Simulation And Experimental Research On The New Technology Of Repetitive Deep Drawing Of Spherical Parts

Sheet metal parts produced by special stamping forming play an important role inthe industrial fields, such as automotive, aviation, aerospace, electronics. Research on thespecial stamping forming of sheet metal has become one of the main developmentdirections in stamping fields. Repetitive deep drawing forming of spherical parts canrestrain the local thinning of wall thickness of forming parts and realize approximateequal-thickness wall forming,which is a new special stamping forming technologyprocess. Finite element simulation, theoretical analysis and experiment research on thistechnology were carried out.Based on the repeated deep drawing forming technology designed, the1-time deepdrawing,2-time repetitive deep drawing and3-time repetitive deep drawing of sphericalparts were simulated via Marc software, though which the curves of stress-strain and thevariation curves of wall thickness in each phase of forming process were obtained andcontrastively analyzed. Research shows that repetitive deep drawing can change the stateof the stress and strain of forming process. It can inhibit the reduction of wall thicknessand then improve the forming limit.3-time drawing can achieve nearly the same wallthickness.According to the deformation characteristics of2-time repetitive deep drawingforming of spherical parts and the finite element simulation results, the forming process isdivided into four phases.Then theoretical analysis about the stress changes of each phasewas performed, and as a result, the calculation formula of the circumferential stress wasderived.Experimental research of repetitive deep drawing process was performed after thedesign of experiment die through which spherical parts of good quality were obtained andthe curves of force and stroke were got. Comparing the spherical parts of repetitive deepdrawing forming with the parts of1-time forming, experimental results were exactly thesame as the simulation results, which further validated the feasibility of technology andthe correctness of the simulation. Combined with the bottom cold straightening, thetechnology can realize the forming of deep cylinder with uniform thickness.