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CASE STUDY Lubrication Restores Stability to Hog Rotor Bearings in Sawmill

pulp-paper-motor-sensor
INDUSTRY

Pulp and Paper

EQUIPMENT TYPE
Motors
FAILURE MODE
Lubrication
IMPACT
$126K saved 
6 hours of downtime avoided 
20 days from initial alert to verified resolution
THE CHALLENGE

In lumber processing, hogs grind wood waste into chips for reuse or disposal. At a large sawmill, elevated vibration acceleration levels were detected on the drive-end (DE) bearing of the hog rotor. Rotor bearings are a critical point of failure that, if left unresolved, could cause unplanned downtime and disrupt wood waste handling operations.

PROBLEM IDENTIFIED

Waites’ monitoring showed consistently high RMS and peak-to-peak acceleration on the hog rotor’s DE bearing. The FFT pattern revealed elevated high-frequency peaks, indicating potential bearing wear due to insufficient lubrication. Analysts recommended immediate inspection, lubrication of both rotor bearings, and listening for abnormal noise with ultrasound or a stethoscope to confirm the condition.

pulp-paper-chart-before

Peak-to-peak vibration on the hog rotor DE bearing surged to 33.79 g, indicating severe bearing distress from lubrication deficiency.

pulp-paper-chart-before-1

FFT spectrum showed elevated high-frequency peaks, consistent with surface wear and insufficient lubrication on the hog rotor bearing.

pulp-paper-chart-after

Following lubrication, the peak-to-peak vibration dropped significantly and stabilized, confirming a restored bearing condition.

QUICK RESOLUTION

The maintenance team lubricated the hog rotor bearings, adding additional grease shots to improve performance. Post-maintenance readings showed stable vibration levels, and Waites’ analysts adjusted the baselines to match the new operating condition.

$ 126,000
COST SAVINGS
6 Hours
DOWNTIME AVOIDED
20 Days
ALERT TO RESOLUTION

RAPID RESULTS

Targeted lubrication prevented 6 hours of potential downtime and saved $126,000 in avoided costs. Early detection and action ensured the hog operated reliably and prevented disruptions to wood waste processing.

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