Experimental analysis and evaluation of the cutting performance of tools in laser-assisted machining of fused silica

Abstract

Laser-assisted machining (LAM) is an effective and economical technique for the machining of fused silica. This study describes the cutting performance of three different cutting tools in the LAM of fused silica based on the Taguchi method, polycrystalline diamond tool (PCD), polycrystalline cubic boron nitride tool (PCBN) and TiN-coated Al2O3/TiC ceramic tool. The optimal parametric combinations of the three cutting tools were characterized through machined surface roughness using analysis of variance (ANOVA) and the signal-to-noise ratio (S/N ratio). The statistical results show that the PCD tool can get better surface roughness and smaller cutting force compared with PCBN tool and coated ceramic tool in LAM of fused silica. In addition, the machined surface morphology obtained by the PCD tool is smooth, and its chips are predominantly semi-continuous chips which are beneficial, in contrast with the fracture chips obtained by the PCBN and coated ceramic tools. In LAM of fused silica, the dominant wear zone on the tool is flank surface with abrasion and adhesion wear. The wear mechanism of the three cutting tools is illustrated by SEM and EDS analysis. The high strength of PCD for cutting is retained even in the presence of carburization which leads to its less tool wear.