Paper manufacturing (papermaking process)
Checking for wear on size press rubber rolls when changing paper sizes
When switching from narrower to wider paper gauge: If there is even a slight amount of wear where the edges of the narrower size press rubber rolls touch, "striping" or other irregularities may occur when wider rolls are used. Up until now, such abnormalities could only be detected by checking the rolled paper after the papermaking process was started. In the worst situations, it has been necessary to perform repeated cycles of applicator roll polishing and test rolling to remedy such problems.
Product used: Prescale (Super Low Pressure LLW)
In size press processes, chemicals and coatings are applied to the surface of dried paper. As a check before papermaking, Prescale film (LLW) is passed through the press (without any size liquid applied) to check for the presence of wear. A final assessment after polishing can also be made using the same method.
[For all types of size presses]
If there are scratches in the size press roll when the size is changed, various losses occur:
Loss of time
Approx. half a day for repairs
Loss of materials
Loss of hundreds of meters of material.
Loss of quality
Quality abnormalities occur if roll wear is overlooked
Without using Prescale
After the size is changed, as the papermaking process is started, the output paper is checked for problems. If "striping" or another defect is found, the faulty roll is polished and papermaking is restarted. If the "striping" has not been fixed, the process must be repeated. Thus, time and material losses occur.
When the size is changed, Prescale is used to check for roll wear before starting the process. It only takes about 30 minutes to perform this check, and it can be done while making other size changes. If scratches are found, polishing and checking with Prescale can be repeated until no further scratches are observed. Papermaking can then be started with confidence. The result is higher productivity and quality.