Vibration control in bar feeders using magnetorheological fluids
Bar feeders provide an additional level of automation to CNC turning centers by feeding bar stock through the machine spindle, eliminating the need to load individual, precut work pieces, as well as the ancillary sawing operation. At up to twelve feet long and rotating at spindle speeds ranging from a few thousand to well over ten thousand RPM, the stock is susceptible to vibration, which is transmitted to the cutting zone and adversely affects precision, surface finish, and cutting tool life. The current state-of-the-art requires special fixturing for each stock diameter, representing a significant amount of changeover time and capital investment. This research investigates how the controllable rheology of magnetorheological fluids can be employed to mitigate bar vibration while reducing or eliminating fixture changes. The system is modeled as a thin beam with a viscous boundary condition, and the resonant frequencies of vibration are calculated as a function of damping. Physical experiments confirm that the magnetorheological fluid conforms to this model, which indicates that such fluids possess the capacity to significantly alter the resonant frequencies of the bar stock and suggests a simple control algorithm for resonance avoidance.
Bar feeders, Machining, Magnetorheological fluids, Turning, Vibration
Pierson, H., Brevick, J., & Hubbard, K. (2012). Vibration Control in Bar Feeders Using Magnetorheological Fluids. In IIE Annual Conference. Proceedings (p. 1). Institute of Industrial and Systems Engineers (IISE).
62nd IIE Annual Conference and Expo 2012