Fabrication of five-layer corrugated cup using ultra-thin titanium sheet

Corrugated cardboard, known for its high cushioning properties and strength, is widely used in transportation. In the present study, we focused on the cross-sectional structure of cardboard with voids. Aiming to produce a lightweight, high-strength corrugated cup, we formed the drawn cup with a void structure and evaluated its strength. In the experiment, test material used was pure titanium sheet TP270. The blank had a thickness of 0.3 mm and a diameter of 80 to 90 mm. The special die used was the roller ball die (RBD) with steel balls tightly packed into the shoulder of the die. The diameter of the steel balls ranged from 6 to 8 mm. The punch had a corner radius of 4 mm and a diameter of 39 mm. Both the punch and die underwent conventional heat treatment. The formability of the clad cup was investigated, including the adhesion between the constituent cups, residual stress of the cups, compressive strength, and plate thickness distribution. The drawn cup did not break, and a corrugated layer was formed uniformly on the cross section of the cup. Furthermore, the maximum sheet thickness reduction rate was approximately 10 % or less. It was also found that it was possible to form the drawn cup with a void structure that exhibits high adhesion and high compressive strength.