Pultrusion of hybrid connecting elements

In order to make technical systems more efficient and resource-friendly, companies are increasingly turning to hybrid lightweight construction. This involves the targeted combination of different material groups – for example, metals with fiber-reinforced composites (FRCs). This combination combines the strengths of both materials: high strength, low weight, and design flexibility. This results in components that are specifically adapted to local loads.

In practice, however, the widespread use of such hybrid components often fails due to a lack of joining methods and automated manufacturing processes. The technologies available to date can usually only be implemented on a laboratory scale or with a high degree of manual effort. The transitions between FRP and metal are structurally challenging and difficult to integrate into existing production chains. At the same time, insufficient recycling options and a lack of life cycle analyses make sustainable application difficult.

This is precisely where we started in the Hybrid-Switch project: Together with our partners, we have developed automated, series-ready manufacturing processes for hybrid lightweight structures made of FRP and metals. To this end, we developed automated manufacturing processes that can be integrated into existing production environments and are also applicable in small and medium-sized enterprises. 

The development focused on transferring innovative hybrid joining technologies to the established series production process of pultrusion. With the help of a new type of “open” tool, sheets can be integrated into the pultrudate during the manufacturing process without the need for additional joining steps. During the curing of the thermosetting matrix, a special powder coating forms a strong, inseparable bond between the sheet metal and the FRP. 

The resulting hybrid component thus has a pure metal part and can be joined to other metal structures using conventional joining methods such as welding or screwing without damaging the temperature-sensitive FRP. 

The hybrid pultrusion developed in the Hybrid-Switch project can be applied to countless applications in numerous industries. Great potential is seen, for example, in automotive, commercial vehicle, and shipbuilding.