Parametric Control Method And Experimental Research On Abrasive Belt Precision Grinding Aero-engine Blades

Blades are the core high-performance components of aero–engines,working in the hostile environment of high temperature,high pressure,high speed and complex alternating loads,the machining accuracy and the surface quality directly determine the comprehensive performance and fatigue life of the engine.However,the aero–engine blades material is difficult to process and poor in rigidity,blade cross-section changes greatly and the bending and torsion characteristics are complex,thus it's very difficult to achieve precision grinding.At present,the abrasive belt grinding technology has been successfully applied in the aero-engine blades precision machining field,and technology basically meets the processing quality requirements.But grinding quality precisely control is arduous due to the multiple contact deformation in flexible abrasive belt grinding process,controllable process parameters are numerous and interactive effects exist between the parameters,and combination of different grinding process parameters will result in non-linear changes state parameters such as force,temperature,vibration and belt wear etc.To solve this problem,this paper proposes a parametric control method based on the accurate testing and analysis of the process state parameters,the grinding process can be accurately controlled through effectively controlling of grinding process parameters,then it's able to improve the aero-engine blades abrasive belt grinding accuracy and quality.The main research contents are as follows:(1)The blade material and complex curved surface grinding characteristics are analyzed,and the profile contour precision detection and evaluation method is established on the basis of accurate blade coordinate system fitting.Influence of grinding process parameters on the grinding process state parameters and grinding quality is studied considering the seven axes six linkage CNC abrasive belt grinding process.(2)Aiming at test system performance requirements of the key process state parameters,a scheme for establishing accurate parameter test system is proposed in this paper.Hardware is selected to achieve the grinding state parameters conversion and signal conditioning,and the LabVIEW software and its RT real-time and FPGA modules are used to complete the system software development,and to achieve multiple signal acquisition control,data transmission,digital signal processing and data storage for force,temperature and vibration signals.(3)The preprocessor methods of grinding parameters are analyzed,such as digital signal filtering,removal of mean and trend terms and windowing.In this paper,different methods of analyzing state signals and their implementation in software system are studied to analyze the collected signals in time domain,frequency domain and time-frequency domain.Basic grinding experiments on the blade material sample are conducted to explore influence of grinding process parameters on the grinding force,temperature and vibration.(4)The grinding process is planned by employing an adaptive grinding method based on cross-section characteristics and residual model reconstruction analysis.The grinding and polishing experiments of the full blade profile is carried out through grinding process parameters optimization selection based on parametric control method and the established state parameter model.The geometric accuracy and surface quality after grinding are analyzed to verify the effectiveness of the abrasive belt grinding parametric control method.