Interaction Paper Moisture and Temperature and Its Effect on Corrugated Board Quality, 1998 Corrugated Containers Conference Proceedings

Side-to-side warp is related to the difference between the top and bottom liner moistures entering, within, and leaving the doublefacer. Experience and theory indicate that the relationship between paper moistures and board shape is non-linear. On-line paper temperature measurements have also been used in lieu of moisture measurements to provide a lower cost, indirect means to measure and control board moisture during corrugating.

This analysis and discussion indicates that paper temperature is not a good indicator of paper moisture, as changes in wrap arm position, paper weight, paper thickness, initial paper moisture, and speed are all shown to produce significant, non-linear changes in the moisture/tempemture relationship.

The poor correlation of paper temperature and moisture, and the non- linear nature of paper shrinkage, suggest the use of a non-linear, moisture-based warp control variable. The concept of Warp Potential, which is exponentially proportional to moisture content is introduced. The suggested warp control variable, termed the Flatness Index, is then equal to the top liners Warp Potential minus the bottom liners Warp Potential.