Research On Forming Process And Spring Back Control For The Automobile Inner Panel Of Rear Door

To manufacture automobile covering part of high quality has become one of the most important topics in the concerning field of sheet forming.Reasonable stamping process arrangement is required and the forming defects occurring during different processes should be solved.In this dissertation,the automobile inner panel of rear door was studied and the relevant design,simulation and actual manufacture were carried on and forming defects of multi-process were focused on.The forming process step: blanking-drawing-trimming-restriking-side trimming was arranged at the analysis of structure characteristics of inner panel of rear door.Firstly,based on the fundamental components of drawing process,the forming direction,binder,inner and outer addendums were designed and the finite element model of drawing process was established.The drawing process was simulated and the major forming defects and their locations during the process with initial conditions were analyzed.In order to optimize wrinkle defects in round corner and make the blank forming more sufficiently,true half round drawbeads were introduced.Based on one step algorithm,polygon blank with irregular holes was designed to improve the splits in local zone D and zone E.Structure process optimization such as “Die surface steps” and “convex hull” were put forward to solve wrinkle defects of zone G.The ARGUS results and CAE simulation results were compared to make sure that the thinning rates of actual drawing products were under 22%.In trimming process,the safety of trimming tools was checked and the tools with ladder wave cutting edges were designed to reduce the stress distributions of trimming tools in local areas.The springback compensation of drawing process was designed and the springback in later three processes were simulated to ensure that the springback states were in precision demands.Actual manufacture and springback check were done to make sure that the final products meet customers' requirements both in forming and in precision quality.