Packaging Corner: Laser reactive marking eliminates labels

Offered as an alternative to traditional labels and ink-based marking systems for coding of secondary packaging, laser reactive marking (LRM) systems create a direct imprint on the side of corrugated cases with no printing or labeling consumables on the production line.

“LRM eliminates the need for labels, making the case marking process much more efficient because there’s greater output without the downtime associated with replacing or refilling consumables,” explains Milan Gracanin, product manager for laser marking systems at Videojet. “Further, it removes issues with poor label adhesion and the possibility of substrate jams that can occur with traditional labeling systems.”

To achieve the mark using LRM, corrugated cases are preprinted with a patch of a laser reactive coating at the box converter. The boxes are then used in normal production with a CO2 laser installed in place of an inkjet printer or labeler. When the laser’s beam contacts the coating, it creates a thermal reaction to create a black mark. The system can produce any kind of code, text, graphic or brand mark.

“LRM creates high-resolution marks that are visually comparable to those made by case coders and labelers,” explains Gracanin, who also notes that the cost of the coating is competitive with that of labels, making the process very cost effective.

Depending on the application, the pre-printed patches typically range in size from 4 x 2 inches to 7 x 5 inches, or larger. Translucent clear and opaque white coatings are selected according to a given application’s need for contrast against the type of corrugated material used (white, Kraft brown or white mottled).

“Jobs can run at production line speeds depending on the code content and other variables,” Gracanin adds. “Although the laser can produce an image as large as the size of the box, the more complex the image, the slower the throughput.”

In addition to reducing downtime on the production line, LRM eliminates the need to store and maintain an inventory of labels—preprinted or blank—as well as printing inks or printer ribbon. Significant reductions in carton SKUs are also possible. Further, aside from an occasional lens cleaning that takes less than a minute to perform, the system requires no regular maintenance with the laser tube’s expected lifespan at 45,000 hours under normal use.