Aero-engine Blade Deformation Control Of Milling Process

Aero-engine blades are one of the core components of the engine and its quality largely depends on the design and manufacturing level of the shape of the blade. The blade is a typical thin-walled free curved surface part, the shape and the manufacturing precision directly determine the propelling power efficiency of the aircraft engine, and the study of processing methods will help improve processing efficiency and precision of these mechanical parts. The traditional methods of processing Aero-engine blades are time-consuming and hard to ensure accuracy. With the development of CNC technology, the current engine blades are mostly produced by the CNC milling machines, but the precision is still dissatisfactory because of the deformation and stress caused in the processing. How to make full use of the potentiality of the CNC machining, in order to improve the machining precision and efficiency of the engine blade, is the key point and difficulty for the research of the current CNC machining.The factors are numerous in affecting the precision of blade manufacturing and they themselves influence each other, so it is difficult to pick up one single factor which influences the accuracy regularity of blade manufacturing. This paper analysis on the standard size and accuracy requirements of aviation engine blade, and compare comprehensively advantages and disadvantages of the existing processing schemes of the blades. Taking reducing the machining deformation error of the blades for the premise, we decide the optimal processing line. Through the study on spiral milling state of engine blade located in the existing fixture, the focus is the analysis of various factors which cause blade precision processing dimensional accuracy error as the existing milling forces. Based on cutter eccentric and tool rod deformation, we should make instantaneous milling force model, and determine the mathematical model of tool rod and blade deformation under the instantaneous milling force. Because of considering the mutual coupling of instantaneous milling force and the blade model deformation for milling force, offline sheer level and multi-level error compensation schemes based on machined surface static error prediction are offered. With the milling force model, using finite element simulation technology to get iteration, the elastic let deformation of each knife sites and revise the original NC tool paths code. Also in order to eliminate machining deformation error, and through the finite element software simulation in ANSYS, the real-time error compensation tool-position trajectory is got to guide practical processing. The correctness and practicability of the compensation plan are verified by experimental results.