OBRABOTKAMETALLOV technology Vol. 27 No. 3 2025 Fig. 3. Modeling of cutting forces along X, Y, Z directions for s = 0.198 rpm, t = 0.5 mm over the spindle speed range V = 216–343 m/min Periodic changes in the area of the cut-off layer due to fluctuations in cutting conditions (V, s, t) relative to their nominal values cause periodic variations in cutting forces, which lead to periodic changes in chip pressure on the tool rake face. In fact, there is a periodic restructuring of the functioning of the “chip-rake face” tribosystem, the characteristics of which directly affect the temperature change in the cutting zone. In this case, a complex relationship is formed between mechanical and thermodynamic processes, which is determined not only by the characteristics of the interacting subsystems of the mechanical part but also by tribophysical phenomena that affect the properties of the environment in the cutting zone. Although the formation of these relationships is caused by external disturbances originating from the mechanical systems of the machine tool, the thermodynamic state of the contact zone is more strongly influenced by the physical and mechanical properties of the tool and workpiece materials, which determine the characteristics of elastic-plastic deformation. Deformation processes at the points of contact between the chip and the front face of the tool are both a consequence of the dynamics of the cutting process and a source of new nonlinear transformations in the machining zone, including those affecting tool wear and the quality of the machined surface. This necessitates an analysis of the mutual influence of the mechanical and thermodynamic characteristics of the cutting process dynamics based on parameters that can be measured in the system. To evaluate the temperature change at the tool rake face due to variations in cutting modes and forces characteristic of each spindle speed, we will identify quasi-static instances in the system dynamics when the speed, feed, and cutting depth reach their extreme values as a result of fluctuations. For each of these time points, we will determine the values of the other two parameters of the machining modes and the values of the resultant cutting forces FXY at that moment (Table 1, 2, column 2–5). Based on the data obtained, the main tribological indicators (3) are calculated using Eq. 3, which determine the maximum temperature of the front edge Tmax, at the moments of extreme values of the parameters V, s, and t (Tables 1, 2, column 6–10). The deviations of the maximum surface temperature
RkJQdWJsaXNoZXIy MTk0ODM1