Tool wear development in gear skiving process of quenched and tempered internal gears

Gear skiving is a highly productive machining process, especially for manufacturing of high strength internal gears as required for high performance electric drive trains. However, the complex process kinematics cause intense variations of the effective cutting parameters during tool engagement. Thus, particularly the tool must meet high requirements to achieve long tool life at required workpiece quality. These requirements are amplified even more when machining quenched and tempered materials from the massive blank. In the presented study, the influence of various key factors on the tool wear development in gear skiving process are quantified. In several tests, the cutting speed, workpiece tensile strength, cooling lubricant strategy, as well as the cutting strategy are varied in order to optimize tool life. Therefore, single-tooth tests on quenched and tempered internal gears from 31CrMoV9 (AISI 4340) steel are conducted and wear flank land width evolution of the tools is examined. In addition, the workpiece is evaluated with regard to surface quality. Results reveal that different factor level combinations can have various effects on tool wear characteristics and therefore on tool life. The correlations presented provide recommendations for practical application and contribute to deeper process understanding.