Experimental investigation of machinability in laser-assisted machining of fused silica

摘要

Fused silica is difficult to machine through conventional machining at room temperature, mainly due to high brittleness, low fracture toughness, high strength, and poor plastic deformation. In this study, we demonstrated experimentally that we are able to machine fused silica with improved efficiency and precision with laser-assisted machining (LAM) by heating workpiece locally in front of the cutting tool utilized a pulse CO2 laser beam. Then, the machinability of fused silica was evaluated. The surface roughness tests with a Taguchi orthogonal array indicated that the pulse duty ratio was the main factor for a minimum Ra value achievement. The experimental results demonstrated a considerable improvement in the machinability of fused silica through the improved surface quality, high material removal rate, low rate of tool wear, as well as the cutting force reduction. The material removal mechanism was a hybrid of quasi plastic deformation and brittle fracture during the LAM of fused silica, which was inferred from the machined surface quality and chip morphology changes compared to the conventional machining.