Research On Process And Equipment Integration Of Electronically Controlled Permanent Magnet Blank Holder Sheet Forming Test Machine

The formability of sheet metal referred to the adaptability of sheet metal to the stamping process.The research on the formability of sheet metal and related issues is generally a marginal subject between material science and stamping technology.The formability of the sheet was usually expressed by the resistance to cracking,molding and setting,the resistance to cracking was the most important index to measure the quality of the forming performance.The sheet metal formability testing machine developed based on the electronically controlled permanent magnet(EPM)blank holder force control technology can significantly simplify the structure of the traditional testing machine,and also has the advantages of energy saving,environmental protection and easy control.Research on related issues has theoretical and practical significance.Using the EPM blank holder force control method,an EPM blank holder sheet forming test machine,which could be used for sheet metal deep drawing forming performance experiments,was developed and designed,and related issues are studied.The main research contents are: according to the requirements of sheet metal deep drawing forming performance experiment,design an EPM blank-holding sheet forming test machine with double-action function;design an EPM magnetic pad,mold and control system and analyze the structure of the test machine;conduct electromagnetic field simulation on the magnetic pad in the control system,and analyze its loading performance;based on the EPM sheet forming test machine,carry out the steel sheet and copper sheet deep drawing test research to verify the reliability of the testing machine.Firstly,the magnetic circuit of the double pole unit magnetic pad was analyzed when it was charged and demagnetized.At the same time,the similarities and differences between traditional clamping and EPM clamping are analyzed,and the feasibility of using EPM clamping is demonstrated.Through the combination of theoretical analysis and numerical simulation,it is analyzed that the two factors that affect the magnetic attraction force of the magnetic pad were the current intensity and the air gap.Secondly,based on the EPM technology and the test requirements of sheet metal forming performance,an EPM blank-holding sheet forming test machine was developed and designed,and two installation modes of the testing machine,front-mounted and inverted-mounted,were designed Which included a magnetic pad with 36 pole units.Developed a deep drawing process control system.Using ANSYS-Workbench software to conduct structural analysis and modal analysis of the testing machine,the rationality of the testing machine design was verified.Thirdly,the electromagnetic field simulation analysis of the magnetic pad was carried out by using the finite element method,and the Maxwell magnetic field simulation results were imported into ANSYS-Workbench,and the magnetic-mechanical coupling simulation was carried out,and the structural deformation of the magnetic pad and the force of the slab under different states were analyzed.Finally,the force of the slab was imported into the Dyanform software for deep drawing simulation analysis.Finally,the 08 AL cold-rolled steel sheet and the H62 copper sheet were selected to carry out deep-drawing tests under different blank-holder force loading conditions.The test results shew that the test requirements for the sheet metal deep drawing performance could be realized by using the EPM blank-holding sheet metal forming test machine.The strain distribution of the test piece was obtained by using the Vialux Auto Grid strain scanning system,and the accuracy of the simulation analysis and the reliability of the testing machine were verified by comparing the test results with the simulation results.