Study On Surface Integrity Control Of High Efficiency Grinding With Flap Wheel For Blisk Blade

At present,the manufacturing of Blisk mainly adopts the method of compound machining,which methods integrate the near forming blank manufacturing,precise forming processing,grinding.However,ball end milling cutter is usually used for precision forming machining.After machining,the blade surface forms obvious peaks and troughs.At the same time,due to the different curvature of the motion path curve,the height of blade profile lines is inconsistent,which will have a great impact on the performance and service life of the engine.Therefore,the blade surface needs grinding to improve surface quality.The grinding technology of Blisk has been relatively mature in foreign countries,but it is strictly blocked in China.Manual polishing is still used as the main method in China.While it is difficult to control the consistency of machined surface,which seriously affects the aerodynamic performance and dynamic balance performance of the engine,thus affecting the life of the engine.Therefore,in order to solve the problems of Blisk grinding technology and break the technical blockade of foreign countries to China,it is necessary to carry out the study of high-quality and efficient blisk grinding technology.In this paper,taking the surface integrity of Blisk blade as the research object,the grinding method of "five axis numerical control + flexible grinding head + flap wheel" is proposed,and the research on the surface integrity of Blisk flexible grinding is carried out.The basic theory and formation mechanism of material removal depth,grinding force,grinding temperature,and surface integrity are systematically and deeply analyzed so as to improve the grinding efficiency and surface integrity.The multi-objective parameter optimization is carried out for the ultimate goal.The main research contents and innovative achievements are as follows:1.The flexible grinding technology of "five axis numerical control + flexible grinding head + flap wheel" is put forward according to the structural characteristics of blisk,and the grinding elastic relationship of flap wheel are analyzed by the flexible grinding head and grinding experiments.It lays the foundation for the research of the blade NC flexible grinding process.2.Establish the prediction model of grinding force and temperature.In view of the characteristics of the flap wheel grinding,the analytical model combined with the test method is selected to deepen the control of the composition structure of the grinding force and temperature.Combining the grinding force and temperature process tests,the influence of the grinding parameters on the grinding force,cutting specific energy and temperature are explored.Besides,the analytical model of grinding force and the response surface prediction model are established,and the optimal model is selected according to the precise of the model.At the same time,the prediction model of grinding temperature is established.3.Establish the prediction model of material removal depth and the life of flap wheel,and determine the optimal grinding range of high efficiency grinding.Through the analysis of material removal mechanism and the experiment of material removal depth,the influence of grinding parameters on material removal depth is revealed,and the prediction model of material removal depth is established by regression analysis method.Besides,the mathematical model of sensitivity and relative sensitivity of corresponding process parameters is calculated to determine the optimized range of material removal depth,and combined the optimized range of the flap wheel life,the optimal range of high efficiency grinding in the high life range of flap wheel is determined,which provides data basis for improving the grinding efficiency.4.The multi-objective process parameter optimization of surface integrity based on material removal is carried out.Based on the formation mechanism of surface integrity,selecting surface roughness and residual stress as inspection indicators,through single-factor grinding tests,revealing the mechanism of the influence of grinding process parameters on surface integrity,combined with the optimization range of material removal depth,the gray correlation degree method is used to optimize the grinding process parameters,determine the significance of the impact of each grinding parameter on the surface integrity and the optimal grinding process parameters,and use the optimal process parameters for the blisk blade,which verifies the reliability of the study.This study achieves the basic analysis and accurate prediction of grinding force and temperature,material removal depth,and surface integrity in the grinding process,and provided the theoretical basis and experimental research support for the practical engineering application of high quality,high efficiency grinding for blisk.