3. Definition of FMEA
A Failure Mode and Effect Analysis uses a
disciplined technique to identify and help eliminate
product and process potential failure modes.
o By ID of potential failures
o Assessing the risks caused by failure modes and Identify
corrective actions
o Prioritizing corrective actions
o Carry out corrective actions
8. Potential Key Product Characteristics
Development
DetectPrevent
R
P
N
D
E
T
O
C
C
S
E
V
Action
Taken
Action Results
Response &
Target
Complete
Date
Recommended
Actions
R
P
N
D
e
t
e
c
Current
Controls
O
c
c
u
r
Potential
Cause(s)/
Mechanism(s)
Of Failure
C
l
a
s
s
S
e
v
Potential
Effect(s) of
Failure
Potential
Failure
Mode
Item /
Process
Step
DetectPrevent
R
P
N
D
E
T
O
C
C
S
E
V
Action
Taken
Action Results
Response &
Target
Complete
Date
Recommended
Actions
R
P
N
D
e
t
e
c
Current
Design
Controls
O
c
c
u
r
Potential
Cause(s)/
Mechanism(s)
Of Failure
C
l
a
s
s
S
e
v
Potential
Effect(s) of
Failure
Potential
Failure
Mode
Item /
Process
Step
Function
DFMEA
Requirements Documents
!
•Regulatory
•Dimensional
•Cosmetic
!
Req. Spec. Document
Drawings
Warranty History
Robustness Tools
!
Boundary Diagram
P-Diagram
Interface Matrix
10
9
8
7
6
5
4
3
2
1
1 2 3 4 5 6 7 8 9 10
S
E
V
E
R
I
T
Y
O C C U R R E N C E
POTENTIAL CRITICAL CHARACTERISTICS
Safety/Regulatory
POTENTIAL
SIGNIFICANT
CHARACTERISTICS
Customer Dissatisfaction
Special Characteristics Matrix
ANOYANCE
ZONE
ALL OTHER CHARACTERISTICS
Appropriate actions /
controls already in place
Cascade Technical
Requirements Into Special
Product Characteristics
24. Severity Column
DetectPrevent
R
P
N
D
E
T
O
C
C
S
E
V
Action
Taken
Action Results
Response &
Traget
Complete
Date
Recommended
Actions
R
P
N
D
e
t
e
c
Current
Process
Controls
O
c
c
u
r
Potential
Cause(s)/
Mechanism(s)
Of Failure
C
l
a
s
s
S
e
v
Potential
Effect(s) of
Failure
Potential
Failure
Mode
Item /
Process
Step
DetectPrevent
R
P
N
D
E
T
O
C
C
S
E
V
Action
Taken
Action Results
Response &
Traget
Complete
Date
Recommended
Actions
R
P
N
D
e
t
e
c
Current
Process
Controls
O
c
c
u
r
Potential
Cause(s)/
Mechanism(s)
Of Failure
C
l
a
s
s
S
e
v
Potential
Effect(s) of
Failure
Potential
Failure
Mode
Item /
Process
Step
Function
Severity
Column
25. AUTOMOTIVE EXAMPLE SEVERITY EVALUATION CRITERIA
Hazardous-
with
warning
Very High
High
Very high severity ranking when a potential failure mode affects safe vehicle
operation and/or involves noncompliance with government regulation without
warning
Low
Very Low
Minor
Very Minor
None
Very high severity ranking when a potential failure mode affects safe vehicle
operation and/or involves noncompliance with government regulation with
warning
Vehicle/item inoperable (loss of primary function).
Vehicle/item operable but at a reduced level of performance. Customer very
dissatisfied.
Vehicle/item operable but Comfort/Convenience item(s) inoperable.
Customer dissatisfied.
Vehicle/item operable but Comfort/Convenience item(s) operable at a
reduced level of performance. Customer somewhat dissatisfied.
Fit & Finish/Squeak & Rattle item does not conform. Defect noticed by most
customers (greater than 75%).
Fit & Finish/Squeak & Rattle item does not conform. Defect noticed by 50%
of customers.
Fit & Finish/Squeak & Rattle item does not conform. Defect noticed by
discriminating customers (less than 25%).
No discernable effect.
10
8
7
6
3
2
1
Hazardous-
without
warning
Moderate
4
5
EFFECT CRITERIA: Severity of Effect
RNK.
SEVERITY EVALUATION CRITERIA
9
29. Occurrence Column
DetectPrevent
R
P
N
D
E
T
O
C
C
S
E
V
Action
Taken
Action Results
Response &
Traget
Complete
Date
Recommended
Actions
R
P
N
D
e
t
e
c
Current
Process
Controls
O
c
c
u
r
Potential
Cause(s)/
Mechanism(s)
Of Failure
C
l
a
s
s
S
e
v
Potential
Effect(s) of
Failure
Potential
Failure
Mode
Item /
Process
Step
DetectPrevent
R
P
N
D
E
T
O
C
C
S
E
V
Action
Taken
Action Results
Response &
Traget
Complete
Date
Recommended
Actions
R
P
N
D
e
t
e
c
Current
Process
Controls
O
c
c
u
r
Potential
Cause(s)/
Mechanism(s)
Of Failure
C
l
a
s
s
S
e
v
Potential
Effect(s) of
Failure
Potential
Failure
Mode
Item /
Process
Step
Function
Occurrence
Column
30. Occurrence Evaluation Criteria
*Note: Zero (0) rankings for Severity, Occurrence or Detection are not allowed
Probability of Likely Failure Rates Over Design Life Ranking
Failure
SUGGESTED OCCURRENCE EVALUATION CRITERIA
Very High: Persistent failures
High: Frequent failures
Moderate: Occasional failures
Low: Relatively few failures
Remote: Failure is unlikely
≥ 100 per thousand vehicles/items
50 per thousand vehicles/items
20 per thousand vehicles/items
10 per thousand vehicles/items
5 per thousand vehicles/items
2 per thousand vehicles/items
1 per thousand vehicles/items
0.5 per thousand vehicles/items
0.1 per thousand vehicles/items
≤ 0.01 per thousand vehicles/items
10
9
8
7
6
5
4
3
2
1
31. Example of Significant/ Critical Threshold
*Used by permission of Ford Motor Company
10
9
8
7
6
5
4
3
2
1
1 2 3 4 5 6 7 8 9 10
S
E
V
E
R
I
T
Y
O C C U R R E N C E
POTENTIAL CRITICAL
CHARACTERISTICS Safety/Regulatory
POTENTIAL
SIGNIFICANT
CHARACTERISTICS
Customer Dissatisfaction
ALL OTHER CHARACTERISTICS
Appropriate actions /
controls already in place
Special Characteristics Matrix
ANOYANCE
ZONE
32. Design Verification (Current Design Controls)
▪ Think of Design Control in two ways; Prevention and
Detection. List them separately.
▪ To save time, add any new (untried) prevention/
detection ideas to the document under Recommended
Actions column.
o Prevention is specifically related to reduction or elimination of a
cause.
o Detection is how well the test or series of tests may find the
design flaw
– Causes
– Failure Mode
33.
34.
35. Detection Rating
Absolute
Uncertainty
Very Remote
Remote
Very Low
Low
Moderate
Moderately
High
High
Very High
Almost
Certain
10
9
8
7
6
5
4
3
2
1
Design Control will not and/or cannot detect a potential cause/ mechanism and
subsequent failure mode; or there is no
Design Control.
Very Remote chance the Design Control will detect a potential cause/
mechanism and subsequent failure mode.
Remote chance the Design Control will detect a potential cause/ mechanism
and subsequent failure mode.
Very Low chance the Design Control will detect a potential cause/mechanism
and subsequent failure mode.
Low chance the Design Control will detect a potential cause/mechanism and
subsequent failure mode.
Moderate chance the Design Control will detect a potential cause/ mechanism
and subsequent failure mode.
Moderately High chance the Design Control will detect a potential cause/
mechanism and subsequent failure mode.
Very High chance the Design Control will detect a potential cause/ mechanism
and subsequent failure mode.
High chance the Design Control will detect a potential cause/ mechanism and
subsequent failure mode.
Design Controls will almost certainly detect a potential cause/ mechanism and
subsequent failure mode.
DETECTION
SUGGESTED DETECTION EVALATION CRITERIA
CRITERIA RNK.
36. Analysis Of Risk
▪ RPN / RISK PRIORITY NUMBER
▪ What Is Risk?
▪ Probability of danger
▪ Severity/Occurrence/Cause
37. Evaluation by RPN Only
▪ Case 1
o S=5 O=5 D=2 RPN = 50
▪ Case 2
o S=3 O=3 D=6 RPN = 54
▪ Case 3
o S=2 O=10, D=10 = 200
▪ Case 4
o S=9 O=2 D=3 = 54
WHICH ONE
IS WORSE?
38. Example
▪ Extreme Safety/Regulatory Risk
o =9 & 10 Severity
▪ High Risk to Customer Satisfaction
o Sev. > or = to 5 and Occ > or = 4
▪ Consider Detection only as a measure of Test
Capability.
39. Example of Significant/ Critical Threshold
*Used by permission of Ford Motor Company
10
9
8
7
6
5
4
3
2
1
1 2 3 4 5 6 7 8 9 10
S
E
V
E
R
I
T
Y
O C C U R R E N C E
POTENTIAL CRITICAL
CHARACTERISTICS Safety/Regulatory
POTENTIAL
SIGNIFICANT
CHARACTERISTICS
Customer Dissatisfaction
ALL OTHER CHARACTERISTICS
Appropriate actions /
controls already in place
Special Characteristics Matrix
ANOYANCE
ZONE
40. Actions
Item
Function
System
Subsystem
Component:
Model Year/Vehicle (s):
Core Team:
Your Company Name Here Potential
Failure Mode and Effects Analysis
(Design FMEA)
Design Responsibility:
Key Date:
FMEA Number:
Page of
Prepared by:
FMEA Date (Orig.): (Rev.):
Potential
Failure
Mode
Potential
Effect (s) of
Failure
s
e
v
c
l
a
s
s
Potential
Cause (s)/
Mechanism (s)
Failure
o
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R.
P.
N.
Recommended
Action(s)
Responsibility
& Target
Completion
Date
Actions
Taken
s
e
v
o
c
c
D
e
t
R.
P.
N.
A c t i o n R e s u l t s
42. Re-rating RPN After Actions Have Occurred
Item
Function
System
Subsystem
Component:
Model Year/Vehicle (s):
Core Team:
Your Company Name Here Potential
Failure Mode and Effects Analysis
(Design FMEA)
Design Responsibility:
Key Date:
FMEA Number:
Page of
Prepared by:
FMEA Date (Orig.): (Rev.):
Potential
Failure
Mode
Potential
Effect (s) of
Failure
S
e
v
C
l
a
s
s
Potential
Cause (s)/
Mechanism (s)
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R.
P.
N.
Recommended
Action(s)
Responsibility
& Target
Completion
Date
Actions
Taken
S
e
v
O
c
c
D
e
t
R.
P.
N.
A c t i o n R e s u l t s
43. Re-rating RPN After Actions Have Occurred
▪ Severity typically stays the same.
▪ Occurrence is the primary item to reduce / focus on.
▪ Detection is reduced only as a last resort.
▪ Do not plan to REDUCE RPN with detection actions!!!
o 100% inspection is only 80% effective!
o Reducing RPN with detection does not eliminate failure mode,
or reduce probability of causes
o Detection of 10 is not bad if occurrence is 1
44. FMEA in a continuous flow process
●Steel Making example:
!
▪ Design FMEA was performed on a Crankshaft to
determine the best material for the product being
considered. This was a critical application.
!
▪ Key features such as Geometry, Strength, Duty Cycle,
were described to the Steel producer.
