller the roughness value of the hob rake face, the better the surface quality of the gear hobbing specimen. Therefore, in hobbing processing, higher gear hobbing surface quality can be obtained by controlling the roughness of the hob rake face.