Subbing 30# for 33# Medium, will it perform as expected?

It was a delight to attend SuperCorr this year and reconnect with so many members and associates.  It was also refreshing to have AskRalph questions face to face.  It’s always exciting to hear voice inflections and read body language.

One member asked a question of subbing out 30# medium for 33# medium knowing that the lighter option should meet the required ECT target, but it does not perform as expected.  Since this is the containerboard mill asking the question, a solution may take a longer period to analyze.  Three different test labs have found very different results.  Interesting that the outside facility that I have the highest respect for was in the middle compared to the mill and the box plant.

Our first level of investigation was on the combined board and SCT sample conditioning at the three test sites.  We then started to investigate the age and flute profile. While this is a newer corrugator and a new paper machine that does not mean that they each have the best technologies.  It could be that the single face operators did not make adjustment for differences in caliper with the lower basis weight and the sheet is not “flowing” through the labyrinth properly.  There are other combined tests that would be beneficial to DST testing.  I am also talking to corrugating roll manufactures for their input.

More to come on this topic later with our finding in an upcoming issue of BoxScore.

— Ralph