Some of the benefits of reusable pallets and containers may help clinch a sale when presented to a potential customer. That was the message John Clarke delivered recently to the first annual meeting of the members of the Reusable Pallet and Container Coalition.
The performance of unit load material handling is determined by three interactive factors: packaging, pallets, and material handling equipment. “They all have to work together,” John, director of the Virginia Tech center for unit load design, told Pallet Enterprise. “They’re all important.”
Reusable pallets and containers may be justified in an application that uses one-way pallets if a customer can achieve savings in cost per use or trip. Another consideration that may help sway a customer is conservation — a program of reusable shipping platforms will use less natural resources than one that relies on one-way or single-use pallets or containers.
In figuring the cost per use, however, a pallet or container supplier must be able to help the customer determine all of the costs involved — the cost of buying the pallet, and shipping, recovering and repairing it. “Some time it’s hard to know” all those costs, John conceded. By contrast, “With single-use pallets, you know what the cost per use is.”
Supplying reusable pallet and containers puts manufacturers and recyclers into a new arena: managing those products for their customers. It’s an arena that can take different forms, such as renting pallets or setting up closed loops to retrieve them and service (repair) them. The pallet industry is finding itself more open to the notion of setting up networks and partnering to provide those kind of services to their customers, John noted. “I think there’s a great opportunity out there to cut costs,” he said.
Environmental considerations also can help sway a customer on going to a reusable shipping platform. Nonetheless, the overarching concern of pallet users is economics, John observed. “Everybody wants to save the environment, but if you can’t justify it economically…There are few times when saving the environment is going to carry the day.” Pallet users who are not convinced they can reduce costs by going to a reusable pallet will not make the change solely for environmental reasons, he said.
John outlined several benefits of reusable pallets and containers. First, they prevent or reduce product damage caused by shipping vibrations. Shipping vibration frequency is measured in Hertz or cycles per second. Trucks and rail cars, for example, produce vibrations in the range of 2 to 15 Hertz. Loaded pallets have a resonant frequency — the frequency at which the load experiences the greatest movement. Pallets with low stiffness may resonate below 15 Hertz. Stiffer, reusable pallets increase the level at which the load will resonate.
A simple test conducted at the Virginia Tech pallet and container research lab illustrates the point. Two small corrugated trays of apples were placed on wooden models representative of pallets. One model was made with 1/2-inch deck boards, the other with 3/4-inch deck boards. The models with the trays and apples on top of them were placed on a testing surface and subjected to vibration. The model with the thinner deck boards vibrated — along with the apples — at a significantly lower frequency than the sturdier model.
“If you have a customer who is shipping a vibration-sensitive product, you might want to go with a better pallet,” John said, because they have more stiffness and resist vibration. Vibrations in transit can damage not only produce but also such high-tech products as computers.
Reusable shipping platforms also can reduce product damage and packaging costs because they eliminate or reduce stress concentrations. John illustrated this point by turning to a research case. The lab was asked to conduct tests for a company that manufactured lighting fixtures. The fixtures were packed in corrugated containers and shipped on pallets with 1/2-inch deck boards. The layer of cartons closest to the pallet frequently incurred product damage by the time the shipment arrived at the destination. Before turning to Virginia Tech, the company upgraded the packaging at greater expense but to no avail.
The problem was with the pallet, not the packaging. During shipping, the 1/2-inch deck boards would bend occasionally with the vibrations of the truck. When the boards bent downward, the weight of the lights was transferred briefly to the stronger components of the pallet, the stringers. The lights were damaged because of the increased compression stress over the stringers.
The case also illustrated a lack of coordination and communication between product design and manufacturing and those responsible for the unit load that probably is not uncommon: the light was designed by someone who thought the fixtures would be supported by a flat platform for shipping.
The lab tested pallets of different deck boards and different types. The solution in this particular case turned out to be 3/4-inch deck boards. They increased the cost of the pallet by about $1 but reduced the cost of the packaging by about $3, according to John. More importantly, the more durable, reusable pallet eliminated the product damage.
Another potential benefit of returnable pallets is that they tend to have larger blocks or stringers, which transfer heavier product weight over a greater rigid bearing area.
John drew another comparison between the Chep Mark III, a heavy-duty returnable pallet, and the GMA pallet. Both pallets are made with stringers. However, the Chep stringers on the Mark III have 360 square inches of surface area compared to only 198 for the GMA; the Mark III has 82% more load-bearing area than the GMA. The difference strikes home even more dramatically when the two pallets are placed under a 2,800-pound load and stacked four high: the pressure is 31 pounds per square inch over the Mark III stringers and 57 pounds per square inch over the GMA.
Another potential benefit of returnable pallets is in load bridging. Reusable platforms may provide a greater level of load bridging than corrugated boxes, which allows for pallets of less stiffness.
Different products and packaging methods exhibit different levels of load bridging. The average deflection of a pallet with a 1,500-pound load may vary up to 60%, depending on the type of packaging. In this example, a unit load of two boxes per layer will deflect the pallet 0.33 inches while a unit load of 12 boxes per layer will deflect 0.57 inches — almost twice as much.
Another benefit relates to the requirements of automated material handling systems. Modern systems require quality pallets of consistent dimensions. Such pallets typically cost more, but the cost of reusable pallets will be spread out over multiple trips.
“If you’re in a tight place in a sale, these are five things that might help…influence the customer,” said John.
