Tech Center to the Rescue: The Case of the Bowing OSB Pallet

Recently, the Nelson Technical Center encountered a problem that was not only causing a big headache but was also costing our customer valuable time and money. 

The Problem: a load of oriented strand board (OSB) pallets were “bowing.

The pallet was a solid wood block-style pallet with an OSB panel for the top deck. Usually, a bowing pallet is not a big issue. Once you load product on most pallets, the weight will will flatten out any bowing. In this case, an empty single-bulk corrugated box was to be glued to the panel deck pallet.

When the box touched the middle of the pallet, it was lifted 1/2" from the pallet on the sides. Unable to glue the box, the customer could not ship the empty boxes to the next location for loading in  product.

For a year, the customer had never experienced this issue. Nelson went to the customer site to inspect the load.

The Findings:
Some onsite troubleshooting led to the following discoveries:

• The box did indeed lift about 1/2” on the sides.
• All the pallets from older loads (some were still at the customer warehouse) were slightly bowed too.
• Some of the older pallets had plywood panels rather than OSB. 
• Both plywood and OSB panel pallets revealed bowing issues.
• The pallets were flat when assembled.
• The problem load was made during a very cold month.

The Solution:
After further investigation into the effect of the heat-treating (HT) process on OSB, Nelson discovered that OSB is likely to bow during the (HT) process. Since these pallets were made in very cold weather, we suspected the bow was worse because they were in the HT process longer than the previous pallet loads.

We fixed the problem by reworking the load.

• By removing the OSB panels, the base pallet immediately returned to a flat pallet.
• The OSB top panel was then reattached to the flat pallet for a flat OSB pallet.
• Going forward, the OSB panel is added AFTER the base wood pallet goes through the HT process.

The Follow Up:
There have been no further bowing issues since this manufacturing change was implemented.

Have bowed or warped pallets ever caused your company problems? Share your story with us by commenting below. We can help find you a technical solution.

Post by: John Clarke, Technical Director