It runs from the stock approach and headbox through the forming section and, in most mills' usage, the press section, where the sheet is still mostly water. Wet-end chemistry, meaning the retention aids, sizing, dyes and fillers dosed into the stock, sets much of the sheet's optical character. Crews say a problem is wet-end when it starts before the dryers.
Shade is swinging and the dye pumps are steady, so it's a wet-end chemistry thing, check the retention.
Do not mix it up with
- Dry end: The dry end begins at the dryer section and carries the sheet through calendering to the reel.
Related terms
Dry end
Back section of a paper machine, from the dryers through calender and reel, where the sheet is finished.
Headbox
Pressurized box that spreads stock in a thin, even jet across the full width of the forming wire.
Wire
Endless woven plastic fabric on which the paper web is formed and drained.
Couch
Suction roll at the end of the forming section where the wet web is dewatered and leaves the wire.
Felt
Endless fabric that carries the wet sheet through the press nips and absorbs the water squeezed out of it.