Gravure Printing Overprinting Precision Tension Control

In the overprinting process of the gravure aluminum foil, tension adjustment and changes directly affect the accuracy of overprinting and printing, which is one of the key factors in the control of the printing process. The tension control system of an aluminum foil printer is a special servo system in which the input amount changes according to an adjustable attenuation law. Tension control is the core of complete machine control. As long as the tension control is stable and the tension change is small, the accuracy of foil overprinting and scrap rate can be easily controlled. However, in the foil printing process, tension fluctuations and change factors are many and need to be carefully analyzed.

First, the diameter of the retractable roll is constantly changing due to the roll of the printing press during winding and unwinding. When the unwinding torque is constant, the diameter decreases, the tension increases, and the winding is the opposite. If the winding-up torque is constant, the tension will decrease as the winding diameter increases. This is determined by the inherent characteristics of the press and is a major factor in the change in tension in the aluminum foil.

Second, the uneven quality of aluminum foil material affects the change of tension, such as the fluctuation of the elastic modulus of the material, the change of the material thickness along the length of the width, the eccentricity of the material volume, and the level of heating will give the whole machine Tension brings a subtle influence.

Thirdly, the printing press will cause sudden changes in the tension of the entire machine during the process of refueling or feeding. The higher the operating speed of the equipment is, the greater the interference is, and the tension changes greatly and the stability is poor. In order to restore the tension to the original stable state, the tension should be automatically and randomly adjusted according to the tension of the tape tension. During overprinting, the printed web must have moderate tension when it is being conveyed. When the tension is too small, the web at the detection position is prone to jitter, which affects the precision of overprinting, the tension must be constant, in order to ensure a constant instantaneous speed, and require the main motor to run. To be stable, you can't be fast or slow, and you can't shake, otherwise it will affect the accuracy of overprinting.