전자기 성형시 금형과 소재의 접촉에 따른 성형성 개선 예측

Electromagnetic Forming is a high speed forming technology which uses electromagnetic (Lorentz’s) forces to shape sheet metal parts. In the current study the effect of the tool-sheet interaction during electromagnetic forming on formability enhancement is investigated using FEM. The decrease in void volume fraction by having the sheet contact with die helps to improve formability. The main purpose of the current study was to predict improvement of formed sheets whether the sheet contacts or does not contact the die under experimental conditions and 3-D finite element analysis. The results show that fractures caused by the voids in the forming sheet appear only in some specific cases and the bulge height of the conical shape was shorter than the height with a free bulge. For the same height conditions, however, the formability was improved for the conical-shaped die when there is sheet contact with the die.