Managing Critical Roll Bearing Deterioration

Mill technicians at Orchids Paper suspected that two roll bearings were deteriorating on their most critical paper machine. Relying on Azima DLI's WATCHMAN™ Insight program to provide early warnings on impending machine faults, the Mill technicians collected vibration data from the suction pressure roll and top press roll bearings. The data was then posted to Azima DLI's Reliability Portal for an analyst to review. The Azima DLI vibration analyst reviewing the data confirmed the mill's suspicions and determined that the top press roll had developed a new bearing defect from the drive side roll bearing. The overall vibration level increased from 0.10 ips to 0.35 ips. The spectrum data indicated a bearing defect. Azima DLI recommended that the bearing be replaced during the next scheduled outage. The suction pressure roll had already been reported by Azima DLI as a priority #2 status but further data collection indicated continuing deterioration of the defect developing from the drive side roll bearing. Data collected one month later revealed substantially increased vibration from the bearing. The overall rise was from 0.25 ips to 0.61 ips. The abrupt increase generated a priority #1 status alert that called for the bearing to be replaced immediately. Even though the mill had a prescheduled outage in less than 18 hours, the precipitous increase in vibration demanded a prompt determination of machine health. An Azima DLI analyst received the data, analyzed it, and reported the results within one hour. Despite the rapid deterioration in the bearing, Azima DLI was able to confirm that the mill could continue operating safely through the balance of planned production, avoiding a potentially costly unplanned shut down. Both bearings were replaced during the pre-scheduled outage.