Manufacturing of lightweight frame structures by innovative joining by forming processes

The majority of the materials used in modern lightweight frame structures are aluminium alloys. But some aluminium alloys, e.g. EN-AW6060, are not or hardly joinable using conventional joining techniques. In this case innovative joining methods like friction stir welding; joining by dieless hydroforming or by electromagnetic compression lead to good joint's quality. Friction stir welding has been widely investigated for joining sheet metal, but joining tubular workpieces creates new challenges in handling and processing, which will be described here. Joining by Dieless Hydroforming has been introduced in both plant and automotive engineering in the 1970ies. This joining method was used to join heat exchangers or camshafts made of steel. Recently, joining of aluminium has been targeted and is addressed below. Joining by Electromagnetic Compression offers the opportunity to manufacture high strength joints by e.g. form-fit. Groove's design has been adopted targeting failure of the basic tube material, which is described here.