A hybrid method of reconstructing 3D airfoil profile from incomplete and corrupted optical scans

In overhauling turbine blades and vanes, the automated machining system must be able to adapt to distorted airfoil surfaces to avoid undercuts or overcuts. Thus 3D profile measurement and reconstruction is required to plan the tool path according to the individual part geometry. In deploying optical sensors for 3D profile measurement, specular reflection on turbine airfoil surface causes loss of measurement data and noisy signals in optical scans. A hybrid method that combines piecewise cubic Hermite interpolation with linear compensation has been developed to reconstruct the surface, with errors less than 30 µm.