Study On The 3D Flutter Stability And Surface Roughness Of Aeroengine Blade In High Speed Turn-milling

Aeronautical blade is a complex thin-walled cured surface part, and has a very important application in national pillar industry, for example aviation industry, always called "the heart of the heart". Because of its high hardness and low density of titanium alloy, which meets the demand of aviation industry, titanium alloy is widely used for aeronautical blade. Now NC machining is widely used in blade machining, but titanium alloy is the difficult-to-cut material, so a series of problems exist in the blade machining. But, in recent years, to meet the complication and high efficiency of product production, High Speed Turn-milling Combined Machining develops rapidly and it has a good performance in difficult-to-cut material machining. Blade is the thin-walled part which has a high demand for shape precision, so it is hard to analyze the cutting force based on the classical theory; machining deformation is one of the most important problems in blade machining, and one of the important factors is flutter. So, in the blade machining, the study and control for machining deformation and flutter stability can lead to a better machining accuracy and surface quality.In this paper, in order to solve the cutting force of thin-walled blade in high speed turn-milling machining, rigid cutting force model for ball-end milling is built; considering the deformation of workpiece-tool system, the flexible cutting force model is built; with the concept of relative transfer function, flutter stability model for the system of high speed turn-milling blade machining is built, also the parametric analysis is done. The main research contents of this paper are as follows:(1) Study the parameters of blade and build the parametric geometric model for blade using the quintic polynomial method. Then, program for section profile and 3D profile using Matlab, and analysis on the effect of parameters on the section profile.(2) In order to solve the cutting force of thin-walled blade in high speed turn-milling machining, rigid cutting force model for ball-end milling is built; considering the deformation of workpiece-tool system, the flexible cutting force model is built; study the iterative algorithm of blade deformation affected by cutting force, then calculate the workpiece deformation and tool deformation on any different manufacturing point, finally build the flexible cutting force model; also do the parametric analysis. Study the periodic change of cutting force in the workpiece coordinate system.(3) Through studying the flutter stability model of Single Degree of Freedom (SDOF) system and multi-degree of freedom (DOF) system (turning/milling system), meanwhile utilizing the concept of relative transfer function, the flutter stability model of high speed turn-milling system is built; utilize Matlab to get the 3D graph of flutter stability, and do the parametric analysis, summarize laws for it.(4) Build the theoretical surface roughness model of high speed turn-milling for blade, simulate with Matlab and finally summarize laws through the comparison between one parameter with different values.