On the Importance of In-plane Shrinkage and Through-thickness Moisture Gradient during Drying on Cockling and Curling Phenomena

Abstract

Cockling and curling are unwanted phenomena that occur already in the manufacturing process and continue through the end use of paper due to moisture content changes. This paper compares the effects of different in-plane tensions and throughthickness drying profiles during the drying process on cockling and curling by means of finite element simulations. In this study, paper is treated as a heterogeneous orthotropic elasto-plastic material. The results predict that finding the optimal way to dry paper is not straightforward; it also depends on fiber orientation structure. On the other hand, defects in the fiber orientation structure of paper can be redressed at some level by drying the paper appropriately.