This equipment is an NC turning center of realistic industrial size. It will be used for fundamental studies of the effect of chatter on tool wear, and to investigate the mechanisms responsible for the process damping which improves the stability of machining at low speeds. There is as yet very little information available about the relationship between chatter and tool wear. A significant effect on tool wear would indicate a need to reexamine the current operations in industries where chatter is accepted as a fact of life (e.g. pocket milling aluminum airframe panels) and to consider the chatter avoidance techniques already available. It may be possible to use the results of the process damping investigations to deliberately introduce process damping and thereby increase the stability of existing operations significantly (several times). Two sensor control algorithms will be developed and experimentally verified. One is a method for chatter avoidance by automatically selecting optimally stable speeds, and the other is a technique for chatter and tool breakage detection. Additionally, simulation models will be developed and verified to be used as aids in determining the quality of the turning operation during the NC programming stage (programming for quality milling). Primarily, these investigations are directed toward operations where machining quality prediction abilities would reduce the time typically required for program verification, while tool breakage detection using the microphone would provide a less expensive alternative to existing force and acoustic emission schemes.
