On the interrelationships of some machinability parameters in finish turning with cermet chip forming tool inserts

This paper presents results of an experimental study on finish turning of steels with cermet chip forming tool inserts. Three major machinability parameters were investigated: chip breakability; surface roughness; and specific cutting pressure. The interrelationships among these three parameters were established with a view to developing methodologies for optimum solutions in finish turning operations. The basic analysis presented in the paper includes a new method for determining the chip breakability level and the achievable surface roughness (R_a) for a given chip groove, work material and a set of cutting conditions (feed, depth of cut and cutting speed). Based on this analysis, the paper proposes the need for establishing a "total machinability" assessment criterion for optimum machining performance of a "cutting tool-work material-machine tool" system.