Numerical investigation of the evolution of grit fracture and its impact on cutting performance in single grit grinding

Abstract

The study of single grit grinding with different geometries is important for understanding the micro-cutting behavior and material removal mechanism during grinding. However, the geometry of the grit changes during the wear process. The most fatal wear form responsible for the change in geometry is grit fracture as it causes considerable material loss instantaneously. This paper presents a new method to simulate single grit grinding with the fracture wear effects incorporated. The simulation procedure consists of three phases. The grinding force is calculated in phase 1, the grit fracture wear is simulated in phase 2, and the geometry of the grit after fracture wear is updated in phase 3. The evolution of grit fracture and its impact on cutting performance are studied by recycling the simulation procedure until the grit wears out. The results obtained reveal that the fracture wear is primarily caused by the maximum tensile stress along the rake surface or inside the grit. The resultant grinding force fluctuates during the chip formation process and is controlled by the number of cutting edges and the effective area of the flank surface. It decreases rapidly at the initial wear stage and varies with the dulling and self-sharpening action induced by the fracture wear. The volume of grinding chip decreases with an increase in the number of micro-cutting edges, which may result from a decrease in the ploughing effect.