építôanyag § Journal of Silicate Based and Composite Materials managing the process of machining on machines on the basis of dynamic modelling for a technological system viacHeSlav MAkSARoV § Department of mechanical engineering, saint-Petersburg mining university § maks78.54@mail.ru alekSey kHAlIMoNENko § Department of mechanical engineering, saint-Petersburg mining university § khalim76@spmi.ru Jüri olT § Department of Production engineering, institute of technology, estonian university of Life sciences § jyri.olt@emu.ee érkezett: 2017. 04. 22. § received: 22. 04. 2017. § https://doi.org/10.14382/epitoanyag-jsbcm.2017.12 Abstract the article considers the issues related to improving the efficiency of multipoint machining by the use of rotary cutters which are equipped with replaceable ceramic inserts on cnc machines by developing a method of multipoint machining process control. A dynamic model is proposed for the multipoint cutting process on the basis of continuum theory, and a mathematical model which is cognisant of the specific nature of the multipoint metal cutting problem, and ensuring efficiency in the description of various chip-making process modes. keywords: multipoint machining, dynamic model, cutting process, generic mathematical model, milling. Viacheslav MAksAroV Professor at saint-Petersburg mining university. Head of department of mechanical engineering from 2012 and dean of electromechanical faculty from 2015. specializes in the field of dynamics of machining technological systems. Aleksey kHAliMonenko Associate professor at saint-Petersburg mining university. specializes in the field of automation and control of production processes, processing quality when using cutting ceramics and methods of increasing processing quality. Jüri olt Professor at estonian university of Life sciences. Head of department of production engineering from 2005. His main researching area are fundamentals of production engineering, materials cutting and design of technological machinery. 1. Introduction At present, process control in mechanical engineering is one of the most promising directions of development in this feld. Improving the efciency of multipoint cutting by means of rotary tools which are equipped with replaceable ceramic bits determines the need for the widespread use of high- performance equipment which permit automated machining processes. Te control of machining processes in automated production is only possible on the basis of new approaches to the study of the phenomena which accompanies the metal cutting process. Te loss of stability in the multipoint cutting process results in self-oscillation, increasing the intensity of cutting tool wear and reducing the service of machine operating mechanisms; it also leads to deterioration of machining quality and accuracy [1, 2]. Terefore, reducing the intensity of any oscillation in industrial process systems which are operated on an automatic cycle mode is at present a pressing issue [3, 5, 7]. Creating preliminary local physical impact (LPI) on the external surface of the layer which is being sheared of is, according to certain laws, one of the most efcient methods of allowing metal deformation conditions to be changed during cutting [8]. Periodical changes of cutting conditions as compared to the basic material are a peculiarity of the process of machining the work pieces subjected to such action. Such a method allows to carry out control of the multipoint cutting process, in its turn afording the opportunity to improve the multipoint machining technology in a wide range of materials and cutting conditions [4, 8]. Te following problems should be solved successively in order to implement the proposed method: ■ isolating the causes of emergence of plastic deformation instability and the conditions of transition to an unstable state in the process of multipoint cutting leading to self-oscillations excitation in the closed process scheme of machining by cutting [2, 10]; ■ choosing and substantiating the rheological model of multipoint cutting process allowing to carry out dynamic modelling of machining process system [8, 13]; ■ developing a dynamic model of industrial process system with regard for rheological peculiarities of multipoint cutting process and oscillations in the closed system loops on the basis of dynamic models proposed earlier [6, 9, 12]; ■ developing a theoretical basis for efcient control of multipoint machining industrial process systems deformation process and vibration immunity [3, 10]; ■ carrying out a set of experimental studies with the purpose of confrming the validity of the theoretical ideas obtained in the process of previous work [7]; ■ developing guidelines for improvement of the efciency of multipoint cutting industrial process on the basis of chip formation process control [11]. 2. Materials and methods Before the experimental studies, available research papers have been analysed. Te analysis allowed to select hypotheses about the sources of self-oscillations onset in the machining industrial process system. Te principal hypotheses are as follows: ■ the existence of a coordinate connection in an elastic system in the presence of nonconservative cutting force; ■ closeness of the machine dynamic system in the presence of cutting dynamic response; 66 | építôanyag § JSBCM § 2017/2 § vol. 69, no. 2