Research On Stamping Forming And Springback Of Automobile Engine Cover

With the slowdown in the growth rate of automobile production and sales,the automotive industry is facing unprecedented challenges,which puts higher demands on the quality of metal stamping parts such as body parts(inner and outer covers).In this paper,the outer surface of the automobile hood is taken as the research object,and the numerical simulation analysis is carried out by software according to the forming quality,dimensional accuracy and strength of the outer cover of the automobile cover.Through the analysis of the pressing surface,stamping direction,process replenishing surface,blank size,deep drawing and other processes,the orthogonal experiment is used to optimize the process parameters.The simulation analysis results are used to optimize the process design and stamping process parameters.The combination of theory and practice effectively controls the defects such as cracking,wrinkling and rebound during the forming process.The main research work is as follows:According to the structural characteristics and design requirements of the outer cover of the automobile hood,the stamping forming process was analyzed,and the stamping process route was designed.In combination with the accuracy and installation requirements of the part,the stamping process of the outer cover of the hood is determined to be four-order.Initially,the selection principle of the process of stamping direction,pressing surface,process replenishing surface and drawing rib arrangement of automobile hood outer panel is summarized and analyzed,as well as the blank size,pressing surface size and blank holder force.The analysis of frictional force and embossing mode gap was carried out and calculated,which laid the foundation for modeling the post-order finite element and performing simulation calculation.Through the analysis of the simulation calculation results such as the forming cloud diagram,the forming limit diagram,and the thickness cloud diagram,the causes of defects such as cracks and wrinkles occurring during the forming process are determined.By optimizing the parameters and types of drawbeads,improving the local area replenishment surface,designing the "profile step" shape,"remaining meat" and other shapes,solving the forming defects such as cracks and wrinkles in the forming process,and reducing the overall shape of the parts.The thinness is controlled between4% and 23%,which ensures the quality of the part.When the circular drawbead was changed to a square drawbead,the material utilization rate was increased by 7.98%.Through the design of orthogonal test,the stamping process parameters of the workpiece are optimized,and the uniformity of the thickness distribution of the drawing is measured.The optimum combination of the process,the blanking force and the friction coefficient are drawn to the outer surface of the hood.Thickness uniformity has a large influence,while the concave-convex mode gap has little effect on thickness uniformity.On the basis of the orthogonal test,the influence of the stamping process parameters on the springback generated by the drawing process is analyzed.Among them,the blanking force and the friction coefficient have a great influence on the rebound of the outer cover of the hood,and the gap of the concave and convex mold is thick.The effect of uniformity is small.Under the optimum process parameters of the rebound,the maximum thinning rate is 12.1%,the minimum thinning rate is 4.98%,and the difference is 7.12%.The comprehensive thickness uniformity and rebound control factors are used.The final stamping process parameters are: The blanking force is 160 T,the friction coefficient is 0.17,and the mold single-sided concave and convex mold gap is 0.735.Through software simulation and field test,the quality of the parts is high,the thickness uniformity and the rebound amount are all in line with the production process requirements.