During predictive monitoring of a paper machine running continuously (24/7), significant variations were detected in the press section—one of the most sensitive areas in the production line. Each roll showed distinct behavior: some with increased radial vibration, others with a marked rise in axial vibration, indicating torsional movement in the press region.
When axial vibration spikes past 18 mm/s, you’re not monitoring anymore—you’re racing failure.
Attention focused on roll V2, which reached critical axial vibration levels, exceeding 18 mm/s. This roll supports guide roll 1SE, located immediately after the press exit and before the first drying section and hood.
Given the severity of V2’s condition and the previously known structural resonance issues in this area – identified in earlier analyses – we decided to advance the measurement of roll 1SE, even outside the scheduled plan, to assess the direct impact on its operation.
Maximum Alert: axial vibration at 18 mm/s on roll V2
During a scheduled measurement, roll V2 hit 18 mm/s axial vibration—an extremely high value for a roll bearing. In any paper machine, this threshold signals imminent failure. The condition was unequivocal: failure was in progress and required immediate action.
Even off-schedule, I chose to take an additional measurement on roll 1SE. Being outside the hood coverage enabled rapid intervention – this decision was crucial.
Critical acceleration spike: from 0.18 G to 7.98 G. Bearing temperature at 94 °C.
Using the CMVA 90 analyzer and a pyrometer, the data were clear:
- Acceleration jumped from 0.18 G to 7.98 G.
- Bearing temperature reached 94 °C.
These values confirmed the bearing was in an advanced stage of deterioration. Based on this, I was direct with the responsible parties:
Either we stop now, or this roll will seize. The decision must be immediate.
Decision-making: Stopping the Machine to Preserve the Process
We gathered operations, maintenance, and coordination teams to deliberate. The scenario was clear to all:
- Stopping meant interrupting production before the end of the wire run, with a high cost;
- Mobilizing a replacement team urgently;
- Losing at least 5 hours of production.
The analysis was solid; the data spoke for itself. This was not a guess but a technically sound confirmation of imminent failure.
The decision was made: the machine was stopped and the roll replaced.
Result: Failure Avoided, Bearing Confirmed Damaged, Operation Preserved
Disassembly confirmed the diagnosis: the bearing was severely worn. Replacement was successful, and the machine resumed normal operation without further impact.
Technical Reflection: The Power of Data in Predictive Maintenance
This case reinforces the strategic role of vibration analysis in industrial maintenance. When conducted with precision and responsibly interpreted, it anticipates catastrophic failures, preserves assets, protects operations, and saves time and resources.
In the pulp and paper industry, where every stoppage directly impacts productivity, making decisions based on reliable data is an operational necessity—not an option. Moreover, the analyst or specialist needs to maintain a sharp sense of urgency, backed firmly by data for decision-making.
Long-term Vision: Addressing the Root Cause
While the maintenance team replaced the roll, I took the opportunity to meet with plant managers and coordinators. I presented all data, spectra, and historical information supporting the decision, stressing:
If we do not address the root cause of the structural resonance, this roll will be only the first of many replacements to come.
The analysis did not end with component replacement—it marked the start of a corrective action at the root level. From this point, we aligned on a commitment to investigate and mitigate the structural condition of the area, ensuring long-term reliability.
We executed ODS, identified all movements and weaknesses, and successfully minimized all variations, bringing the press section to an acceptable operating condition.
