Higher drawing depth and less wrinkling due to drawbeads in paperboard forming

Deep drawing of paperboard has shown promising results for the packaging industry due to its high productivity, economical process routes, and geometrical freedom. Paper, as a material, offers a combination of compostability and recyclability while consisting of renewable resources. However, formed paper can exhibit wrinkles due to the excess material during the deep drawing process. Wrinkles form differently depending on the anisotropic behavior caused by fiber orientations. To control material deformation while forming asymmetric components the sheet metal industry uses draw beads. This paper investigates the impact of draw beads on paperboard forming. The goal is to avoid additional process steps while increasing the achievable drawing depth as well as the wrinkle control. The design of the draw beads, including their advantages and disadvantages, is discussed based on experimental tests and compared with numerical simulations. Results show that while draw beads increase drawing depth and reduce wrinkles, their position and length affect the severity and distribution of wrinkles, as well as the wrinkle-free distance.