Research On Deformation And Stability Of Thin-Walled Aluminum Alloy Members In Side Milling

With the development of maching of manufacturing industry and the progress of numerical control technology,aluminum alloy thin-walled components have been used widely.Since deformation and chatter are easy to occur during side milling of aluminum alloy thin-walled components,the dimensional accuracy and surface quality of the workpiece are seriously affected.Therefore,this paper has studied the modeling of fiveaxis flank milling and force-induced deformation and the stability of thin-walled aluminum alloy member during side milling.Among the thesis,the milling force modeling lays a foundation for the force-induced deformation and chatter prediction of thin-walled parts;the study of the deformation of thin-walled components can be applied to error compensation and then improving machining accuracy;the milling stability prediction can be used to suppressing the flutter of thin-walled members and improving machining efficiency.The main content is divided into the following three parts:A method for calculating instantaneous undeformed chip thickness is proposed,then a five-axis side milling force prediction model combined with a micro-element milling force model is established.By classifying and analyzing the changes of tool posture during the five-axis flank milling process,a calculation model of instantaneous undeformed chip thickness is presented.The coefficient calibration experiment of milling force,five-axis side milling simulation experiment and machining experiment are carried out respectively,and the calculation efficiency and accuracy of the proposed five-axis side milling milling force prediction model are verified by comparing.The deformation calculation model for the side milling of thin-walled components is established.With the tool equivalently replaced,the calculation method of the axial position of the tool cantilever beam model under different micro-element loads is proposed,and the calculation formula of the milling cutter deformation is derived.The thin-walled parts are modeled based on finite element method,and the material removal is simulated with the aid of element activation and killing technology.The iterative deformation calculation steps of thin-walled components are described.The APDL language program is programmed to calculate and analyse the deformation of thin-walled components when the tool is moved to different positions of the workpiece during side milling process.After side milling experiment of thin-walled components was carried out,the deformation predicted by simulation and the deformation obtained from the experiment were compared and analyzed and the accuracy of the established deformation model was verified.A third-order full-discrete method is proposed,which can be used to predict the stability of the side milling system of thin-walled components.The multi-point contact dynamic equations of thin-walled components are established,and the transition process of the equations from physical space to modal space is explained.To provide parameters for system stability judgment,the APDL language program is programmed to extract the modal data of thin-walled components during side milling process.The milling experiment is conducted to verify the proposed three-order full-discrete method.The effectiveness of the method was verified by machining experiments under multiple sets of process parameters.With the extracted modal parameters,the chatter vibration of thinwalled components in side milling is predicted through simulation experiments when the tool is at different positions.