Dynamic Characteristics And Stability Analysis On BTA Deep-hole Boring Bar

This paper studies the evolution mechanism of boring bar system chatter with BTA boring system nonlinear distribution characteristics in the incomplete filling of the time-varying parametric chatter, fluid flow chatter and two coupled chatter etc. Inside and outside the cutting fluid flow of BTA deep hole processing system will couple with the rotational boring bar, inducing a series of combined perturbations, affecting the machining accuracy of the Inner hole. This paper, using stability theory, studies on nonlinear motion stability of BTA deep hole processing system, researches on global bifurcations of nonlinear system, and provides a theoretical basis for the production and processing.Firstly, the subject build relationship between the critical pressure of BTA deep hole boring bar processing system and bending deformation, get the influence of the axial pressure and rotational speed on the bar bending deformation, according to the support situation of the cutter crown, discussing the critical pressure of bending deformation and the reflection regularity of inner hole aperture processing error when the boring bar length changes.Second, the subject studies the effect of axial velocity of the inside and outside cutting fluid on BTA boring bar lateral chatter. The calculation results show that the sensitivity of the first and second order frequency to velocity is higher than to axial pressure, and the degree of sensitivity of the first-order energy spectrum is greater than the second-order energy spectrum. During the influence factors of the bar frequency, the velocity lies on the leading position.Thirdly, the subject researches stability of the combination chatter between inside and outside cutting fluid chatter and cutting chatter, the results show that the effect of change of speed on combined chatter is more obvious, and the combination chatter motion is quasi periodic motion, and periodic solutions tend to asymptotically stable state, and obtain the analytical conditions of the stability criterion.Finally, the subject researches bifurcation characteristic of nonlinear dynamic stability of the BTA deep hole processing system, the results show that BTA deep hole processing system has weak nonlinear parametric excitation movement characteristics, workes out the critical conditions of the intersect between stable manifold and unstable of hyperbolic fixed point of system, the simulation results demonstrate that during fluid-solid coupling chatter effect, solid effect lies on the leading position, and the maximum value of resonance frequency occurs at the small of flow velocity and the radius of free surface.The conclusion of this paper has a certain guiding significance on actual pr oduction control system of BTA deep hole processing.