Research On Quality Improvement Of Local Area In Stamping Process Of Automotive Rear Triangular Window Reinforcing Plate

Drawing process is an important process for stamping of automobile panel parts.It is important to improve the quality of automotive parts by improving the local quality and solving the defects of automobile parts during the drawing process.Based on the basic theory of finite element method for sheet metal forming,finite element numerical simulation techniques were used to predict and resolve the problem of forming defects that might occur in actual production.And the above method has become the mainstream method of automotive panel parts production.This subject takes a typical rear triangular window reinforcing plate of an automobile as the object of research and analysis.Through the analysis of the part structure,the local key area of the part was tried to be formed by one-step process.According to the basic structure of the drawing process,the drawing process is sequentially performed.The part forming direction,punching direction,pressing surface,and supplementary addendum surface were designed.The finite element modeling of the drawing process was performed using the finite element simulation software DYNAFORM,and the thinning rate was set as the forming quality evaluation standard.The forming defects and their causes under the initial drawing were Simulated and analyzed.By introducing the equivalent drawbead technique,the feeding condition of the blanks was improved,but the forming defects were not controlled.Subsequently,by optimizing the blank size and shape,a polygon billet was designed to improve the forming quality of the key zone of the drawing workpiece.On the premise of guaranteeing the forming quality,one-step drawing of the key area of the drawn part was abandoned,and the “process bulge” in the area A of the local key area,the “process crater” in the area of the concave package,and the corner area of the branch board were eliminated.The optimization of the process design of “Uplift” which had caused the forming defects of the products,was controlled,But the defects had not been completely solved.Based on equivalent drawbeads,a single layer of discontinuous semi-circular solid reinforcements,double-discontinuous semi-circular solid reinforcements,and inner closed double-layer semi-circular solid reinforcements were designed and optimized to achieve maximum thinning control at 27%.Using single factor test and orthogonal test to determine the best combination of stamping process parameters: blank holder force 110 T,friction coefficient 0.12,punch bilateral gap 2.2t,the maximum thinning rate is controlled within 26%.The process forced the wrinkles zone only appear on the flange area.With the above parameters the final forming quality of the drawn parts met the production standards,which verified the optimization method is practical and effective.The research for stamping process for automotive parts will benefit the future stamping process design and provide the defects prevention measures.