V. Wippo
S. Hirt
H. Dittmar
P. Jäschke
S. Kaierle
L. Overmeyer

Laser based repair of CFRP for the aerospace industry

SPIE Proceedings Vol. 11273: High-Power Laser Materials Processing: Applications, Diagnostics, and Systems IX
Type: Zeitschriftenaufsatz (non-reviewed)
Carbon fibre reinforced plastics (CFRP), particularly with a thermoplastic matrix material, have increasingly been used in the last decades. This is especially true in industrial sectors with a strong focus on lightweight applications such as the aviation industry. During the production of CFRP parts imperfections can occur resulting in the need of rework. Furthermore, a damage can occur in service time. In both cases, a large amount of carbon fibres and matrix material has to be mechanically removed, which comes along with high tool wear. Afterwards, the area has to be refilled. This is done by adhesive bonding of CFRP patches. Normal adhesives have long curing times of several hours. To enhance the repair process of thermoplastic CFRP, a two step laser based process was developed. In the first step, CFRP is removed by laser ablation, which allows a high reproducibility and accuracy. Goal is to generate a flat surface with a defined matrix amount. In the second step, laser heat conduction welding is used to refill the removed area with thermoplastic patches. This study was conducted with a carbon fiber fabric within a polyphenylene sulfide matrix. In order to develop a high quality heat conduction process, the ablation process was optimized to generate a defined surface. For the evaluation of the welding process, lap shear samples were welded with different setups. These samples were tested and fraction pattern evaluated.