La Poste upgrades roller conveyor O-rings

Some really strange boxes and parcels roll down the line at the La Poste Colissimo postal sorting facility, located close to Grenoble, France. A few packages, especially auto parts, have pointed surfaces that cut, scratch or damage the O-rings on the roller conveyor.

In addition to the abuse from the sharp edges, the conveyor features a 180-degree power curve that requires a transition from line-shaft driven rollers on the straightaway to motor-driven ones on the curved portion, leading to additional stress on the conveyor’s 60 O-rings.

As a result, the facility’s maintenance department had to replace the unit’s standard O-rings every day or two. Since the 81-yard conveyor operates 15 hours a day, six days a week, the team was replacing the belts six hours a month, delaying processing at the facility, which cost $172 each time—and $2,044 annually.

Encountering intense competition in the package shipment space, La Poste aspires to be the leader in overnight delivery, which is growing much faster than the rest of the declining postal industry, as most of the growth is fueled by e-commerce.

La Poste’s plan envisions not just 24-hour service, but delivery within hours. Consequently, the Grenoble facility, which opened in October 2019, was built for speed and equipped with the latest materials handling and information technology. Packages travel through the plant at roughly 8.9 feet per second on the fastest conveyor. The plant processes between 7,000 to 12,000 packages an hour, relying on several conveyors.

Routine contact between the facility’s maintenance director, Jean-Philippe Fayet, and a supplier led to a possible solution. After trying twisted O-rings, which delivered a slight improvement, the supplier offered black high elastic, high tension (HEHT) O-rings, which are known for their longevity and rugged durability.

The black HEHT O-rings have a special urethane formulation that delivers a Shore A durometer (hardness) rating of 85 (the O-rings that came standard on the conveyor were 83A-85A). Designed to handle the level of elasticity and tension that La Poste requires, the new O-rings have been replaced only once during the first several months of operation.

La Poste has been conducting testing to quantify the exact savings achieved with the project, and it also evaluates the usage of the black HEHT O-rings in two other conveyors. It also continues to work with the supplier to discover other opportunities for improvements, which will reduce downtime and enhance processing performance.

“They saved my life,” Fayet says.

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