Technological dynamics of non-stationary systems during finishing intermittent cutting.
DOI:
https://doi.org/10.15276/opu.2.70.2024.01Keywords:
unsteady technological system, intermittent cutting, parametric oscillations, stability, resonanceAbstract
In this work the stability and peculiarities of oscillations of unsteady technological systems during finishing boring in complex cutting modes - machining of discontinuous surfaces or deep holes of small diameter, etc. are studied. In mechanical engineering technology such operations are performed quite often, and with ever-increasing requirements for machining accuracy. It is clear that in the first case periodically repeated transient processes of tool plunging and tool exit cause impact effects on the cutter, which leads to chipping of cutting edges, increased wear and negatively affects the output machining accuracy. The elastic-dissipative-inertial system (EDIS) closed to the cutting process becomes unsteady not only due to the interruption of links, but also due to the periodic change of parameters. In this case, dynamic models are described by differential equations with variable coefficients. Systems with periodically changing parameters are called nonstationary, and oscillations are called parametric. In modern engineering technology, many problems arise in which dynamic factors dominate. Parametric oscillations are described by Mathieu equations, which reflect complex dynamic processes such as resonances and auto oscillations. Experiments were carried out on the bench to study oscillations during boring of steel, cast iron and bronze specimens with interrupted surfaces, with the number of interruptions per revolution varying from 1 to 20. The character of oscillations is established and the conditions of stability of solutions on the Ains-Strett diagram are reflected. A methodology of constructing time forms of oscillations has been developed, which makes it possible to predict amplitudes, frequencies and resonance phenomena in intermittent cutting.
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