Enhancement on deformation uniformity of the target sheet by bulging process with magnetic medium and overlapping sheet

In the field of sheet forming, how to improve its performance is one of long-term goals. It is also an important basis for determining the quality and reliability of sheet forming. In this paper, the influence of overlapping sheet conditions on bulging behavior of Al1060 sheet using force-transmitting medium has been studied. That is, it uses a “soft-and-hard” double-side pressure loading method. The results show that the bulging behavior and forming ability of the aluminum sheet may be changed by adding an overlapping sheet. Compared with the condition without overlapping sheet, when the thickness of the overlapping sheet is 0.5 mm, the maximum thinning rate reduces from 43.95 to 38.16%. It improves the deformation uniformity of the entire target aluminum sheet, and the forming performance also increases with it. Compared with the situation of 1 mm overlapping sheet thickness under the same condition, the uniformities of the wall thickness distribution and the forming properties of the target aluminum sheet with an overlapping sheet thickness of 0.5 mm are significantly better and it reveals the causes. It also establishes that a theoretical model of the warp stress varies with angle, and provides scientific guidance for the improvement of light alloy forming performance and the expanding of the implementation about thin-sheet magnetic media pressure technology.