Stiffness

1. Maximize refining to a point that is compatible with other tests.
— fibrillation with a minimum of cutting helps maximize stiffness.
2. Reduce ash content of sheet if possible.
3. Check press loading.
4. Tighten wet-end draws.
5. Reduce degree (severity) of calendering if finish and caliper will permit.
6. Run sheet moisture at standard.
— high moisture contributes to low stiffness.
7. Diagonal stiffness can be improved with a well formed sheet.
8. If necessary run basis weight at maximum.
9. Consider a possible furnish change.
— long fibered pulps are desirable for stiffness.
10. Good curl control will improve result of stiffness test.
11. Velocity forming (slight drag) may improve stiffness by 5 – 6 %.
12. Increase size press solids and/or pick-up to increase stiffness.
— starch at the wet end is also beneficial.
13. Control sheet moisture.
— a drier sheet is stiffer.