Investigation of the influence of process parameters and cutting tool material on the tool wear in hard skiving of internal gears

Hard finishing of gears is an essential step in gear manufacturing to correct distortions caused by heat treatment, particularly in view of the increasing demands for low-noise gearboxes driven by automotive electrification. While external gears are commonly hard finished, hard finishing of internal gears is often avoided due to technical or economic limitations. Hard skiving offers a productive and efficient option for gear hard machining, but limited tool life currently restricts its use to small and medium batch sizes. In this study, the tool wear in hard skiving of internal gears was investigated using three cutting tool materials (cemented carbide RC26 and two PCBN grades CB35 and CB83). The axial feed fa and the cutting depth ap were varied as well, each in three levels, to investigate their influence on tool wear. The results show that cemented carbide RC26 exhibited the longest tool life for most process parameters investigated, with the best performance of this cutting tool material achieved at an axial feed of fa = 0.25 mm and a cutting depth of ap = 0.15 mm. In contrast, PCBN presented challenges due to its high brittleness, which made it more susceptible to chipping under certain cutting conditions. These findings provide a basis for further investigations, particularly exploring a wider range of process parameters and cutting material combinations.