An adaptive laser cladding methodology for blade tip repair

Worn-out blade geometries differ from the nominal geometry. Studies about numerical control tool path recalculation or control processes at constant melt pool are the most used approaches to generate a good repair process, but they use the same parameters for all parts, in spite of the different thermal behavior due to the difference in thickness. This paper presents an innovative based adaptive laser cladding methodology for obtaining the optimal process parameters taking into account the real geometry of the part, providing a unique solution to solve the part-to-part variation repair problem in blades. This solution can be implemented on its own or combined with monitoring and control process techniques. Laser power was identified as the most effective process parameter that permitted to modify and adapt the obtained width to the presented in a blade different from the nominal. The study of the obtained width when varying laser power on machined thin wall of different widths showed that MetcoClad718 and Ti6Al4V clad width behavior exhibited three phases. From the comparison of experimental data with programmed overwidths, it was possible to determine equations that related the required power for variable widths. Results show that it is not necessary to know the nominal input power to repair blade tips with variable geometries. The required power is directly obtained from the methodology equations. The performance of the proposed methodology was validated by laser cladding on machined MetcoClad718 mock-up blades and by means of the repair of Ti6Al4V compressor blades. Good agreement between experimental and programmed widths was obtained.