Cranes Come Under The Microscope

The packaging industry is hungry for paper, with sales in this sector increasing by 3.4 percent last year alone. This is the area of operation for the paper machine 6 (PM6) at the Palm paper factory in Wörth am Rhein, Germany.

The 650 000 tons of corrugated base paper it produces each year is handled at various stages by eleven double girder overhead cranes, all playing their own role in the paper production on PM6. In order to safely transport these
large paper rolls, the hoisting gears of the eleven cranes must always be in top operating condition.

For this reason, Palm tasked Konecranes to look at eight of its most critical cranes. Following the results of the oil analysis and subsequent endoscopic investigation, the maintenance experts identified a significant risk to future production and replaced one of the hoisting gears.

Paper production around the clock
At the Palm paper factory, located in Aalen in Baden-Württemberg, everything revolves around recovered paper. Nine paper machines in five factories annually produce approximately 2.2 million tons of newsprint and corrugated base paper.

Correspondingly high are the demands from the eleven double-girder bridge cranes that have been in use in the factory in Wörth am Rhein since the start of production in 2002.

“The cranes are in use day and night,” says Sven Bohrer, electrical engineer at the Palm paper factory. “If one should break, production will stop or slow down, costing time and money.”

Because you can look deep inside the oil, the wear metals and waste substances it contains make it possible to draw conclusions about the state of the entire gear.

“In this way, we also use trend analysis to provide the
best possible picture of any change within the condition of the gearbox.”

The result for Palm was that seven of the eight cranes were found to be
healthy, as the gear oil contained few to no foreign elements or waste substances indicating contamination or wear. However, the gear oil of a crane used in the roll warehouse had a noticeable increase in its wear partial count, triggering the lab to issue a “Caution” notification on the
analysis report.

“Iron particles in the oil can be an indication of increased wear and a deeper look may be required for this particular hoist,” comments Nico.

Getting to the root of the problem
If the reason for the wear is not clearly identified and removed, the gear may be permanently damaged. “If the gear is jammed while there is a roll on the hook, it becomes very difficult to recover,” he explains. In order to determine whether there was already damage, Konecrane
used the Crane Reliability Study (CRS). The modular analysis allows the team to check safety relevant components, like the hoisting gear as
well as the steel structure, the motors and the electrical equipment of the crane.

“Just as in the medical field, we use the endoscope to reach inaccessible places without having to dismantle the entire gear,” says Nico. “For the
CRS, we use an oil-resistant model developed for industrial use which can be fitted with different lenses.”

Following the endoscopic investigation, Konecrane can be certain that the hoisting gear must be replaced. In addition, the cable drum, the cable
drum support, the slip-ring unit, the cylinder coupling and the motor coupling must be renewed.

“Thanks to discovering the wear early on, there was no risk to safety and we were able to replace the old gear with a new one without affecting production,” concludes Nico.

Konecranes, Nico Zamzow
Tel +49 6103 7333-235