Tool Face Temperatures in High Speed Milling

Abstract

While it is now generally understood that in continuous chip forming processes such as turning, there is no magic high speed above which tool temperature decreases and tool life increases with increased cutting speed. However, it has been suggested that this may not be the case in intermittent cutting operations such as face milling. It is argued that in such an operation, the tool temperature oscillates between an ambient value at the beginning of a cut and a maximum value at the end of a cut. As cutting speed is increased, the cutting time per cut will decrease and hence the fractional approach to the equilibrium value. Thus, even though the equilibrium temperature will increase with cutting speed, it is conceivable that the maximum temperature at the end of a cut will decrease. This possibility has been tested experimentally using the chip-tool thermocouple technique to record temperature vs time curves for a variety of cutting conditions. In no case was the exit temperature found to decrease with increase in cutting speed.