Research On Machining Measurement Of Blade Complex Surfaces And NURBS Surface Reconstruction

China has included the development strategy of large aircraft in the development projects in the next 15 years.The aviation industry has an increasingly prominent strategic position.The level of blade manufacturing has greatly affected the working performance of aero engines.Free-form surface reconstruction of the blade free-form surface during the machining process is necessary for the subsequent compensation processing of the entire blade.The main object studied in this subject is aeroengine blades,which are complex torsional curved surfaces.The process of surface reconstruction is the reconstruction of complex curved surface models.The algebraic curve and surface methods usually used cannot describe complex curved surfaces.This topic chooses The parametric curve and surface method is used to reconstruct the model,and the parametric curve method is used to obtain the required contours of the aeronautical blades for blade modeling,and then the machining and measurement processes are simulated and the physical machining trajectory planning is performed,and then the solid machining and measurement are performed.Finally,the leaf data points were collected for data processing and leaf model reconstruction.The main research contents of the subject include:(1)This topic uses parametric curve and surface methods to establish and analyze blade models.The definition,properties,mathematical models,and simulation analysis of curve and surface reconstruction methods based on Bezier theory,B-spline theory,and NURBS theory Discuss and determine the method of surface reconstruction for this subject.(2)Due to the particularity of the complex curved surface of the blade body,before the three-dimensional modeling of the blade,the airfoil and the cascade are calibrated according to HB 5647-98,and the mathematical parameters of the cascade are modeled.Use the spline diagram method to construct the profile of the airfoil and extract the necessary initial parameters.Construct the spline through the high-degree polynomial to solve the model of the airfoil.According to the requirements of HB 3D modeling of blades in HB 7774.4-2006,complete Three-dimensional modeling of the blade,and programming and optimization of the CAM machining program according to the required machining conditions,and Vericut simulation of the NC machining process.(3)The turning and milling machining and measurement experiments of the blades were completed,the experimental machining scheme,the required tools and experimental materials were determined,and the turning and milling machining of the blades was completed with the help of the VMC1100P vertical machining center.The OPS-20M workpiece measurement system is used as the contact measurement implementation solution,and the German ZEISS scanner is used as the non-contact measurement implementation solution.The blade profile data points obtained by the measurement are stored.(4)Determine the inverse interpolation method for data fitting by NURBS,compile related programs to check the fitting effect,perform noise removal on the data obtained by non-contact measurement,smooth data points and other data processing,and use the NURBS method on the leaf section The data points obtained by the contact measurement were used for curve fitting,and the forward modeling method was used to perform model reconstruction and 3D deviation analysis in UG and Geomagic Studio and Geomagic Qualify software.