Experimental investigation on the ductile machinability of fused silica during in-situ laser assisted diamond cutting

Fused silica finds widespread applications in optical equipment; nevertheless, the machining of fused silica to obtain high-quality surfaces was a common problem in the industry. In-situ laser assisted diamond cutting (LADC) is a promising process for machining hard and brittle materials. In this study, systematic numerical analysis and experiments were conducted to investigate the ductile machinability of fused silica in in-situ LADC. The laser beam path and power density passing through the diamond tool were determined through optical simulation. The corresponding laser heating experiment of fused silica was carried out using the finite element (FE) simulation, aiming to derive the temperature distribution under different laser power levels. The comparison between the temperature values obtained experimentally and those predicted by the FE simulation confirmed the high accuracy of the developed FE model. The influence of laser power on the ductile machinability of fused silica was investigated quantitatively through grooving and end face turning experiments. The experimental results have shown that the ductility and machinability of fused silica under in-situ LADC were improved. With the laser assistance, the critical depth of cut (DOC) was increased up to 294.9 %, from 82.06 nm to 324.03 nm. Compared to conventional single point diamond turning, a significant improvement in the surface quality was obtained, resulting in the formation of a smooth and homogenous surface with a Sa of 19.4 nm for a laser power of 11 W.