Processing of glue coated film and glue bars in printing technology

Processing of glue coated film and glue bars in printing technology

When laminating, there are glue bars with a spacing of about 3cm between the full plate, which means that during the laminating process, due to uneven coating of the glue liquid, white bars are generated between the BOPP film and the printed product, especially in cold toned full plate solid printing products, and the glue bars are more prominent after applying matte film, seriously affecting the appearance and quality of the product. Therefore, it is necessary to stop the machine for inspection and troubleshooting.

The specific exclusion methods and steps are as follows:

(1) After inspection, it was found that the rubber bars in front of the unpressed rubber roller had already been formed. When viewed, it can be seen that there are horizontal white bars with a spacing of 3cm and uniform distance densely arranged on the BOPP film. Using thinning water to scrub BOPP film with adhesive bars, it was found that the adhesive bars were caused by the accumulation of adhesive liquid, indicating that the problem occurred in the adhesive stage during the film feeding process.

(2) Use a dial gauge to check the upper rubber roller and the coating rubber roller separately, and the results show that the upper rubber roller has a radial wear of 5 μ m, which meets the requirements; The glue roller has a radial wear of 24 μ m, exceeding the standard requirements. After disassembling, it was found that the copper sleeves at both ends had worn into an elliptical shape. After reprocessing the copper sleeves and testing the machine, it was found that the problem had not been solved.

(3) When adjusting the speed of film feeding and gluing, it was found that the gap between the glue bars had changed. At low speeds, the effect of laminating products was better than at high speeds, changing from glue bars with a spacing of 3cm to glue bars with a spacing of about 8cm. At this point, it was clearly felt that the intensity of the chain edge vibration had decreased significantly, so it was inferred that the unstable speed of the belt type continuously variable transmission caused the production of rubber bars. The speed is sometimes fast and sometimes slow, which can easily cause momentary pauses between the BOPP film and the glue roller (which cannot be observed by the naked eye), resulting in the accumulation of glue and the formation of glue bars.

After inspection, it was found that there was a sliding gap between the movable disc of the variable speed pulley and the shaft, and the shaft sleeve inside was worn. The main and driven discs were also deformed to varying degrees, so the groove width at the same diameter of the disc could not be consistent on the circumference. This would cause the belt speed to constantly change during operation, ultimately affecting the unstable transmission torque of the gearbox. After correcting the wheel and reprocessing the shaft sleeve, the problem with the rubber bar was completely resolved.

Processing of glue coated film and glue bars in printing technology

Processing of glue coated film and glue bars in printing technology