United Technologies Corporation

Dean Nguyen

Philip J Ramey

Robert L Faiz

David J Parker

Nicholas P Flonc

Kenneth M Adams

William J Walker

A method for fabricating a composite swashplate ring utilizing a thermoplastic expandable mandrel which is rigid during braiding, yet softens after resin impregnation to allow expansion in a mold to increase fiber consolidation. Preferably, the mandrel accepts the incorporation of preformed structures prior to braiding with the braided mandrel suitable for incorporation in a resin transfer mold such that a dry fiber braided article having preformed structures may be impregnated with resin and consolidated to produce a net-shaped composite swashplate ring without machining.

Fabrication process for composite swashplate

A shrinkable foam mandrel that can be easily removed and composite resin transfer molding process that uses the foam mandrel. The foam is dimensionally stable at a first temperature that typically corresponds to the cure temperature of the composite resin. The foam is capable of irreversibly shrinking to less than about 0.5 said foam's original size at a second tempertaure that is above said first tempertaure. The foam is encapsulated by a non-stick elastomer skin and covered with fibers. The fiber covered elastomer encapsulated foam is disposed in a female mold cavity and resin is injected into the female mold cavity. The resin and fibers are cured and the resulting composite component is removed from the female mold. The temperature is raised to the second temperature and the elastomer encapsulated foam male mandrel irreversibly shrink to less than about 0.5 its original size. Finally the shrunken male mandrel is removed from said composite component. These mandrels are a solution to the aerospace industry's flyaway mandrel problem as they are lightweight and can easily be removed from the composite component.

Removable irreversibly shrinking male mandrel

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Stamford, CT, United States of America

Dean Nguyen