Identification And Traceability Of Vibration In Milling Process

Milling is usually used in mechanical processing,but the strong vibration state appeared in the process of the milling will lead to unqualified conditions of machining workpieces,and there are many reasons that lead to the strong vibration state.According to the main reasons of the strong vibration,based on theoretical analysis and experimental research,this thesis studied the vibration state of milling process,and the main research results are as follows:Based on the theoretical analysis,the dynamic model of milling system is established,and the influence factors of milling force are analyzed.Based on the dynamic differential equation,the factors that influence the vibration state of milling are determined.It consists of the cutting system itself composed of machine tools and tools,as well as the four cutting parameters of the cutting system,and the experimental program is designed.By means of the hierarchical cutting experiment,the root-mean-square of the vibration signal are determined as the time-domain parameters of the vibration state,And the relevant threshold is determined.According to the frequency domain analysis of the vibration signal and the characteristics of the spectrum,the types and characteristics of the two kinds of cutting vibration states are determined.In the amplitude spectrum,tooth frequency and its higher harmonic frequency is the characteristic frequency of forced vibration;when the high frequency component peak,it is the basis of cutting chatter.The modal analysis of the machine tool is carried out by the percussion experiment,and the modal parameters such as the eighth order mode and its mode are obtained by the multi-point excitation method.The method of ODS working deformation is used to obtain the frequency components in the cutting process.Then,through the ODS to the experimental modal decomposition technique,the contribution of the natural frequency of the machine tools under different working conditions is obtained,the root of the forced vibration is found,and suggestions for reducing vibration are proposed.