Abstract

Manufacturing composite materials by conventional methods is known to be costly as it requires many steps, equipment and tooling. The challenge this presents can benefit from the moldless approach and rapid, automated prototyping enabled by additive manufacturing. Today, additive technologies are changing the manufacturing processes of plastics and composites, allowing short series to be automated and scalable for adaptation to long series, always oriented to final part production. In addition, the mechanical limitations presented by 3D printing processes of polymeric materials have been enhanced by the reinforcement of short or continuous carbon and glass fibers, mainly. Moreover, the hybridization of additive technologies with conventional processes makes it possible to overcome their current limitations, taking advantage of many of their benefits and increasing the fields of application.

In this context, the idea of developing a technology that allows obtaining intermediate parts or preforms with high geometric complexity, which require a subsequent process, such as resin transfer molding (RTM), that confers mechanical performance similar to that of composites. In this work, an alternative method of manufacturing carbon fiber reinforced preforms using an additive process based on Fused Fusion Deposition Modeling (FDM) is detailed, as well as the production of composites from these preforms. Thus, the 3D preform is manufactured from fiber filaments coated with a thermoplastic binder. Then, this preform is subjected to a thermosetting resin injection process in a mold to obtain the final composite. In summary, a new method of additive preforming in combined with RTM is proposed to manufacture carbon fiber reinforced polymer composites (CFRPC).

Abstract

The main objectives of this research work are to find new ways of reducing costs in the manufacture of composite materials, automate processes and improve energy efficiency by looking for alternatives to the use of autoclave, always meeting the quality requirements. For this, an out of autoclave curing process is studied through an innovative system of automatic and fast curing of composite parts for the aeronautic, automotive and construction sectors. The process allows the curing of prepregs of various materials and geometries. The process includes the provision of temperature by heating plate with electric resistances, pressure and vacuum adjustable through an air compressor, and cooling through circuit through mechanized plates. The main innovative feature of this system is the pressure supply with compressed air to the piece by means of a moldable and reusable silicone membrane, which allows to extend the field of study to complex elements saving the current limitation of hot plates presses, and without the need to place countermold. CFRP cured parts are manufactured in this new system, then their properties are compared with autoclave cured parts and similar properties are obtained, and auxiliary materials are considerably reduced. It can be concluded that this system improves energy efficiency, reduces costs and optimizes times.