POLYVINYL FLUORIDE FILM ENABLES PRODUCTIVITY IMPROVEMENT

The aerospace industry has long been plagued with expensive and unreliable pressure devices for the molding of epoxy prepreg hollow fiberglass shapes. Many contractors have attempted to meet aerospace requirements and design criteria using thick (up to 1 inch) elastomeric bags with caul plates or they have done the exact opposite and attempted to use fine film material without much success. With the advent of composite rotor blades on the production horizon, the need for an economical, disposable pressure medium with inherent release characteristics became apparent. Silicone-rubber pressure bags are now used as the pressure medium for the molding of fiberglass rotor blades. The bags are very expensive to fabricate and require the subsequent operation of placement of Teflon tape over the entire surface of the bag as a release agent. During removal of the bag from the blade, damage is often incurred, resulting in costly repair and retesting for leaks. This paper describes the program that is evaluating the use of thin film material for the fabrication of disposable pressure bags. This development will eliminate the silicone-rubber bag, Teflon taping, recurring repairs, subsequent leak tests, and lengthy turnaround time.