Enhancing Tool Life in High-Speed Machining of Compacted Graphite Iron (CGI) Using Controlled Modulation

The application of controlled, low-frequency modulation superimposed onto the cutting process—modulation-assisted machining (MAM)—is shown to be quite effective in reducing the wear of cubic boron nitride (CBN) tools when machining compacted graphite iron (CGI) at high machining speeds (>500 m/min). The tool life is at least one order of magnitude greater than that in conventional machining. The improvement in wear performance is a consequence of a reduction in the severity of the tool–work contact conditions in MAM: reduction in intimacy of the contact, formation of discrete chips, enhanced fluid action, and lower cutting temperatures. The propensity for thermochemical wear of CBN, the principal wear mode at high speeds in CGI machining, is thus reduced. The MAM configuration employing feed-direction modulation appears feasible for implementation at high speeds and offers a potential solution to this challenging class of industrial machining applications.