Joining with versatile joining elements formed by friction spinning

Mechanical joints are an essential part of modern lightweight structures in a broad variety of applications. The reason for this is the rapidly increasing number of different material combinations needing to be joined in areas of application like the automotive industry. It is currently common to use numerous standardized elements (if necessary, from different joining technologies) instead of individually adapted joining elements. This leads to a large number of different joining elements per product and thus to high costs. An innovative approach to overcome this issue is the design and manufacturing of application adapted joining elements. A promising strategy for the manufacturing of adapted joining elements of this type is the so-called friction spinning process. The joining elements formed in this way can be specifically adapted to the application in question in terms of shape and mechanical properties. The joining process using this friction spun joint connectors (FSJC) benefits from the use of friction-induced heat and supports the process by reducing the joining forces required through a variation of the rotational speed and the feed-rate. By controlling the significant process parameter (e.g. the joining force), it is possible to substantially influence the quality of the joint or the joint properties. The following contribution will present results of ongoing research at Paderborn University and includes the process concept, the process properties, the tooling and the results of the experimental investigations of the joining of two preholed sheet metal parts with help of this new joining process.