Surrounded by fibres: The metal inserts in the recesses are also fixed at the rear with a fibreglass patch.
Fibre
The modern car is also a hybrid construction of fibre-reinforced plastic and metal. In order to join the two different materials quickly and reliably, textile researchers from Bremen, Germany are trialling spot welding. In automotive engineering, it's certainly true that this joining process and the industry's short cycle times are closely interlinked.. Nevertheless, researchers at the University of Bremen still use the method of automatically connecting metal parts to each other via welding points when welding fibre-reinforced plastic (FRP) components to body panels.
"We deliberately opted for spot welding because it is one of our existing production methods – which means we are ready for series production right from the start," says Sabrina Jenkel of FIBRE (Fibre Institute of Bremen). She developed this novel method in close cooperation with the Institute of Materials Science (IWT) in Bremen and companies from the welding and forming industry as part of a project for Germany’s Central Innovation Programme for SMEs (ZIM).
Automated spot welding of FRP and metal
Before the joining process, first organic sheets are made with small recesses into which small metal inserts are pressed. These act as welding spots with which the fibreglass component is welded to the car body. "We want to be sure that it makes no difference to the welding robot whether it is joining a metal component or a fibreglass one to the body structure," says Jenkel. According to the industrial partners involved in the project – FormTech, AKON-CAD, Reiner Seefried and Verkontec – the already patented method should enable carmakers and suppliers to join FRP components, such as spare wheel recesses and end and rear panels, to car bodies faster and more efficiently in future. The research project will continue until spring 2018.