Robotic preforming of thick near-net composites

Abstract

Electronic Jacquard looms in conjunction with modified take-up systems can be used to produce relatively thick fabrics, with a variety of weave styles including orthogonal, angle interlocked and layer-to-layer interlocked structures. These fabrics have a number of applications such as ballistic plates and billets for machined composites. However, 3D woven composites have a number of limitations including limited formability, lack of bias fibers and significant material wastage (if the parts have complex geometly with significant taper). A robotic preforming approach is presented here to overcome the limitations of conventional 3D weaving. A large gantry robot, along with fiber deposition end-effectors, has been built to deposit a dry carbon yarn directly on a (double-curvature) mould surface. Hence thick curvilinear parts can be produced using this technique. The carbon yarn can be deposited in any preferred orientation, with increased density in certain critical regions. The component can have a complex boundary in addition to thickness taper. Additional feature of this process is the incorporation of through-thickness reinforcement.