Wälzlager - 2010-06-09
In modern paper manufacturing, machines operate at speeds up to 2,000 m/min. This places high demands on the bearing assemblies, which is especially true for the bearings used at high temperature in the dryer application where the paper is dried over heated rollers.
A paper manufacturer used spherical roller bearings with case-hardened inner rings and solid brass cages in this area of the plant. However, the reliability of these bearings did not meet the manufacturer's needs. Since every bearing failure results in long downtimes and high costs, NSK was asked to offer suggestions for improvement.
NSK engineers with expertise in the paper industry responded by first investigating the operating conditions: they suggested replacing the bearings with spherical roller bearings from the TL series (“Tough and Long Life”). This bearing series was specially designed for use in dryer rollers for paper manufacturing machines that operate at very high temperatures.
These bearings are part of NSK's Tough & Long-Life™ series and feature a special surface treatment. This method ensures high bearing race hardness and high stabilised dimensional accuracy at temperatures up to 200oC.
Once the bearings were replaced, bearing-related downtimes were easily cut in half. The operator now estimates only €107,000 for production losses during bearing replacement, instead of €214,000 annually. In addition, NSK provided training for maintenance personnel at no extra cost, while also offering the user a programme for backing up bearing inventory. These measures reduce maintenance costs and training expenses, so that the total annual savings add up to just under €142,000.
This example shows how vital it is to choose the right bearing, especially in demanding applications. It also confirms that calling on help from bearing experts brings high savings.