Analysis Of The Chatter Stability In Frequency Domain Theory

As one of the main means of manufacturing, milling has been widely used inmanufacture of metals.Chatter is one of the most important dynamic instability phenomena in the cutting process, which will seriously affect the machining quality and productivity, and cause wear and damage of the tool, and also reduce the service life of machine tools and cutting tools.Vibration control in milling process has important application value, which is currently one of the frontier research topics in the field of mechanical design and manufacturing.This paper deals with the dynamic analysis and stability prediction of the milling process.The main research content and achievements are as follows:(1) Considering the regeneration effect in the milling process, the two DOF milling dynamics model is established and the method of milling chatter stability analysis in the frequency domain is put forward. IntroducingThe single frequency method and multi frequency method frequency method. With the rotation of the cutter, orientation factor changes with time, which is the difference between the processing of milling and other machining, The orientation factor has periodicity, so it can be expanded into Fourier series, single frequency method is the average Fourier coefficient method, and multi frequency method is the mothod that the orientation factor can be expanded into Fourier series.When the cutting width is small, the milling force waveform is very narrow and discontinuous, such waveforms is narrow and discontinuous, so the waveform harmonic force is very strong in the average value, thereforewe will use the multi frequency method. at last proposed the two method the corresponding stability criterion.(2) Theoretical analysis on dynamic milling model and frequency domain based on stability, stability limit prediction of two degree of freedom milling system, and is verified by simulation. Then, studied the multi frequency method as the order increases, the difference of lobe diagram. And analyzed the influence of tool stiffness and damping factor on the stability of lobe diagram.(3)further considered the effect of damping, Established the dynamic milling model based on process damping, and then conducting the stability limit prediction and analysis, study found that in the low speed rotating conditions, due to the influence of process damping, compared with not considering damping when the lobes will be a clear upward trend, the lower the speed lobes up more. With the increase of rotational speed can influence the process of damping is more and more small. The process damping effects on speed is greater,at last used the simulation to verify the accuracy of the lobes.The work on dynamics analysis and prediction of milling stability in this paper is helpful and useful to the parameters optimization of machining process, machining of high efficiency and the enhancement of the level of milling process.