Grindability of glass-inlaid zirconia for fibre-optic connectors

This paper reports on the grindability of glass-inlaid zirconia structure for fibre-optic connectors using metal-bonded diamond wheels with different grit sizes. The surface roughnesses of the glass fibre and zirconia ferrule were investigated as functions of diamond grit, grinding speed and feed rate. The results showed a distinct difference in responses for the two materials with respect to surface roughness and material removal. The combined structure was directly ground to obtain surface roughnesses Ra of the fibre and ferrule smaller than 30 and 90 nm respectively. The surface roughness values for the two materials both decreased with a decrease in diamond grit size, but the reduction in surface roughness for the fibre was not significant when the grit size was smaller than 15 Am. higher grinding speed did not always give a better surface finish for the two materials. The feed rate was crucial for material removal mechanisms in the grinding of the glass fibre–zirconia ferrule, especially in glass grinding where there was a critical threshold for a brittle– ductile transition.