Though there's a great difference between any of them and breakdown recovery.
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Please have a look to this summary taken from an very interesting article about maintenance strategies:
The types of maintenance are:
- reactive maintenance
- preventive maintenance
- predictive maintenance
- proactive maintenance
Reactive maintenance — also known as run to failure. Here, the equipment is used until it fails. Then the equipment is repaired or replaced.
This strategy is acceptable and may be preferred for equipment with low costs and low probability of failure.
Preventive Maintenance (PM) is used on equipment that has a high cost of failure. For this purpose, "failure" means more than when equipment come to an and to function— it also covers situations where the equipment is unable to perform its intended function at needed quality, cost, and right through.
To avoid high cost of failure, preventive maintenance includes some periodic checks, lubrication, adjustment, replacement of parts, etc.
Preventive maintenance is time-based instead of condition-based. It often takes place before there is a problem or after the damage is known.
Predictive maintenance improves on preventive maintenance by using actual equipment performance to determine when maintenance should occur.
With this strategy, periodic or continuous monitoring detects the onset of wear or degradation, and the information is then used to predict potential problems and the best time for maintenance. Predictive maintenance is typically used where failure cost is high. Monitoring for predictive maintenance is available for rotating equipment, electrical equipment, process equipment, transmitters and valves, and other equipment types.
Proactive maintenance is fundamentally different from the other approaches.
Proactive maintenance seeks to improve performance, in addition to maintaining asset availability. It uses monitoring and diagnostics to determine both equipment health and performance. Maintenance is performed on healthy equipment if a performance improvement can save or make money.
A typical facility uses a mix of all above stategies.
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Aurel... good answer. I would like to point out something though that you or others might find more useful.
Predictive maintenance improves on preventive maintenance by using actual equipment performance to determine when maintenance should occur.
This is correct... predictive work should be based on the findings of the other 3 methods.
With this strategy, periodic or continuous monitoring detects the onset of wear or degradation, and the information is then used to predict potential problems and the best time for maintenance. Predictive maintenance is typically used where failure cost is high.
This is the area that I disagree with. Periodic monitoring is a function of both preventive and proactive methods.
Predictive maintenance is for replacing items you know will fail, before they fail, on a specific interval. I use results from my PMs and failures to establish real time or run time criteria for predictive repairs. Other than this, I do not allow PMs to influence my predictive work in any way.
For example... I have a cutter machine running heavy load 20hrs a day. I know I can get 4.5 to 5 months out of the feed roll bearings. PMs and plenty of blown bearings show me this. As a predictive measure I replace the bearings on a set schedule at 4 months. A PM inspection on these bearings at 4mo (heat and vibration) would declare them good. But I know better and change them out regardless of the current inspection.
Having a good preventive routine as well as enforcing a separate predictive schedule has drastically reduced downtime and repair costs in our facility.
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