Novel approach to produce reinforced plastic weld seams using an additive friction stir welding process

Abstract Friction stir welding (FSW) is a well-established method for joining metal components in lightweight construction. Despite its excellent joining properties, the process has primarily been used in high-tech applications requiring exceptional joint strength. However, the unresolved challenge of gap bridging limits its wider adoption. Recently, efforts have been made to extend FSW to plastic components. To address some of its limitations, this study presents a hybrid approach for thermoplastic materials, combining FSW with additive manufacturing techniques. In this method, a filament serves as a filler material during the welding process. This approach aims to improve both the mechanical and aesthetic properties of the weld seam by incorporating reinforced plastics, while also addressing the gap-bridging requirements of industrial applications. Newly developed stirring tools enable precise delivery of filler material into the process zone. Their modular design allows for the conveyance of both molten and solid material into the joining zone, with the conveying capacity adjustable through modifications to tool geometry. The results of joints made from various homogeneous plastic types, including ABS, PC, and PA6, are presented. The quality of the weld seams is assessed through mechanical characterization, complemented by microscopic examination to evaluate weld integrity.