Experimental study of the temperature field generated during orthogonal machining of an aluminum alloy

During the machining of metals, plastic deformation and friction lead to the generation of heat in the workpiece, which results in thermomechanically coupled deformation. Recently, several numerical models of this highly coupled process have been produced in response to increased interest in high speed machining. It is important to characterize the thermal field in the cutting zone in order to completely verify these models of high speed machining and to direct further advancement in this area. In this work, HgCdTe infrared detectors are used to experimentally measure the temperature distribution at the surface of a workpiece during orthogonal cutting. From these temperature measurements, the heat generated in the primary shear zone and the friction zone can be examined and characterized. A modified Hopkinson bar technique has been developed to perform orthogonal machining at speeds ranging from 10 to 100 m/s. In the present work, a cutting velocity of 15 m/s is employed in all the tests in order to demonstrate the capability of the apparatus and characterize thermal fields during low speed machining. Temperature fields are obtained during the orthogonal cutting of aluminum as a function of depth of cut. It is seen that depth of cut can vary both the maximum temperature as well as the distribution of the temperature field in the aluminum workpiece. the maximum temperature increased with depth of cut (238°C for 1.5 mm cut, 207°C for 1.0 mm cut and 138°C for 0.5 mm cut) and the temperature field extended further beneath the cut surface with decreasing depth of cut.