МОДЕЛЮВАННЯ ВПЛИВУ НЕЛІНІЙНИХ КОЛИВАНЬ НА ЯКІСТЬ РОБОЧОЇ ПОВЕРХНІ ДЕТАЛЕЙ НА ФІНІШНИХ ОПЕРАЦІЯХ

The paper investigates the influence of finishing operations on the roughness of machined surfaces in the case when the machine-tool-fixture-tool-part (MTFTP) system is in the zone of nonlinear oscillations. For this purpose, models of dynamic oscillatory processes accompanying the machining of working surfaces of parts are built in the Simulink system of the MATLAB package. The formation of self-excited oscillations of the MTFTP mechanical system during finishing operations is determined with one or two degrees of freedom associated with the heterogeneity of the processed material and external disturbing forces in the ranges of fundamental and subharmonic resonances containing, in addition to the excitatory element itself, also zones of dry friction of the tool with the processed surface. These studies not only demonstrate the behavior of mechanical systems capable of self-excited oscillations, but also allow their results to be successfully applied to optimize the quality characteristics of machined surfaces during finishing operations. It has been shown that resonant curves under nonlinear oscillations of mechanical systems of finishing operations affect not only the formation of the roughness of the machined surface, but also the appearance of scorch marks on them and the formation of defects such as cracks.