Springback and Wrinkle Control in Deep Drawing of Paperboard with Segmented Blank Holder

Abstract

Deep drawing of paperboard enables highly productive forming processes for packaging products made of a recyclable material. However, the inherent anisotropy and low elasticity of paperboard pose challenges for deep drawing processes, especially resulting in direction-dependent springback and wrinkling of the formed parts. This paper presents an approach that addresses these challenges by using a segmented blank holder. The goal is to improve component quality both locally and globally by applying different blank holder forces to each segment. To this end, a concept is presented for a pneumatically driven segmented blank holder, along with two different forming geometries. Deep-drawing tests with segment-specific blank holder force distributions were performed and compared with those using a conventional blank holder. Although segmentation of the blank holder did not improve performance when the force per segment was identical, an uneven force distribution was able to improve forming in terms of shape accuracy and wrinkle pattern. Depending on the selected force distribution, significant compensation for springback anisotropy and the creation of wrinkle-free straight areas was shown to be possible.