Behavior of various cracks in the machining of glass

摘要

Today, high quality free-from-crack surfaces of brittle materials are expected to be machined by ductile mode chip formation. Firstly, abrasions and cracks formed on or beneath the machined surface were observed through turning tests with diamond cutting tools and it was discussed that the crack-free machining of glass would be possible. Secondly, the turning tests of glass with single crystal diamond conical indenters, tip radius of which are 5, 10 and 100 $mu@m respectively, were performed for the purpose of investigating the criteria for crack- free chip formation, especially paying attention to the effect of indenter's tip radius. As a result, some crack-free grooves formed on the glass surface were observed, and it was concluded that one of the most important factors for ductile mode chip formation is the radius of tip curvature and suppression of a median crack.