Chain Stitch Research Articles

A new manufacturing methodology, termed shape-inclusive lay-up, has been developed for manufacture of dry-fibre preforms using non-crimp fabric (NCF). Shape-inclusive lay-up enables preforms for three-dimensional components to be produced and stored flat, introducing the shape only when the preform is loaded into the mould. The lay-up process is jigless, and complex components can be produced as a single preform, reducing both preform production and moulding times. Aerospace components with varying degrees of complexity can be manufactured using this technique, including skin components and reinforcement structures. A range of technologies has been developed for automating the lay-up process. This paper focuses on the requirements of the joining process. The various methods of ply attachment investigated are described. The method that both satisfies the process requirements and is suitable for automation is single-sided stitching using a loose chain stitch. The stitching process has been studied and implemented for the production of dry carbon preforms. A stitching device in the form of a robotic end-effector is described. Prototype testing is detailed and the results of these tests are discussed.

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