Abstract
Some basic issues in the theory of metal cutting are analyzed in the earlier part of this paper. Several controversial subjects are clarified by the experimental results presented. The remainder of the paper describes a further attempt to ascertain the effect of cutting speed and feed on the mechanism of chip formation in high-speed machining operations. A differential equation of the temperature field in the chip as well as that in the workpiece has been set up, and the nature of the solution studied. It has been found that the temperature distribution both in the work material and in the deformed chip in the immediate vicinity of the tool-chip interface depends upon a dimensionless number which is expressible as the ratio of the product of the cutting speed and feed to the thermal diffusivity of the metal cut. This ratio is called the thermal number, and its significance in metal cutting is illustrated and the limitations discussed.
