Honeycomb Paper Crate Palletisation: Why Pattern Decides Crushing
Palletisation questions arrive when the bottom layer of a container arrives crushed while the top is intact, or when a pattern that worked for one box height fails for another. Honeycomb paper crates carry load through their walls, and the pattern determines how that load reaches the pallet. The answers below cover the pattern rules that matter and how to verify them.
Why does the bottom layer crush first?
Because it carries the whole stack. In a five-high pallet the bottom crate carries four times its own load, and if the crates are palletised two pallets high in a rack the figure doubles again. Crushing at the bottom is expected if the crate's compression strength is below that load, and the pattern decides whether the load reaches the walls or the deck.
How does the pattern change the load path?
Columns transmit load through the crate's corners, which are its strongest points. Interlocking spreads load through the walls and the deck, which are weaker. A column pattern gives higher capacity but less stability; an interlock gives stability but loads weaker elements. The right choice depends on whether the shipment needs compression strength or resistance to shifting, and most failures come from choosing one benefit without measuring the other.
ISTA packaging test protocols for transport packaging.
What should the pattern rule be stated as?
As a pattern name plus a load case plus a stability requirement. For example: column stack, five high, verified to carry the full stack for thirty days at 70 percent relative humidity, with corner alignment within 10 mm. That statement can be checked and it tells the warehouse exactly what to do. A pattern name alone leaves the load case implicit, and the load case is what fails.
What does overhang do?
Overhang — where the crate extends beyond the pallet deck — transfers load into the crate's wall rather than its corner, which reduces capacity sharply. It also invites damage from handling equipment. A common rule limits overhang to 25 mm on each side, and the rule exists because a small overhang produces a large loss of strength in a column stack. The pallet's size should be chosen to match the crate footprint rather than the reverse.
How does the pallet itself interact?
A deck that deflects loads the corner crates more than the centre ones, so the bottom layer's load is not uniform even with a perfect pattern. A pallet with a stiff deck and blocks aligned to the crate corners gives the most uniform load. A pallet with a flexible deck and stringers between corners concentrates load on the crates above the stringer ends, which is why failures appear at specific positions rather than across the layer.
ISO 2233 Packaging — Complete, filled transport packages and unit loads — Conditioning for testing.
How should the pallet load be tested?
By loading a pallet in the specified pattern to the specified height and measuring compression of the bottom layer over a defined period at the service humidity. A single-crate compression test does not predict this, because the pallet and pattern redistribute load. The test should also include a handling step, such as a fork lift and a short transport simulation, because the pattern that survives static load can still shift under handling.
What should the purchase order state?
The pattern name with a diagram, the stack height, the load duration and humidity for the compression claim, the maximum overhang, the pallet type and deck stiffness, and the handling method. Add the requirement that any change of crate height or pallet supplier triggers a re-test, because the pattern's load path depends on both.