Interdependence between High-Speed Mill Chatter and Unsteady Lubrication of Metal Rolling Process

A metal-rolling process with chatter is chosen as the case for analysis. An isothermal, full film unsteady lubrication model is developed. The influences of time dependent variables such as back tension stress, variation on lubrication are investigated. By utilizing this model, roll forces and torque variation with respect to time can be successfully predicted. Chatter vibration in cold rolling due to unsteady lubrication phenomena is discussed. The current unsteady lubrication theory indicates that, when the nondimensional frequency of back tension stress variation is in a specific range, the roll force and torque variations can be significantly “amplified”.