OBRABOTKAMETALLOV Vol. 27 No. 3 2025 TEchNOLOgy Conclusion Based on the results of digital simulation modeling using data from real-life experiments, deviations of the contact temperature from the nominal value were determined for instances when one of the cutting parameters takes on an extreme value as a result of fluctuations. It was established that the combination of processing parameters at such moments generally leads to an instantaneous increase in the maximum temperature on the tool rake face, characterized by the concept of a thermal flash, but at the same time, for some combinations, a slight decrease in this indicator is possible. Within the range of parameters studied, the optimal cutting speed was identified, at which the output of all three processing parameters to extreme values leads to a minimal change in temperature on the rake face. It has also been established that this cutting speed is the boundary that divides the studied speed range into two intervals, differing in factors that destabilize the thermal state of the contact zone. When turning a workpiece at a speed below this limit, the greatest temperature deviations occur when the cutting depth and cutting speed reach extreme values. When the processing speed exceeds the optimal value, the main sources of contact temperature changes become the cutting depth and feed rate. Therefore, the factor limiting the productivity of the machining process in terms of minimizing temperature fluctuations is the variation in the area of the cut-off layer due to kinematic disturbances characteristic of the investigated cutting system at higher turning speeds. The research results presented in this paper can be used to select rational processing parameters, taking into account the kinematic disturbances of the machine tool support group and the thermodynamic state of the contact zone, which depends on their manifestations. The methodology allows evaluating and selecting technological parameters in which force fluctuations minimize possible impulse changes in the temperature of the tool rake face during dry turning. However, it is applicable only for operations that do not use coolant; in the case of the presented work, this was the operation of finishing turning a part of the “Connecting leg” type. The influence of coolant on pulsed heat release changes will be assessed in further studies. First and foremost, the presented methodology will be effective for machine tool fleets with medium and high degrees of wear, accelerating time-consuming tests to determine optimal operating modes when new tools are delivered. The use of temperature fluctuations caused by kinematic errors as an additional parameter for evaluating the optimality of cutting parameters in vibration monitoring and compensation systems can improve process stability and reduce the overall temperature in the cutting zone. Taking into account temperature changes calculated from the vibration activity signal of the tool is particularly relevant for metal-cutting machines with a long service life, which are characterized by significant periodic disturbances in the cutting system from the feed drives and the main drive. References 1. Komanduri R., Hou Z.B. Areview of the experimental techniques for the measurement of heat and temperatures generated in some manufacturing processes and tribology. Tribology International, 2001, vol. 34 (10), pp. 653–682. DOI: 10.1016/S0301-679X(01)00068-8. 2. Grzesik W. Experimental investigation of the cutting temperature when turning with coated indexable inserts. International Journal of Machine Tools and Manufacture, 1999, vol. 39 (3), pp. 355–369. DOI: 10.1016/S08906955(98)00044-3. 3. Sutter G., Faure L., MolinariA., Ranc N., PinaV.An experimental technique for the measurement of temperature fields for the orthogonal cutting in high speed machining. International Journal of Machine Tools and Manufacture, 2003, vol. 43 (7), pp. 671–678. DOI: 10.1016/S0890-6955(03)00037-3. 4. Shan C., Zhang X., Shen B., Zhang D. An improved analytical model of cutting temperature in orthogonal cutting of Ti6Al4V. Chinese Journal of Aeronautics, 2019, vol. 32 (3), pp. 759–769. DOI: 10.1016/j.cja.2018.12.001. 5. Barzegar Z., Ozlu E. Analytical prediction of cutting tool temperature distribution in orthogonal cutting including third deformation zone. Journal of Manufacturing Processes, 2021, vol. 67, pp. 325–344. DOI: 10.1016/j. jmapro.2021.05.003.
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