A well-known international cosmetics company was considering to move from competitor's paperboard grade to Metsä Board's one. To verify how Metsä Board's grade performs in their end product, the customer ran short qualification trials. They were pleased with end results with a plain box design. However, when testing a box with two windows the box did not run properly on the packing line.

To tackle the challenge, a common project was started between Metsä Board and the cosmetics company. Tests quickly showed that paperboard specifications needed to be adjusted for the multi-window box. Based on careful measurements and tests with different paperboard grades, changed fiber orientation and new window designs combinations, three best candidates were identified and then tested on packing and cellophane lines of the company. A winner combination was found and the best performing candidate will be soon tested for a longer qualification round.

In parallel to these laboratory measurements, also extensive simulation work was carried out to deeper understand the influence of the window design, board material properties and fiber orientation.