Damage detection and reconstruction algorithm in repairing compressor blade by direct metal deposition

Aero-engine blade repair is challenging due to its complicated geometry and unique defects after serving in a harsh environment. Traditional manual-based remanufacturing processes are not capable of yielding consistently repaired part quality, significantly limiting the application of repair technologies. For building up materials on damaged blades, it is required to detect and extract the repair volume and generate corresponding tool path for additive manufacturing. Therefore, the objective of this paper is to propose an automated damage detection and reconstruction algorithm for jet engine blade repair. Reverse engineering was utilized to reconstruct models of nominal and damaged blades. The reconstructed damaged model was best fitted with the nominal model by transformation matrix and using overlapping area comparison method. Through area comparison method, the damaged blade was separated into intact section and damaged section. A set of parallel and equidistant casting rays were used to intersect with damaged layers to extract the repair volume. Laser scanning tracks were generated according to the extracted geometry. The laser-assisted direct metal deposition process was performed to deposit Ti-6Al-4V particles on the damaged region. Finally, microstructure analysis was carried out to evaluate the repaired part quality. The repair experiment validated that the proposed algorithm is suitable and efficient for automated repair of curved blades.