Research On Forming Limits Of Electronically Controlled Permanent Magnet Auxiliary Sheet Metal Deep Drawing

The stamping process could be used to process sheets of different materials into workpieces of various shapes and sizes according to actual needs.With the continuous development and application of new technologies,it is an inevitable trend to introduce other physical fields on the basis of traditional stamping processes and develop new forming processes and equipment.Electronically control permanent magnet(EPM)technology has the advantages of green environmental protection and convenient operation.Combining it with traditional deep drawing technology has positive significance for improving sheet metal forming performance,developing new process methods and expanding the application field of sheet metal forming technology.Using the technical difficulties in EPM assisted deep drawing of box parts and basic issues such as the principle of EPM technology were studied.The EPM magnetic component was inserted into the appropriate part of the punch.A new process plan and mold for EPM assisted deep drawing was designed.The influence of different parameters on EPM assisted deep drawing of box parts was analyzed.The experimental research of EPM assisted deep drawing was carried out.Firstly,the deformation characteristics of box-shaped parts was analyzed,the failure causes of deep drawing was summarized,the working principle of EPM technology and EPM assisted deep drawing was analyzed.On this basis,the corresponding drawing die was designed.The calculation formula of magnetic attraction of magnetic field component was given by means of theoretical deduction.Secondly,the charge and demagnetization simulation of the designed magnetic punch was carried out by using the finite element software.The results show that the magnetic attraction force of the magnetic punch was evenly distributed in the fully magnetized state,and the single-side magnetic field assembly can provide a maximum magnetic attraction force of 9300 N for the slab.After reverse magnetization,the magnetic attraction force is only 8.4 N,which can be regarded as complete demagnetization.For the 08 AL circular steel plate with a diameter of 220 mm and a thickness of 1 mm,a deep-drawing finite element model of a square box-shaped part was established.By comparing the forming effects of the new process and the traditional process when the drawing height was 40 mm,it is preliminarily verified that the new technology can improve the forming limit of sheet metal.Thirdly,under the conditions of different forming parameters,the finite element simulation of EMP assisted deep drawing was carried out on the 08 AL steel plate.Taking the maximum FLD damage value and the minimum wall thickness in the forming results as the evaluation criteria,the influence of the parameters such as the size of the edge corner,the size of the slab,the fillet of the punch and die,and the coefficient of friction on the deep drawing process of the box-shaped part are obtained.Finally,the magnetic attraction force measurement experiment was carried out on the double magnetic pole magnetic field assembly.The magnetic attraction force in the fully magnetized state is 9289 N,which is basically consistent with the numerical simulation results;The drawing experiments of square box parts with traditional technology and new technology were carried out by using circular slab.The results show that the new technology can form a higher depth of the parts.The wall thickness distribution results of formed parts further verified the accuracy and reliability of the simulation results.