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Below we'll discuss how reliability-centered maintenance works, how you should implement it and see how reliability-centered maintenance can benefit you.
First established in the aviation industry, reliability-centered maintenance (RCM) is the process of identifying potential problems with your assets and determining what you should do to make sure those assets continue to produce at maximum capacity. Another way to look at RCM is it's a way to analyze breakdowns to determine maintenance methods and unique maintenance schedules for your individual assets.
Reliability-centered maintenance is often mistaken for preventive maintenance; however, there is one key difference: preventive maintenance isn't selective like RCM, making it less efficient. When performed correctly, reliability-centered maintenance reduces inefficiency by looking at each individual asset carefully before assigning maintenance tasks.
Reliability-centered maintenance uses a general workflow involving four steps:
Reliability-centered maintenance takes a bit more time to implement initially, but it helps your plant operate effectively in terms of production availability, how many spare parts you need in stock and other factors directly relating to the overall cost.
When beginning the reliability-centered maintenance process, it's a good idea to start with your most critical asset or the one that will cause the biggest headache if it breaks down.
So, you've chosen an asset you want to evaluate using RCM. It's time to assess it based on seven standard questions set forth by the SAE, which is the regulatory organization on reliability-centered maintenance, among other engineering standards. Let's take a look at each question laid out in SAE's JA1011 standard.
For example, say your bottle-capping machine can cap 1,000 bottles an hour at optimum capacity. You see from past maintenance data that your bottling machine has needed to be repaired every 800 hours on average (sometimes referred to as mean time between maintenance or MTBM). Each time it needs to be worked on, it's shut down for three hours. If you run the bottling machine 20 hours a week, every 40 weeks (800/20) you'll experience downtime and lose about 3,000 capped and finished bottles (1,000 bottles x 3 hours). Based on the bottling machine's data, it should be able to go approximately 1,200 hours before needing repairs. If you can increase the bottle-capping machine's average time between repairs by 50 percent, you should see nearly 1,000 more finished bottles every 40 weeks.
If the bottle capper breaks down causing that three-hour downtime, you might be looking at a total bill of $1,666, with $66 for labor ($22 per hour x 3 hours), $400 for parts and $1,200 for a decrease in productivity ($400 per hour x 3 hours). Quantifying these costs will help you forecast expenses brought on by failures.
When it comes to implementing reliability-centered maintenance, the seven questions discussed above can be broken down into three phases: decision, analysis and act.
Phase 1 – Decision: The first three questions combine to make up the decision phase. To avoid wasting time, justify and plan for implementing an RCM plan. Discuss readiness, needs and desired outcomes with your maintenance staff, project leaders, subject-matter experts and executives. The decision-making phase should be reserved for outlining goals in line with the budget, timeline and management concerns.
When it comes to choosing the equipment for RCM analysis, think about which pieces are most critical to operations as well as the repair vs. replacement cost, and then look at past data to get a snapshot of how much you've spent on previous maintenance. Include the following questions in your decision-making phase:
Defining a data-driven list of the machine's functionality helps your team choose the capacity at which it wants the machine to run as opposed to its actual performance.
Phase 2 – Analysis: Questions four through six help you analyze or actually conduct the RCM study. First, your team should identify functional failures. These can include poor performance, performing unnecessary functions or complete failure. For example, a total functional failure would be the belt on the bottle capper breaking, causing the machine to stop completely.
The next step in the analysis phase is identifying and evaluating the effects of the failure(s). Your team should document what can be observed or what actually happens during a failure. How does it affect overall production? How does it affect safety?
The last step in the analysis phase is identifying failure modes or what causes each failure? A popular technique to uncover these causes is using failure mode and effect analysis (FMEA). This analysis technique breaks down all possible failures that could occur in the design, manufacturing or assembly process, as well as a product or service. Ask questions such as:
FMEA looks at failure modes, root causes, failure indicators, failure criticalities, failure probabilities and effects by considering asset history and team/employee experiences. Most FMEA analysis programs use the information gathered to drive the planning of mitigation tasks to help detect failures early or prevent them altogether.
Many companies automate the analysis process using a computerized maintenance management system (CMMS). A CMMS tool helps with planning and minimizing the chances your team will miss scheduled work and equipment failures by generating tasks and scheduling inspections.
Phase 3 – Act: Phase 3 incorporates the seventh question (select maintenance tasks). After planning, making decisions and analyzing, it's time to act on the information you've analyzed to update your maintenance tasks and system procedures and improve asset design. Think about grouping your failure management techniques into two groups: proactive tasks and default actions.
Deciding which technique is best for your situation depends on your RCM analysis and understanding how your failure modes affect your assets and impact your overall production.
Some of the biggest benefits you'll see when implementing a reliability-centered maintenance plan include minimizing the frequency of overhauls, reducing equipment failures, refocusing maintenance tasks on critical assets, increasing component reliability and more. What do all of these benefits have in common? They all affect your bottom line. Let's take a look at a couple of real-world examples.
The NIF lasers essentially make up one giant laser the size of three football fields, so you can imagine how expensive and dangerous a breakdown might be. Using reliability-centered maintenance saved the NIF nearly $80,000 in one isolated instance alone, according to the NIF's former facilities and maintenance manager, Nick Jize. Through an RCM program, it was determined a motor in the laser-amplifying cooling system was put on a watch list and scheduled for weekly vibration analysis. Through vibration analysis, it was revealed that the bearings were deteriorating and loosening, allowing the NIF to replace the motor before it failed. Proactively replacing this motor prevented almost eight hours of "shot delays" for a one-time savings of $80,000, according to Jize. The NIF continuously updates its RCM procedures.
Reliability-centered maintenance is designed to be performed continuously as opposed to a one-time analysis. It is a valuable tool that enables you to extend the life of your assets, maintain their integrity, minimize or eliminate unplanned downtime and reduce maintenance costs. Reliability-centered maintenance can help you: