Tension Control Principle and trouble shooting method of automatic paper machine

First, the paper tape tension control principle 

1, the tension set through the operation panel of the web paper tape tension given value input to the paper frame of the PLC equipment, make sure that the tension of the tape away from the feeder is in the range of 100-400N. 

2. The PLC equipment of the given output paper frame controls the air pressure change of the floating roller cylinder by the electric-pneumatic conversion device (E/P) . 

3, tension sensing when the web of paper tension and floating roller force changes, the floating roller will swing around its fulcrum an angle. The paper tape tension angular displacement potentiometer 1POT installed on the rotary bracket shaft will have the corresponding voltage change, and the corresponding voltage signal will be transmitted to the PLC equipment of the paper frame again. 

4. Tension control according to the position change of the floating roller, the speed of the paper belt and the diameter of the web, output the control signal to IPC after the operation of PLC equipment, the tension regulating control board IPC controls the brake device of web paper through the electric-pneumatic conversion device (E/P) .

Second,Common troubles and trouble-shooting in the production process, the paper tape tension control system is used frequently, the work intensity is big, so its failure frequency is high. Take the 4 faults which our company often encounters as an example, briefly analyzes its elimination method. 

1. In the process of paper breaking, with the diameter of the running paper reel becoming smaller, the tension of the paper tape becomes larger, which causes the swing of the floating roller to become larger (especially when sending the paper receiving signal to prepare for paper receiving) , at this time paper frame easy to break paper fault. Considering that red and green paper arms (with red and green labels on the arms respectively) will break in production, in the temporary consideration of the red and green paper arm brake parts of the case of failure, focus the inspection on the public control section of the red and green paper arms. The specific elimination steps are as follows: first, check the paper tape tension angle displacement potentiometer 1POT on the rotary bracket shaft, that is, pull the floating roller up and down under the condition of power failure, if it is found that the resistance value of 1POT of the tape tension angular displacement potentiometer changes abnormally, it should be replaced immediately, recalibration (the DC voltage of the tension angular displacement potentiometer 1POT should be 1.9 V when the floating roller is at the bottom and 7.5 V when the floating roller is at the top) . After the above-mentioned process, the paper break fault is removed and the production process returns to normal. It should be noted that the tape tension angle displacement potentiometer 1POT installation must be reliable, otherwise it is easy to lead to inaccurate tension feedback value, thus affecting the tape tension control.

Third,During the production process, when the automatic pick-up machine starts to increase speed, the display value on the tension display table should increase to the set value as the machine speed increases, but the reality is that the values on the tension display do not change. At first, we suspected a problem with the tension control section, but the problem persisted after the tension display was changed. Subsequently, we tried to manually set the tension in the case of production, tension control is normal, this means that the tension control part is no problem. Finally, we suspect there is a problem with the speed signal that controls the paper frame. By checking the speed encoder connected by the side of the paper roller in the paper-out part of the paper frame, it is found that the connecting rod of the fixed shaft of the speed encoder is broken, which causes the PLC equipment of the paper frame not to receive the speed signal in time, so that the tension display table values display abnormal. After re-fixing the speed encoder to fix the shaft connecting rod, the fault is resolved.

Fourth,The tension control of red and green paper arms is unstable during a printing process, we suddenly found that the tension control of red and green paper arms is unstable, check the paper tape tension angle displacement potentiometer 1POT display voltage, found normal. Considering the complexity of the fault, not a single point of failure, we initially suspect that the PLC equipment control part of the problem. So we will be in the normal production state of the paper frame PLC equipment on the tension analog feedback plate 3PC and the paper frame PLC equipment on the tension analog feedback plate 3PC to exchange, re-power, it was found that the tension of the red and green arms of the paper frame recovered to normal, while the tension of the red and green arms of the other paper frame was unstable. After replacement, troubleshooting, production returned to normal.

Fifth,Red Arm tension control is not stable, green arm tension control is normal. In a printing process, we found that red arm tension control is not stable, green arm tension control is normal. First, check the red paper arm of the brake pad part, found that the brake pad is normal. Then, the output voltage of the tension regulator board 33PC was measured and found to be normal. Finally, check the relevant electrical-pneumatic conversion device (e/P) , found that the problem. By replacing the associated electrical-pneumatic conversion unit (E/P) , production returned to normal. The stable and fast response tension control system plays an important role in printing quality. When there is a tension problem in web printing production, it is advisable to check the relevant parts according to the tension control principle, so as to gradually eliminate the trouble and ensure the orderly production.