The assessment of plastic deformation in metal cutting

Because plastic deformation is a nuisance in the metal cutting process, its proper account is of high interest. A new meaning for the chip compression ratio is discussed showing that, on the contrary to shear strain, this parameter represents the true plastic deformation in metal cutting. The chip compression ratio can be used to calculate the total work done by the external force applied to the tool and then might be used for optimization of the cutting process. It is demonstrated that the cutting speed influences the energy spent on the deformation of the chip through temperature, dimensions of the deformation zone adjacent to the cutting edge and velocity of deformation. The separate impacts of these factors have been analyzed and the physical background behind the known experimental dependence of the chip compression ratio on the cutting speed is revealed. The influence of the cutting feed, tool cutting edge angle, cutting edge inclination angle and tool rake angle have also been analyzed.