Paperboard is widely used for packaging and cartoning food products to provide rigidity and mechanical support. Laminating an ultra-thin aluminum foil to the paperboard adds oxygen and moisture resistance that serves to prevent spoilage of food. In the aseptic packaging industry, the final touch is an inner layer of polyethylene that makes the package liquid-tight. This combination of materials, combined with UHT (ultra-high temperature) sterilization, allows milk and juice products to be shipped and stored without requiring refrigeration until opened by the consumer.

For this application trial, the customer asked us to determine the feasibility of laser cutting 102 mm (4.0") diameter foil-coated paperboard tubes to length. Because the composite tubes have a wall thickness of 1 mm (0.04"), we set up our cutting head with a 63.5 mm (2.5") positive-meniscus focusing lens that provides a 100-micron (0.004") spot with a 1.8 mm (0.07") depth of field. A 2.8 bar (40 PSI) air assist, delivered coaxially with the beam, was used during the cutting process to remove vaporized material from the cut area.

Using a Firestar f201 laser at a power level of 200 watts, we cut the foil-coated paperboard tubes at a rate of 10.2 meters per minute (400 inches/minute). For a 102 mm (4.0") diameter tube, this equates to a cycle time of 1.9 seconds to cut around the 320 mm (12.6") circumference. Notice that the cut paperboard edge exhibits an exceptionally clean cut with very slight discoloration.