| Hollow aluminixun alloy structure has many advantages,such as light structure,high strength,stable mechanical properties and good sound insulation effect.More and more hollow aluminium alloy structures are used in the manufacture of high-speed train body,it effectively reduces the weight of the body and improves its carrying capacity.However,due to its weak rigidity,hollow aluminium alloy structure has some problems in milling,such as low machining stability,serious machining deformation and so on.In this study,milling process of 6005A hollow aluminium alloy structure is studied by finite element method.The influence of machining parameters on cutting force,cutting temperature and deformation is analyzed,and the machining parameters are optimized.The main contents and conclusions of this paper are as follows:(1)Starting from the analysis of the performance and machining technology of the thin-walled hollow aluminum alloy structural material,the constitutive model of the 6005A aluminum alloy material,the failure criterion and the chip separation criterion for milling are analyzed.Based on ABAQUS finite element simulation software,a three-dimensional finite element model for milling hollow aluminium alloy structure is established,and the accuracy of the model is verified.The process parameters of hollow aluminium alloy structure milling process are analyzed with the change of machining time.The cutting force change and the distribution of cutting heat,as well as the stress and strain distribution of the workpiece are obtained when the tool is used to process ribs with different angles.(2)The single factor simulation analysis of the influence of machining parameters on cutting force,cutting temperature and workpiece machining deformation during the mill:ing process of hollow aluainum alloy structure was carried out.With the increase of spindle speed and cutting heat,the resistance of cutting tool to material removal decreases and the deformation decreases,but the fluctuation of cutting force increases and the stability of cutting force decreases.With the increase of feed per tooth,the material removal rate increases,the cutting force and the cutting temperature increase,but within the smaller feed per tooth,the change of cutting force and deformation is small,which can properly improve the feed per tooth to improve the machining efficiency.With the increase of back engagement,the friction between tool and workpiece increases,the cutting force and cutting temperature increase,and the workpiece rib deformation is serious.(3)Orthogonal experiment was designed to optimize the milling parameters of hollow aluxminium alloy structure.Firstly,the influence order of cutting parameters on cutting force,cutting temperature and deformation was analyzed.The results show that the main influenee on cutting force is spindle speed,and increasing spindle speed can reduce milling force;the most important influence on cutting temperature is feed per tooth,reducing feed per tooth can reduce cutting temperature;and the most important influence on cutting deformation is back feed,reducing cutter feed.The amount of knife on the small back can reduce the deformation of the "let knife" of the ribs.Multi-objective optimization was carried out with milling force,milling temperature and machining deformation as the evaluation index.The optimal machining parameters are combined with spindle speed of 11000r/min,feed per tooth of 0.08mm/z and back engagement of 1mm.The results of this study show that the finite element metihod ean provide a feasible method for the study of the machining mechanism of large cross-section hollow thin-walled aluminun alloy.The research content of this study has theoretical value and practical guidance for the machining and production of the train body. |
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