It’s a typical day in the storeroom. People are coming and going. There are brief conversations as the storeroom clerk reviewed work orders and parts requests. Standing in the cage door was John, asking quickly for an idler bearing for a conveyor drive.
“John, that’s the third time you’ve replaced that bearing recently, what’s going on out there?” asked the clerk of the technician.
“Same bearing, different location, we see these burn up all the time now – this equipment was just installed eight months ago. I’ve verified the quarterly preventive maintenance (PM) was completed, it says to grease the bearing, so I even looked at the nipple to make sure there was grease on it, and there was.” Having followed the procedure for lubrication, the team was convinced the bearings were faulty.
Remembering a book he purchased at the International Maintenance Conference on maintenance-based failure mode and effects analysis (FMEA), the technician scheduled time for a cross-functional team consisting of an engineer, maintainer, operator, electrician, instrumentation tech, CMMS admin and manager to review data and develop a reliability maintenance strategy for the conveyor drive. The team showed up, listened to the FMEA process presentation, collected what data they could find and regrouped the following week to perform the FMEA.
Searching the parts usage history, they discovered seventy-two of these bearings had failed, 15.4% of the population, between six and eight months after installation. After discussions about risk tolerance and risk mitigation, they broke down the drive components and performed failure modes analysis on each one.
“We’ve been following the procedure just as it states in the CMMS,” said one technician. The reliability engineer discussed with the team the causes of failure. He asked how many pumps of grease were required when greasing the drive.
“The PM states pumps, so that’s what we do,” replied one technician. The team was taking their time to understand the cause of failure and the design when they discovered nine pumps of grease were required to fill the delivery tube to get the grease to the actual bearing the first time after install. The manager pointed out that although a quarterly PM of three pumps was performed, it was only on the third execution of the PM that the grease was getting to the bearing. By this time, the damage was done.
The reliability engineer had work orders generated for all four hundred and sixty-five similar bearings to be inspected for damage, greased properly, and placed on a watch list.
The site maintenance manager said, “Two hundred and eighty two bearings required replacement. Luckily, we were able to get it covered under warranty, the labor too, since the installers were supposed to perform the first greasing during commissioning.”
The site manager called together both maintenance and operations and stated, “It’s not enough to follow a procedure, ensuring reliability requires an understanding of the equipment and the risks, and applying logical strategies for caring for that equipment.
The reliability engineer found seven thousand, two hundred and forty-five more like bearings in their network installed the same way, corrected them, and saved gazillions of dollars and was a hero for eternity.
