Slugs

1. Fiber lumps (slugs, bundles) break loose from approach system or headbox.
— source should be eliminated through frequent flushing or system boil-out.
2. Perforated rolls running at incorrect speed or stopped altogether result in slugs and eventually holes.
3. Headbox should be periodically checked for fiber strings.
— ensure water flow to roll glands is normal.
4. Ensure that headbox, breast roll, couch, and dandy roll showers are operating properly, if present.
5.. Broke scabs, dirt and the like (in or on the web) will result in holes.
6. Size press solutions may become contaminated with paper debris or starch scabs that can pick out.
7. Improperly cooked starch can cause pickouts.
— often indicated by return screening problems.
8. Temperature or pH shocks may cause salting out of additives that will contribute to holes.
9. If identified as pitch or slime related, a proper deposit control program can eliminate.
— larger, tear-drop shaped defects are generally due to slime/pitch control problems, starch scabs, or inadequately dispersed additives such as gums, defoamers, retention aids, etc.