TAILORABLE HEATING SYSTEM FOR OUT-OF-AUTOCLAVE TOOLING AND HEATED COMPOSITE APPLICATIONS

摘要

Out-of-autoclave processing techniques can enable significant manufacturing cost savings. When using polymer matrix composite tooling for out-of-autoclave cures, a key aspect of mold design is the heating system. This paper describes a novel, thin, conformable heating system for tooling based on the use of thermoset resin containing carbon nanotubes or carbon nanofibers which forms a uniform heating element. Current industrial systems for heating composite tooling typically consist of recirculating heated fluid systems, which require the use of plumbing and manifolding, external attachment to the tool, pumping and control systems, and heat transfer fluids. In comparison, the Boyce Components, LLC K-Factor? carbon nanotube-based heating system may be applied to the interior of a composite tool, and covered by a single ply of pre-preg and subsequent surface coats to provide a novel, alternate heated tooling technology. Benefits for this type of heating system include ease of fabrication, simple construction, close-coupling of heat flow to the part being cured, rapid heat-up and cool-down, and a high level of temperature uniformity across the mold face. Experiments were performed utilizing a statistical DOE (Design of Experiments) approach for the determination of heating parameters (resistance, resistivity, power density, and thermal performance) as a function of heater layer thickness, carbon nanofiber concentration, and electrode spacing. Experimental results are presented.