Gloucester's New RollAir Collapser Improves Bubble Control and Film Quality

Unique collapsing frame for blown film lines combines noncontact airboards with composite rollers.

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Unique collapsing frame for blown film lines combines noncontact airboards with composite rollers. The result is consistent quality and higher line speeds for a diverse range of films. A key component of blown film quality is maintaining bubble control from die to nip. The more control a processor has in running a film bubble up the collapsing frame and into the nip, the less chance there is of wrinkles, scratches, or other damage to the web. Most towers utilize either rollers or airboards to collapse film prior to the nip. Gloucester Engineering Co. Inc., Massachusetts, has com-bined the best features of both systems in one unique and innovative solution to bubble control and film quality: a RollAir Collapser with both a noncontact airboard plus composite rollers. The RollAir Collapser provides consistent control and quality regardless of film gauge or surface characteristics, says Bill Hellmuth, senior product manager of blown film systems at Gloucester Engineering. It works equally well with thin films, transparent films, coextruded films, extensible films, and tacky films. It combines the best traits of both rollers and airboards. The system utilizes two air flotation sections below a set of composite rollers. The airboards, mounted in the lower frame have hundreds of perforations through which air pressure floats the bubble. Air flotation is provided in the area where bubble con-tact may not turn traditional rollers. This eliminates scratches in the film. The film then runs through the composite rollers, which give the bubble slight traction in the machine direction as it advances to the nip. The result, Hellmuth says, is that the film moves in a much straighter direction to the nip than with full airboard collaps-ing systems. This eliminates the potential for air entrapment behind the bubble, im-proving layflat quality. The composite rollers are half the weight and inertia of alumi-num and do not transfer heat from the film like aluminum rollers do. Gloucester Engineering has a RollAir Collapser installed in its technical center in Gloucester. The collapsing frame is 74 inches wide and 160 inches long. Hellmuth says they can be made in a variety of sizes and engineered to fit on any Gloucester blown film line. Retrofits for other manufacturers' lines can also be dis-cussed. Hellmuth says the system costs about the same as conventional air boards, and in-cludes all components necessary for operation like blowers, filters, air-distribution plenums, air-control slide gates, and hoses.