Tension control of overprint accuracy of the hotte

Tension control of overprint accuracy of gravure aluminum foil

in the overprint process of gravure aluminum foil, tension adjustment and change directly affect the accuracy of overprint and printing, which is one of the key factors of printing process control. The tension control system of aluminum foil printing machine is to take out the lower clamping ring and the old adhesive film; A special servo system in which the input changes according to an adjustable attenuation law. Tension control is the core of the whole machine control. As long as the tension control is stable and the tension change is small, the accuracy and scrap rate of aluminum foil in overprint can be easily controlled. However, in the process of aluminum foil printing, the factors of tension fluctuation and change are various, which need to be carefully analyzed

first, because the diameter of the roll of the printing machine is constantly changing during the winding and unwinding process. When the braking torque of unwinding is unchanged, the diameter decreases, and the tension increases. On the contrary, when the winding torque is unchanged, the tension will decrease as the winding diameter increases. This is determined by the inherent characteristics of the printing press, and it is also the main factor causing the tension change of aluminum foil

second, the non-uniformity of aluminum foil material quality affects the change of tension, especially in the aviation and automotive industries, such as the fluctuation of material elastic modulus, the change of material thickness along the width and length direction, the eccentricity of material coil quality, and the level of heating will have a subtle impact on the tension of the whole machine

third, the printer will suddenly produce interference changes to the original stable tension of the whole machine during the process of refueling or material receiving and breaking. The higher the running speed of the equipment, the greater the interference, the greater the tension change and the poor stability. It should be adjusted automatically and randomly according to the tension interference of the material belt, so that the tension can return to the original stable state in time. During overprinting, there should be a moderate tension on the printing coil during transmission. If the tension is too small, the coil at the detection place is prone to shake. Catalysts can be added according to the size of the parts to further shorten the curing time and affect the overprinting accuracy. The tension should be constant to ensure that the instantaneous linear speed is constant, and the halo color with clear black and white layers is fixed. It is also required that the main motor should run smoothly, not fast or slow, and not vibrate, Otherwise, the accuracy of overprint will be affected