Correlation between friction and wear of CBN cutting tools in precision hard machining

In this paper the contribution of tool wear to friction was determined for precision hard turning using CBN cutting tools. The tool nose wear VBC and the corresponding changes of component forces Fc, Ff and Fp resulting from tool wear evolution were continuously measured during wear tests. Based on the mechanics of non-orthogonal cutting the normal and friction forces acting on rake and flank faces were calculated for all measuring points and, as a result, relevant changes of the friction coefficient were determined. Additionally, friction variations due to tool wear under different cutting conditions including feed rate, depth of cut and tool nose radius were discussed in terms of the ploughing energy produced by the tool nose.