Forming Process Optimization And Springback Control For Aluminum Alloy Rear Door Outer Panel

(1)The reasonable stamping process was arranged based on the structure and forming characteristics of the part and the formability of aluminum alloy plate.Then,UG modeling design and Autofrom finite element numerical simulation technology were adopted to work out the reasonable forming process die surface,including the drawing tip,process addendum surface,and binder was designed.Subsequently,the forming quality of three kinds of drawbead layout schemes was verified through using numerical simulation.The results demonstrated that non-enclosed double drawbead scheme can control the uniform flow of plate with better forming quality in a more effectively way.Three kinds of aluminum alloy plates: AA6009-T4,AA6016-T4 and AA6111-T4 were selected to simulate the forming process of the part,the results showed that AA6016-T4 has sufficient plastic deformation,but appears local crack easily,With the aggravation of environmental pollution,energy shortage and increasing automotive configuration,automotive lightweight has become a research hotspot.The large-area application of lightweight material aluminum alloy replacing steel in body can effectively reduce automotive weight.The stamping formability of aluminum alloy plate is inferior to the steel panel,especially in large automotive panel forming process,more prone to crack,wrinkle,springback,surface damage and other quality defects.Therefore,it suggests that it should not simply adopt the experience and the standard of ordinary steel panel in designing aluminum alloy panel forming process.Meanwhile,compared with the wide application of Aluminum alloy in foreign automotive body,China is only at the studying and attempting stage,so it requires more in-depth research on the forming process of aluminum alloy panel.Taking an aluminum alloy rear door panel as the research object,finite element numerical simulation and mathematical optimization methods were used to explore how to efficiently and accurately carry out the rear door outer panel forming process design,forming quality optimization and influencing factors analysis,springback control.The research results and methods are of a certain guiding significance for researching and designing other automotive aluminum alloy panels forming process.The main research contents of this paper contain the following several aspects: AA6111-T4 has relatively poor formability,but has no crack,AA6009-T4 has moderate formability.(2)Due to the forming process of the part prone to crack and wrinkle,four process parameters of blank holder force,friction coefficient,die clearance and die radius were selected as optimization variables,with the maximum thinning and thickening rate as the optimization objectives,using the Box-Beheken test and the two order response surface method to establish nonlinear mapping relationship between optimization variable and objectives,and predicting the effects of single factor and multi factor interaction on optimization objectives.Then,multi-objective optimizing is conducted through using NSGA-II genetic optimization algorithm and the process parameters combination which can effectively control crack and wrinkle is found.(3)Aluminum alloy elastic modulus is easy to springback,while the part unloading and trimming springback were large and uneven distribution.Consequently,die face compensation technology was adopted for the iterations compensation of the forming process surface,the trimming springback was controlled within the tolerance range of ±0.50 mm after four times compensation.