Analytical prediction of part dynamics and process damping for machining stability analysis

Abstract

The milling of titanium alloy thin-walled parts is confronted with the double challenges of hard to machined materials and hard machined structures. Aiming at the problem that the effect of the damping process is significant and difficult to measure in the process of machining titanium thin-walled parts, the mathematical model of the process damping is established. The tangential and radial ploughing force coefficients that characterize the damping of the process are obtained based on the power spectral density matrix and the principle of energy balance. The structural dynamic modification method is used to solve the nonlinear problem of the workpiece characteristics with the material removal and the change of the relative position of the tool and the workpiece. The time delay differential equation which considers the damping effect of the process and the dynamic characteristic of the workpiece is solved by the full-discretization method, and the three-dimensional stability lobe diagram of the milling thin-walled parts is obtained. A series of experiments have been conducted to verify the accuracy of the stability prediction.