OBRABOTKAMETALLOV Vol. 27 No. 3 2025 technology Vibration characteristics, as exemplified by the tool holder assembly, exhibit a broadband signal. Analysis of the low-frequency range shows that three main frequencies can be distinguished in the vibration spectrum of the tool holder assembly. The first of these coincides with the frequency of the spindle assembly vibrations. The others, including those in the mid-frequency range, are components of kinematic disturbances. Based on the data obtained, the dynamics of the cutting process were simulated, taking into account the influence of vibration disturbances (1) [29]. Examples of cutting force dynamics for different cutting speeds are shown in Fig. 3. The range includes both speeds used in full-scale experiments on the machine: V = 216 m/min, V = 270 m/min, V = 343 m/min, and intermediate values obtained by simulation digital modeling. Regarding the cutting process power indicator dynamics, the upper limit of the optimal workpiece spindle speed range will be values below the first frequency component of kinematic disturbances (12.5 Hz (Fig. 2)), i.e., n < 700 rpm or V < 252 m/min. Spindle speeds n = 800 rpm (V = 270 m/min) and n = 930 rpm (V = 318 m/min) can be used as processing parameters, provided that the part rotation frequency remains constant, since variations in the rotation frequency of the workpiece by 1 Hz can lead to a significant deterioration in the dynamics of the cutting process (Fig. 3). In this case, small variations in the cutting parameters in the quasi-stable parameter zone (V = 343 m/min) correspond to significant variations in cutting forces, exceeding the variations of similar parameters at V = 216 m/min and V = 270 m/min by 1.6 to 2 times. The results of modeling variations in three cutting parameters using the example of processing speed within the optimal range (216.5 m/min) and beyond it (343.6 m/min) in terms of minimizing variations in the cut-off layer are shown in Fig. 4, a, b. It is worth noting the effect of suppression of high-frequency components of disturbances from the spindle assembly and the establishment of natural vibrations of the cutting system at V = 343.6 m/min, while kinematic disturbances from the tool holder assembly continue to disturb the trajectory of the tool in the longitudinal direction, which leads to variations in the area of the cut-off layer. a b Fig. 2. Example of processed data for tool oscillatory velocity in the longitudinal direction: a – time-domain signal; b – amplitude spectrum of oscillatory velocity in mid-frequency and low-frequency range
RkJQdWJsaXNoZXIy MTk0ODM1