New developments and applications based on a numerical model for the optimisation of the centred gear skiving process

Gear skiving, known for its high productivity in manufacturing internal gears, has become increasingly popular. Due to complexities including tool profile calculation, kinematics, and variable cutting conditions, and its relatively recent adoption, there is still a lack of in-depth knowledge about the process. Consequently, gear practitioners often rely on their own experience when developing new cutting strategies to mitigate specific process issues and reduce tool wear. The initial focus of this work is on a thorough literature review of the research and development activities related to gear skiving that was previously missing. Then, a numerical program for the geometric simulation of the process has been developed, enabling analysis of the interplay between setup parameters, and cutting conditions. The simulation has led to new insights and cutting strategies that reduce cumulative machined total cutting length, while keeping the cycle time unchanged or reduced, without significantly impacting the tool load. Experimental tests on annealed steel gears have confirmed that these strategies can reduce tool wear by up to 50%. Furthermore, the novel numerical program has been developed to assess the impact of re-sharpening conical tools on the process. Re-sharpening alters tip diameter and profile of conical tools, affecting cutting performance over their service life. The study identifies tools sensitive to this phenomenon and introduces a strategy to minimize performance variations, validated by experiments. Finally, this work introduces a novel design methodology for skiving tools using screw theory, a concept previously unexplored in skiving literature. Unlike traditional experience-based design methods, this approach selects the number of teeth, helix angle, and tip diameter based on qualitative indices to enhance tool productivity and cutting conditions. New equations for the tool operating pitch diameter are derived, providing insights into the implications of tip diameter on the full process. While still under investigation, this methodology shows promise.