Experimental study on multi-stage deep drawing for rectangular cup with high aspect ratio

Abstract

Multi-stage deep drawing process for rectangular cup using finite element method has been analyzed to understand the main process parameters, to modify the tool configurations for achieving sound intermediate blanks, and to obtain the rectangular deep-drawn cup in the prior study. As shown in the results of the numerical analysis, it has been ensured that the rectangular deep-drawn cup could be obtained. In this study, the tool fabrication and development considering the effects of the intake angle and the ironing operation are performed. The developed tool sets are applied to the multi-stage deep drawing process of this study, and a systematic experiment for the rectangular deep drawing process is carried out. From the first trial in the experiment, several failures are predicted. To solve these failures, the contact surface on the lower die is modified. As shown in the experimental results for the second trial by applying the modified lower die, it is investigated that the failures such as wrinkling and tearing phenomena are not observed, and the excessive deformation behavior due to thinning and thickening effects is decreased. Furthermore, the thickness distributions on the major axis and the minor axis of the intermediate blanks are investigated to be already satisfied by the target (ironing) thickness, respectively. By this systematic approach, it is confirmed that the experimental results show a good agreement with the designed and required configuration of the final product.