Failure Mode and Effects Analysis
based on FMEA 4
th
Edition
Mark A. Morris
ASQ Automotive Division Webinar
November 30, 2011
mark@MandMconsulting.com
www.MandMconsulting.com
Purpose of this Course
• Enable participants to understand the
importance of FMEA in achieving robust
capable designs and processes.
• Teach participants how to improve the
efficiency and effectiveness of their FMEA
efforts.
• Get the right people involved in the process of
FMEA, and get results.
• Have Fun Learning!!!
Learning Objectives
Participants will be able to:
Explain the purpose, benefits and objectives of FMEA.
Select cross-functional teams to develop FMEAs.
Develop and complete a FMEA.
Review, critique, and update existing FMEAs.
Manage FMEA follow-up and verification activities.
Develop FMEAs in alignment with AIAG FMEA reference manuals.
Changes in the FMEA Manual (4
th
Ed.)
• Improved format, easier to read.
• Better examples to improve utility.
• Reinforces need for management support.
• Strengthens linkage between DFMEA/PFMEA.
• Ranking tables better reflect real world use.
• Introduces alternative methods in use.
• Suggests better means than RPN to assess risk.
• Recommends against threshold RPN values to initiate
required action.
Process FMEA Report
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Recommended
Actions
Responsibility
& Target
Completion Date
Action Results
Actions
Taken
S
e
v
O
c
c
D
e
t
R.
P.
N.
POTENTIAL
FAILURE MODE AND EFFECTS ANALYSIS
(Process FMEA)
FMEA Number ___________
Page _____ of ______
Prepared by _________________________
FMEA Date (Orig.) _______ (Rev.) _______
Core Team _________________________________________________________________________________________________________________________
Model Year(s) Program(s) ________________
Item _________________________________
Process Responsibility ______________________
Key Date _________________________________
Current
Process
Control
(Prevention)
Function
Process FMEA Analysis
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Describe
the function or
requirement to
be analyzed
Describe how the
item could
potentially fail to
perform its function
State the effects
of the failure in
terms of the specific
system, subsystem,
or component
being analyzed
Identify potential
causes of the item
not performing its
intended function
This column is reserved
for the methods that
have been used to
prevent a specific cause
This column is used
to document methods
that have been used to
detect either the cause
or the failure mode
Process Step
is simply
the focus of
the analysis
Process FMEA Analysis
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Severity
evaluates
the impact
of the effect.
Occurrence
rates how often
a specific cause is
likely to result in
the failure mode
being analyzed.
Detection
ranks our ability
to detect either a
cause or a resulting
failure mode. Use
best detection
available.
Risk Priority Number
is the product of
the severity, occurrence,
and detection rankings.
Classification is an optional
column commonly used
to identify safety risks.
Four Common Classes of FMEA
• System FMEA
– Focuses on how interactions among systems might fail.
• Design FMEA
– Focuses on how product design might fail.
• Process FMEA
– Focuses on how processes that make the product might fail.
• Machinery FMEA
– Focuses on how machinery that perform processes might fail.
The focus for this evening is on Process FMEA.
AIAG Model for Quality Planning
Design FMEA
Process & Machinery FMEA
Understanding a Failure Sequence
Failure
Mode
Direct
Cause
Immediate
Effect
Cause
Detection
Failure Mode
Detection
Is it a Cause or Failure Mode?
Failure
Modes
Effects Causes
Failure
Modes
Effects Causes
Failure
Modes
Effects Causes
System Level
Subsystem Level
Component Level
12
Examples of Weld Process Failure Modes
• System (Welding Line)
– Robot Failure
– Loss of Incoming Water
– No Signal to Weld
• Subsystem (Weld Gun)
– Cracked Jaw
– Failed Servo Motor
– Failed Shunt
• Component (Servo Motor)
– Overheats
– Loss of Position
– Premature Seal Failure
A Rational Structure for Quality Planning
TM
Product
Design FMEA
Internal Process
Control Plan
Tool Design
Machinery FMEA
Internal Processes
Process FMEA
Customer Plant
Control Plan
Process
Process FMEA
Product
Design FMEA
Internal Process
Control Plan
Tool Design
Machinery FMEA
Internal Processes
Process FMEA
Customer Plant
Control Plan
Process
Process FMEA
Motivation for Specific FMEAs
Product
Design FMEA
Internal Process
Control Plan
Tool Design
Machinery FMEA
Internal Processes
Process FMEA
Customer Plant
Control Plan
Process
Process FMEA
Life
Cycle
Cost
R&M
First-Time
Capability
Customer
Satisfaction
DFMEA Information Linkages
The Underlying Message
• Don’t correct a weak product design by focusing on a
super robust process.
• Don’t correct a weak process design by focusing on
design changes to the product.
PFMEA Information Linkages
Rational Structure and
Project Specific Control Plans
Product
Design FMEA
Internal Process
Control Plan
Tool Design
Machinery FMEA
Internal Processes
Process FMEA
Customer Plant
Control Plan
Process
Process FMEA
Identify and Manage
Information
Required for
Contract Review
Identify and Manage
Deliverables
Required for
Design Review
Identify and Manage
Deliverables
Required for
Build & Buy-Off
Three Phases of Control Plan
Product
Design FMEA
Internal Process
Control Plan
Tool Design
Machinery FMEA
Internal Processes
Process FMEA
Customer Plant
Control Plan
Process
Process FMEA
Phase 2
Control Plan
for
Pre-Production
Phase 1
Control Plan
for
Prototype
Phase 3
Control Plan
for
Production
Containment Considerations
• Cost of Defects
• Risk of Defects
• Bracketing Strategies
• Protecting On-Time Delivery
• Cost of Stopping Production
• Cost of Recall Campaigns
• Benefits of Traceability
FMEA Teams
• Multi-functional teams are essential.
• Ensure expertise from manufacturing engineering, plant
operations, maintenance, and other appropriate sources.
• Select team with ability to contribute:
– Knowledge
– Information
– Experience
– Equity
– Empowerment
• Pick the right team members, but limit the number of team
members based on the scope of the issues being addressed.
• In addition to the FMEA team.
– Call in Experts as Needed
Relevant Resources and Expertise
Common Team Problems
• No Common Understanding of FMEA
• Overbearing Participants
• Reluctant Participants
• Opinions Treated as Facts
• Rush to Accomplishments
• Digression and Tangents
• Hidden Agendas
• Going through the Motions
• Seeing FMEA as a Deliverable
A Process Flow for FMEA
1. Define the Scope
• Scope is essential because it sets limits on a
given FMEA, that is, it makes it finite.
• Several documents may assist the team in
determining the scope of a Process FMEA:
– Process Flow Diagram
– Relationship Matrix
– Drawings, Sketches, or Schematics
– Bill of Materials (BOM)
Process Flow Charts
High Level Flow Chart
Detailed Flow Chart
2. Define the Customer
• Four major customers need to be considered:
– End Users
– OEM Plants
– Supplier Plants
– Government Agencies (safety and environment)
• Customer knowledge can contribute precise
definition of functions, requirements, and
specifications.
3. Identify Functions, Requirements, Specifications
• Identify and understand the process steps and
their functions, requirements, and specifications
that are within the scope of the analysis.
• The goal in this phase is to clarify the design
intent or purpose of the process.
• This step, well done, leads quite naturally to the
identification of potential failure modes.
Defining Functions
• Describe the Functions in Concise Terms
• Use “Verb-Noun” Phrases
• Select Active Verbs
• Use Terms that can be Measured
• Examples:
– Pick and Place Unit Secure Part
Advance Part
Locate Part
– Robot Position Weld Gun
Process Steps, Functions, Requirements
Process Steps Functions Requirements
Process and Functional Requirements
Identify Process and Function – Traditional Format
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Clearance hole
for 12 mm bolt
- Hole size
- Hole location
- Free of burrs
Identification of Failure Modes
Functional
Requirements
Function
Not Done
Function
Done Poorly
Omission
of an Action
Incorrect
Actions
Surprise
Results
Correct
Actions
Example: Failure Modes
Function
Failure Modes
Dispense
Paint
Properly
No Paint
Spitting Paint
Stream of Paint
Too Much Paint
Too Little Paint
Void in Fan
Color Change System
Spray Paint
Example: Failure Modes
Function
Failure Modes
Send Accurate
Feedback Signal
Color Change System
Measure Fluid Flow
No Feedback Signal
Intermittent Signal
Signal Too High
Signal Too Low
Feedback Signal with No Flow
Flow Meter Restricts Flow
Example of Failure Modes
Example of Failure Modes
Identify Process and Function – Traditional Format
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Clearance hole
for 12 mm bolt
- Hole size
- Hole location
- No burrs
No hole
Hole too
large
Hole too
small
Hole violates
MMC
boundary
Hole not
drilled
thru
- Hole Depth
Failure Mode
Identification Worksheet
Functional requirements
or specifications:
Potential Failure Modes
Process Step:
5. Identify Potential Causes
• Potential cause of failure describes how a process
failure could occur, in terms of something that can be
controlled or corrected.
• Our goal is to describe the direct relationship that exists
between the cause and resulting process failure mode.
• Document a unique failure sequence with each potential
cause.
Causes
Failure
Mode
Direct
Cause
Immediate
Effect
Causes
Precede the
Failure Mode
Direct
Cause
Direct
Cause
FMEA Worksheet Form
Transfer of Failure Mode to Worksheet
Example of Causes
Example of Causes
Identify Causes of Failure – Traditional Format
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Clearance hole
for 12 mm bolt
- Hole size
Hole too
large
- Hole depth
Feed rate too
high
Spindle speed
too slow
Wrong drill
size
Drill improperly
sharpened
Wrong tool
geometry for
material
Hole not
drilled thru
Missing drill
6. Identify Potential Effects
• Potential effects of a process failure are defined as the
result of the failure mode as perceived by the customer.
• The intent is to describe the impact of the failure in terms
of what the customer might notice or experience.
• This applies to both internal and external customers.
Causes and Effects
Failure
Mode
Direct
Cause
Immediate
Effect
Causes
Precede the
Failure Mode
Effects are the
Result of the
Failure Mode
Immediate
Effect
Immediate
Effect
Two Focal Points for Effects
An effect is the immediate consequence of the failure
mode.
• What is the pain that is felt by the end user?
• What is the pain felt by downstream manufacturing or
assembly operations?
Example of Effects
Example of Effects
Identify Effects of Failure – Traditional Format
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Clearance hole
for 12 mm bolt
- Hole size
Hole too
large
- Hole depth
Feed rate too
high
Spindle speed
too slow
Wrong drill
size
Drill improperly
sharpened
Wrong tool
geometry for
material
Hole not
drilled thru
Missing drill
Bolt may not
hold torque
Violation of
specification
Assemble with
missing
fastener
7. Identify Current Controls
• Current Process Controls describe planned activities or
devices that can prevent or detect the cause of a failure
or a failure mode itself.
• There are two classes of controls:
– Preventive controls either eliminate the causes of the failure mode
or the failure mode itself, or reduce how frequently it occurs.
– Detective controls recognize a failure mode or a cause of failure
so associated countermeasures are put into action.
• Preventive controls are the preferred approach
because they are most cost effective.
Two Types of Detection
Failure
Mode
Direct
Cause
Immediate
Effects
Cause
Detection
Failure Mode
Detection
• Set-Up Validation Sign-Off• Go/NoGo Gage
Wrong Nozzle in Bin
Wrong Paint Nozzle
Paint Splatter
Too Much Paint
Too Little Paint
Example of Process Controls
Example of Process Controls
Identify Current Controls – Traditional Format
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Clearance hole
for 12 mm bolt
- Hole size
Hole too
large
Feed rate too
high
Spindle speed
too slow
Wrong drill
size
Dull drill bit
Drill improperly
sharpened
Wrong tool
geometry for
material
Bolt may not
hold torque
Violation of
specification
DOE Results
DOE Results
DOE Results
Set Up
Verification
Set Up
Verification
First Piece
Inspection
Load Meter
Set Up
Verification
Set Up
verification
8. Identify and Prioritize Risk
• Risk in a Process FMEA is identified in three
ways:
Severity – which measures the effect.
Occurrence – to assess the frequency of causes.
Detection – ability to detect causes or failures.
• It is appropriate to assess these three scores
through the understanding of your customer’s
requirements.
Severity of Effect
Frequency of Occurrence
Detection by Current Control
Assess Severity, Occurrence, Detection
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Severity
evaluates
the impact
of the effect.
Occurrence
rates how often
a specific cause is
likely to result in
the failure mode
being analyzed.
Detection
ranks our ability
to detect either a
cause or a resulting
failure mode. Use
best detection
available.
Example of Severity, Occurrence, Detection
Example of Severity, Occurrence, Detection
Prioritization of Risk
Several strategies exist for the mitigation of risk, for
example:
1. High Risk Priority Numbers
2. High Severity Risks (regardless of RPN)
3. High Design Risks (Severity x Occurrence)
4. Other Alternatives (S,O,D) and (S,D)
NOTE: “The use of an RPN threshold is NOT a
recommended practice for the need for action.”
Identify Current Controls – Traditional Format
Process
Step
Potential
Failure
Mode
Potential
Effects of
Failure
S
e
v
C
l
a
s
s
Potential
Causes/
Mechanisms
of Failure
O
c
c
Current
Process
Control
(Detection)
D
e
t
R.
P.
N.
Current
Process
Control
(Prevention)
Function
Clearance hole
for 12 mm bolt
- Hole size
Hole too
large
Feed rate too
high
Spindle speed
too slow
Wrong drill
size
Dull drill bit
Drill improperly
sharpened
Wrong tool
geometry for
material
Bolt may not
hold torque
Violation of
specification
DOE Results
DOE Results
DOE Results
Set Up
Verification
Set Up
Verification
First Piece
Inspection
Load Meter
Set Up
Verification
Set Up
verification
5
2
2
2
4
2
2
5
5
5
2
5
5
50
50
50
40
50
50
9. Recommend Actions
• The intent with recommended actions is to
reduce risk.
• Recommended actions will be focused to:
– Reduce Severity
– Reduce Frequency of Occurrence
– Improve Detection
Managing Recommended Actions
• Transfer FMEA action items onto the mechanism
used to track and ensure closure of open issues
on the project.
• Decisions to take different actions or not to act
must be approved.
• Review status of FMEA action items on a regular
basis.
Recommended Actions
Recommended
Actions
Responsibility
& Target
Completion Date
Action Results
Actions
Taken
S
e
v
O
c
c
D
e
t
R.
P.
N.
10. Verify Results
• Whenever you change a process one of two
things happen:
– Things Get Better
– Things Get Worse
• Verify actual performance following the
implementation of the recommended actions.
Summary and Closure
Key Points to Remember
Upon successful completion of this course, you should know:
1. Potential FMEA Reference Manual is the authoritative reference.
2. Severity scores of 9 or 10 must be used for safety related risks.
3. Occurrence ranks how often each cause is likely to result in failure.
4. It is appropriate to focus on high severity items first.
5. Credit for preventive actions shows up in the frequency of occurrence.
6. Risk Priority Numbers provides a rank order to risks and action items.
7. An effective approach is to continually focus on the top five concerns.
8. Process FMEA should result in tangible improvement to process
performance.
Questions and Answers
Please type your
questions in the panel
box
Thank You For Attending
Please visit our website
www.asq-auto.org for future webinar dates
and topics.
