Calculation of stiffness parameters and vibration analysis of a cold rolling mill stand

The elastic deformation of rolling mill elements during the rolling process is important. By knowing the displacement of rolls, the optimum gap between the work rolls can be calculated. In present research, a vibration model with two degrees of freedom is proposed for a cold sheet rolling mill and the stiffness parameters of different mill elements are calculated. A numerical simulation and a finite element analysis are also carried out for the related vibrations. Afterwards, the maximum displacement of rolls is calculated using the vibration transient response of the work roll and backup roll. It is found that the system vibration reaches the critical damped level, and the rolls return to their resting positions quicker, and the effects of oscillations on the sheet being rolled decreases. As a result, precision of reduction in sheet thickness increases. Moreover, due to decrease in the sheet speed, the oscillation amplitude of rolls declines and movements of rolls turn into movements without oscillating. Finally, to verify the effectiveness of the proposed method, the experimental data are compared with calculated stiffness parameters and the rolling force.