TSI, TSO and Fibre Orientation, An Introduction, 2001 Papermakers Conference Proceedings

Stuart Loewen, Marc Foulger--The Tensile Stiffness Orientation, or TSO, is an important paper quality that has a significant impact on both the performance of the paper machine and the end-use performance of the paper or board. When correctly interpreted, the cross-machine profiles of the TSO Angle give clear direction on how to improve the headbox jet flow profile. The results are improved edge roll quality, paper machine productivity and printing and converting performance. The related Tensile Stiffness Index or TSI properties also play a critical role in paper quality, in ways that are not measured by more traditional paper physical tests.

Unfortunately, both the TSI properties and TSO Angle are frequently misunderstood or misinterpreted by papermakers. This paper is an introduction to understanding, interpreting and optimizing the Tensile Stiffness properties in paper. It describes how the TSI and the TSO Angle are measured, what the measurements mean, and how they can be used to optimize final sheet characteristics. Both on-machine and off-machine measurement techniques are discussed; along with the resulting information about the fibre orientation and its relationship to the standard sheet properties, as well as the operating settings of the paper machine. Some typical target TSI and TSO profile numbers are included.