An Analysis of the Mechanics of Metal Cutting

An attempt is made to go beyond an idealized description of the process of metal removal. The details of two-dimensional orthogonal cutting are investigated, and several concepts and hypotheses are introduced which apply equally well to the most general cutting operation. Of these, the most significant is the great importance of the small time available for the plastic deformation to occur. Ekstein's paradox is explained, and the influences of speed of cutting, depth of cut, and rake angle are correlated by the consideration of dynamic plasticity. In addition, the effect of non-homogeneity of the material is analyzed and shown to account for the gradual change from the discontinuous to the continuous type of chip as the cutting speed is increased, and for the marked increase in the specific cutting force as the depth of cut is decreased. A partial theoretical analysis of the state of stress, in the chip and the workpiece, and energy considerations are also found helpful in the description of what probably happens when metal is cut.