A geometry reconstruction approach based on cross-section curve blending for adaptive repair of blades

摘要

Due to the inevitable distortion and defects of a worn part, the nominal CAD model from the design stage is no longer suitable for the use in the repair process. This causes the main problem of precisely repairing complex blades. In this paper, an approach to geometry reconstruction based on cross-section curve blending with wavelet decomposition for blade adaptive repair is proposed. It is useful to satisfy the demand of smooth transition machining and improve the precision for the repairing of blades. Firstly, the cross-section curve of the repair blade is decomposed with wavelet which can describe the curve geometry property in detail. Also, blending between curves with constraint is implemented while key geometric features can be preserved such as aerofoil chordal lengths and leading edge radii ratio. Secondly, by using the cross-section curve blending and deformation error compensation methods, adaptive model for shape distortion and defects is reconstructed to solve the part-to-part variation machining problem and to realize precision repair for geometrically complex blades. Finally, tool paths used for the last NC machining process can then be generated to implement the repairing process work adaptively. Examples show that the geometry reconstruction approach is feasible for adaptive repair of blades and the results carry high precision and efficiency.