A Robotic Polishing Trajectory Planning Method Combining Reverse Engineering and Finite Element Mesh Technology for Aero-Engine Turbine Blade TBCs

The roughness of thermal barrier coatings (TBCs) prepared on the surface of aero-engine turbine blades affects the lifetime of the coating and the life cycle and aerodynamic performance of the blades. To reduce the TBC surface roughness, this study proposes a robot polishing trajectory planning method that combines reverse engineering and finite element mesh technology. First, a 3D model of the blade was reconstructed in reverse engineering by using the fast surface modeling method. Then, a dense mesh with controlled spacing was obtained by mapping the finite element mesh arbitrary quadrilateral elements on the surface of the blade model. Finally, a robot polishing path of the blade was generated by sorting the index of mesh nodes. Using this approach, polishing experiments of aero-engine turbine blades were systematically carried out, and the coordinate system conversion method from the robot off-line programming simulation environment to the actual work station was used to map the robot trajectory. Meanwhile, the point cloud registration method was introduced to improve the system calibration accuracy. The experiments showed that the technical solution proposed in this paper could reduce the overall surface roughness of the thermal barrier coating from above Ra 8 μm to about Ra 0.5 μm, which contributes to the performance improvement for the TBCs of aero-engine blades.