Study On Bending Process Of Micro-tube Of 6063 Aluminum Alloy By Electrically-assisted Forming

With the increasing demand of people and the rapid development of science and technology,products are gradually moving towards miniaturization,portability and multi-functionalization,which has become an industrial development trend.Especially on micro-satellites,with the continuous miniaturization and high-performance of new-generation satellites,more and more high-precision electronic systems such as high-resolution CCDs are integrated in smaller and smaller spaces.The heat transfer requirements and bending shape of the microtubes must change with the shape of the satellite,but the bending of microtube is a complex forming process under the coupling of multiple factors.There are many forms of bending defects,and it is difficult to achieve integrated control of defects.Therefore,it is of great significance to study micro-bending forming process of 6063 aluminum alloy microtubes by electrically-assisted forming.This paper studied the electrically-assisted bending forming process of 6063aluminum alloy microtubes,using a combination of experiment and finite element analysis,the micro-tube electrically-assisted bending multiphysics coupling deformation behavior,including current field,temperature field,stress and strain field,etc.The effects of tube diameter,bending radius,bending speed and current density on the quality of tube bending are analyzed.Then gradually optimize the forming parameters.Based on the finite element analysis software ABAQUS,the finite element simulation of electrically-assisted tensile of 6063 aluminum alloy micro tube was carried out,and the influence of various parameters on the tensile properties of micro tube was analyzed.The simulation results show that the temperature in the necking zone of the microtube increases exponentially with the increase of current density and current loading time,and the softening tensile stress of the microtube gradually decreases.Through the finite element simulation of electrically-assisted bending of 6063aluminum alloy microtubes,the changes of current field,temperature field and stress-strain field during microtube electrically-assisted bending and the size effect of microtube bending defects were analyzed.the results show that:when the microtube is assisted by current,the deformation area of the microtube is heated and the flow stress is reduced,which is beneficial to bending.Compared with microtube bending,the cross-sectional distortion of microtube electrically-assisted bending is greatly improved,and with the increase of current density,the increase of tube diameter and the decrease of bending radius,the decrease of cross-sectional distortion is larger.when 50A/mm~2 current was applied,the cross-sectional distortion of R10-6(bending radius 10mm,tube diameter6mm)is reduced by 14%compared with the current-free bending.However,the electrically-assisted bending will increase the change rate of the wall thickness of the micro tube,thus increasing the risk of bending crack and wrinkling,which lays a foundation for the experimental study of the electrically-assisted bending process of 6063aluminum alloy micro tube.It laid a foundation for the experimental study of electrically-assisted bending of 6063 aluminum alloy microtube.The influence of parameters such as the diameter,bending radius,bending speed and relative wall thickness of the microtube on the cross-sectional distortion was studied.Through the analysis of the range of orthogonal experiment,the factors influencing the distortion of the micro-tube bending section were obtained from large to small in order of tube diameter>bending radius>bending angle>bending speed.According to the orthogonal variance analysis,it is found that the diameter and bending radius have a greater influence on the cross-sectional distortion,while the bending angle and bending speed have a smaller influence.The distortion of the bending section increases with the increase of the tube diameter,the decrease of the bending radius,the decrease of the relative wall thickness,and the decrease of the relative bending radius.combined with the experiment and finite element simulation,it provides an important basis for the reasonable selection of process parameters,the control of section distortion and wall thickness change,and the improvement of bending quality.