DUCTILE REGIME SINGLE POINT DIAMOND TURNING OF QUARTZ RESULTING IN AN IMPROVED AND DAMAGE-FREE SURFACE

Quartz (fused silica) is one of the advanced engineered ceramic materials designed to operate in extreme environments. The mechanics of material removal in glass (Quartz) can be classified into two categories; brittle fracture and ductile plastic deformation. Good optical quality surfaces can be achieved by removing the material in a ductile manner. The strength, hardness and fracture toughness of the workpiece material are the governing factors that control the extent of brittle fracture. The main goal of the subject research is to improve the surface quality of Quartz to be used as an optic device (mirrors and windows) via single point diamond turning (SPDT). Sub-surface damage analysis was carried out on the machined sample using Scanning Acoustic Microscopy (SAcM). Surface roughness (Ra) values of less than 45 nm without sub surface damage were obtained. Tool wear was also investigated.