Innovative Methods for Automated Controlled Removal of Thermal Barrier Coatings (TBCs) and Bondcoats from Turbine Airfoils for Rework and Repair

This proposal uses commercially available products in a new and unique way to deliver multiple laser beams to the target simultaneously in order to increase processing efficiency. We will demonstrate the idea using mostly low power lasers available to us, but it can be scaled up using larger lasers. In addition, we will investigate methods of process monitoring to determine when the metal layer has been reached. We hope to demonstrate cycle times of less than 10 minutes per part and compare our data with other available methods. The method should address TCB thickness variations (0.005" - 0.020"), end point detection, no damage to underlying layers and zero recast. BENEFIT: Anticipated results will be applicable to not only removal of TBC coatings, but should also have application in other areas such as high speed hole drilling. The proposed Phase I work will determine the fundamental laser parameters required to controllably remove TBC coatings at high speed. This includes the optical set up and controlled feedback loops. Variations on the optical set up and choice of laser could be used in a variety of other areas, but in the aerospace/defense arena as well as the commercial manufacturing arena.