Research On The Prediction Of Machining Deformation In Turning For Pure Copper Thin-walled Planar Parts

Thin-wall planar parts made of pure copper are the key sample pieces for the precision physics experiments,in which the high surface quality and high machining accuracy are deeply required.However,due to the poor rigidity,the part could be easily distorted by residual stress and other factors,which results that it’s difficult to ensure the machining accuracy.Therefore,this paper takes the pure copper thin-walled planar part as the research object and through finite element modeling combined with experimental testing and other methods,the researches on the prediction of machining deformation are then carried out,among which the simulation model of machining-induced residual stress(MIRS)and the deformation prediction model considering the multifactor effects are established,respectively.And on this basis,the evolution law of MIRS and the machining deformation are also explored,which provides a theoretical reference for the improvement of machining strategy.The specific research contents are as follows:(1)Using the finite element software Advant Edge,a three-dimensional(3D)turning simulation model was established to predict the residual stress induced by turning pure copper.Then the model was verified by stress tests that carried out by X-ray diffraction method combined with electrolytic stripping.On this basis,the evolution laws of MIRS under different cutting parameters are also investigated.(2)Based on the mapping method and considering the stress release in the process of continuous flanging,a machining deformation prediction model considering non-uniform IRS and non-uniform MIRS was established.In order to realize the construction of non-uniform IRS field,a mapping algorithm based on shape function interpolation was used to realize the stress data transfer between the different meshes.In addition,considering the continuous change of cutting speed in face turning with constant speed,a two-dimensional(2D)linear interpolation algorithm was proposed to establish the non-uniform MIRS field.Finally,ultraprecision turning and surface measurement experiments are conducted to verify the model.(3)Based on the machining deformation prediction model,the evolution laws of machining deformation are explored,in which the deformation under the independent action of initial residual stress(IRS)and machining residual stress was analyzed,respectively.Simulated results show that compared with the single continuous processing,the strategy of double surface processing is easier to control the deformation induced by the IRS.In addition,reducing the feed rate is more advantageous to decrease the deformation induced by the MIRS.What’s more,the effect of IRS on the final part deformation plays the dominant role,and in order to control the final deformation,the improvement of the initial residual stress state of the workpiece should become the focus of attention.(4)Using Matlab GUIDE development tool and the secondary development of ABAQUS based on Python program,the software of machining deformation prediction for thin-wall planar parts was developed.The software is mainly used for parametric modeling and simulation of machining deformation under the action of single factor or multi-factor coupling.The application results show that the software can realize the prediction and analysis of machining deformation for the given parameters.