OBRABOTKAMETALLOV Vol. 25 No. 1 2023 technology Ta b l e 1 The boundary of the cutting system stability h3, mm 0.3 0.32 0.34 0.35 0.37 0.38 0.4 0.41 0.42 0.43 n, rev/m 300 340 400 440 500 600 660 700 760 820 h3, mm 0.436 0.44 0.445 0.4455 0.455 0.46 0.46 0.473 0.483 0.491 n, rev/m 880 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 As it can be seen from Figure 4, the hodograph of the Mikhailov vector touches the imaginary axis and returns back to the first quarter, if this characteristic crosses the imaginary axis and returns back, it will be the mechanism for displaying the loss of stability of the system. Subsequently, with the increase in the amount of the cutting wedge wear, this is exactly what happens. The results of all studies are summarized in one general table, which is given below. Graphically, the area of stable dynamics of the cutting process, corresponding to the data given in Table 1, is shown in Figure 5. n, rev/m h, mm The area of stable dynamics of the cutting system The area of unstable dynamics of the cutting system Fig. 5. Areas of stable and unstable behavior of the cutting system As shown by Figure 5, the stability limit of the cutting system tends to grow indefinitely, while there is no pronounced maximum of this characteristic. In other words, the area of stable dynamics of the cutting system does not have a local extremum that would reflect the maximum dimensional stability of the tool corresponding to the statement, put forward by A.D. Makarov. As the reason for such a strange behavior of the cutting control system, it can be indicated that the control system model given in this section does not actually include the structural adjustment of the force response, which is identified and described in [9]. To clarify this assumption, consider the variant of force responses at a cutting speed of 1,600 rpm, which are shown in Figure 6.
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