FMEA stands for Failure Mode and Effects Analysis . It is a simple, versatile and powerful tool that helps a team identify process defects to eliminate or reduce. Its aim is to identify process steps at risk of contributing to a failure.
| Cause | Failure Mode (Defect) | Effect |
|---|---|---|
| Potential source of failure | How the requirement or process fails | Impact on the customer |
FMEA is a structured approach to:
- Identifying ways a process may fail to meet critical customer requirements.
- Estimating the risk associated with specific causes of those failures.
- Evaluating the current control plan for preventing failures.
- Prioritizing actions needed to resolve a process problem
What Are the Purpose and Benefits of PFMEA?
While the team’s focus in the Analyze phase was identifying critical factors driving customer dissatisfaction, FMEA adds the ability to:
- Document and track actions being taken to reduce risk.
- Identify value-adding and non-value-adding steps.
- Identify process variation caused by personnel or training.
- Improve the quality and reliability of products and services
- Reduce product development time and cost.
How Do I Build an FMEA?
Developing this tool requires the participation and expertise of a cross-functional team. It is led by the person responsible for the system, product or service that needs improvement. For each process step, the team identifies:
- Failure Modes. The ways the requirement or process can fail to meet specifications.
- Potential Causes. Deficiencies that can result in a failure mode. Potential causes are sources of variation, usually associated with key process inputs.
- Potential Effects. The impact on the customer if the failure mode is not prevented or corrected.
Once the team identifies a failure mode, it calculates the RPN (Risk Priority Number) for that failure mode as follows:
RPN = Severity × Occurrence × Detection
The maximum RPN is 1,000 because each factor is scored on a scale from 1 to 10, as shown below.
| Factor | Definition | 1 (Minimum) | 10 (Maximum) |
|---|---|---|---|
| Severity | How significant is the effect on the customer? | Least significant | Most significant |
| Occurrence | How likely is the cause of the failure mode to occur? | Unlikely to occur | Likely to occur |
| Detection | How likely is the system to detect the cause or effect if it occurs? | Likely to be detected | Unlikely to be detected |
In Conclusion, creating a PFMEA involves three main steps, each with its own activities:
| Preparation | FMEA Process | Improvement |
|---|---|---|
| 1. Select a team.
2. Develop the process map and identify the process steps. 3. List the key inputs and outputs needed to meet internal and external requirements. |
4. For each process step, list the ways it can vary (causes) and identify associated failure modes.
5. Assign severity, occurrence and detection scores to each cause. 6. Calculate the RPN for each potential failure mode scenario. |
7. Rank by RPN.
8. Determine actions to reduce the RPNs. |
FMEA addresses process risks using the knowledge and experience of a cross-functional team.
It can be used at any time for a product, process or service when:
- A risk analysis is needed.
- The nature of a failure needs to be better understood.
- Failure points need to be identified
It connects causes with failure modes so they can be prioritized using the RPN: a higher RPN indicates greater risk.
It is also used in the DMAIC process.
Recommended Books on This Topic:
The Automotive IATF 16949:2016 Memory Jogger
Related Links:
- Lean Six Sigma Project Roadmap
- Measure
- Process Map
- Fishbone Diagram
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The explanation is very clear and helped me a lot. Thank you.
Very well explained and practical.
Thank you, María Guadalupe,
I invite you to review the different concepts we have published. Your suggestions and comments are always welcome.
Kind regards.
Eduardo Cisneros