Pinholes, reducing

1. Check that centrifugal cleaners are operating correctly:
(a) correct pressure drops.
(b) no worn cones.
(c) no induction of air.
2. Minimize air in stock.
3. Check setting of forming board to ensure adequate room for uniform, minimum breast roll discharge.
4. Maintain alignment of drainage elements on forming table with scrupulous accuracy.
— use grooved rolls in first part of table, and maintain wire tension.
5. Check vacuum level and slice clearance on suction breast former.
6. Avoid light spots in sheet from headbox defects.
7. Check that forming fabric is not blocked.
8. Use a finer forming fabric (consider double layer fabrics).
9. Check headbox and/or refiner freeness to see if stock development is appropriate for grade.
10. Minimize draws, and take sheet off couch with largest practicable take-off angle.
— this may mean changing the position of the tail blower to before the box and will necessitate changing the position of felt trail roll.
11. Reduce flatbox vacuums.
12. Check pickup felt to ensure enough surface wetness for good sheet adhesion to felt or pick-up from wire.
See also Air in the system.