Process engineering of glass-sealed sensors

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The leading-edge technology for fiber-reinforced epoxy composites uses elevated pressure (0.6 MPa) and temperature (200 C) autoclave environment to achieve rapid and homogenous integration between the fibers and the polymer matrix. Convergent Manufacturing Technologies, Inc., is a world leader in process development and modeling for such components. A number of sensors must be inserted into the autoclave in order to monitor the process, with the connection feed-throughs currently sealed with epoxy seals; such seals face curing strain, differential thermal expansion/contraction vs the metallic housing, and thus become unreliable under thermal & pressure cycling of up to 0.6 MPa and 200 C. This research will develop expertise to replace the epoxy seals with glass seals which offer significantly higher operating temperatures (e.g. up to 600C in some cases), corrosion resistance, seal stability, experience no curing strain, and their thermal expansion coefficient can match that of the metal housing within few %. Such stable, elevated-temperature/pressure capable seal will allow to properly monitor the composite parts curing process in nearly-perfectly reproducible environment, with long-term thermo-mechanical stability.