Abstract
This paper presents distinct element simulation of both conventional and laser assisted machining (LAM) of silicon nitride ceramics. A silicon nitride ceramic material was modeled using bonded particles. The effect of laser heating was translated to the property changes for the ceramic material. It was found that the chip formation process during machining of ceramics begins with cracks that initiate close to the tool tip and propagate into the workpiece. Some of the cracks move upwards to reach the surface to form segmented chips of various sizes. Subsurface damage occurs on the machined part. The damage zone is significantly reduced with laser heating because it promotes shear-induced plastic flow during material removal. Cutting force is much lower in LAM than in conventional machining due to the reduction in material strength with laser heating. The simulation results appear to be consistent with experimental observations in ceramic machining.
