Internal bond improvement

1. Increase refining.
2. Increase wet end pressing.
3. Increase sheet moisture entering breaker stack.
4. Decrease internal sizing, either resin or synthetic.
5. Increase strength additives in the furnish, i.e., starch or gums.
6. Decrease calendering.
7. Consider possible furnish changes.
8. Check head.
— an excessively high head contributes to poor internal bond due to incorrect jet-to-wire velocity ratio.
9. Increase sheet pick-up of surface size by:
— increasing sheet moisture into size press.
— increasing size press sizing temperature and/or concentration.
— reducing size press loading pressure.