Economical and automated manufacturing processes of FRP for use in lightweight applications
The use of modern materials, such as fiber-reinforced plastic composites (FRP), enables weight savings due to the excellent stiffness-to-mass ratio, reduces the consumption of fossil raw materials and reduces exhaust emissions from e.g. motor vehicles. The operating range of electric vehicles is increased, making them more attractive.
Production and further processing of pultruded fiber composite components
The transition from conventional materials to new lightweight materials is being inhibited due to manufacturing challenges that have not yet been solved. The properties and machinability of composites differ significantly from metals, so established metalworking manufacturing processes must be replaced by technologies adapted to the challenges of the new materials. For large-scale production, there is a need for economical, automatable manufacturing processes for machining (e.g. cutting) as well as for the production of reliable multi-material components, which firmly connect metallic elements with FRP components.
For multi-material components that also contain metal components, there is currently no satisfactory separation process. For the joining of FRP and metal components, load introduction elements are often integrated into fiber composite components. This can be done, for example, by additive processes. Bonding strength of the supplemented material are insufficient without surface pretreatment of the interface. Laser-based pretreatment in the form of selective fiber exposure or defined structuring of the FRP has shown promise in preliminary studies in combination with plastic injection molding and thermal spraying. However, the process speeds achieved to date are too low.
In the pultrusion process, metallic layers can also be integrated directly into the composite part. This improves the crash behavior of components and enables the subsequent use of conventional fasteners (screws, rivets). A prerequisite, however, is a strong material/form-fit connection in the interface between metal and FRP. Currently, the metal inserts are pretreated in a complex process involving powder coating or a subsequent, additional patching process. Here, too, a laser-based pretreatment process of the metal integrated into the process chain would be an attractive alternative to ensure the required bond strength between the metal layer and the pultruded component.
Use of USP lasers
As an alternative to mechanical processing, quasi-cold material removal with ultra-short pulse lasers offers the potential to overcome existing challenges, e.g., surface pretreatment of pultruded components for subsequent printing of tethering elements or integration of a laser-structured steel strip into pultruded components. The laser power available with the CAPS sources also opens up the possibility of multiplying the still too low process speeds for structuring but also for efficient cutting of metal-reinforced pultruded components.
The stated goal of this project is to significantly increase the marketability of hybrid materials and associated manufacturing processes, thereby revealing the potential of very high average power USP lasers for these applications.