Corrugations

1. Corrugations are soft and hard spots in reel due to uneven heating of calender rolls or uneven basis weight profile on forming fabric.
— if due to calender rolls, adjust air for proper cooling.
— if due to sheet on the forming table, make necessary corrections.

2. If winder core shaft is crooked, send to shop for straightening.

3. If corrugations are not due to uneven heating, calender rolls may be improperly ground or incorrectly crowned.

4. Adjust spreader bar or bowed roll at the drum reel or winder.

5. Adjust alignment and/or loading of the reel bar on the drum.

6. Check the tension of the paper as it is being wound onto the reel. If the tension is too high, it can cause corrugations. Adjust the tension control system accordingly.

7. Inspect the condition of the reel drum and make sure it is smooth and free from any defects. If there are any rough spots or damage on the drum, they can contribute to the formation of corrugations. Smooth out any imperfections or replace the drum if necessary.

8. Examine the condition of the paper itself. If it is too thin or has inconsistencies in its basis weight, it can lead to corrugations. Adjust the paper manufacturing process to ensure consistent thickness and weight.

9. Monitor the temperature and humidity levels in the paper mill. Fluctuations in these factors can affect the formation of corrugations. Maintain a stable environment to minimize the chances of corrugations occurring.

10. Train and educate operators on proper handling and winding techniques. Improper handling of the paper during the winding process can cause corrugations. Ensure that operators are aware of the correct procedures to prevent this issue.

11. Regularly inspect and maintain the calender rolls. If they are worn out or damaged, they can contribute to the occurrence of corrugations. Replace or repair any faulty rolls to maintain smooth and even paper production.

See Corrugations, prevention.