Laser as an innovative tool for laminates repair

The challenges during the mechanical machining of Fiber Reinforced Plastics like delamination, fiber tearing and rapid tool wear are well known, nevertheless, the relevance of CFRPs in the industrial community is still increasing. Due to this fact the development of new methods for machining and treatment is needed to close this technological gap. A promising cost-saving and time-saving technique is represented by the laser ablation of bulk material. This paper presents the implementation of a laser system for the treatment of laminates whose mechanical properties have been compromised by external damage during the operation. The purpose of this approach is to remove damaged material to provide a cavity for refilling with repair plies. Our results show that it is possible to achieve a reliable and automatable process with an even removal rate to perform arbitrary repair cavity geometries. The laser machining set-up, equipped with a pulsed UV-laser and a galvo-scanning head, avoids heat affected zones (HAZ) and detachment of fibers from the thermoplastic matrix (here: PEEK). The laser-ablated and repaired laminates were then used to prepare standard specimens to be tested according to DIN 65148. Detailed results of the DIN 65148 of the repaired structure are presented in the final part of the paper