Strapping is the cheapest way to stop a pallet load spreading, and the most common cause of damage to the boxes at the top and bottom of it. A band under tension applies a concentrated load wherever it changes direction, and on a box that point is almost always a vertical edge. Where the edge has not been designed to take it, the strap wins.
Where the load lands
The band presses on the top box at the corners and pulls against the base of the load. Between those two points it passes along the vertical edges of the stack, and it is there that the crushing happens. A box with a folded seam running up the corner has the least resistance at exactly the place the strap bears hardest.
The corner post
A corner post – plastic, board or a folded section – spreads the strap load along the edge instead of into one point. They are inexpensive and they remove most strap damage. Where a fleet is being strapped regularly, they should be in the specification rather than bought as a remedy after the first complaints.
Tension
Enough that the band cannot be lifted away from the box by hand, and no more. Over-tension is the usual fault, because it feels more secure and because a strap that is too tight looks the same as one that is correct. Where a strap is leaving a visible depression in the box, the tension is wrong regardless of how secure it feels.
Number and position
Two bands for a standard pallet, three for a tall or heavy one. Position them over the vertical edges, not across the middle of a face. Where a load has to be banded across a face because of its shape, use a spreader – a sheet offcut will do – so the load goes into the panel rather than through it.
Re-tensioning on a long route
Bands lose tension as a load settles and as the box walls creep slightly. On a route with several transfers, plan to check and re-tension at a transfer point rather than expecting the original tension to survive the whole journey. It takes a minute at a point where the pallet is already being handled.
What to look for on arrival
Crushed or split vertical edges, a band sitting in a groove it has cut into the box, and a load that is no longer square to the pallet. Each one points at a specific correction – corner protection, lower tension, or a different band position – rather than at a general complaint about strap damage.
What to check on the first banded load
After banding, look at the corners where the band turns. Where the board has taken a set, the tension is too high or the corner is unprotected. Where the band has cut in, add a protector rather than reducing tension, because the load still needs the containment.
Then check on arrival. A load that has walked is a containment problem; one that has not moved and has crushed corners is a tension problem. They look similar in a photograph and need different corrections.
What we can do
We build PP corrugated turnover boxes with reinforced vertical edges so banding has somewhere to bear, and we will mark the band path on the drawing. Tell us how the load is secured today. The design answer to the same problem is in building a strap path into the box.