Evaluation of temperature, force, and chip formation in orthogonal turning of leaded brass

Abstract

The primary purpose of this research was to investigate the role of lead inclusions in leaded brass or free-machining brass on chip temperatures, cutting force, feed force and deformed chip thickness. The experiment was conducted by performing an orthogonal turning on the leaded brass and measuring the cutting force, feed force and deformed chip thickness while varying the cutting speed, feed rate and depth of cut. The machining conditions were varied at several levels according to the factorial experiment of the statistical design of experiments. Calculation of temperatures formed in the primary and secondary deformation zones of chip formation predicted that temperatures exceeded the melting point of lead at the highest speed. Examination of the surfaces of the chips under a scanning electron microscope showed evidence of melted lead. The amount of melted lead was not sufficient to conclusively support the temperature calculations. The relationships among the cutting force, feed force and cutting conditions are best described by the power law model as a function of feed rate and depth of cut. In terms of deformed chip thickness, the linear model as a function of cutting speed, and feed rate best characterizes cutting relationships.