When it comes to securing loads on goods for transport, stretch wrap plays a key role in keeping the loads from shifting around in an economical and effective fashion.
Load stability is a matter of safety, since shifting loads can cause serious highway accidents and cause damage to products. And the process of stretch-wrapping pallets, which happens in factories and shipping centers everywhere, is a critical function, as is the consistent quality of the film, according to David Finnemore, senior technical consultant at Windmöller & Hölscher KG.
Europe is taking a leading role in regulating load stability on highways. A European standard says that, as of 2018, trucks will be subject to inspection and must show proof of load stability. The rules follow the European Union's Directive of Road Worthiness and the EUMOS 40509 regulation. EUMOS stands for the European Safe Logistics Association, based in Brussels.
W&H, based in Lengerich, Germany, makes the equipment that produces the stretch film. Finnemore said good pallet wrapping is important for all shipped solid goods.
North America is behind Europe on standards for load stability, "but we are catching up quickly," said Kurt Riemenschneider, president of Highlight Industries Inc., which builds stretch-wrapping machinery in Wyoming, Mich., near Grand Rapids. The company also is a longtime maker of equipment for testing the stretch film.
European shipping firms use more soft-sided trailers — known as curtain-sided trailers — and generally run on narrower roads than the United States. But Finnemore and Riemenschneider said the issues and problems are similar.
"They're ahead us a little bit in writing the regulations," said Riemenschneider, who wrote one of the original ASTM standards covering the issue.
In North America, ASTM and the International Safe Transit Association (ISTA), are working on standards for stretch film and unit load stability, Riemenschneider said. ASTM D 4649-03 is a standard guide for the selection and use of stretch wrap films, both for palletizing loads for shipping of warehousing.
Luke Venechuck, senior packaging engineer at Highlight Industries, is vice chairman of the ASTM committee, and he expects the new revision of the stretch wrap standard will be completed in 2018. Riemenschneider said Venechuck serves on the ISTA testing committee, which also is reviewing the issue.
Curtain-sided trailers are popular in Europe because they give easy access to the load from the sides of the truck, not just from the rear. But Finnemore said that does not change the basic need to create a stable pallet — regardless of the means of transport.
"Load stability is a global issue, no matter what form of transportation is used, whether it be road, rail, sea or air," he said. "Each method of transportation places different stresses on the loads."
W&H is active in the load-stability movement. Finnemore, who came to W&H in 2010 after 13 years at Gloucester Engineering, said the issue was brought to W&H's attention in 2011 during a meeting with David Angel Hernandez of Grupo Valueing, the Spanish packaging consultancy, professor Marc Juwet from the KaHO Institute at Catholic University of Lueven, Belgium, and Jelle Dendauw, managing director of ESTL NV, the Belgian load stability engineering firm.
The responsibility to properly securing the load includes by the consignor — the company creating the load unit — and the hauler.
EUMOS suggests that road tests be combined with dynamic laboratory tests. But "live" truck tests can be expensive. So the 2011 meeting at Catholic University in Leuven was to view a prototype acceleration bench that conforms to EUMOS 40509. A wrapped pallet load is accelerated on a test track in a laboratory, documented by a high-speed camera.
Finnemore said the meeting was eye-opening.
"Subsequently, we took the decision to play an active role in both understanding the key factors associated with securing a load on a pallet, while developing our extrusion technology to produce consistent high-quality stretch films, to assist stretch wrappers to achieve stable loads," he said.
W&H became a member of EUMOS and has taken an active role working with the full supply chain of resin suppliers, film converters, stretch wrap makers, distributors and legislative bodies.
At W&H's 2012 in-house exposition in Lengerich, the machinery manufacturer also held the inaugural Load Stability Symposium for the 80 people in attendance.
And Finnemore's list of the key factors impacting the stability of stretch-wrapped pallets shows how much of a complete "system" is involved: the shape and friction coefficient of the primary or secondary packaging units; the stacking and wrapping pattern; the use of tie sheets between layers of product; the selection of a suitably tough stretch film; using settings on the stretch wrapping machine; and the use of bottom roping to ensure a good connection between the load and the pallet.
Finnemore said that, over time, W&H has learned from U.S.-based suppliers of stretch-wrapping machines, Highlight Industries and Lantech, that it's very important to use correct stretch film thickness for the wrapper to create a recipe for the required containment force, for individual load types.
"Even if a film with sufficient stiffness and resistance to breaking is chosen, the load will be unstable if the wrapper under- or over-stretches the film, or cannot apply the necessary tension to the film, creating the in-pallet containment force," he said.
Finnemore said that, today, some wrappers pre-stretch the films as much as 300 percent, depending upon both the film and load type, before wrapping it around the load under tension.
The focus on load stabilization signals the need for more consistent film quality, Finnemore said. At K 2016, W&H introduced the FPM (Film Performance Monitor), on its Filmex II cast stretch film line. FPM gives 100 percent traceability, W&H officials said, by linking data from all process steps, from the film production through the wrapping.
For Finnemore, FPM is a big selling point for W&H's customers, the stretch film makers. As more companies enter the stretch film market, the diversity of suppliers will naturally create more variety of film quality levels, he said.
Data from the FPM is continuously gathered, and each roll is given a QR code that follows the film down the full production chain in what W&H officials tout as the company's version of Industry 4.0, which they dub Packaging 4.0.
As awareness spreads about the load stability issue, equipment and film officials look for more regulation and guidelines.