Isra Vision, a provider of surface inspection systems, is now offering its 100% inline inspection solution PrintSTAR technology. The product features continuous quality and process control of printed images, lamination and coatings.

A medium-sized packaging producer is now using 100% verified and inspected quality, powered by Isra, for applying cold seal adhesives to flexible packaging. The expertise gained from the inspection is then used to further improve printing processes.

Today’s packaging industry is increasingly focused on sustainability – protecting the environment, using energy and resources sparingly, and recycling. Sustainable production also means that defect rates and waste need to be reduced to a minimum.vA medium-sized producer of cold-sealed flexible packaging films for the food and cosmetics industry faces a challenge here. The packaging it produces has to be completely impermeable to high moisture levels, oxygen, and aromas. The films are also printed according to customer needs.

The company has been using various print inspection systems for many years while paying close attention to the latest trends in vision technology. In this case, the packaging specialist was on the lookout for an efficient inspection system to be used in a combined laminator for adhesives with aqueous solvents. Until now, printed symbols were used in cold seal applications to align the cold seal pattern to the print. However, this process increased the complexity of many production steps. The main goal was inspection of the applied cold seal, as well as its registration to front side prints resulting in a sharp increase in process quality.

The application places high demands on inspection. The cold seal is applied to a metalized substrate on the reverse of the printed film. Metalized surfaces are particularly challenging to inspect due to their strong reflective properties. In addition, the inspection of print registration proves particularly difficult given that the film is opaque. The customer opted for the 100% inline inspection system PrintSTAR.

The process works as follows: After printing, the flexible film is moved to the laminator, where a patterned adhesive is applied to the reverse side of the film. The application must then be aligned with the print on the front in the precise position in the register at a speed of up to 1,000 fpm. Another challenge is that the various films are typically finished with reflective surfaces.

The 100% inspection system detects all defects in the cold seal and monitors the process to ensure that the coating is even, free from voids, and aligns with the repeating print. Using high-resolution LCD cameras combined with ultrabright LED lighting, the PrintSTAR system detects both individual and recurrent cold seal defects in real-time. Both sides of the film are checked with the same system plattform. Furthermore, the inspection system allows users to set acoustic alerts to warn them if the cold seal application is in misalignment to the print – thereby freeing up operators to turn their attention to other tasks in the coating process, even while the inspection is running.