Managing Process Control of Directed Energy Deposition Turbine Repairs: Past, Present, and Future

Directed Energy Deposition has been a focus of Rolls-Royce for the past few decades, with applications in the manufacture and repair of Gas Turbine Engine Components, such as titanium and nickel compressor blisks, and high-pressure turbine blades. One challenge facing the implementation of this technology has always been, “How do you reliably control a process with a lot of potentially unstable variables and inspect the resulting high value components?” In the past, the approach rested squarely in the world of traditional metallurgy, establishing process and property relationships, and relying on a fixed process window to ensure part compliance. In the present and future, work under development by Rolls-Royce, including in-process monitoring sensors, derived process metrics with meaningful and established relationships, and both open and closed loop control schemes, allow researchers and manufacturing engineers to wield much more precise control over DED. These developments have the potential to accelerate the development of DED repair and manufacturing process applications and greatly reduces the risk of producing non-conforming parts.