Paper Machine Evaluation by Fiber Orientation Profile Analysis, 1994 Nonwovens Conference Proceedings

Irwin M. Hutten

Fiber orientation in paper is identified by polar angles, as determined by ultrasonic measurements. Cross direction (CD) profiles of fiber orientation are related to paper machine process parameters and headbox flow conditions. Uneven profiles cause quality problems, for example, twist warp in single wall corrugated board. In this report, “top of the reel trials” run on three different linerboard paper machines are profiled by cross direction fiber orientation analysis and related to process variables. The profiles are numerically characterized by the angle, displacement, and variability of a regression line through the cross direction plot.

The most significant variable is the “rush/drag” relationship between headbox jet velocity and wire speed. Fiber orientation profiles become worse as rush or drag approaches zero. There is an anomalous sign change in the polar angles as the jet:wire relationship goes from rush to drag or vice versa.