Single-point diamond machining of glasses

A machine tool of very high stiffness has been constructed and used for single-point diamond grooving of blanks of soda-lime glass and optical glassy quartz. Results show that below a critical depth of cut predicted in order of magnitude by a fracture mechanics analysis, material is removed by the action of plastic flow, leaving crack-free surfaces. Subsequent observations by scanning electron microscopy indicate that a crucial part in the detachment of ribbons of swarf is played by the operation of residual stresses after the passage of the tool, particularly in the case of the amorphous ceramic.