Comparing two box constructions usually means waiting for field failures, which takes a season. A rough drop rig answers the same question in an afternoon, provided the test is consistent – not precise, consistent.
What the test tells you and what it does not
It ranks constructions against each other under one defined insult. It does not predict service life, because real handling delivers far more varied insults than any corner drop. But if construction A survives twice the drops of construction B, that ranking almost certainly carries into service, and that is enough to make a decision.
Height and orientation
Pick a height representative of your handling – commonly around waist to shoulder height for manual work – and hold it constant. Drop on the same corner every time, because corner impacts are what damage these packs, and because randomising orientation without enough repetitions just produces noise.
Drop empty and loaded. Loaded behaves completely differently, and the loaded case is usually the one that matters.
Repetition is everything
One drop proves nothing; drop-to-drop variation is large. Use several units per construction and take the average to failure, or use pass-or-fail at a fixed number of drops. Either works; single samples do not.
Condition the samples
Cold boxes behave differently from warm ones, and this is the variable most often ignored. If the pack will be used from a freezer or a cold yard, test it after conditioning at temperature. Testing warm when the application is cold gives a ranking that may not hold – a point made repeatedly in crate performance under freezing.
Record how it fails
The failure location is more informative than the failure height. Corner splits, wall tears and joint failures each point at a different design change. Photograph every failure; after ten units the pattern is usually obvious.
Know when to stop
This rig is a comparison tool, not a qualification. If a customer needs certified drop test data to a published standard, this does not provide it and should not be presented as if it does. Send units to a laboratory for that, and use this rig to decide which one deserves the laboratory fee.
Building the rig
Two uprights, a release mechanism that does not impart spin, and a rigid base are all that is needed. A hinged shelf or an electromagnet release works; a person letting go does not, because the release is never the same twice. Mark the drop height once and never move it.
Film it. Slow-motion playback on a phone shows the failure sequence – whether the corner folds first, whether a joint opens before the wall deforms, or whether the base separates – and that sequence is the most useful output the rig produces, more than the pass or fail.
Test what you actually stack
Drop a loaded stack rather than a single box occasionally. Stacks behave differently – load transfers between units and the failure moves – and a construction that performs well alone sometimes performs worse as a stack, which single-unit testing never reveals.
What we can do
We build returnable sleeve containers and other constructions and would rather you tested them this way than relied on our claims. Tell us your handling height and load, and we will suggest comparison constructions worth putting on the rig – including ones we do not sell.