Adaptive positioning and accuracy evaluation of film cooling holes in aero-engine turbine blades based on 3D vision

Film cooling technology is pivotal for ensuring the structural integrity of turbine blades and the reliability of engine performance. However, machining errors in film cooling holes can significantly compromise cooling efficiency and curtail blade lifetime. To address machining errors induced by casting deformations and to meet the engineering demand for quantitative evaluation of positioning accuracy, this paper proposes an adaptive positioning and accuracy evaluation method for film cooling holes based on 3D vision. First, a binocular structured light system is employed to acquire high-precision point clouds of the blade, and an improved two-stage registration strategy is developed to estimate the blade spatial pose accurately. Second, the cross-sectional point clouds of the blade are segmented and their parametric features are extracted. Subsequently, a non-rigid registration model based on mean camber line features and a hole position mapping model are established to jointly compensate for casting deformation and residual nonlinear errors, thereby achieving adaptive positioning of film cooling holes. Finally, film cooling holes are machined according to the adaptive positioning results. Once system repeatability is validated, epipolar constraints are utilized to reconstruct the machined holes, enabling precise quantitative evaluation of spatial deviations. Experimental results demonstrate a spatial positioning accuracy of 0.0171 mm, validating the effectiveness and potential for engineering application of the proposed method.