Temperature uniformity analysis and development of open lightweight composite molds using carbon fibers as heating elements

One of the most critical steps in developing new composite products is the design and the manufacturing of molds. Especially in the high end composite materials manufacturing sector, the design of molds and tools comprises a major challenge. As far as the manufacturing of CFRPs is concerned, liquid composite molding processes and autoclave techniques are highly temperature-sensitive. The ability of carbon fibers (CFs) to conduct electric current can be used in heat transfer applications in the composites manufacturing industry. Using CFs as heating elements, ultra-light carbon fiber reinforced plastic (CFRP) sandwich-structured molds can be developed, in order to accelerate the resin flow via the Joule effect. In the present study, the manufacturing procedure of such CFRP sandwich-structured molds is provided. Using the thermal and electrical properties of the constituent materials, numerical models were built up to study the temperature field uniformity and the heating-cooling rates of the molds. A thermal camera as well as thermocouples were used in order to verify the numerical models, in the case of a flat mold and a hat-shaped mold for different applied power levels.