Actual Problems in Machine Building. Vol. 10. N 1-2. 2023 Innovative Technologies in Mechanical Engineering ____________________________________________________________________ 8 technology to measure temperature in tests on cast iron and aluminium using WC instruments [6]. Kitagawa and others are using inline thermocouple technology to investigate the effect of cutting temperature on tool wear in high-speed machining of Inconel 718 and grinding of Ti-6Al-6V-2Sn alloy [7]. Another main way to measure cutting temperature is the use of infrared thermal cameras or pyrometers [8, 9], but these methods have a drawback — this is the limited penetrating ability of the camera. In 1940 M.P. Levitsky excluded from consideration the heat entering the material being processed, assuming that only the cutter and chips are involved in the heat exchange. Levitsky considered the work of deformation and the work of chip friction against the front surface of the cutter to be sources of heat generation. American scientists Trigger and B.Ts. Chao conducted analytical studies of temperatures at the contact surfaces of the tool with chips and with the material being machined, gradually improving the approaches to calculations. In 1951 they published a paper called ―An Analytical Evaluation of Metal Cutting Temperatures‖. The researchers took into account two sources of heat release (plastic shear and friction of chips on the front surface of the cutter), neglecting the heat of friction on the back surface of the tool. Using force and speed ratios developed by G. Ernst and M. Merchant [7], Chao and Trigger received formula (1) for calculating the average temperature θS chips leaving the shear zone: (1) where θO is the ambient temperature; А is a part of the deformation energy that is spent on chip heating; B1 is the part of the total heat remaining in the workpiece; J is the mechanical equivalent of heat; C is the specific heat capacity of the heated chips; ρ is the density of the chip material; t is the feed; w is the depth of cut; Formula (2) for calculating cutting temperature: (2) In subsequent work, the researchers analyzed the effect of temperature on the wear of the cutter along the front surface, making the appropriate temperature calculations. To simplify the calculations, Chao and Trigger assumed a uniform distribution of the heat release intensity q (Fig. 1a, straight line 3) along the length of the chip-cutter contact. This led to the fact that the highest temperature turned out to be near the departure of the chip from the cutter (Fig. 1a, curve 1), which did not correspond to the position of the wear hole on its front surface. By specifying the heat flux power distribution in the form of curve 5 (Fig. 1b), the researchers obtained a more satisfactory agreement between the temperatures calculated from the side of the chip and the cutter (curves 4 and 1).
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