Research On Machining Process Of Aero Engine Stator Inner Ring

As an important component of high-pressure compressor stator,stator inner ring with split structure is widely used on various types of turbofan aero-engines.The machining accuracy of stator inner ring is up to IT7 level.Small profile tolerance of passageway surface and high precision of blade’s installation-hole position are required.The machining accuracy has a significant influence on the flexibility of high-pressure compressor inlet blade,and also plays a key role in the coordination between high-pressure compressor and intermediate casing.The traditional processing method of stator inner ring has great hidden defects.Two parts of the ring being processed as a whole will cause deformation of the parts after cutting off,which leading to excessive error.The interference between the passageway surface and the stator blades will cause the stuck of the compressor operating mechanism and seriously affect the performance of the engine.In order to solve the problems of parts deformation and oversize error,it is necessary to analyze the machining process and optimize processing parameters.Make sure the final dimension characteristics are qualified for assembling and working of aero-engines.The main research works and achievements are as follow:Find out the parts’ characteristics that affect the performance of stator inner ring and the difficulties in processing procedures.Basing on data analysis,this research takes the method of advance cutting in order to release internal stress,and designs an optimized processing procedure of "whole ring roughing,split cutting and half ring finishing".The method and dimension of positioning fixture are determined by analyzing the clamping and positioning requirements in stator inner ring’s finish turning,and calculating positioning error both in axial and radial directions.By calculating the recommended pre-tightening force of bolts when parts are compressed,the proper torque of pressing nuts is obtained,and the local deformation of parts after pressing is calculated.According to the calculation results of positioning error and clamping force,the design model of fixture is determined,and the function and structure of fixture base,press plate and other components are designed.Based on the machining allowance and technical requirements of the stator inner ring’s front section,the technical difficulties of NC lathe processing are analyzed,and effective control measures are established.By calculating the cutting power and cutting force in the turning process,the deflection deformation of the tools and the elastic deformation of the parts are analyzed.The finishing cutting parameters of the stator inner ring parts are determined.Through selecting appropriate cutting tools,combining with technical difficulties and cutting parameters calculation results,NC lathe programming is carried out,and a reasonable NC programming scheme and processing flow are built.The optimized processing technology of stator inner ring has been verified by batch production,and the qualified rate of parts has been greatly improved,which can meet the requirements of assembling and working of assembly parts,and effectively solve the problem of severe deformation causing by cutting off the finished parts.