Wear mechanism analysis and its effect on the cutting process of CBN tools during laser ultrasonically assisted turning of tungsten carbide

Tungsten carbide, known for its high hardness and brittleness, presents a challenge in traditional processes due to severe tool wear and shortened tool life, impacting machining efficiency. This paper introduces a hybrid turning method – laser ultrasonically assisted turning (LUAT) – for precision and efficient machining of tungsten carbide. LUAT combines tool ultrasonic vibration with laser-induced workpiece heating to enhance the cutting performance of tungsten carbide. Thermal modeling is utilized to determine suitable LUAT parameters. Comparative experiments are conducted to assess the advantages of LUAT in enhancing tool performance and improving surface quality. Results indicate that, compared to traditional turning, ultrasonically assisted turning, and laser assisted turning, LUAT significantly reduces tool wear and enhances tool lifespan. In LUAT of tungsten carbide, the tool wear on the rake face exhibits long strips parallel to the tool edge, while the flank face presents triangular wear land, shallow pits, and grooves. Investigation into wear characteristics and mechanisms of cubic boron nitride (CBN) tools reveals that adhesion, oxidation, and diffusion are major wear factors, with chipping and tipping being abnormal wear patterns for CBN tools. Intensified tool wear elevates cutting forces and cutting temperatures, deteriorating the surface quality of tungsten carbide turning. However, LUAT mitigates these effects, resulting in lower cutting forces and temperatures within the same wear time, improving surface quality.