Research On The Effect Of Residual Stress On The Deformation Of Pure Copper Substrate In Double-sided Lapping

Double-sided lapping technology is an ultra-precision machining method for obtaining high precision surface.It has the advantages of simple equipment,convenient operation and high production efficiency,and has gradually become the mainstream processing method for producing high-precision planar components.For the high-precision machining of thin-walled copper plane components,due to the weak rigidity of the workpiece and the sensitivity of the stress,the machining accuracy is difficult to be guaranteed and maintained,and there will be many problems in the process of machining,one of which is easy to deform.Therefore,in this paper,through theoretical analysis and finite element simulation of the influence of residual stress on the deformation,the influence weight of initial residual stress and machining residual stress on the deformation is obtained,and the process optimization of deformation control is carried out to guide the actual production.The main researches are as follows:(1)The influence mechanism of residual stress on machining deformation is analyzed theoretically.The main cause of machining deformation is the redistribution of stress caused by the existence of initial residual stress and the introduction of machining residual stress.Through the establishment of two-dimensional model,based on the theory of elastic mechanics,the calculation formula of machining deformation is obtained respectively when only the machining residual stress and the initial residual stress are considered,so as to analyze the influence law of machining deformation,which provides a theoretical basis for the three-dimensional simulation analysis of the deformation of double-sided lapping.(2)Based on the element birth and death method and the mapping method,a finite element simulation model for the prediction of machining deformation of double-sided lapping copper components is established.In order to obtain the influence of initial residual stress and machining residual stress on the processing deformation of pure copper components in double-sided lapping,the initial residual stress of the workpiece was measured,the material removal rate under common parameters and machining residual stress were obtained through double-sided lapping experiment,which provided data support for the prediction of the finite element model.Compared with the deformation simulation model,this paper carried out the verification experiment of double-sided lapping of pure copper components,analyzed the surface warpage and shape of the workpiece after machining,and verified the accuracy of the deformation prediction simulation model,and the method of modifying the simulation model is proposed,which provides a reference for the prediction and simulation of machining deformation.(3)Based on Preston equation,a mathematical model for material removal of double-sided lapping workpiece is established,so as to obtain optimized process parameters to control workpiece deformation.Considering the main cause of workpiece deformation in the process of double-sided lapping,according to the removal model,the processing parameters of the upper and lower lapping plates of the optimized double-sided lapping machine are obtained to control the processing deformation.The accuracy of material removal model and the feasibility of optimizing process parameters are verified by experiments,which provide guidance for the actual processing and production.