Change from 1312RE to 1312FR without stopping Board-line is a very complex change and one with a
high degree of risk of producing some product that is not within our quality standards and specifications.
There are many variables involved and too many situations where control might be lost. It is very important
to be able to identify faulty product and prevent it from reaching market place. Our standard testing
schedule might not be adequate for this task. Some additional testing of product at the Dry End is required
to ensure that all product released to the Warehouse and our customers is of good quality.
Product most likely to be affected during this product change is 1312RE. To be on safe side – the most likely board to be affected is 1312RE that happened to be in the first quarter of Dryer Zone 2 and all 1312RE
board in Zone 1 at time of Dryer Chain speed change.
If above is correct then last 30 minutes of 1312RE board are most likely to be affected by extended drying
time. Our experience is that critical time frame is narrower than this (10-15 minutes) but so far we were not
able to pinpoint exact timing of that (it seems to be different for every campaign).
Board exposed to extended drying time is most likely to suffer from calcination which destroys bond between paper and core of the board and also burns the edges making them soft. Other parameters covered by our standard testing are not affected. In my opinion, dry bond test and edge hardness test would be sufficient to identify faulty product.
Last 30 minutes of 1312RE board should be subjected to test of dry bond and edge hardness in 5 minutes time intervals. Test results should be recorded in SFCQP.