OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 6 2 4 For a qualitative assessment of the reliability of the model characteristics, fig. 5, a shows its comparison with the results obtained during the final real experiments aimed at verifying the adequacy of the proposed method. It is possible to observe a significant influence of feed changes on the character of vibrations and the stability of the cutting process (Fig. 5, b), which in turn also leads to a decrease in the quality of the workpiece surface [32]. This follows naturally from equation (4), the development of which demonstrates that feed variations in the direction X2 directly affect the motion of the tool in a direction X1 that takes into account the surface irregularities left by the tool. In addition, in the experimental characteristics of tool vibrations it is found that in the direction X2 with increasing feed rate new frequency components appear in the region of 165 Hz, this is due to the increase in cutting forces along the auxiliary flank of the tool, which can also lead to undulations of the workpiece surface. The evaluation of this effect has an independent value. a b Fig. 5. Example of changes in cutting characteristics at tp (0) = 0.5 mm; V 3 (0) = 190 m/min: a – data obtained during the experiment Exp.Fi and on the basis of simulation modelling Model.Fi, i = 1,2,3; b – values of vibration acceleration amplitude during cutting for directions X1, X2, X3 In the third stage of the method under consideration, we consider the “skeletal” geometry of the part surface modelled by the digital model in the radial direction, i.e. for the height characteristics of the surface quality (Fig. 6), and the reconstructed geometrical topologies of the part surface for the final experiment. The “skeletal” surface topology is understood as a set of deviations of the observed topology, i.e. caused by vibratory tool displacements, from the reference topology formed by the geometric tool trace on the cutting surface without taking into account perturbations and tool deformation displacements L(U) ⸦ (0). As can be seen, the surfaces reconstructed on the basis of experimental data on the tool deformation displacements during cutting 1 and 3 (Fig. 6) show not only the successive passes of the cutting tool
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