The use of variable spindle speed for vibration control in face milling process

Vibration control is one of the most important issues in the metal cutting process. It has been recognized for several decades that many machining process performance measures are influenced by vibrations: e.g., surface finish, tool wear, and cutting force characteristics. Vibrations result in a poor surface finish of the machined workpiece, reduce the life of the cutter, accelerate machine tool system component wear, and may lead to an unacceptable noise level in the work environment.The use of variable speed cutting for vibration control in the face milling process is a relatively new concept. The variable speed approach has the added feature of flexibility. When cutting conditions or part geometry are changed, the speed trajectory can easily be changed to reduce vibrations. This can be accomplished in software rather than hardware, thereby making this technique potentially quite practical.The use of variable spindle speed cutting for vibration control in face milling process has been studied. Both simulation and experimental results show that the self-excited vibrations that can occur during constant speed cutting, and hence limit the possible size of cut, can be suppressed by continuously varying the spindle speed. Through both analytical and experimental studies, the shape of the variable speed trajectory has been examined, in terms of both the trackability by the spindle servo system and performance in terms of vibration suppression. It was found that a sinusoidal wave because of its acceleration and jerk characteristics can be tracked more precisely than some other periodic waves.The dynamic face milling force model was used to study the effects of speed trajectory parameters, namely, speed variation frequency and amplitude. Results, in general, show variable speed cutting to be fairly robust to the specific nature of the machining situation in terms of both processing conditions and system dynamics. Speed trajectory design was, however, shown to be somewhat dependent upon the nominal cutting speed and dominant frequencies of the system.U of I OnlyETDs are only available to UIUC Users without author permissio