Research On High-efficiency In-situ Measurement And Toolpath Optimization For Blade Controlled Grinding

The blade is the key component of turbine equipment and plays a decisive role in modern industrial production.Its surface accuracy directly affects the working efficiency and reliability of related equipment.In the surface error correction of blade precision manufacturing,elastic abrasive belt tools are widely used to achieve controlled grinding by iterative removal.In this process,it is necessary to measure the residual errors of blades many times and adjust the tool path according to the error.The traditional off-site measurement and tool path planning methods restrict the machining efficiency and final accuracy.To solve this problem,according to the configuration characteristics of the blade surface,in-depth research on key technologies such as highefficiency in-situ measurement and path optimization in the blade controlled grinding is carried out.Technical solutions and implementation paths are creatively proposed around the technologies such as high-efficiency in-situ measurement,parametric reconstruction of the complex surface,tool path generation,and grinding path optimization.The primary research of this paper is as follows:A high-efficiency in-situ measurement method based on blade key point sampling is established.According to the blade configuration characteristics and measurement accuracy,key points are extracted for sampling measurement,which will significantly improve measurement efficiency.Based on conformal mapping theory,a fast iterative knot placement method is proposed to extract key points from the blade section profile,which can greatly improve in-situ measurement accuracy and sampling planning efficiency.The experimental results and comparative analysis show that the compression ratio of measurement points can reach more than 97% and the measurement error can be reduced by 50% compared with the uniform sampling method.High-efficiency in-situ measurement can quickly obtain the residual error of the blade and provide data support for subsequent surface reconstruction and path optimization.A multi-factor fast reconstruction method for blade complex surfaces is established.This method converts the fitting tolerance requirements into geometric rules of knot placement and solves knot placement quickly through real-time calculation,which can get rid of the excessive dependence of traditional methods on iterative calculation and significantly improve surface reconstruction efficiency.The results of numerical simulation and experimental research show that the number of knots required by this method can be reduced by 20%-35% and the calculation time can be shortened by 86%-92% compared with the traditional methods,and the calculation efficiency can reach 4-14 times.The fast reconstruction of complex surfaces can convert the discrete measurement data into continuous and derivable parametric surface models,which can provide key geometric information for subsequent path planning.A conformal parameter tool path generation method for the blade is proposed.Using conformal parameters to construct tool paths can reduce the attitude adjustment of the removal tool in the blade edge area and significantly improve the machining kinematics.The kinematics analysis of the tool path combined with the machine tool model shows that the maximum speed of the machine tool drive axis can be reduced by90% and the limit feed speed under the constraint can be increased by 4 times by adopting conformal parameter paths.Through the confirmatory removal experiment,it is proved that the optimization of kinematic characteristics can effectively improve removal accuracy and stability.The conformal parameter tool path generation method can generate tool paths with excellent shape and kinematic characteristics on blade complex surfaces,which provides a theoretical basis for subsequent tool path optimization.A stepwise tool path optimization method for elastic abrasive belt equal residual height grinding is proposed.Based on the abrasive belt removal model,the feed rate planning of parametric blade grinding is studied.On this basis,to eliminate the adverse effect of the drastic change of blade curvature on the removal uniformity,a stepwise tool path optimization is used to achieve equal residual height removal,which can effectively improve the removal uniformity and surface precision while maintaining the tool path shape characteristics.The simulation results show that the standard deviation of the removal depth after the path optimization can be reduced by 80% compared with the uniform path and 45.4% compared with the traditional optimized path,and the removal uniformity can be significantly improved.A verification experiment of the technical effectiveness was carried out.On the series-parallel hybrid belt grinding machine,iterative removal grindings of the blade surface were carried out,and the expected surface accuracy was achieved,with the maximum surface shape error less than 0.01 mm.The total measurement time is reduced by 95.5% compared with the intensive measurement,and the measurement efficiency is significantly improved.Compared with the single removal,the mean residual error of the iterative removal results is reduced by 60%,the standard deviation is reduced by69%,and the surface waviness is reduced by 88%.It is confirmed that high-efficiency in-situ measurement and path optimization has a significant effect on improving the convergence efficiency of blade surface error and the final surface accuracy.Takes the blade complex surface as the research object,by using high-efficiency in-situ measurement and path optimization,a blade Controlled Grinding technology is created,which effectively improves the convergence efficiency of blade surface error and the final surface accuracy,and is of great significance to realizing large-scale automatic and precision production of blades.