Research On Measurement Method And Realization Technology Of Aeroengine Blades

Aero engine blades are precision parts,and their geometric accuracy and surface processing quality have a great impact on the performance of aeroengine.The shape of the blade has a great influence on the air flow,which is directly related to the propulsion of the aeroengine.As the aero engine blades surface is a complex free space surface,and its high precision requirements,so the geometric accuracy is difficult to guarantee.And the accuracy is generally guaranteed by means of detection,the current commonly used method of measurement is not accurate,can only roughly determine whether the shape of the aeroengine blades cross section is qualified.Domestic coordinate measuring machine and its software system are basically foreign imports,high cost,and more used in blades sampling,can not be massively tested.Aircraft engine blades are mostly made by titanium alloy which makes it costly and often requires high level process and long processing cycle,thus there will be a huge loss of waste when process failure happens.In order to avoid the occurrence of the above problems,this paper analyzed the aeroengine blades by using the coordinate measuring machine with rotary table and the development of the aeroengine blades detection system.Provided a data basis for the processing of the aeroengine blades,according to the processing allowance for adaptive processing,improved the blade forming rate.This paper focuses on the main problems such as the detection method of aeroengine blades,the planning of the aeroengine blades measurement path,the processing of the airplane blades measurement data and the development of the aeroengine blades detection software system.The main contents of this paper are as follows:(1)According to the geometric shape characteristics and detection principle of the aero engine blades,determined the detection method of the aero engine blade and built the experimental platform.In this paper,a method of selecting the distribution of the measuring points by the curvature is proposed,and the curvature distribution of the blade section line is measured without affecting the computational efficiency.Combined with characteristics of the coordinate measuring machine with rotating table,Plan the measurement path.The VERICUT simulation software is used to detect the collision,and the measurement path is optimized to generate the actual measurement path by using the mechanism of kinematics,Cartesian space coordinate system.(2)According to the chaotic situation of the nearest point distribution of themeasurement point set to the closed curve,a method of finding the nearest point set of the measuring point set to the theoretical intercept is designed by combining the fast iteration method.Ensured the orderly distribution of measurement point set and the nearest point set of the measuring line.Provide mathematical basis and improve the matching efficiency of match of measurement point set to theoretical cutting line.According to the observation of the matching method and results of measurement point set,in this paper,a matching optimization algorithm according to the the index as error sum of squares is minimal along with maximum error is minimal.Not only reduces work of the calculation of measured points set matches with theoretical cutting line,but also improves the accuracy of the final match result.Considering the discordance between blade measurement coordinate system and the theoretical coordinate system,a Initial matching method is put forward,which makes both,basically,on the same position,significantly reduced slowly match or match error occurs caused by coordinate discordance.And finally,generates a match method contains initial matching,exact matching and optimal matching.(3)Based on Open CASCADE open software platform,using VC ++ language combined with measurement path planning and measurement data processing methods,to complete the development and preparation of blade detection software system.This software mainly includes three-dimensional CAD model read module,CMM probe calibration module,CMM coordinate system establishment module,measurement path planning module,measurement data processing module and detection result output module.(4)Imported the software into a coordinate measuring machine with a rotary table,made experiment with actual aeroengine blades.By comparing the results of the final measurement of the software with the measurement results of the bridge coordinate measuring machine of Hexagon Company,which is the leading company of foreign coordinate measuring machine,the feasibility and reliability of the detection method and software has been verified.