Optimization of dynamic behaviour of printing roller systems

Abstract

Due to increase roller width and web velocities, the vibration characteristics are significant for the quality and efficiency of the printing processes. Approved methods like balancing of the rollers and maximizing the bending stiffness have come to technical limits. This work deals with finding possibilities for improving the dynamic behaviour of roller systems in flexographic printing machines. Piezoelectric sensors based on piezopaint are developed for measuring dynamic forces in the nip of the printing rollers. A mathematical model of the roller system was derived and implemented in Matlab/Simulink. Active bearings with integrated piezoelectric actuators are designed. An experimental-based control using a feed-forward and a feedback control algorithm shows good results of vibration reduction of the plate cylinder. A semi-active method for reduction of vibration amplitudes of more than 85% using profile rings was designed and verified by the measurements.