1. Six Sigma Greenbelt Training
FMEA
Six Sigma Greenbelt Training
Dave Merritt

2. The Six Sigma Methodology
Focus
Process Map Y
Measurement System Analysis Y
Process Capability Y
Phase 1:
Define/Measure
Phase 2:
Analyze
Graphical Methods X’s
Hypothesis Testing X’s
Phase 3:
Improve
Analysis of Variance X’s
Design of Experiments Vital Few X’s
The analyze and improve phases help you understand your X’s (inputs) and to narrow down to the vital few X’s.
Statistical Process Control Vital Few X’s
Failure Mode and Effects Analysis Vital Few X’s
Phase 4:
Control

3. Learning Objectives Explain the function of an FMEA
Demonstrate how to develop an FMEA
Review FMEA definitions

4. What is a FMEA?
Failure modes and effects analysis (FMEA) is a step-by-step approach for identifying all possible failures in a product design, a manufacturing process, or a service. “Failure modes” means the ways, or modes, in which something might fail.
The Idea…
…is to identify ways a failure can occur and then plan to prevent them from occurring.

5. Purposes and Benefits of FMEA
Improves the quality, reliability, and safety of products
Increases customer satisfaction
Reduces product development timing and cost
Documents and tracks actions taken to reduce risk

6. Types of FMEA’s
System FMEA: Used to analyze systems and subsystems in the early concept and design stages. Focuses on potential failure modes associated with the functions of a system that are caused by the design.
Design FMEA: Used to analyze products before they are released to production.
Process FMEA: Used to analyze manufacturing and assembly processes.

7. Understanding the Relationships of Causes to Effects
A cause can have a one-to-one relationship with an effect
Cause 1
Effect 1
Cause 2
Or one cause can have multiple effects
Effect 1
Effect 2
Cause 1
The purpose of this slide is to introduce the cause and effect relationship
Or multiple causes for one effect
Cause 1
Cause 2
Effect 1

8. Failure Mode Fishbone Model
Cause
Materials
Methods
Machine
Failure
Mode
(Defect)
However, with an FMEA, the causes link to the Failure Mode which than links to the effect.
Effect
Human
Measurement
Environment
The causes link to the Failure Mode, which then link to the effect.

9. Failure Mode Fishbone Model
Cause
Materials
Methods
Machine
Failure
Mode
(Defect)
Effect
Human
Measurement
Environment
The goal of FMEA is to understand your process well enough to anticipate, detect and ultimately prevent the Failure Mode.

10. Results of a well constructed FMEA
List of potential failure modes
List of potential critical characteristics
List of effects
List of causes
Documentation of current controls
Prioritization of improvement activities
Documentation of the history of improvements
A starting point for development of control plans

11. The FMEA Form
Lists Failure
Modes for
Each Process
Step

12. The FMEA Form - Detail
List the process steps in sequential order
Failure Mode: The manner in which a part/process can fail to meet specification. Usually associated with a defect or non-conformance.
Typical Failure Modes: Bent, cracked, deformed, impure, dirty, binding

13. The FMEA Form - Detail
Failure Effect: Impact on customer if Failure Mode is not prevented or corrected. Customer can be downstream or the end user.
Typical Failure Effects: (for the end user)
Noise, Unstable, Rough, Excessive Effect required
Typical Failure Effects: (for the next operation)
Cannot fasten, Cannot bore/tap, Does not fit, Does not connect

14. The FMEA Form - Detail Rates the Severity of each effect to
the customer on
a scale of 1-10.
Severity (SEV): How significant is the impact of the Effect to the customer (internal or external)?

15. The FMEA Form - Detail
Cause: A manufacturing deficiency that results in a Failure Mode. Causes are sources of manufacturing variability associated with Key Process Input Variables. Causes are described in terms of something that can be corrected or can be controlled.
Typical failure causes:
Improper torque — over, under
Improper weld — current, time, pressure
Inaccurate gauging
Inadequate gating/venting
Lists the Causes for each Failure Mode: Each Cause is Associated with an undesired process input.

16. Occurrence rates how often a particular Cause or Failure Mode Occurs
The FMEA Form - Detail
Occurrence rates how often a particular Cause or Failure Mode Occurs
Current Controls: The mechanisms that prevent or detect the Failure Mode before it reaches your customer. Current Controls include SPC, Inspections, Monitoring, Training, and Preventive Maintenance

17. The FMEA Form - Detail
Detection rates how well the Cause or the Failure Mode can be detected.

18. Risk Priority Number (RPN) = SEV  OCC  DET
The FMEA Form - Detail
Risk Priority Number (RPN) = SEV  OCC  DET
A reminder: Severity, Occurrence, and Detection are Scored on a (Best) to 10 (Worst) Scale. RPN directs priority on corrective action.

19. Additional FMEA Definitions
Critical Characteristics: Items that affect customer safety and/or could result in non-compliance to regulations and thus require controls to ensure 100% compliance.
Significant Characteristics: Those items that require SPC and Quality planning to ensure acceptable levels of Quality (Key Process Input Variables).

20. Severity Ranking

21. Occurrence and Detection Ranking

22. Overall FMEA Process Select the Process FMEA team
Develop a Process Map and identify all process steps
List all the Key Process Outputs to satisfy internal and external customer requirements
List Key Process Inputs for each Process Step
Rank the inputs according to importance
Begin populating the FMEA with the process steps
List the associated Failure Modes
List the associated Effects for each Failure Mode
Assign Severity ranking for each Effect
List Potential Causes for each Failure Mode
11. Assign Occurrence rating for each Cause
List Current Controls for each Cause
Assign Detection ratings to each Cause
Calculate the risk priority number for each potential failure mode scenario
Establish a Threshold RPN level
Determine recommended actions to reduce all RPNs
Take appropriate actions
Re-calculate all RPNs
Make the FMEA a LIVING
DOCUMENT!
These steps are “as needed” and are completed in an FMEA Worksheet. Next slide

23. FMEA Worksheet

24. Class Exercise – 30 minutes - Groups
For the process step shown below, begin populating the FMEA Worksheet
Pouring a Beer
2. Use the information in the worksheet to populate the FMEA form

25. Who Prepares a FMEA?
The responsible design or process engineer leads the FMEA team
The team approach is required!
Involve representatives from all affected activities
Typical members should include Design, Manufacturing, Assembly, Quality, Reliability, Service, Purchasing, Testing, Supplier, and other subject matter experts as appropriate.
Note: The authoring design or process engineer is responsible for making sure the FMEA remains updated. LIVING DOCUMENT!

26. When is a FMEA Started?
When new systems, products, and processes are being designed.
When existing designs or processes are being changed.
When carry-over designs/processes will be used in new applications, or new environments.
After completing a Problem Solving Study (to prevent recurrence of problem).
For a Design FMEA, after product functions are defined, but before the design is approved and released to manufacturing.
For a Process FMEA, when preliminary drawings of the product are available.

27. In this session you learned
The importance of a FMEA
Causes & Effects and how they can be related
How a FMEA is constructed and its definitions
The importance of the Risk Priority Number (RPN)
How a Process Map is used to understand the relationship of key input and output variables
When a FMEA is needed and considered complete

28. Class Exercise – Example