Stiffness characteristics of carton folds for packaging

Recent studies for packaging using cartons have modeled carton folds as equivalent mechanisms by considering creases as revolute joints and panels as links. This raises the interest in the study of stiffiness characteristics of creases, which have a variable stiffness in contrast to a constant stiffness of a revolute joint and subsequently that of a whole carton fold. This paper investigates the stiffness characteristics of creases and reveals for the first time the folding motion and moment diagram in carton manipulation. Three characteristic stages were provided to characterize the crease stiffness, which has a variable value during carton manipulation. The paper further investigates the integrated stiffness of a combination joint and develops the integrated stiffness of a complete carton fold. The study is then extended to the integrated stiffness of a type of carton folds.