10.14489/td.2018.06.pp.056-063

2018, 06 June

DOI: 10.14489/td.2018.06.pp.056-063

Kozochkin M. P.
QUESTIONS OF TECHNICAL STABILITY OF THE CUTTING PROCESS
(pp. 56-63)

Abstract. When carrying out computational and experimental work to improve the vibration resistance of metal cutting machines, in most cases, it’s emphasized on satisfying the stability conditions in accordance with the requirements of the Lyapunov theory. It is demonstrated that these conditions are not enough to ensure surface quality, and that it is necessary to pay attention to the technical stability of the cutting process. In accordance with the Lagrange theorem, during the cutting process the tool is in nonequilibrium condition. The stability of its position is largely determined by the characteristics of the separated swarf and the amount of potential energy stored by the time the swarf elements are shifted. The decrease in potential energy is encouraged by increasing rigidity along all directions and rational arrangement of the main stiffeners relative to the cutting force vector. Improving the static rigidity of tools and workpieces does not guarantee compliance with the requirements of technical stability in finishing. This is due to the presence of high-frequency forms of oscillations, manifested when the swarf elements are shifted and its effect on the cutting tool is weakened. At these moments, these forms of vibrations tend to break the contact of the tool with the workpiece in the radial direction. An increase in the amplitude of oscillations in directions other than tangential leads to a loss of the technical stability of the cutting process, to the occurrence of impacts in the cutting zone. The article shows that self-oscillations correspond to technically stable cutting, the phase trajectories of which are tend to the attractor elongated in the tangential direction. A technically unstable state corresponds to self-oscillations trajectories of which are tend to an attractor elongated perpendicular to the tangential direction. Examples of surfaces obtained under self-oscillation conditions are given. The methods of their monitoring are under discussion.

Keywords: cutting process, stability, attractor, self-oscillation, vibration, diagnostics.

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M. P. Kozochkin (Stankin Moscow State Technical University, Moscow, Russia) E-mail: Данный адрес e-mail защищен от спам-ботов, Вам необходимо включить Javascript для его просмотра.

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