Abstract
Heat generated in the cutting zone during metal cutting has an undeniable controlling influence on the dimensional accuracy of the workpiece and tool life. The heat dissipation process in the cutting zone is critical to the type of metalworking fluid (MWF) used and the way it is delivered to the cutting zone. Although extended studies have analyzed the thermal aspect of the machining process, few, if any, have incorporated the influence of the delivery method (application) of the MWF on the convective heat transfer process. In this paper, a comprehensive approach analysis was taken to assess the heat generation in the cutting process. Analytical models were developed to estimate the amount of heat generated in the shear zone and the heat partition in the shear plane during the milling process. In addition, the heat transfer coefficients of metalworking fluids during flooding, minimum quantity lubrication (MQL), and through-spindle cooling (TSC) strategies were evaluated. Regarding MQL, the determination of heat transfer coefficients of metalworking fluids involves the use of a homogeneous single-phase flow assumption of the two fluids (air and lubricant). Next, the average temperature change in the workpiece was estimated by considering the conductive and convective heat transfer coefficients of the workpiece and fluids. Finally, the analytical models of the temperature change in the workpiece were experimentally validated against workpiece-embedded thermocouple measurements. It was found that the results of the models show good agreement with the experimental results.