Scalable Manufacturing of Composite Components using Nanostructured Heaters

Manufacturing of structural composites traditionally employs autoclaves to achieve high quality parts, including high fiber-volume-fractions and low porosity. A laminate comprised of stacked prepreg plies are cured under a vacuum in addition to ~7 bar of pressure to prevent formation of voids, particularly in interlaminar (inter-sheet/ply) regions. However, manufacturing composites within an autoclave is accompanied by high acquisition and operation costs due to the necessity of specialized heated pressure vessels. Furthermore, these costs increase dramatically as the size of structure increases. The capacity of autoclaves limits the size of parts, and the production rate is primarily affected by autoclave availability. As a result, there has been interest in development of alternative techniques. Out-of-autoclave (OoA) prepreg has been introduced commercially as an alternative to autoclave-cured prepreg, however it still imposes similar limitations due to the need for an oven, plus OoA material does not yet yield the same properties as those cured in an autoclave under pressure. Thus, MDC and MIT have developed a process to manufacture quality prepreg-based composite laminates out-of-oven (OoO) using conductive curing via embedded and/or surface-mounted carbon nanotube networks (CNT) that have been demonstrated at 550C.