Watermarking with dandy

1. Dandy marks.
— Increase cleaning shower pressure.
— Install a wipe on the dandy.
— Use a steam shower on the dandy.
— Clean dandy with a high-pressure hose.
— Remove dandy for cleaning.
— Run sheet drier under dandy.
— check dandy speed.
— Increase defoamer addition if dandy is throwing.
2. Poor impression.
— Close-up sheet as good formation will improve the watermark.
— Increase refining if other tests will permit.
— Adjust sheet moisture under the dandy to run as wet as possible.
— Check dandy position relative to forming fabric and raise or lower as required.
— Check dandy speed if it is driven.
— Check the operation of dandy drainage elements or dandy suction box.
3. Dandy crushing.
— Free up stock and/or reduce the moisture content of the sheet under dandy.
— Increase vacuum on wet boxes.
— Check the operation of suction boxes for skipping or intermittent vacuum.
— as a last resort slow down machine.
4. Dandy picking.
— Increase moisture content of sheet under dandy.
— Increase cleaning shower pressure.
— Install a wipe on dandy.
— Check dandy for a build-up of stock or other foreign material.
— Clean or replace dandy.
5. Check for holes, a loose or damaged cover, or out-of-round trunnions on dandy roll.
— Repair or change the dandy roll.