Savvy pallet buyers are absolutely correct in paying attention to the strength of the pallets they purchase. Pallets must be strong enough to safely carry the intended load. While strength is crucial, however, too many buyers still don’t know that a stiff pallet is a better pallet. It can provide the opportunity to save you money in overall unit load packaging while improving operational efficiency. It can help make your supply chain sing. Let’s dive in.
Strength and stiffness are both crucial measures of pallet performance. Simply put, pallet strength can be defined as the average load that causes pallet failure.
“It’s the uniform load rating that a pallet can safely support before a failure condition occurs,” explains Kevin Freeman, PE, Director of Engineering, at UFP’s LX Center. (UFP is PalletOne’s parent company.) “Failure is typically defined as the separation of fasteners from wood or any wood member of the pallet breaking.”
By not overloading the pallet, we circumvent the risk of the pallet breaking. We avoid the danger of falling goods and pallet debris that could cause injury and grind work to a halt.
Pallet stiffness, however, speaks to the maximum deflection of a pallet or pallet components over a prescribed period. “It refers to the amount of deflection in a pallet under design load at a given support condition, whether fully supported on floor, forklift support, or rack supports,” he adds. “Deflection behavior will change with each support condition.”
As a pallet deforms, it increases the risk of product damage and operational problems. We’ll begin with product damage.
As a pallet bends, the symmetrical contact and top pallet deck are lost. The bottom of the box and the top of the pallet are no longer flush. With less of the box remaining in contact with the pallet, it develops an increase in concentrated pressure points. Too much pressure can result in damage to the product within containers.
There are also material handling considerations. Forklift operators may have trouble cleanly inserting fork tines into the pallet. Likewise, some automated storage systems are extremely sensitive to pallet deflection and may impede shuttle cart clearance beneath the load. A lack of stiffness can also result in less load stability and more shifting during transportation. So how do we make a stiffer pallet?
Pallet stiffness can be improved by changes to pallet design, such as increasing deckboard thickness and stringer height. Pallet deflection can also be reduced by moving the outside stringers inward from the ends of the deckboards to create a wing pallet. A shorter deckboard span translates into less deformation.
In practical application, a lack of stiffness can become a problem when pallet buyers choose to go with a thinner deckboard that is less expensive. It can become more costly once the greater likelihood of product damage and supply chain interruption are factored into the equation.
Freeman stresses the importance of unit load design rather than selecting pallets and packaging independently. “When all of the components of a unit load system are evaluated together, including pallet, boxes, containment, significant reductions in packaging can be realized, he notes. The result is equivalent shipping performance with a reduction in total packaging material, resulting in reduced material waste and packaging expense.
Figure 1 (Left) – Box stacking configurations can influence load bridging. Interlocked boxes or alternating layer configurations (seen to the left) can assist load bridging better than straight column stacked. Load bridging can reduce the load that pallets need to carry, resulting in packaging savings.
There is a lot to like about a stiffer pallet. Because boxes or pails sit flat on the surface, there are fewer pressure points and less damage. Stiff unit loads are more stable and are easier to handle. With a stiffer pallet, you may require less packaging material, creating overall savings in unit load packaging. In one case, research at Virginia Tech identified an overall 53% reduction in combined packaging and pallet expenditure when pallet stiffness was increased. But ultimately, as Freeman notes, a systems approach will help you pinpoint the best pallet for your application.
At PalletOne, we rely on sophisticated pallet design software, deep experience, and our corporate testing facility to help you find the best pallet for your application – to help make your supply chain sing. To review your pallet specification, why not reach out to PalletOne today?
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