Method Of CNC Abrasive Belt Gringding Of Aero-engine Blade

Aero-engine blade as a high precision parts and components of the aircraft,its machining accuracy and surface quality is directly related to the performance of the whole machine and its operation safety.As for precision parts with complex curved surface,including the aircraft engine blade,in order to improve the surface quality,generally using the method of grinding and polishing to remove residual material parts of the surface.In the 1990 s,the grinding of blade surface usually adopts manual grinding.Its processing quality completely depend on the technique of workers.Since entering the new century,with the development of numerical control technology and abrasive belt grinding technology,CNC belt grinding gradually replaced manual grinding,the machining quality and efficiency of blade had developed variously.In recent years,with the rapid development of aviation industry,request of the blade machining quality and machining efficiency is getting higher and higher.Polishing processing is not only to remove residual material and lower surface roughness values,but also a ultimate process of blade's contour machining,thus the current method of grinding and grinding technology can not meet the needs of practical production.In order to improve the blade grinding production efficiency and achieve a certain blade form in one process,this paper adopts the integration of a measurement-modeling-grinding processing method,namely by building integrating online measurement of aircraft engine blade grinding center to complete the grinding processing of blade body surface,joint flange,hub transfer,clapper and other parts in one process.In this paper,the unevenness of aircraft engine blade body profile allowance distribution and the challenge of grinding difficult machining parts have been solved.Around the above problems,this paper has carried out research as follows:First of all,the paper analyzed existing problems in current aircraft engine blade machining grinding process,and according to the above problems,the planning scheme of the overall operation of the grinding center has made.At the same time,the key technology and CNC abrasive belt grinding machine grinding station axis movement is analyzed,and solution on the basis of each part of the blade grinding is worked out.Secondly,according to the knowledge of complex surface parts processing,the geometric relationship between the walking step length,the residual height and theprocessing bandwidth along with both the approximation error caused by the linear interpolation in the blade grinding process and the normal vector rotation error caused by the tool swing is analyzed.On this basis,the feeding step length and bandwidth calculation are studied.In addition,conducted a study in extraction method of blade machining allowance,reconstructed the blade model according to three coordinate measuring data and compared with theoretical model to calculate machining allowance of each cutter contact point.At the same time,the further optimization of allowance extraction has take placed,namely reconstruct allowance distribution model through calculating the cutter contact point allowance of measurement section,and then reverse calculate the allowance of each cutter contact point.Afterwards,studied CNC abrasive belt grinding algorithm of each part of the aircraft engine blade.For the blade body surface,put forward the linkage CNC abrasive belt grinding method with seven shaft,namely using six axis for posture adjustment and the seventh shaft for grinding quantity control.At the same time,according to extract all of the machining allowance and relevant algorithm,established the material removal model.And on this basis,studied the seven axis linkage motion control algorithm.For the difficult parts such as clapper,hub transfer,joint flange,put forward with the method of lateral grinding,and the algorithm of lateral grinding and the interference in the process of grinding adjustment method is studied.Finally,based on the Open CASCADE geometric modelling platform,using the above algorithm combining with the object-oriented C++ programming language,a Ribbon interface style of aircraft engine blade CNC abrasive belt grinding proprietary software has developed.The software is mainly to realize the off-line cutter location calculation and cutter path optimization technology,the technology of reconstruction leaf curved surfaces and extract of surface allowance and technology of CNC program generation of each part of the blade grinding.At the same time,using the software to generate the corresponding NC machining program and carried out the blade grinding experiment.Compared the results of the analysis before and after grinding,the correctness of method and algorithm of grinding and reliability and practicability of the software has been verified.