Lean Manufacturing
RELIABILITY CENTERED MAINTENANCE
Reliablity centered maintenance is a system for designing a cost effective maintenance program. It can be a detailed complex, computer, statistically driven, but at its basics it is fairly simple. Its ideas can be applied to designing and operating a PM system, and can also guide your learning as you do maintenance, troubleshooting, repair, and energy work.
These are core principles of RCM. These nine fundamental concepts are:
- Failures happen.
- Not all failures have the same probability
- Not all failures have the same consequences
- Simple components wear out, complex systems break down
- Good maintenance provides required functionality for lowest practicable cost
- Maintenance can only achieve inherent design reliability of the equipment
- Unnecessary maintenance takes resources away from necessary maintenance
- Good maintenance programs undergo continuous improvement.
Maintenance consists of all actions taken to ensure that components, equipment, and systems provide their intended functions when required.
An RCM system is based on answering the following questions:
1. What are the functions and desired standards of performance of the equipment?
2. In what ways can it fail to fulfil its functions? (Which are the most likely failures? How likely is each type of failure? Will the failures be obvious? Can it be a partial failure?)
3. What causes each failure?
4. What happens when each failure occurs? (What is the risk, danger etc.?)
5. In what way does each failure matter? What are the consequences of a full or partial failure?
6. What can be done to predict or prevent each failure? What will it cost to predict or prevent each failure?
7. What should be done if a suitable proactive task cannot be found (default actions) (no task might be available, or it might be too costly for the risk)?
Equipment is studied in the context of where when and how it is being used
All maintenance actions can be classified into one of the following categories:
- Corrective Maintenance – Restore lost or degraded function
- Preventive Maintenance – Minimizes opportunity for function to fail
- Alterative Maintenance – Eliminate unsatisfactory condition by changing system design or use
Within the category of preventive maintenance all tasks accomplished can be described as belonging to one of five (5) major task types:
- Condition Directed – Renew life based on measured condition compared to a standard
- Time Directed – Renew life regardless of condition
- Failure Finding – Determine whether failure has occurred
- Servicing – Add/replenish consumables
- Lubrication – Oil, grease, or otherwise lubricate
We do maintenance because we believe that hardware reliability degrades with age, but that we can do something to restore or maintain the original reliability that pays for itself.
RCM is reliability-centered. Its objective is to maintain the inherent reliability of the system or equipment design, recognizing that changes in inherent reliability may be achieved only through design changes. We must understand that the equipment or system must be studied in the situation in which it is working.