What is FMEA?
Failure Modes and Effects Analysis (FMEA) is a systematic technique of reviewing components, assemblies, and sub-systems to identify as many failure modes as possible and understanding their cause and effects on the product.
The Failure Modes and Effects Analysis Model
The FMEA model is constructed from several sections, each section either evaluates the failure mode or gives it a score. The process is made up of the following sections:
- Item under review – this can be a part or an assembly etc.
- The potential failure mode – this identifies how the item under review can potentially fail. There can be several potential failure modes for each item.
- Potential effects of failure – this is where all the possible effects of each failure are identified
- Severity – this is the first score rating out of 10 where 10 is the absolute worst and 1 has a negligible effect on the product if it failed.
- Potential causes – this is where all the potential causes of the failure are identified
- Occurrence – the second score rating considers how often the failure is likely to occur, again 10 being most certainly likely to occur and 1 being highly unlikely to occur.
- Current Process Controls – understand what controls are currently in place that would capture and identify each failure mode
- Detection – the third score rating considers the probability of the failure mode being detected by the current controls that are in place
- Risk Priority Number (RPN) – this the score derived from multiplying the severity, occurrence, and detection score rating together
Once the analysis has been completed and the RPN calculated, corrective or recommended actions are assigned to each failure mode. The Severity, Occurrence, & Detection scores are then applied again to establish the new risk priority number once the actions have been applied.
The most common FMEAs are:
- Design FMEA
- Process FMEA
Filling out your FMEA
Each potential issue is then rated within 3 risk dimensions:
- SEVERITY – Severity of issue
- OCCURRENCE – Likelihood of issue occuring
- DETECTION – If not detected in-house, how likely it is the issue to impact the customer?
In order to tackle the risks, big companies usually analyze root cause(s) and form an action plan of corrective actions, implement the actions, following up to assure that measures were effective, and re-evaluate the risk level over time. This should be repeated in order to keep getting best results.
Frequent FMEA Mistakes
This is a list of frequent mistakes (coming from New Tricks for an Old Tool, published in Quality Progress in May 2017):
Learn more by reading our blog post: The Process FMEA: Template, Use Cases, and Example