PARAMETRICAL PHENOMENA UNDER ON-MACHINE PROCESS CONTROL

Abstract

The problem on the stationary tool trajectories instability relative to the workpiece taking into account the periodic parameter variation of the interacting subsystems and of the dynamic coupling formed under cutting is considered. Parameter changes are caused by cyclic variations of the workpiece stiffness in the direction normal to the rotative axis, as well as variations of the allowance for machining periodic with the period of its rotation. It is shown that the periodic parameter changes induce the instability mechanisms not analyzed before. Moreover, in this case the loss of stability is basically dependent on the spindle speed. In addition, the instability is also associated with the kinematic perturbations caused by the periodic component of the support longitudinal feed velocity. Some examples of instability depending on the mathematical model parameters of the cutting system are given.

Keywords

• stationary motion trajectory, stability, periodic changes of parameters, parametric excitation.