P. Jäschke
V. Wippo
H. Dittmar
U. Stute
D. Kracht

Development of innovative laser based processes for composites repair and processing using ablating and welding techniques

International Symposium on Laser Processing for CFRP and Composite Materials (LPCC)
26.-27. April
Type: Konferenzbeitrag
In consequence of an increased interest in using endless carbon fibre reinforced composites based on thermoset and thermoplastic matrix materials, automated and highly productive processing technologies for repairing steps of consolidated materials are sought. Today, damaged areas in the surface of CFRP parts have to be repaired by use of manual grinding techniques. The damaged part is removed and the resulting structure is refilled by means of a patch of new fibre plies. Depending on the applied processing techniques, the repair process of fibre reinforced components is still a very difficult and time consuming process. Correspondingly, it is the aim of the investigations to develop a novel technique for composites repair, providing high geometrical accuracy, reducing processing time and most importantly, enabling fully automated control, thus reducing requirements for skilled personnel and eliminating human errors. The method presented here is based on a laser ablation technique. According to the material properties of CFRP structures and the sensitivity to thermal loads, short pulsed IR and UV laser radiation is used to realize a precise ply by ply removal for preparation of the repair geometry. The influence of different process parameters like hatch distance and number of cycles on the ablation depth and throughput is discussed. In addition, the laser transmission welding technique is evaluated with respect to the possibility of joining unreinforced, short and long glass fibre reinforced plastics to CFRP, e.g. for fixing patches to endless carbon fibre reinforced structures. In this context, the influence of the kind of reinforcement on the weld seam formation is studied.