Research on mechanism of ultrasonic-assisted nano-cutting of sapphire based on molecular dynamics

Ultrasonic vibration grinding improves the surface quality and processing efficiency of sapphire machining compared with conventional grinding, but its nano-scale deformation mechanism is still unclear. In this study, the molecular dynamics method was used to simulate the ultrasonic vibration cutting of a single abrasive grain along the [1¯010] direction on the sapphire (0001) surface to study the effects of different vibration directions, amplitudes and frequencies on the cutting force, stress, temperature, number of amorphous atoms, surface morphology and subsurface damage layer. The results show that the tangential and radial vibration cutting reduces the tangential force, normal force and total force compared with conventional cutting. At the same time, it is also found that different vibration directions have different effects on material removal efficiency and subsurface damage depth. In the material removal efficiency, the radial vibration cutting has the highest removal efficiency, and the tangential vibration cutting and conventional cutting have the same removal efficiency. In the subsurface damage depth, the subsurface damage depth in tangential vibration cutting is the smallest, the subsurface damage depth in conventional cutting is the second, and the subsurface damage depth in radial vibration cutting is the largest.