Composites

Fig. 1: Laser process to generate repair geometry

Laser material removal of CFRP

Laser cutting process

Due to their special material properties as e.g. stability and stiffness at a comparatively low density, fiber-reinforced composites play an integral role in the aerospace and automotive industry as well as in the production of sports equipment and in the construction of wind power plants. In fact, composites are gaining increasingly in importance through the continuous development of discrete materials, material combinations, and production processes of more complex components. New fields of application open up almost daily. At the same time however, the increasing spread of composites shows the difficulties of their further processing. Here, the strong abrasive effect of carbon fiber needs to be mentioned, which increases the costs of the conventional machining processes (e.g. drilling, milling) due to high wear of the tools and thus, limits possible applications. Also, machining processes exert great forces on the components. On the one hand, this can cause material damages (e.g. delamination, crack). On the other hand, the occurring forces necessitate a complex fixation of the component.

At the Laser Zentrum Hannover e.V (LZH), one of the leading institutes in the area of laser processing of fiber-reinforced composites, laser-based machining processes and systems are being developed in order to meet the challenges mentioned above. The high number of different laser sources allows for an optimal adaption of the laser source (e.g. pulsed or cw-laser-systems; wave lengths from λ = 193 nm to 10.6 µm) to the material properties (e.g. absorption behavior and the type of matrix; fiber material) of the composites.

Laser-based processes for the material processing of composites with the advantages of wear-free and force-free machining are already successfully applied at the LZH in the following areas:

Cutting/Trimming
Labeling
Drilling (> 25µm)
Surface activation/cleaning
3D-Structuring
Welding

The group Composites works closely with partners from the industry as well as with partners in publicly funded projects (national and international). Already existing laser-based processes are being further developed and new processes and fields of application are being researched, as e.g.: