With the continuous development of the printing and packaging industry, many equipment manufacturers have improved or newly designed the local structure and performance of the coating and laminating machinery to improve the performance of the machinery, but there is no manufacturer to carry out dynamic online detection and control of the coating volume. The coating roller is partially immersed in the paint in the trough, and the paint in the trough is transferred to the substrate by the coating roller; another multi-roller coating mechanism includes a coating roller, a dosing roller and a pressure roller, the pressure roller is pressed together with the dosing roller, the coating roller is partially immersed in the paint in the trough, the coating roller transfers the paint to the dosing roller, the coating roller and the dosing roller are driven at different speeds, the paint is smoothed out by the speed difference between the two rollers, and the amount of coating is controlled by the pressure between the two rollers, the substrate is run between the pressure roller The substrate runs between the pressure roller and the dosing roller and the dosing roller transfers the paint to the substrate under the action of the pressure roller. In the first coating method, the amount of coating is controlled by adjusting the distance between the squeegee and the surface of the coating rollers, and in the second method, the amount of coating is controlled by adjusting the pressure between the rollers, which are not quantifiable or difficult to regulate in real time, making it difficult to ensure the accuracy of the coating amount and to meet the requirements of the process, or even impossible to use.
  A coating volume online control system comprising a multi-roller coating mechanism, said multi-roller coating mechanism is connected to a servo motor, a glue dispenser supplies the multi-roller coating mechanism, said servo motor is connected to a PLC controller via a servo drive, said PLC controller is communicatively connected to a human-machine interface, said PLC controller is connected to the glue dispenser control, said PLC controller control is connected to an audible and visual alarm, and said multi-roller coating mechanism is provided with a level sensor, a coating width detection mechanism and a coating length detection mechanism correspondingly, said level sensor, coating width detection mechanism and coating length detection mechanism being connected to the PLC controller.
  The multi-roller coating mechanism has a coating gel tank filled with coating fluid, which is applied to the substrate by means of the drive between the rollers. The coating thickness is determined by the rotational speed of the coating rollers, which is determined by a servo motor which is regulated by the PLC controller via a servo drive. It is difficult to measure the thickness of the coating directly, so the level of the coating liquid in the coating tank is measured by a level sensor to obtain the amount of glue used. The coating width detection mechanism and the coating length detection mechanism measure the area of the coating, which is calculated by the PLC controller, and the amount of glue used is divided by the area of the coating to obtain the amount of coating within a certain time, and the calculated amount of coating is compared with the reference value.
  When the deviation between the two is too large, the alarm is immediately activated by an audible and visual alarm. When the calculated coating volume is greater than the reference value, the PLC controller automatically controls the speed of the servo drive, i.e. the speed of the coating roller is adjusted faster to reduce the coating volume and vice versa, thus ensuring the accuracy of the coating volume and achieving automatic control of the coating volume.
  Generally speaking the coating width is less than the width of the substrate, which is determined by the width between the two blocks in the multi-roller coating trough, which can be manually measured and fed directly into the system, or it can be automatically detected by an ultrasonic distance measuring sensor mounted on one of the blocks to measure the distance between the two blocks. Specifically, the coating width detection mechanism comprises an ultrasonic distance sensor and a meter, said ultrasonic distance sensor being mounted on one of the glue blocks. The meter counter starts counting at the rising edge of the glue dispensing and terminates at the rising edge of the next dispensing.
  The level sensor is an ultrasonic level sensor, which is set directly above the glue tank in the multi-roller coating mechanism. The ultrasonic level sensor is used to detect the level of the glue tank, and the PLC determines the level of the last glue dispensing and the level of the current glue dispensing, calculates the weight of the single glue dispensing by the difference between the two levels and provides the dispenser with the glue dispensing instructions.

Translated with www.DeepL.com/Translator (free version)