Investigation of improved label cutting by CO₂ lasers with wavelength optimization

The digital printing revolution has changed the landscape of label creation significantly. With the flexibility of printed design, the need to easily change the cut shape to match has become very important. Traditionally, cutting has been done with mechanical die-presses where the user is locked into one design for a production shift and the cost and hassle of storing multiple dies makes it unfeasible to have many cut shapes available. Laser cutting with high-speed scan heads has changed this to a dynamic and easily flexible process where cut design changes can be done on the fly via software without stopping the production line. This paper presents capabilities of sealed-off CO₂ lasers for cutting a variety of labels and the impact of laser wavelength on cut quality and throughput. We investigated multiple CO₂ laser wavelengths such as 9.3µm, 10.2µm and 10.6µm on a number of common plastic and paper labels. These results were measured for overall cut speed, heat effect on the cut edge, and unwanted scoring of the paper liner underneath. We concluded that for many common polypropylene based labels, the 10.2µm wavelength was the best choice, while the 9.3µm wavelength was the best for many PET based labels. For most plain paper labels, we observed similar cut speeds and quality for all three wavelengths.