Thin-walled Box Structure Of The Milling Machining Three-dimensional Stability Of Basic Research

In the thesis, the stability theories for the milling are studied, the FEM analysis for the milling dynamics of thin-walled parts and the three-dimensional stability analysis due to chatter in the milling of thin-walled parts are performed by making full use of the methods of theoretical analysis, dynamic experiments of process system and computer numerical simulation, which lays the foundation for the inhibition of chatter and achievement of stable milling.As for the study of basic stability theories of milling, regenerative chatter theory and the specific assessment method of stability lobe are ananlysed. The two-dimensional, three-dimensional, one-dimensional stability theory is studied respectively. In them the relevant dynamic milling force models, calculation of milling stability limits and ways of plotting stability lobe are presented.As for the FEM analysis for the milling dynamics of thin-walled parts, dynamic milling force model for end milling is established. The selecting principles of indispensable milling parameters are presented. The modal analysis for the milling of thin-walled parts is made to calculate the thin-walled parts modes about the cutting steps including natural frequency and mode shapes. The analysis of dynamic characteristics for the milling of webs is made. The dynamic characteristics of webs of different cutting steps at different speeds are studied in datail. Simultaneously, the maximum displacements of webs about the same cutting step at different speeds are analysed.As for the three-dimensional stability analysis for the milling of thin-walled parts, the two-dimensional stability lobes for the milling of lateral walls are plotted to analyse the nilling stability influenced by different modal and cutting parameters like natural frequency and radial depth of cut. The three-dimensional stability lobes for the up and down milling of lateral walls are plotted to make the three-dimensional stability for it. The two-dimensional stability lobes for the milling of webs are plotted to analyse the stability influenced by different modal parameters like mode superposition. The three-dimensional stability lobes for the milling of lateral walls based on three-dimensional stability theory and three milling parameters are plotted and the three-dimensional stability analysis is made. The stability on different cutting steps of the milling of webs is studied in detail.