A grinding force model in two-dimensional ultrasonic-assisted grinding of silicon carbide

Ultrasonic-assisted grinding (UAG) is a suitable machining solution for hard and brittle materials, effectively reducing cutting forces and improving the machined surface quality. With the development of UAG system, multi-dimensional vibration devices have emerged and been applied in the machining of advanced materials. In this study, a discrete numerical model is proposed for two-dimensional ultrasonic-assisted grinding (2D-UAG) of silicon carbide (SiC) to describe the dynamic cutting behaviors and a grinding force model considering the material removal mechanism is further established. In the model development, the three-dimensional surface topography of grinding wheel is simulated and adopted to determine the cutting state of individual grit. Meanwhile, a workpiece profile update procedure and a novel approach to realize the decomposition and synthesis of grinding forces are proposed. Experimental validation demonstrates that the prediction error of this proposed model is limited within 11.14% with an average value of 8.16% under conventional machining parameters. Furthermore, the tool amplitude and workpiece amplitude affect the grinding force in a similar manner. As the ultrasonic amplitude increases from 1 µm to 9 µm, the grinding force declines first and then goes up and the inflection point appears around 5 µm. The inherent characteristics of grinding forces in 2D-UAG of hard and brittle materials can be explained by obtaining the variation trends of the average cutting depth of individual grit and the number of active grains. The modeling methodology presented in this study provides a reference for studying the 2D-UAG process of brittle materials.