Robot-guided Pre-machining for Repair by Cold Spray

Cold spraying is currently developing as a high potential technique for the repair of metallic components, particularly for the deposition of heat-and oxidation-sensitive materials. However, for the appropriate application, it is essential to prepare the component surface suitably to ensure optimum prerequisites for the subsequent material deposition by cold spray. Thus, this work proposes a concept for robot-guided pre-machining for repair by cold spray that includes removal of the damaged volume while considering the requirements for subsequent material deposition. In this concept, digital component and damage data define the dimensions and boundary conditions for material removal. This involves designing a parametric pre-machining target geometry for the damaged component by computer-aided design software that can handle variable surface types. The pre-machining target geometry is adapted to the damage characteristics by considering length, width, depth and orientation. To produce the pre-machining target geometry by machining tools, the adjusted component is exported to computer-aided manufacturing software. The applicability of this concept has been successfully demonstrated on digital use cases with exemplary components and damages as well as by practical application with a milling robot in a laboratory environment. The results demonstrate the capability of this concept for preparing damaged components and promise a high potential to ensure the required prerequisites for high-quality component repair by cold spray.