Stability and vibration analysis of turning and face milling processes

The selection of cutting conditions to maximize material removal rate while providing good surface quality has been an elusive topic: which has been investigated by a number of researchers in the past. Strategies based on the selection of a constant and variable spindle speed, both off-line and on-line, have been typically developed for the turning and simplified miling processes. However, most industrial machining processes are characterized by complex workpiece surface discontinuities and dynamics. Hence, the main objectives of this research are to investigate the effect of workpiece surface discontinuities on the stability and vibration of the machining processes and to develop strategies to machine a part with maximum material removal rate while maintaining a good surface quality.; In order to achieve these objectives, an enhanced dynamic model of the machining process is first developed. The dynamic model is used to compute the cutting forces, vibration, surface quality, and stability of the machining process. An analytical frequency domain method to compute the stability of the dynamic model during constant and variable spindle speed machining is also developed.; The analytical frequency domain and the numerical time domain methods are then used to investigate the effect of workpiece surface discontinuities and variable spindle speed machining on the stability and vibration of the turning and face milling processes. In addition, off-line strategies that can be used to machine a part with maximum material removal rate and/or minimum vibration are also developed. However, in the presence of variations in the system parameters, the off-line strategies may no longer be optimal. Hence, an on-line strategy to compensate for these changes based on the minimization of the total energy input into the system is also proposed.; Experimental validation of the outputs of the dynamic model, namely the cutting forces, standard deviation of vibration, surface quality, and the stability of the machining processes, and the strategies used to machine a part with maximum material rate and/or minimum vibration is also presented.