Evaluation of the influence of the reaction rate of the thermodynamic subsystem on the dynamics of the cutting process in metalworking

OBRABOTKAMETALLOV Vol. 23 No. 2 2021 TECHNOLOGY Thus, the earlier conclusions based on numerical analysis of the developed mathematical model are experimentally con fi rmed. The conducted studies have shown that the time constant of the thermodynamic subsystem of the cutting system signi fi cantly affects the dynamics of the deformation movements of the tool. In addition, studies have shown that there is some optimal range of acceptable values of such a time constant, in terms of ensuring a minimum of energy spent on the vibration of the instrument. All this is quite well correlated with the results of experimental studies conducted by us, as well as other authors, in particular, this is con fi rmed the existence of an optimal cutting mode from the point of view of ensuring maximum tool life. Continuing these arguments, and taking into account the fact that the dynamics of the processing process is continuously related to the dynamics of temperature changes in the cutting zone, which in turn depends on the time constant of the thermodynamic subsystem, the optimal temperature is largely determined by the value of the constant we have introduced. Conclusion The paper reveals the mechanism of self-organization of the cutting process, through the prism of the interaction of the three subsystems of the cutting system, the subsystem describing the deformation movements of the tool, the subsystem of the force reaction of the cutting process to the shaping movements of the tool, as well as the thermodynamic subsystem of the cutting system. The paper proposes and con fi rms the hypothesis that there is a minimum vibration energy of the tool, which is functionally dependent on the variation of the time constant of the thermodynamic subsystem of the cutting system. The mechanism of minimizing the tool vibration activity during cutting, considered in the work, allows to optimize the process of turning metals in terms of the roughness of the treated surface, due to the advance preparation of the tool, by which we mean the formation of a preliminary contact area of the tool and the part, taking into account the selected cutting elements, at which its vibrations during turning are minimal. References 1. Grabec I. Chaos generated by the cutting process. Physics Letter A , 1986, vol. 117, no. 8, pp. 384–386. DOI: 10.1016/0375-9601(86)90003-4. 2. Lapshin V.P., Tyunyaev R.A., Khristoforova V.V. [Evaluation of the effect of the feed rate on the equilibrium modes of the drive providing milling of the workpiece of variable thickness]. Dinamika tekhnicheskikh sistem , DTS- 2015 [Dynamics of technical systems], Rostov-on-Don, 2016, pp. 180–184. (In Russian). 3. Reznikov A.N., Reznikov L.A. Teplovye protsessy v tekhnologicheskikh sistemakh [Thermal processes in technological systems]. Moscow, Mashinostroenie Publ., 1990. 288 p. 4. Ryzhkin A.A. Teplo fi zicheskie protsessy pri iznashivanii instrumental’nykh rezhushchikh materialov [Thermophysical processes during wear of tool cutting materials]. Rostov-on-Don, DSTU Publ., 2005. 311 p. ISBN 5-7890-0348-6. 5. Huang S.N., Tan K.K., Wong Y.S., De Silva C.W., Goh H.L., Tan W.W. Tool wear detection and fault diagnosis based on cutting force monitoring. International Journal of Machine Tools and Manufacture , 2007, vol. 47, iss. 3–4, pp. 444–451. 6. Arsla H., Er A.O., Orhan S., Aslan E. Tool condition monitoring in turning using statistical parameters of vibration signal. International journal of acoustics and vibration , 2016, vol. 21, iss. 4, pp. 371–378. 7. Alonso F.J., Salgado D.R. Application of singular spectrum analysis to tool wear detection using sound signals. Proceedings of the Institution of Mechanical Engineers , Part B: Journal of Engineering Manufacture , 2005, vol. 219 (9), pp. 703–710. 8. Dimla Sr D.E., Lister P.M. On-line metal cutting tool condition monitoring. I: force and vibration analyses. International Journal of Machine Tools and Manufacture , 2000, vol. 40 (5), pp. 739–768. DOI: 10.1016/S0890- 6955(99)00084-X. 9. Orhan S., Er A.O., Camu ş cu N., Aslan E. Tool wear evaluation by vibration analysis during end milling of AISI D3 cold work tool steel with 35 HRC hardness. NDT & E International , 2007, vol. 40 (2), pp. 121–126. 10. Tobias S.A. Vibraciones en Máquinas-Herramientas [Machine tools vibrations]. Bilboa, Spain, Ediciones Urmo, 1961.