Analysis and inspection of the beam rotation contr

2022-08-23
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Analysis and maintenance of the beam rotation control circuit of the slitter winding workstation

Abstract: This paper mainly introduces how to control the rotation direction of the beam of the slitter bearing the winding workstation in the slitting process. To maintain a stable position of the winding and pressing roll, and analyze and eliminate the faults

key words: beam control troubleshooting

1. Preface

our company introduced an automatic BOPET film production line from Brukner company in Germany in 1987, and also introduced a film Slitter from Atlas company in Britain. The slitter is the last process. The process flow chart of the slitter is shown in Figure 1. It is mainly responsible for unwinding, slitting, and The rewinding process divides the big master coil into various specifications of products. The setting and control of various process parameters in the slitting process is the main factor to ensure the product quality. Among them, the beam bearing the winding workstation plays an important role in maintaining a stable position of the winding contact roller, so as to ensure the winding pressure set according to the process requirements

after slitting the film, the slitter divides it into inner and outer sides for winding. The winding workstations on the inner and outer sides are installed on the beam controlled by the hydraulic cylinder. Under the control of the hydraulic cylinder, the beam drives the beam to rotate back and forth within a certain angle range through the telescopic movement of the piston and connecting rod of the hydraulic cylinder, so as to achieve the purpose of ensuring the pressure required for normal winding and the purpose of loading and unloading. Now, the automatic control process and faults are analyzed

2. Circuit analysis

the block diagram of beam rotation control is shown in Figure 2. The control circuit diagram is shown in Figure 3. The electrical signal output by the photoelectric sensor through line 836 is 0-12v. When the beam between the emission and reception of the photoelectric sensor is completely blocked, the output is 0V. When the beam of the photoelectric sensor is completely not blocked, the output is 12V. When the beam is blocked, the output electrical signal is a certain value between 0-12v. When the slitter works normally, the electrical signal output by the photoelectric sensor is about 6V. When the slitter presses the start button, the pressure roller 15 is in the start position under the action of the cylinder. At this time, the light beam of the photoelectric sensor behind the winding pressure roller is in a completely unobstructed state, and its output electrical signal is 12V, which is respectively supplied to the P I d controller and the comparator through line 836. When the comparator works normally, the 24V sent from line 1318 is turned on by the triode in a circuit, and then a high level is output from line 1144 to the input of PLC plci63 3. After the electric signal sent to the PID controller is compared with the given signal sent by line 838, the PID control signal is generated and output from line 837 to vt5006, so as to control the proportional direction control valve and then the position of the beam. During the normal operation of the slitter, as the winding diameter gradually increases, the winding pressure roller squeezed by the winding product increases and blocks the beam of the photoelectric sensor, and its output electrical signal decreases. After this signal is compared with the given signal, the PID outputs the control signal to vt5006, increasing the control ability of the proportional control solenoid valve a, making the oil circuit open, driving the piston to drive the piston rod to shrink, Make the beam rotate towards the unloading direction, and the beam rotates towards the unloading direction, driving the winding product to move towards the unloading direction gradually, and the winding pressure roller also makes it move towards the unloading direction closely with the winding product under the use of the cylinder, so that the part of the light beam of the photoelectric sensor blocked by the winding pressure roller is reduced, so that the electrical signal output by the photoelectric sensor increases to the level close to the given signal, and the winding process always breaks the balance and restores the balance, Ensure the relatively stable position and pressure of the winding pressure roll, that is, with the continuous increase of the winding diameter, the beam rotates continuously in the direction of unloading

on the contrary, if the rotation angle of the beam is too large, the photoelectric sensor beam will be partially blocked by the winding roller 15, which will increase the output level of line 863. After comparing with the signal given by 838, the PID will output the control signal to vt5006, thereby increasing the control ability of the proportional direction control valve B, causing the proportional direction control valve to reverse, and the hydraulic cylinder to act in the opposite direction, so that the beam will rotate in the winding direction, The rewinding product and the rewinding pressure roller lean towards the direction of loading, so that the blocked part of the light beam between the emission and reception of the photoelectric sensor is increased, that is, the light beam transmitted from the emission to the reception is reduced, so that the output level of the photoelectric sensor is reduced and close to the given value level, so as to achieve balance and stability at a certain level. In this way, a closed-loop control is formed by photoelectric sensor, PID controller, vt5006 hydraulic oil cylinder, beam, winding product and pressure roller to ensure the normal production

3. Fault analysis and treatment

fault I; After the normal slitting of the slitter is completed and the coil is unloaded, the beam of the outer winding cannot rotate in the direction of coil loading, that is, the piston and connecting rod of the hydraulic cylinder cannot stretch out after contracting. First, check that the level of 836 at the output end of the photoelectric sensor is 12V, indicating that the photoelectric sensor beam is not blocked; Then check that the level indicator at the input point I 63 3 of the PLC is not on, indicating that there may be a problem with the comparator. As can be seen from Figure 3, if he was an 18-year-old student of Aerospace Engineering at the time of line 836 and has an output voltage, the input 24V of line 1318 is to the terminal 8 of the comparator. When the comparator works normally, the high level is output from terminal 9 from line 1144 to the input point I 63 3 of the PLC, and the level indicator should be on, In actual inspection, I 63 3 indicator light is not on. Focus on checking the circuit of the comparator. It is found that there is a level at terminal 8, but the output level of terminal 9 is 0V. Through circuit analysis and detection, the T1 triode of which is broken down, resulting in a short circuit to the ground of the broken down T1 triode at terminal 9. Therefore, the level of output line 1144 from terminal 9 to the input point I 63 3 of PLC is 0. PLC detects this signal, which is equivalent to that the pressing roller has completely blocked the beam of the photoelectric sensor, Thus, the hydraulic cylinder is forbidden to act in the direction of winding. After replacing the triode, the comparator works normally and the slitter returns to normal operation

fault 2: during the working process of the slitter, the inner and outer beams often move towards the unloading direction at the same time, so that the products in the winding move towards the unloading direction, and finally lead to the separation of the winding pressure roll and the products, and the loss of the winding pressure, resulting in the deviation of the film after slitting in the outer layer of the products, resulting in the breaking of the film, which cannot be produced, and the timing of the occurrence is irregular, sometimes when the slitter is just started up, sometimes after slitting and winding to a certain length

fault analysis: in principle, when the beam between the emission and reception of the photoelectric sensor is blocked, or there is no electrical signal output on line 836, the beam rotates in the direction of easy unwinding operation and high working efficiency, but the normal situation will be corrected by the PID controller. From the fault phenomenon, it is the internal and external beams that rotate outward at the same time, indicating that the problem should be the common part of the control circuit of the internal and external beams. It can be seen from the circuit diagram that the power supply part should be the main part, but it has been shut down for many times for detection. Power supply, Chizhou, Anhui: develop new aluminum based materials to create new support for the industry. The photoelectric sensor output, PID input and output and comparator work normally. Finally, the method of tracking and detecting the power supply output voltage is adopted. When the internal and external winding beams rotate in the direction of unloading, at this time, It is found that the voltage of the power output (see 1363 in Figure 3) is 15V higher than the marked one, that is, the given signal was originally taken from 10V, but now it is taken from 25V, resulting in the given voltage input from 1363 being much higher than the given value required for normal operation, and greater than the maximum output voltage of the photoelectric sensor of 12V. Therefore, the electrical signal output from PID to vt5006 always makes it output the signal that makes the proportional directional valve act in the unloading direction. Even if the photoelectric sensor beam is not completely blocked, it cannot be corrected. Later, it was found that after years of operation of the slitter, the ground wire connector of the regulated power supply to the ground was loose, resulting in poor contact. When the ground wire was in poor contact, the original output voltage was + 15V, + 10V, -15v, and the voltage became + 30V, + 25V, and 0V. After this ground wire was re grounded, it returned to normal, and this fault did not appear again. The slitter has been working normally until now

According to the different base materials of the formula

Author: Li Wenyu (Shantou ocean first polyester film Co., Ltd.)

from: packaging magazine

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