Stability analysis of high speed milling process considering internal damping of composite cutter bar and gyroscopic effect in rotating coordinates.

Composite cutter bar with high dynamic stiffness and damping can be used to suppress chatter in high speed milling process. However, for a rotating composite cutter bar, a new region of instability occurs at the high-speed range because of such factors as the internal damping of the composite cutter bar and gyroscopic effect. This paper proposes a dynamic model of high speed milling system with composite cutter bar in fixed and rotating coordinate frame. Based on the viscoelastic constitutive relation of composite material, the damping model is established by using the energy approach. The dynamic equations of the milling system are established according to Hamilton principle. The natural frequency and decay rate of composite cutter bar are studied by the proposed theory. The stability results are obtained by using the semi-discretization method and verified by the time domain response curves. The influences of gyroscopic effect, internal damping, ply angle and aspect ratio are examined. It is shown that gyroscopic effect has a significant effect on stability lobe diagrams at the high speed range. A new unstable region appears at the high speed range when the internal damping of the composite cutter bar is included. [ABSTRACT FROM AUTHOR]