Static pinning takes on new uses for sealing

Horizontal flow wrapping using shrink films to provide skin-tight packaging for cartons, food products, and pharmaceuticals is a popular packing method where the film is fed around a forming box to create a tube. Generally an overlap, often sealed together by heat-seal or heat-shrink processes, of 25-35 mm of film is needed. But due to tension on the film, the overlap can come apart if the seal is not formed correctly, causing high rejection rates and requiring rewrapping. Packagers often compensate by using wider films to produce a larger, more expensive overlap. Meech Int. (Witney, England) has come up with a method of sealing that it says can save money by reducing the overlap to only 3-4 mm. The Meech 992v3 30-kV static generator produces a controlled level of static charge operating in a constant current mode. The charge creates a temporary bond between the materials. When installed on a horizontal flow wrapping line, the pinning head on the Meech unit produces a charge that holds the film in place as it moves into the shrink tunnel.