A new approach to the prediction of temperature of the workpiece of face milling operations of Ti-6Al-4V

The machining of titanium alloys is critical because of high temperature reached at the tool nose, the segmentation of chip that causes chipping of the tool. The strategy used in the job shop is to use low cutting speed (50-70 m/min) and high feed rate (0.1-0.2 mm/tooth) in flooding condition in order to reduce the tool temperature and avoiding chipping. The edge preparation and the coating play an important role from thermal point of view. In particular a right compromise between sharp edge and the needs of the coating has to be taken into account. A reliable thermal model of cutting process of titanium alloy is useful in order to design the cutting edge, calculate the optimal quantity of coolant, and analyze the effect of the coatings. In this paper a new methodology to the temperature prediction of milling is proposed. The temperature of the workpiece, during the milling operation, has been measured using infrared camera. During the experiments cutting speed and feed rate have been changed. After data analysis a FEM model of cutting process during milling has been developed. The rheological model is calibrated using different milling tests. The results of the model have been compared with the experimental data, obtaining a good agreement. The approach can be useful to the insert tool designer in order to improve the cutting tool performance. (C) 2010 Elsevier Ltd. All rights reserved.