Process parameter determination of the axial-pushed incremental rolling process of spline shaft

The process parameters of the axial-pushed incremental rolling process are studied in this paper to solve the problems in present production process of spline shaft. Firstly, the principle of the axial-pushed incremental rolling process is introduced. Based on the material of 42CrMo, the simplified finite element models of the process are established up. Then, the effects of process parameters and the material flow behavior during the process are investigated by finite element analysis (FEA). After that, the reasonable process parameters during the novel process (die angle 9°, feed speed 0.5 mm s⁻¹, and speed of rolling die 25 r min⁻¹) are determined to meet a good balance between the forming force, product precision, and processing efficiency. To verify the determined parameters, validation tests with the blank material 42CrMo were carried out on an axial-pushed incremental rolling equipment. The experimental results (tooth shape and forming force) show a good agreement with FEA results. Through the dimension measurement, the addendum and root circle diameters of formed spline shafts are 51.61, 51.72, and 51.66 mm and 48.66, 48.78, and 48.69 mm, respectively. The formed spline shafts with the determined process parameters reach to the requirement of direct use (required addendum circle diameter 51.56~51.75 mm, required root circle diameter 48.5~48.7 mm). Finally, the feasibility of the determined process parameters with other materials (no. 20 and no. 45 steel) is investigated. The dimensions of the formed spline shafts just slightly deviate from the theoretical value. This problem is solved by adjusting the feed speed and the speed of rolling die. Therefore, the determined process parameters of the axial-pushed incremental rolling process are usable for the production of spline shaft.