Research On Error Propagation Analysis Of The Thin-Walled Parts In Multi-Stage Machining Process

The complex and thin-walled parts are widely used in aerospace industry. Deformation will easily be caused during the machining process because of its poor rigidity. The research is supported by the National 863 project: The study of precision control methods of complex and multi-process thin-walled parts based on composite error analysis. The error propagation analysis method is studied around the project.In the thin-walled parts process of machining, the coupling effect of quality parameters and error propagation increase the difficulty of control. The dissertation aims to find the influencing factors on the machining error during the numerically controlled machining by analyzing the numerically controlled milling machining of the spherical vertical milling knife based on the process of milling, so as to lay the foundation of the systematic theory for the effective control of the machining errors based on the analysis of error source. In accordance with the milling machining characteristics, the machining accuracy error influencing factors was analyzed though modeling. By carefully considering the influence of the machine's moving errors, installation error, technical system pressure distortion and technical system heat deformation, it includes all the errors into the technical standard coordinates via the homogeneous coordinate transform. Then apply vector superposition method to build the machining accuracy analysis model. Moreover, each error and composite error is calculated by using the Matlab software, the built machining accuracy model is open and practical.Since the considering error are discrete error, in order to assess the accuracy of the parts characteristics, this paper established a mathematical model of the error evaluation, using the Matlab software calculate the error of flatness, cylindrical, Parallelism, roundness.