Research On The Integrated Processing Technology Of Thin-plate Servo Forming Collaborated With Blank Holding

Based on the elasto-plastic mechanics and sheet metal forming theory,the deep-drawing forming of the square box was studied.The force of the plate was analyzed and the model was established in the flange and the straight edge of the workpiece.A BHF servo-controlled closed-loop system is studied.The system is a program control system.According to the requirements of the sheet forming process,the PID controller is programmed according to the preset BHF control curve.The servo motor rotates to drive the blank holder.The mechanism moves to achieve real-time control and flexible adjustment of the BHF.Using ABAQUS finite element software to perform simulation under the initial value of BHF,and the nodes at the typical area of workpiece were selected.The thickening and thinning conditions were analyzed to study the flow of material in the typical area.According to the simulation results under the initial BHF,the thickening and thinning of the workpiece under the constant BHF are studied.Five BHF values are selected for analysis,the wrinkling and cracking of sheet forming under different constant BHF were studied.According to the forming conditions and the maximum thickening and thinning curves of the plate under different constant BHF,three different BHF curves were worked out,and the stamping simulation was performed under the BHF loading curve.Analyze the variation of the thickness of the workpiece under the three curves and compare them.Select the most suitable BHF curve for the forming.Under the optimum BHF curve,the typical deformation region of the workpiece is selected and the results of the thickening,thinning,and flow conditions of the blank and the constant BHF are compared and analyzed.Forming tests were made to verify the results of finite element simulation.The results show that in the stamping simulation of square box,the maximum thickening rate and the maximum thinning rate are respectively at the flange corner and the bottom corner of the sheet,and the thickness of the sheet at the bottom and straight edges of the workpiece is nearly constant.The use of a suitable BHF curve for deep drawing of the sheet can better shape the forming properties of the sheet and improve the results of the formed part.