Research On Variable Blank Holder Force Stamping Process For Automotive Panel Based On Dynaform

As a typical stamping forming part,automobile panel plays an important role in the whole sheet metal forming industry.Its forming quality directly determines the quality of automobile products.The quality control of automobile panel includes surface quality,dimension precision and thickness thinning rate.Engineering practice shows that different processes and the same process but different process parameters may affect its quality,because the reasonable control of process parameters directly reflects whether the defects such as wrinkling,thinning or even cracking will occur in the forming process.Therefore,this paper takes the automobile engine cover plate as the research object,and proposes the research of variable blank holder force drawing technology in the process of automobile cover plate drawing.The main work includes:1、In this paper,the stamping process of automobile engine cover plate is studied by numerical simulation.The forming limit,thickness change and maximum principal strain of the part are analyzed and evaluated.The research shows that under the condition of constant blank holder force,it is easy to thin seriously.2、In view of the problems mentioned above,the simulation analysis of the influence of various process parameters such as variable blank holder force,variable friction coefficient,variable stamping speed and variable die clearance on the forming performance in the process of deep drawing is carried out,and the corresponding influence rules are obtained.The results show that when the variable blank holder force loading mode is incremental,the maximum thinning rate increases with the increase of friction coefficient,and the maximum thickening rate decreases;the impact of stamping speed on the change of part thickness is small;the maximum thinning rate decreases with the increase of die clearance,and the maximum thickening rate increases.3 、 In order to obtain the reasonable process parameters,the stamping process parameters of the automobile engine cover plate are analyzed based on the orthogonal test method.The optimization variables are variable blank holder force,friction coefficient,stamping speed and die clearance,and the optimization target is the maximum thinning rate.The orthogonal test results are studied by the range analysis method,and the best process parameters are obtained.The numerical simulation results are obvious It shows that the optimized process parameters have the best forming effect.4、On the basis of numerical simulation and analysis of stamping forming of automotive hood plate,the optimum technological parameters obtained by orthogonal experiment were used to carry out actual die test.The actual forming results of the parts were obtained.The maximum thinning rate of automotive hood plate was 14.29%,and the maximum thickening rate was 8.57%.The experimental results are consistent with the simulation results in forming state and thickness variation,which also verifies the accuracy of the simulation analysis.