Research On Contact State And Material Removal Characteristics Of Compliant Abrasive Disc Grinding Of Aero-Engine Blade

Blade is the key component of aero-engine,and its profile accuracy and surface quality restrict the performance and service life of aero-engine.As one of the main means to obtain the working surface of the blade,the precision grinding process is the key link to ensure the accuracy of blade profile and the consistency of blade surface.However,the aero-engine blade has the characteristics of thin-walled structure,weak rigidity,variable thickness and variable curvature,and the grinding process mostly adopts the clamping method of cantilever clamping.Thereby,the difference of mechanical properties in different regions of the blade results in the change of the state of the blade during grinding,which leads to the poor consistency of the material removal on the surface of the blade after grinding.In addition,the blade surface elements are many,the root processing space is narrow,and the accessibility of tools is poor.At present,the precision grinding of blades still depends heavily on the process flow of machining-testing-grindingtesting with manual assistance,and the machining quality stability is poor.Therefore,in order to improve the existing blade grinding process,improve the machining efficiency,and meet the requirements of blade machining,the contact characteristics and material removal depth of compliant abrasive disc grinding are studied in this manuscript in order to realize the control of material removal effect of blade grinding.The main research contents of this thesis are as follows:(1)The characteristics of blade grinding process are analysed.Firstly,the special structure and material characteristics of the blade are studied.The grinding characteristics of aluminum alloy blade are studied,and the difficult problems in the grinding process are pointed out.Secondly,in order to meet the requirements of blade grinding,the abrasive disc grinding process is put forward,the principle and characteristics of abrasive disc grinding process are analyzed,and the theoretical model of material removal rate of abrasive disc grinding is established by combining the method of dimensionality reduction and Preston equation.(2)Compliant abrasive disc grinding and its characteristics are studied.In order to adapt to the characteristics of blade grinding process,a compliant abrasive disc grinding process is proposed,and an abrasive disc grinding device with adjustable compliance is developed.The simulation verifies that different compliance has a significant influence on the blade grinding state.Finally,the simulation analysis of the contact characteristics of abrasive disc grinding is carried out in depth,and the influence of contact wheel speed,contact inclination angle,grinding depth and contact wheel compliance parameter on the contact state in the process is mastered.(3)The prediction of material removal depth in compliant abrasive disc grinding is studied.Firstly,the material removal process of compliant abrasive disc grinding is analyzed,the process is simplified equivalently,and the material removal simulation model based on Archard theory is established.Secondly,the maximum material removal depth in the grinding area is used to characterize the material removal effect,and the influence of contact inclination angle,grinding depth and compliance parameters on the material removal depth is studied respectively.Meanwhile,based on the Taguchi method,a three-factor and three-level orthogonal experimental scheme was designed to explore the influence of coupling process parameters on material removal effect.Finally,combined with multiple regression and BP neural network prediction methods,a prediction model of material removal depth in abrasive disc grinding of aero-engine blade grinding is established.Compared with the prediction results of the two prediction models,BP neural network is selected as the prediction algorithm.(4)The machining experiment and model verification of aero-engine blades are completed.Firstly,an abrasive disc grinding experimental platform with adjustable compliance is built,the grinding force,material removal depth and surface topography measurement of abrasive disc grinding process.Secondly,the grinding contact experiment of abrasive disc is carried out to verify the influence of various parameters on the contact characteristics.Meanwhile,the maximum material removal depth under different working conditions is measured and compared with the predicted value,which verifies the reliability of the prediction model.Finally,the blade surface abrasive disc grinding process experiment was carried out to measure the material removal depth and surface topography of the workpiece surface after grinding.The results show that the material removal consistency of the blade surface after grinding is good.