Evaluation of the influence of the reaction rate of the thermodynamic subsystem on the dynamics of the cutting process in metalworking

OBRABOTKAMETALLOV Vol. 23 No. 2 2021 TECHNOLOGY a b Fig. 10. Machine with equipment ( a ), measuring complex on the tool ( b ) a b Fig. 11. Pre-burn tool ( a ), tool with a formed back face ( b ) As can be seen from fi gure 10, the experimental tool contains three vibration accelerometers and an arti fi cial thermocouple built into the wedge in the immediate vicinity of the contact zone of the back face of the tool with the work piece. To embed the thermocouple in the wedge, it was previously cut by the method of electroerosive metal cutting, in the prepared hole the thermocouple is fi xed with hot glue. During the experiment, a part made of round rolled steel (45 steel) with a diameter of 50 mm was processed, the spindle speed was 810 rpm, the cutting depth was 1 mm, and the feed was 0.11 mm/rev. Photos of the back surface of the instrument under a microscope are shown in fi gure 11. As can be seen from fi gure 11, the experiment was carried out until the tool wear area was formed along the back face (see Figure 11 (b)), at which, according to the approach proposed in this paper, a value of the time constant TQ is formed at which the turning process is stabilized. When the cutting process is stabilized, the SCR (root mean square value) of the signals taken from the vibration accelerometers installed along the axes of the tool deformation decreases sharply, but the most obvious reduction in the vibration load can be seen on the surface of the processed part, the photo of which is shown in fi gure 12. As can be seen from fi gure 12, the area of stabilization of the vibration activity of the tool is visually observed on the processed part, after which the quality of the processed surface is signi fi cantly improved. To understand the relationship between the time constant of the thermodynamic subsystem of the cutting