Grinding temperature within contact arc between wheel and workpiece in high-efficiency grinding of ultrahard cutting tool materials

This paper describes the grinding temperature characteristics during creep-feed grinding of cermet (Ti(C,N) alloy), which shows extreme difficulty in grinding. Creep-feed grinding is one of the high-efficiency grinding methods, and has inherent thermal problems because there is a long contact arc between wheel and workpiece. Furthermore, as cermet has low thermal conductivity, the grinding temperature tends to rise dramatically. Therefore, measurements of the grinding temperature distribution within the contact arc were made using a thermocouple method. Changes in the temperature distribution during grinding were also examined. It was found that when the grinding temperature within the contact arc reaches 150 °C or more, burnout occurs and the temperature suddenly increases to over 400 °C. The burnout starts from the rear of the contact arc and extends almost throughout the contact arc as grinding progresses. In other words, even if grinding fluid is being supplied, a phenomenon similar to dry grinding occurs in the contact arc in such circumstances. The optimum conditions of wheel and worktable speed were found in order to improve the cooling effects.