| Copper plate parts are widely used in industrial production and civil electrical appliances.Considering economic factors,the thickness of general copper plate parts is relatively thin,and their forming properties are usually poor.Compared with steel sheet forming,the work done by the blank holder force accounts for a larger proportion of the total forming energy consumption.Electronically controlled permanent magnet technology has been widely used in various fields due to its advantages of strong magnetic force,energy saving and environmental protection.Therefore,the electronically controlled permanent magnet technology is applied to the blank holder process in the deep drawing of copper plate,and the magnetic attraction is used as the blank holder force,which has broad application prospects in realizing low-carbon forming.Using theoretical analysis,finite element simulation and experimental methods,the copper sheet deep drawing process is used as the research object to study the key technical issues of the electronically controlled permanent magnet blank holder deep drawing.The main contents include: analysis of the electronically controlled permanent magnet blank holder method The working principle of the,combined with the characteristics of deep drawing,the design of the electronically controlled permanent magnet magnetic pad,the magnetic circuit analysis of the magnetic pad,the study of the influence of different current intensities on the magnetic attraction of the magnetic pad,the experimental study of the copper plate electronically controlled permanent magnet blank holder and deep drawing,The energy consumption analysis of the deep drawing process of the electronically controlled permanent magnet blank holder is carried out.First,based on the electromagnetic field theory and electronically controlled permanent magnet technology,the structure and working principle of the electrically controlled permanent magnet pad are theoretically analyzed,and the principle accuracy is verified through the finite element software simulation of the magnetic circuit state of the magnetic pad during demagnetization.Based on the principle of electronically controlled permanent magnet and the characteristics of deep drawing,the magnetic field area and the forming area are overlapped,and the magnetic pad of the eight-pole unit and the supporting drawing die are designed.The rationality of the design of the magnetic pad of the eight-pole unit is verified by theoretical analysis and finite element simulation.Secondly,through the ANSYS finite element software and the magnetic attraction experiment,the magnitude of the magnetic attraction of the magnetic pad under different currents is obtained.It is found that the magnetic attraction change trend of the two is the same,and the values are basically consistent,which verifies the accuracy of the ANSYS software simulation.At the same time,the results show that the magnetic attraction force increases linearly with the increase of the current intensity.When the excitation current is40 A,the magnetic attraction force of the magnetic pad can reach 32649 N.Once again,the H68 copper plate was selected,and the drawing experiment of cylindrical parts based on the electrically controlled permanent magnet blanking method was carried out under different current intensities.The experimental results were compared and analyzed by Dynaform finite element simulation,and it was found that the simulated part and the experimental part had consistency in the forming effect.When the current is 15 A,the blank holder force is too small,and the sheet material has serious instability and wrinkles.When the current is 25 A,the blank holder force is appropriate and the sheet metal forming effect is good.When the current is 35 A,the blank holder force is too large,and the sheet material is unstable and ruptured.The results show that as the current intensity increases,the blank holder force provided by the magnetic pad increases.At the same time,it was verified that the blank holder force provided by the magnetic pad in the blanking process was consistent with the magnetic attractive force obtained by ANSYS simulation.It shows that ANSYS software can be used to determine the magnetizing current intensity parameters of the magnetic mat according to the required blank holder force of a specific slab,so as to achieve the purpose of quantitatively controlling the blank holder force of the electronically controlled permanent magnet magnetic mat.Finally,the method of combining theoretical calculation and finite element simulation is used to analyze the energy consumption of different blank blanking methods.The results show that when the blank holder force is 16717 N,the H68 copper plate with a diameter of 94 mm is drawn 25 mm deep,and the energy consumption of the electric permanent magnet blank blanking method is the smallest,which is only 57.4% of the traditional blank blanking method,which is equivalent to The electromagnetic blanking method is 4.1%,and the blanking energy consumption accounts for the smallest proportion,and with the increase of the drawing stroke,the energy saving effect is more obvious.Through the method of finite element simulation,it is found that as the thickness of the sheet material decreases,the proportion of the energy consumption of the blank holder increases;with the decrease of the strength coefficient,the proportion of the energy consumption of the blank holder increases.At the same time,it is concluded that the proportion of the energy consumption of the blank holder of the electronically controlled permanent magnet blank holder is always the lowest at any thickness and strength coefficient of the sheet.This shows that the electric permanent magnet blank holder method is used for deep drawing and most of the total energy is used for deep drawing.Sheet metal forming has the highest effective utilization rate of energy,which proves that the electronically controlled permanent magnet blanking method has the advantages of energy saving and emission reduction. |
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