What is Failure Mode and Effects Analysis (FMEA)?
FMEA is an acronym of Failure Mode and Effects Analysis, a process where all possible equipment failures are identified and recorded to predict their corresponding impact on productivity as a whole. It develops an action plan from the bottom up by observing what components are most susceptible to breakdowns. FMEA is a fundamental part of effective preventive maintenance and predictive maintenance strategies.
An FMEA investigates the potential consequences of unprecedented breakdowns on the rest of the facility, searching for any materials, manufacturing, or systems that fall short of standard practices. This way, the root cause will be easier to identify as organizations map out failure modes through their harmful effects.
The Purpose of FMEA
An FMEA gathers information about the effects of asset failure on the production floor. Each is assigned a risk priority number so that they can be rated by the degree of severity. These failure modes will have criteria for full, partial, or degraded functions that apply to specialized equipment such as a hydraulic pump.
The effects portion discloses the repercussions of a failure event at increasing levels. You may find a local effect between two components or an end effect describing a compromised subsystem. The difficult part is formulating a strategy to overcome those effects.
Different Types of FMEA
FMEAs are grouped into several risk assessment subtypes:
FFMEA
A Functional FMEA looks at the big picture of how a facility is managed, instead of just picking apart each component of the system. An FFMEA closely examines the risks that would directly affect a system’s functions, weighing them against normal performance indicators to see if those align with the intended use.
DFMEA
A Design FMEA analyzes the relative risk of assets throughout the design phase. It is generally conducted to discover likely problems with an asset and correct them before they are used in assembly and packaging. A DFMEA provides a shortcut to maintenance and increases the durability of assets.
PFMEA
A Process FMEA detects every point of failure in a certain process: It uncovers the possible failures of a current procedure in the system and how they should be dealt with. A PFMEA will factor in the steps leading up to a final product, through the machines and method of operation. This includes halted activities, technician errors, and safety hazards.
FMECA (Failure Mode, Effects & Criticality Analysis)
A failure mode, effects, and criticality analysis rates various assets by their risk profile. It’s an inductive model that links elements into a failure chain through the root cause or mechanism. Asset criticality is also centered on maintenance reliability, revealing why an incident happened, then assigning these modes to different probabilities.
Read more: What is Reliability Centered Maintenance?
How to Perform an FMEA
An FMEA can be introduced to encourage active problem solving from within the organization. After approval, the required data is usually collected from your OEM guidelines, conversations with operators, and work order forms.
It would be beneficial to have an FMEA flow diagram or worksheet that helps you identify high-risk areas. And a good place to start is by collecting accurate data on all actions taken by your staff.
Here are the 9 steps to completing an FMEA:
1. Select what process to analyze for the incident (Design, Process, or Functional). Draw a tree or flow diagram to visualize how different components interact.
2. Appoint team leaders to foresee the failure modes of every item on the chart. Assets are prone to wear and tear from excessive rusting, short-circuiting, deformed parts, or infrequent maintenance.
3. Describe the downstream effects of failure by discovering the root cause. Did a shutdown of the assembly line occur? Or were there signs of defective materials?
4. Calculate the severity score to find the degree of impact on nearby procedures. Measure the current state of an asset with respect to damage, performance degradation, and system operations.
5. Assign the probability of occurrence, severity, and detectability for each failure mode. Estimate how often this type of failure occurs to give a proper risk assessment.
6. Determine the Risk Priority Number (RPN) using the three rankings mentioned above. Multiply Severity, Occurrence, and Detection together to get the RPN of every item on your worksheet.
7. Assign a rating for failure detection using sensors in your control system. From a score of 0 to 10, rank these failures by their likelihood of detection.
8. Take action to reduce the rippling effects of prevalent risks. What are some ways to lower the RPN value? Think about installing alarms or monitors that would minimize the cost of damages.
9. Run another calculation of the RPN after changes have been put in place. Are your systems finally below the critical threshold after carrying out risk-based initiatives?
How to Calculate FMEA in Maintenance
To recap, FMEAs can help you detect, prevent, or mitigate any risks associated with the identified failure, acting as an organized approach to elevating quality objectives and process reliability.
Examples of failure mode and effects analysis include creating a diagram of the AC power supply and a flow chart of hardware methods containing the motor and bearing pieces.
Through a cost-benefit analysis, you will acquire insights on the criticality of the plant.
Define both your qualitative and quantitative parameters. First, label the failure’s severity and occurrence frequency on a scale of 1 to 10. Next, analyze the actual numbers. You will need formulas to calculate failure modes in real-time.
Be sure to prepare a backup system or alternative route to increase security with redundancies. Then, solve for the RPN as explained before and build a criticality table to plot the values. Focus on replacing parts to restore performance back to the original settings.
The best strategy is to plan ahead for breakdowns before they even occur. This can be done systematically on every problem you encounter by listing them on a maintenance backlog and taking the necessary actions.
Read more: Asset Criticality Analysis: Effectively Rank Assets by ‘Criticalness’