Investigation Of Electromagnetic Forming Technology Of 1060 Aluminum Alloy Array Structure

Metal thin-walled array structural parts are widely used in microelectronics and microelectromechanical products,but traditional forming techniques are prone to problems such as cracks,springback and poor moldability of thin-walled parts.Electromagnetic forming is a method of high-speed forming of metal workpieces using pulsed magnetic field force,which can significantly improve the forming limit of hard-to-deform materials and reduce springback.However,there is a lack of systematic research on the influence of different sheet thicknesses and initial heat treatment states on the forming limit and properties of materials under high-speed deformation conditions.The formation of thin-walled array structural parts can be realized by using the equalizing pressure coil,but the existing equalizing pressure coil has a complex structure and is prone to failure.Therefore,this paper takes 1060 aluminum alloy as the object,and uses macro and micro experiments to study the effect of different sheet thicknesses on the high-speed forming properties of aluminum alloys in O state and H24 state.A high-speed forming method of array structure based on planar racetrack coil is proposed,and finite element simulation and experiment are used to study the electromagnetic force distribution on the aluminum alloy plate,and the influence of different process parameters on the mold fit and uniformity of the workpiece after forming.The main research contents and conclusions are as follows:(1)Quasi-static stamping and electromagnetic forming studies were carried out on AA1060-O and AA1060-H24 alloys with thicknesses of0.2,0.5 and 1 mm,respectively.Through the experimental study of forming limit,it is found that compared with quasi-static stamping,the forming limit of AA1060-O alloy under electromagnetic forming conditions is less improved,and only dislocation plane slip occurs.And the formation of dislocation cells improves the formability,in which the maximum strain of the 0.2 mm specimen is increased by 246.2%.The dislocation proliferation,grain refinement and Taylor factor of AA1060-H24 alloy increased after electromagnetic forming,which improved the hardness of parts.Compared with quasi-static stamping,the introduction of initial dislocations under electromagnetic forming conditions is beneficial to improve the forming limit and hardness of the material.(2)The array structure fabrication of 0.2mm thin aluminum plate under the action of plane racetrack coil was carried out by combining finite element simulation and experiment.The electromagnetic field-structural field coupling model is established to analyze the influence of discharge voltage,pad thickness and discharge times on sheet metal forming properties.The simulation results are consistent with the experimental results.The study found that when the voltage was increased from 4k V to 7k V,the film adhesion of the sheet was improved.The thickness of the spacer is increased from 0mm to 1.5mm,and the film sticking property of the sheet increases first and then decreases.This is because the increase in the thickness of the spacer leads to bulging at the bottom of the sheet after forming.Multiple discharges help to improve the stickability of the part.Finally,an array structure with a filling rate of 0.89 was formed under the conditions of 6k V discharge voltage,1mm thickness of spacer,and two consecutive discharges.(3)Aiming at the problem of insufficient film adhesion in direct electromagnetic forming,the research on the forming process of electromagnetically driven soft film was carried out.The effects of rubber thickness,driving plate thickness and discharge times on sheet metal forming were investigated experimentally.The study found that the rubber thickness has a great influence on the sheet metal forming,and the discharge times have little effect on the electromagnetically driven soft film forming.After electromagnetic forming of sheet material,electromagnetic drive soft film shape correction is performed,and the filling rate is increased from 0.89 to 0.925.Using electromagnetic drive soft film forming filling rate reached 0.965.