Predictive Maintenance [also termed Condition Based Maintenance (CBM)] is a condition-based programme which carefully monitors the lubricant and machinery condition of in-service equipment. Analysis allows accurate prediction of equipment failure. And corrective action can be taken to avoid equipment downtime.
As CBM inspections are performed while the equipment is in service, disruption to normal system operations is minimized. It is widely acknowledged that CBM results in higher system reliability.
The CBM approach of timely maintenance offers significant cost savings over routine or time-based maintenance because corrective action/maintenance is performed only when warranted. In comparison, time-based maintenance is performed regardless of the equipment condition. Time-based maintenance is labour-intensive, ineffective in identifying problems that develop between scheduled inspections... and is not cost effective.
CBM technologies uses infrared, acoustic, vibration analysis, and oil analysis to evaluate equipment condition. Vibration analysis is particularly productive on high speed rotating equipment, but can be the most expensive part of a CBM programme. Oil Analysis is a long-term programme that can be more accurate than any of the other available technologies. Especially when employing wear particle analysis or ferrography where the metal wears present in the lubricant are quantified and identified to high precision. The equipment problems become known long before the effects of abnormal vibration surfaces, having the worse equipment troubles averted.
However, this is contingent upon the oil samples being taken properly, and stored properly en-route to testing. Equipment such as sampling valves and glass sampling bottles help ensure that results are representative of the actual equipment condition.
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Maintenance Approach |
Maintenance actions |
Parallels with the Human Body |
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Proactive |
Monitoring and correction of the root causes of machinery breakdown |
Cholesterol and blood pressure monitoring with diet control |
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Predictive Maintenance |
Monitoring of vibrations, heat, wear debris, lubricant condition |
Blood tests and ECG for early detection of health problems |
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Preventive Maintenance |
Periodically replace important components |
Organ transplants |
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Breakdown Maintenance |
Fix machinery only after it has broken down |
Clone the person after the person has died of a heart attack/stroke |