Insights into scratching force in axial ultrasonic vibration-assisted single grain scratching

Ultrasonic vibration-assisted grinding is typically used for ultra-precision machining of hard and brittle materials in aerospace, medical and semiconductor industry. Single grain scratching force is a key to understand its mechanism. Herein, a scratching force model of axial ultrasonic vibration-assisted single-grain scratching was proposed, based on the deformation of chips, friction, and material pile-up forces of a single grain during scratching. The single-crystal silicon carbide was selected as the model material. The molecular dynamics method was employed to simulate single-grain scratching. The scratching forces obtained from the simulations were consistent with the theoretical model with a difference of 4.13 %. The period of the normal force and tangential force is half of that of the vibration and the axial force. The discrepancies are 11.26 % and 4.05 % in tangential and normal directions, respectively, referring to experiment. Axial ultrasonic vibration-assisted scratching facilitates the cyclical removal of brittle and ductile phases, which corroborates the conclusion about the periodicity of the force. Our insights might be helpful in the arrangement of grains on the surface of the grinding wheel and advanced machining design.