Best practices for corrugating preprinted liners

The following guidelines have been proven to be highly successful in the corrugation and die cutting processes of preprinted liners. The goal is to retain and control the moisture with less heat not more. A key temperature to note is 212° waters boiling point.

Single Facer

1. Check the S/F liner rolls for moisture content and use the highest available.
2. S/F liner temperature should be no higher than 180° before entering the S/F.
3. Use wet steam from a high-pressure 180-psi line to condition medium NOT dry steam. Dry steam actually removes moisture.
4. Adjust glue gap on the metering roll on a fingered machine to .0013” and .0016” on a fingerless singlefacer.
5. Exit temperature of the singleface web just beyond the pressure roll, corrugator roll nip measured on the liner side should be 210° or below.
6. Run a full bridge.

Glue Machine / Preheater

1. Always run preprinted or coated side away from preheater vessel.
2. Preprinted liner temperature should never be over 180° measured from the wire or unprinted side at any time before entering the hot plates.
3. Glue gap should be .0006”.
4. Glue solids at the glue machine should be 28° or slightly higher. For e-flute and wide webs, 30° is recommended.
5. Keep double face web tension to a minimum at the doublebacker.

Double Facer

1. All hot plates must be clean and level.
2. Clean belts.
3. Weight rollers and ballast rolls must move freely and be level.
4. Use weight rolls and contact pads or bars sparingly.
5. Hot plate temperature should not be over 350° at any section.
6. When running e-flute, it is ideal for the first section of hot plates to be no higher then 305°.

Miscellaneous

1. Delivered boiler pressure to any vessel should not exceed 175 psi.
2. Waiting time between the corrugator and finishing equipment should not exceed 6 hours; if possible convert immediately after corrugation.
3. Adding a starch additive to the doubleback formula will improve bonding with minimal application while improving machine speeds and overall quality.
4. Use ample tie sheets at the dry end of the corrugaor to ensure integrity of the stacks during the transfer of the units through the plant.
5. Corrugating speeds should be over 500 fpm and faster when possible.