Hi, Thanks for taking the time to review us again on a different website. As previously mentioned, What you’re seeing is likely due to some of the fluting becoming slightly crushed on the edges during production. Corrugated cardboard gets its strength and thickness from the wavy, arch-like middle layer (the fluting) which is glued between two flat liners. When this fluting is compressed—most often along cut edges, flaps, or creases—the board can appear thinner than expected.
This effect is usually limited to just a few centimetres from the edges, and the main body of the board should still reflect the correct thickness. For the most accurate check, we recommend measuring the thickness across the central panel of the box, where the fluting remains intact and wave shaped.
The box ordered was over 50cm in length but only 10cm deep.
For boxes with this proportion, the fluting is naturally less rigid when the depth is shallow, which can make the material feel more flexible during folding — particularly before the base is taped and the structure locked in. We would recommend for this size of box purchasing an 0201 ALT or 0203 for extra strength when constructed, or ordering in double wall which is 6mm thick.
We are available on the phone or email if you are unsure if a box will be strong enough for your requirements before placing an order.
Updated 13/11/25 11:02
In relation to your point about compression, as explained this is only on the cut edge and only into 2cm into the flaps and not the structural part of the box ie the sides.