Composite Tooling for Today's Technology

Autoclave processing of pre-impregnated materials - fiberglass, kevlar, graphite, requires the use of high temperature and high pressure to obtain laminate integrity required to meet the sophistication of application by today's design engineer. Processing through an autoclave environment requires the use of tools capable of withstanding the processing requirements and capable of meeting the production demand without breakdown or replace. Plastic-composite tooling is being fabricated from pre-impregnated glass/graphite-epoxy materials that will withstand autoclave processing temperatures and pressures with a projected life durability expectancy of 500 cycles. These materials require the use of processing techniques as a minimum that are equal to the process for producing the end product whether it be fiberglass, graphite, kevlar or hybrid combination thereof. To demonstrate the accuracy, stability and durability through autoclave cycle several design shapes of complex curvatures and surfaces were fabricated using a hybrid laminate of pre-impregnated fiberglass and' graphite. Included in the shapes are the canopy skin, crew door inner skeleton, bubble fairing, leading edge sheath caulplate for the UH-60A, the canopy, wishbone, and tail rotor skin molds for the S-76 Aircraft, and the main rotor pocket skin for the CH-53E Aircraft. A characteristic laminate change occurs in the surface of the tool on repeated exposure to the autoclave environment. The surface of the tool will develop a rich ebony appearance as a result of oxidation of the surface through repeated autoclave cycling.