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FMEA and Risk Analysis

Learning Objective

By the end of this lesson, the learner should be able to:

  • Explain the purpose of Failure Mode and Effects Analysis (FMEA).
  • Understand failure modes, effects and causes.
  • Understand how FMEA supports risk prioritization.
  • Understand the role of Severity, Occurrence and Detection.
  • Understand the Risk Priority Number (RPN) under the stated scoring system.
  • Connect risk analysis with practical improvement actions.

1. Introduction

Failure Mode and Effects Analysis (FMEA) is a structured method for evaluating potential failures, their effects and their causes.

FMEA helps an improvement team identify risks systematically and prioritize them for action.

For a Black Belt, FMEA provides a structured way to ask:

What could fail? → What would happen? → Why could it happen? → What should we do about the risk?

2. Failure Mode

A failure mode describes the way a process, product or activity could fail.

Examples may include:

  • Incorrect assembly
  • Incorrect measurement
  • Missing information
  • Process step not completed correctly

The failure mode describes how the failure could occur.

3. Effect

The effect is the consequence of the failure mode.

For example:

Failure Mode: Incorrect assembly
Effect: Product does not meet the required specification.

Understanding the effect helps the team assess the potential impact of the failure.

4. Cause

The cause is the reason a failure mode could occur.

For example:

Failure Mode: Incorrect assembly
Cause: Components can be positioned incorrectly during assembly.

Identifying the cause is important because improvement actions should address the underlying risk rather than simply respond to the resulting failure.

The source defines the basic FMEA relationship as failure mode → effect → cause.

5. Risk Prioritization

FMEA commonly uses three rating dimensions:

Severity

How serious is the effect if the failure occurs?

Occurrence

How frequently or likely is the failure mode to occur?

Detection

How likely is the current system to detect the failure or its cause before the effect reaches the customer or next stage?

These ratings support risk prioritization under the organization’s defined scoring system.

6. Risk Priority Number (RPN)

Under the stated FMEA scoring approach, the Risk Priority Number (RPN) is commonly calculated as:

RPN = Severity × Occurrence × Detection

The resulting value can be used to help prioritize risks for attention.

Important Black Belt Point

RPN should not be treated as merely a mathematical score.

The purpose of FMEA is to understand risk and support appropriate action.

The scoring system and prioritization criteria should therefore be applied consistently within the project or organization.

7. FMEA as a Risk-Management Tool

A structured FMEA can follow this sequence:

Identify Failure Mode
↓
Identify Effect
↓
Identify Cause
↓
Assess Severity, Occurrence & Detection
↓
Prioritize Risk
↓
Take Appropriate Action
↓
Review the Risk

This makes FMEA a practical improvement and risk-management tool rather than simply a worksheet exercise.

8. Tools & Techniques

The source identifies the following tools and techniques:

  • FMEA Worksheet
  • Severity
  • Occurrence
  • Detection
  • RPN
  • Risk Assessment

9. Application Example

Medical-Device Product Assembly

A medical-device team evaluates risks associated with product assembly.

The team identifies potential failure modes, determines their effects and causes, and assesses the associated risks.

The team can then prioritize important risks and determine appropriate actions to reduce or control them.

10. Case Study

Automotive Brake-Component Assembly

An automotive plant identified a high risk associated with brake-component misassembly.

The improvement team addressed the risk using poka-yoke fixtures.

The fixtures reduced the risk of incorrect assembly and improved safety compliance.

Black Belt Learning

This case demonstrates an important connection:

FMEA identifies and prioritizes risk → Improvement action addresses the risk → Poka-yoke helps prevent the error

The Black Belt should connect the risk analysis to an actual process-control or improvement action.

11. FMEA and Poka-Yoke

FMEA can identify situations where human or process errors could create significant risk.

Poka-yoke, or mistake-proofing, can then be considered as one possible improvement approach.

For example:

FMEA: Identifies incorrect component assembly as a significant risk.

Improvement: Introduce a fixture that allows the component to be installed correctly and prevents incorrect positioning.

Thus, FMEA can help identify where risk exists, while improvement tools can help determine how the risk may be reduced.

12. Black Belt Perspective

A Black Belt should ask:

  1. What can fail?
  2. What is the effect of the failure?
  3. What could cause the failure?
  4. How serious is the effect?
  5. How frequently could the failure occur?
  6. How effectively can the current process detect it?
  7. Which risks require attention?
  8. What action can reduce or control the risk?
  9. How will the effectiveness of the action be evaluated?

The key principle is:

FMEA is more than a scoring exercise; it is a structured method for understanding and managing risk.

13. Lesson Practice

  1. Why is FMEA more than a scoring exercise?
  2. How should high-priority risks be treated?
  3. How can FMEA connect to poka-yoke?
  4. What is the difference between a failure mode, effect and cause?
  5. What are the three commonly used rating dimensions in FMEA?
  6. Under the stated scoring system, how is RPN calculated?

14. Key Learning Points

  • FMEA systematically evaluates potential failures, effects and causes.
  • A failure mode describes how something could fail.
  • An effect describes the consequence of the failure.
  • A cause identifies why the failure could occur.
  • Severity, Occurrence and Detection support risk evaluation.
  • RPN = Severity × Occurrence × Detection under the stated scoring system.
  • FMEA helps prioritize risks for action.
  • FMEA can connect directly with improvement methods such as poka-yoke.

15. Lesson Conclusion

FMEA provides the Black Belt with a structured approach to identifying, evaluating and prioritizing potential risks.

The essential sequence is:

Failure Mode → Effect → Cause → Risk Assessment → Prioritization → Action → Risk Reduction

The ultimate purpose is not simply to calculate an RPN. It is to use structured risk analysis to support appropriate actions that reduce or control important process and product risks.