Analysis of die designs for the stamping of an automobile rear floor panel

The stamping process of manufacturing a one-piece rear floor panel of a passenger car has been investigated in the present study. An analysis of the original die design, in which a split defect occurred at the drawn-cup wall, was performed using circle-grid analysis as well as the 3-D finite-element method. The split defect is due to the large area of sheet metal under the blank-holder that limits the flow of the metal towards the cup area. An optimum die design, which consists of a separate die face and a wedge mechanism mounted in the lower die frame, was proposed to provide additional metal for the cup area and to eliminate the split defect without adding an extra operation. This optimum die design was validated by the results of circle-grid analysis performed for the first and second draw operations and also by the good-quality panels produced.