Controlling the Folding of the Blank in Paperboard Tray Press Forming

The press forming process of paperboard trays is challenging. The production of trays that fulfill all functional and visual property requirements is demanding. Blank preparation is an essential part of paperboard tray press forming. The aim of this work was to study how a creasing pattern can be utilized in the compaction and folding of the substrate in tray corners. The investigation of creasing pattern designs focused on the positioning of creases, the optimization of the amount of creases, and the width of the creases. The results of the study show that the amount of creases in the tray corner is the most important variable in the pattern design. The substrate folds more evenly and the wall of the tray is smoother when the material has the optimum amount of folds for it to compact during the press forming process. Changes in the creasing pattern primarily affect the amount of unclosed creases in the flange of the tray, which can make tight lidding of the tray impossible. The outcome of the study is a morphological analysis of the introduced creasing pattern alternatives and a selection of formulas that can be utilized in the creasing pattern design process.