Paper Mill Boosts Production Efficiency, Reduces Machine Downtime with Spherical Roller Bearings

A major paper mill was experiencing problems with its calender rolls, where multiple cracks were developing on the inner rings of the roller bearings. Frustrated by experiencing up to 10 failures annually, which led to excessive downtime and maintenance, the mill invited NSK’s team of experts to investigate and resolve the issue.

As part of NSK’s Added Value Program AIP, a comprehensive application review revealed that a competitor’s standard spherical roller bearings being used in the calender roll did not feature carburized inner rings, leaving them vulnerable to the high heat and thermal stress in the application.


  • Application: Calender roll (Country: USA)
  • End-product: paper
  • Number of machines: 1
  • Status: still in operation after 5 years
  • Problem: High bearing failure rate
  • Objective: Decrease change-outs and downtime


  • NSK investigated the application and inspected the competitor’s failed bearings
  • NSK collaborated with the mill engineer toward the goal of replicating NSK successes earned at mills experiencing similar, related issues
  • The use of NSK’s TL (Tough and Long Life) design spherical roller bearings, with innovative material and heat treatment technology, was recommended
  • Bearings were installed and have run 5 years without failure


NSK’s TL series spherical roller bearings are ideally designed for paper machine dryer roll applications — and wherever elevated temperatures prevail — optimizing machine uptime and efficiency with superior resistance to inner ring fracture and exceptional dimensional stability at high temperatures.


Download NSK’s case study (two-page, PDF).



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