Analysis of surface and subsurface damage of micro-ground BK7 glass using on machine fabricated PCD micro-tool

Abstract

This paper presents the research results of the morphology of subsurface damage (SSD) in BK7 glass ground with on-machine fabricated PCD micro tool. Grinding generated damages are assessed and characterised using bonding interface sectioning technique combined with field emission scanning electron microscopy (FESEM). Both the damage depth and surface roughness are found to be influenced by the depth of cut, feed rate and spindle speed. Two major type of grinding damage have been identified likely chipping damage and micro-cracking damage. Lateral, median and cone cracks are found to be existed in the sub-surface. These crack size varies from below to above 1 μm. The mechanism of damage nucleation and propagation are discussed also. Although the machined surface seems to show ductile mode behaviour even at higher material removal, analysis of subsurface damage shows that the material removal is a combined effect of grain dislodgement, micro-cracking and plastic deformation.