Research On Active Compensation And Simulation Technology For Machining Deformation Of Thin-walled Parts

Milling is a widely used manufacturing process in aeronautic and aerospace industries for machining thin-walled work-piece. Due to the weak rigidity of the work-piece, especially the medium or small thin-walled work-piece, manufacturing deformation caused by the cutter/work-piece deflection influences extremely the accuracy and the surface quality of the work-piece and even makes useless products. Consequently, the prediction of the manufacturing deformation in milling process and the investigation of active compensation of thin-walled work-piece have great significance to improve processing quality and processing efficiency. This article studies the effect of the cutting force on the weak rigidity components, accurately predicts the tool deformation of the components, adopts effective active compensation in view of the predicted manufacturing deformation, then could control the manufacturing error in the required range. The main work is as follows.Firstly, the simulation of Finite Element Method of some medium or small typical thin-walled work-piece is analyzed. The result is compared with experimental data. It's proved that this method is effective.Secondly, an active compensation method is proposed. In the method, numerical values of optimization compensation of sample points are computed by iterative method according to machining errors of these points. Based on the compensation numerical values of sample points, the compensation numerical values of other points can be got by some mathematic method such as Lagrange's interpolation, least square polynomial fitting method, weighted least squares polynomial fitting method and B-spline fitting method. Then, tool path can be changed according to the compensation numerical values , so does the numerical control program.Thirdly, the system to generate the active compensation program is developed, using VC++ and Matlab language. Visual drawing of comparing data, tool trace of compensation and numerical control compensation program can be generated by using this system.Finally, study cases of machining of thin-walled part are given. Based on theoretical analysis and numerical simulation, the cutting path and machining NC program are changed by using the compensation system. The validity of the active compensation method proposed in this paper is demonstrated by experimental machining as study case.