Fold cracking

Why do folds crack?

The fold cracking is a problem when producing packaging board but also for printed matters in higher grammages. The result is that a costly and nice packaging or printed material turns out to be of lower quality, giving a poor impression. 

- The purpose of scoring is to be the start of a perfect folding, says Birgitta Lundgren. When scoring there should be a delamination between the board's fibre layers but with no loss of strength. If the scoring is not correctly done it will crack when folded, which can cause runnability problems in the packaging machines.

- By studying scores in a microscope we can for example check if the delamination has been done in the right way. By measuring the score depth it is also possible to see if the scoring tools were correctly adjusted or if the score was not deep enough.

- With the aid of our light and scanning electron microscopes we can analyze what the scores look like, says Marie Tjärnström. This is used for problem solving and in competitor analyses. By analysing good and bad scores in our microscopes and combining with FTIR analyses of e.g. the coating, we find explanations to differences and problems. 

Contacts: Jessica Sjöstedt, +4670 243 99 98 E-mail