Inspection of blade profile and machining deviation analysis based on sample points optimization and NURBS knot insertion

As the core component of aviation industry, the machining accuracy of blade has great impact on the performance of aeroengine. Blade inspection can get knowledge of machining accuracy and can be used to compensate the machining error. In consideration of measuring time and efficiency, measuring trace planning based on sample points optimization (SPO) is introduced, and NURBS knot insertion (NURBS-KI) method is proposed to reconstruct the blade contour. Then, the designed model and the reconstructed model are compared to analyze the machining error. The reconstruction result shows that the presented method can better restore the blade contour, and NURBS-KI algorithm is proved in this paper to be an effective method to reconstruct blade curve and surface based on small number of measurement points. As illustrated in deviation analysis results, the machining error is within the design tolerance, and the finishing allowance can be removed afterwards. •Sample points optimization (SPO) is proved in this paper can better restore the blade contour than merely using chord tolerance method.•Knot insertion can help to reduce reconstruction error.•Error analysis results show that the machined blade fits well with the design intention.•All the models and results are displayed through MATLAB.