Obrabotka Metallov 2020 Vol. 22 No. 1

OBRABOTKAMETALLOV Vol. 22 No. 1 2020 77 EQUIPMENT. INSTRUMENTS References 1. Hahn R.S. On the theory of regenerative chatter in precision grinding operation. Transactions of American Society of Mechanical Engineers , 1954, vol. 76, pp. 356–260. 2. Tobias S.A., Fishwick W. Theory of regenerative machine tool chatter. The Engineer , 1958, vol. 205, no. 7, pp. 199–203. The In fl uence of the Cutting Speed of Metals on the Regeneration of the Vibratory Oscillations of the Tool in Machines of the Turning Group Victor Lapshin * Don State Technical University, 1 Gagarin square, Rostov-on-Don, 344000, Russian Federation https://orcid.org/0000-0002-5114-0316 , lapshin1917@yandex.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2020 vol. 22 no. 1 pp. 65–79 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2020-22.1-65-79 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Article history : Received: 21 December 2019 Revised: 13 January 2020 Accepted: 07 February 2020 Available online: 15 March 2020 Keywords : Nonlinear dynamics Vibrations Cutting process Oscillation regeneration Funding The reported study was funded by RFBR according to the research project № 19-08-00022. ABSTRACT Introduction . Tool vibrations accompanying the cutting process are largely related to the long-established regenerative effect, which signi fi cantly affects the dynamic characteristics of the metal cutting process, which is indicated in numerous foreign publications of leading European specialists in the fi eld of Metalworking. In the works of some Russian scientists specializing in the analysis of metal cutting processes on metal-cutting machines, the position of the existence of an optimal cutting speed that provides the best quality of the processed surface and the greatest tool life is considered. Therefore, the paper considers the question of the probable connection of this optimal speed with the regeneration of tool vibrations during metal turning. Objective : the possibility of assessing the in fl uence of the regenerative effect on the dynamics of the processing process is considered, without taking into account additional in fl uences on the process, both from the machine side and from the cutting process itself, in order to determine the existence of optimal cutting modes. The study investigated : a mathematical model describing the dynamics of tool vibrations in the conditions of metal processing on machines of the turning group, while only the case of longitudinal turning of the product is considered. Research methods : on the basis of mathematical modeling of the dynamic cutting system, three variants of the possible behavior of the processing process are considered, taking into account the in fl uence on the regeneration of tool vibrations, the period of rotation of the spindle with the part fi xed in it. As the fi rst case, a neutral variant in which this period is not associated with the carrier frequency of the speed of axial deformations of the tool is considered. The second option determined the optimal speed of rotation of the spindle, which completely coincided with the carrier frequency of the speed of axial deformations of the tool. The third option shows the worst-case version of the spindle rotation speed, which makes the spindle oscillation period such that the regenerative effect is maximized. Results and discussion . The results of modeling are presented, revealing the dynamics of the system, taking into account the three options selected for the speci fi ed spindle speed of the machine. The results of research show that even in the simplest description of cutting forces, the dynamics of the system is quite complex, which is signi fi cantly affected by the regenerative effect revealed in the work. The numerical experiment con fi rms the theory proposed in the paper about the existence of an optimal processing speed, in terms of the in fl uence of tool vibration regeneration on the cutting process. The results obtained are in line with well-known domestic works devoted to the practical analysis of the possibility of building optimal cutting systems and link them with the work of leading European experts in the fi eld of dynamics of metal processing processes. For citation: Lapshin V.P. The In fl uence of the Cutting Speed of Metals on the Regeneration of the Vibratory Oscillations of the Tool in Machines of the Turning Group. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2020, vol. 22, no. 1, pp. 65–79. DOI:10.17212/1994-6309-2020-22.1-65-79. (In Russian). ______ * Corresponding author Lapshin Viktor P. , Ph.D. (Engineering), Associate Professor Don State Technical University, 1 Gagarin square, 344000, Rostov-on-Don, Russian Federation Tel.: 8 (900) 122-75-14, e-mail: lapshin1917@yandex.ru