Comparison between Numerical Simulations and Experiments for Single Point Diamond Turning of Silicon Carbide

Single Point Diamond Turning (SPDT) experiments conducted on single crystal 6-H Silicon Carbide (SiC) has shown chip formation similar to that seen in the machining of metals. The ductile nature of SiC is believed to be the result of a high pressure phase transformation (HPPT), which generates a plastic zone of material that behaves in a metallic manner. This metallic behavior is the basis for using AdvantEdge, a metal machining simulation software, for comparison to experimental results. Simulations (2-D) were carried out by matching the SPDT experimental conditions, conducted at nanometer (nm) depths of cut and varying tool rake angles. The experiments were performed by machining the circumference of the single crystal wafer, thereby conforming to a 2-D orthogonal cut. The cutting and thrust forces generated from the experiments under ductile cutting conditions compared favorably with the simulation. As the depth of cut is decreased (250 nm, 100 nm, and 50 nm), the experimental conditions transition from a brittle to ductile environment, with the 50 nm cuts being dominated by ductile events.