Failure Mode and Effect
Analysis
1
*
Learning Objectives
 Provide familiarization with FMEA
principles and techniques.
 Summarize the concepts, definitions,
application options and relationships with
other tools.
 Learn how to integrate FMEA into your
Company SOPs
2
Definition of FMEA
FMEA is a
*
systematic design evaluation procedure
whose purpose is to:
1. recognize and evaluate the potential
failure modes and causes
associated with the designing and
manufacturing of a new product or a
change to an existing product,
2. identify actions which could
eliminate or reduce the chance of
the potential failure occurring,
3. document the process.
3
FMEA is Function-driven
*
FMEA begins with a definition of the
FUNCTIONS an item is supposed to perform.
The inputs must come from several sources to
be effective:
Design
Engineer
Production
Manufacturing
Engineer
Supplier
Quality
Reliability
Engineer
Program
Management
5
Background
*
Developed in early 60’s by NASA to “failproof” Apollo missions.
Adopted in early 70’s by US Navy .
By late 80’s, automotive industry had
implemented FMEA and began requiring
suppliers do the same. Liability costs were
the main driving force.
Used sporadically throughout industry
during 1980’s.
Adopted by Seagate in 1996. Initial
application in design centers. Now it’s time
to apply FMEA to process applications in
Seagate. Six Sigma is the catalyst.
6
NASA used FMEA to identify
Single Point Failures on Apollo
project (SPF = no redundancy &
loss of mission). How many did
they find?
420
and we thought we had No problems!
7
Types of FMEA’s
SYSTEM
DESIGN
PROCESS
*
System FMEA is used to analyze systems
and subsystems in the early concept and
design stages.
Design FMEA is used to analyze products
before they are released to production
Process FMEA is used to analyze
manufacturing, assembly and
administrative processes
8
When Is the FMEA Started?
AS EARLY AS POSSIBLE
Guideline:
Do the best you
can with what
you have.
9
When to Start
 When new systems, products and
processes are being designed
 When existing designs and
processes are being changed
 When carry-over designs or
processes will be used in new
applications or environments
 After completing a Problem Solving
Study, to prevent recurrence of a
problem
10
Process FMEA Form
PROCESS FMEA
PRODUCT:
FMEA NO.
PROCESS/ OPERATION:
PAGE
PLANNING REFERENCE:
Oklahoma City
PROCESS DESCRIPTION
FUNCTION
SEVERITY
POTENTIAL
FAILURE MODE
POTENTIAL
EFFECTS OF
FAILURE
S
*
OCCURRENCE
POTENTIAL
CAUSE(S) OF
FAILURE
DATE:
DETECTION
O
CURRENT
CONTROLS
OF
BY:
RPN = S x O x D
D R P N ACTION
PRIORITY
CORRECTIVE RESPONSIBILITY
ACTION
& DATE DUE
ACTION
TAKEN
R E S U LT IN G
S
O
D RPN
11
Process Failure Mode


The potential failure mode is the manner in which the
process could fail to perform its intended function.
The failure mode for a particular operation could be a
cause in a subsequent (downstream) operation or an
effect in associated with a potential failure in a
previous (upstream) operation.
PREVIOUS
OPERATION
EFFECT
NEXT
OPERATION
FAILURE
MODE CAUSE
12
Process Causes
Process FMEA considers
process variability due to:
OPERATOR
METHOD
SET-UP
ENVIRONMENT
MACHINE
MEASUREMENT
13
Current Controls
 Assessment of the ability of the control to
detect the failure before the item leaves
the manufacturing area and ships to the
customer.
 Capability of all controls in the process to
prevent escapes
Process Capability
SPC
Sampling
Gage R&R
DoE
Testing
14
Types of Measures
*
Typically, three items are scored:
SEVERITY
As it applies to the effects on the local system,
next level, and end user
OCCURRENCE
Likelihood that a specific cause will occur and
result in a specific failure mode
DETECTION
Ability of the current / proposed control
mechanism to detect and identify the failure
mode
15
Severity
Effect
Criteria: Severity of Effect Defined
May endanger operator. Failure mode affects safe vehicle operation and / or
Hazardous:
involves noncompliance with government regulation. Failure will occur WITHOUT
Without Warning
warning.
May endanger operator. Failure mode affects safe vehicle operation and / or
Hazardous: With
involves noncompliance with government regulation. Failure will occur WITH
Warning
warning.
Major disruption to production line. 100% of product may have to be scrapped.
Very High
Vehicle / item inoperable, loss of primary function. Customer very dissatisfied.
Minor disruption to production line. Product may have to be sorted and a portion
High
(less than 100%) scrapped. Vehicle operable, but at a reduced level of
performance. Customer dissatisfied.
Minor disruption to production line. A portion (less than 100%) may have to be
Moderate
scrapped (no sorting). Vehicle / item operable, but some comfort / convenience
item(s) inoperable. Customers experience discomfort.
Minor disruption to production line. 100% of product may have to be reworked.
Low
Vehicle / item operable, but some comfort / convenience item(s) operable at
reduced level of performance. Customer experiences some dissatisfaction.
Minor disruption to production line. The product may have to be sorted and a
Very Low
portion (less than 100%) reworked. Fit / finish / squeak / rattle item does not
conform. Defect noticed by most customers.
Minor disruption to production line. A portion (less than 100%) of the product may
Minor
have to be reworked on-line but out-of-station. Fit / finish / squeak / rattle item
does not conform. Defect noticed by average customers.
Minor disruption to production line. A portion (less than 100%) of the product may
Very Minor
have to be reworked on-line but in-station. Fit / finish / squeak / rattle item does
not conform. Defect noticed by discriminating customers.
None
No effect.
Ranking
10
9
8
7
6
5
4
3
2
1
16
Occurrence
Probability of Failure
Possible Failure Rates
Cpk
Ranking
³ 1 in 2
< 0.33
10
Failure is almost inevitable
1 in 3
³ 0.33
9
High: Generally associated with
processes similar to previous
1 in 8
³ 0.51
8
processes that have often failed
1 in 20
³ 0.67
7
Moderate: Generally associated
with processes similar to
1 in 80
³ 0.83
6
previous processes which have
1 in 400
³ 1.00
5
experienced occasional failures,
but not in major proportions
1 in 2,000
³ 1.17
4
1 in 15,000
³ 1.33
3
1 in 150,000
³ 1.5
2
£ 1 in 1,500,000
³ 1.67
1
Very High:
Low: Isolated failures associated
with similar processes
Very Low: Only isolated failures
associated with almost identical
processes
Remote: Failure is unlikely. No
failures ever associated with
almost identical processes
17
Detection (“Escape”)
This is best thought of as Escape Potential - the higher the
score, the greater the problem
Detection
Criteria: Liklihood the existence of a defect will be
detected by test content before product advances to
next or subsequent process
Ranking
Almost Impossible
Test content detects < 80 % of failures
10
Very Remote
Test content must detect 80 % of failures
9
Remote
Test content must detect 82.5 % of failures
8
Very Low
Test content must detect 85 % of failures
7
Low
Test content must detect 87.5 % of failures
6
Moderate
Test content must detect 90 % of failures
5
Moderately High
Test content must detect 92.5 % of failures
4
High
Test content must detect 95 % of failures
3
Very High
Test content must detect 97.5 % of failures
2
Almost Certain
Test content must detect 99.5 % of failures
1
18
*
Risk Priority Number
RPN = O x S x D
Occurrence x
Severity x
Detection
19
Basic Steps
1.Develop a Strategy
– Form a FMEA team
ST91260A
DRIVE
FIRST PRIORITY
SECOND PRIORITY
THIRD PRIORITY
HDA
ASSEMBLY
SYSTEM &
FIRMWARE
LABELS
DISC PACK
PCB
ASSEMBLY
BASE SUB
LATCH
MAG ASSY
BASE DECK
SP. FLEX
MEDIA
BASE DECK
SPINDLE
COVER
MOTOR POLES,
POLE SPACER
BREATH. FILTER
DISC CLAMP
STATOR
SPACERS
ROTOR
SEAL
RECIR FILTER
DAMPER
BAL. WT
FINAL ARM
ARM SUB
ARM SUB
ARM COIL
ARM SUB
BOBBIN
ROT. ARM
Teams will be established to evaluate the application of FMEA in areas shown by the
shading on the following diagram. Each "FMEA" Team under the direction of the FMEA
Facilitator will:
- ESTABLISH a strategy focusing on new technology, past issues, new or redesigned
components, both from the product (design) and process perspectives..
- PREPARE a Design and a Process FMEA for the selected components or
subassemblies..
- DETERMINE functions, potential failure modes, effects, causes, and verification
activities planned or in-place..
- RECOMMEND corrective actions to the product team..
20
Basic Steps
1. Develop a Strategy
2. Review the design/process
– Develop process map and
identify all process steps
21
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
– List all the value-added
process
– For each process step,
list process inputs
(process
characteristics
22
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential
failure modes
CAUSES
EFFECT
23
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential
consequences of each
failure mode
24
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential consequences of each failure mode
6. Assign severity (SEV) score
PRODUCT:
FMEA NO.
PROCESS/OPERATION:
DESIGN (OR PROCESS) FMEA
Oklahoma City
FUNCTION
SEVERITY
POTENTIAL
FAILURE MODE
POTENTIAL
EFFECTS OF
FAILURE
PAGE
PLANNING REFERENCE:
OCCURRENCE
S
POTENTIAL
CAUSE(S) OF
FAILURE
DATE:
DETECTION
O
CURRENT
CONTROLS
OF
BY:
RPN = S x O x D
D RPN ACTION
PRIORITY
CORRECTIVE RESPONSIBILITY
ACTION
& DATE DUE
ACTION
TAKEN
RESULTING
S
O
25
D RPN
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential consequences of each
failure mode
6. Assign severity (SEV) score
7. Identify the cause(s) of
each failure mode.
26
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential consequences (effect) of
each failure mode
6. Assign severity (SEV) score
7. Identify the cause(s) of each failure mode.
8. Assign occurrence (OCC)
scores.
27
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential consequences (effect) of
each failure mode
6. Assign severity (SEV) score
7. Identify the potential cause(s) of each
failure mode.
8. Assign occurrence (OCC) scores.
9. Identify current controls to
detect the failure modes.
28
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential consequences (effect) of each
failure mode
6. Assign severity (SEV) score
7. Identify the potential cause(s) of each failure mode.
8. Assign occurrence (OCC) scores.
9. Identify current controls to detect the failure modes.
10. Assign an escaped detection
(DET) score for each cause and
control.
29
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential consequences (effect) of each failure mode
6. Assign severity (SEV) score
7. Identify the potential cause(s) of each failure mode.
8. Assign occurrence (OCC) scores.
9. Identify current controls to detect the failure modes.
10. Assign an escaped detection (DET) score for each cause and
control.
11. Calculate the Risk Priority Numer
(RPN) for each line in the FMEA.
30
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential consequences (effect) of each failure mode
6. Assign severity (SEV) score
7. Identify the potential cause(s) of each failure mode.
8. Assign occurrence (OCC) scores.
9. Identify current controls to detect the failure modes.
10. Assign an escaped detection (DET) score for each cause and
control.
11. Calculate the Risk Priority Numer (RPN) for each line in the
FMEA.
12. Determine the action to be taken.
31
Basic Steps
1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
5. List the potential consequences (effect) of each failure mode
6. Assign severity (SEV) score
7. Identify the potential cause(s) of each failure mode.
8. Assign occurrence (OCC) scores.
9. Identify current controls to detect the failure modes.
10. Assign an escaped detection (DET) score for each cause and
control.
11. Calculate the Risk Priority Numer (RPN) for each line in the
FMEA.
12. Determine the action to be taken.
13. Recalculate the RPNs based on the
actions plans.
32
Shortcomings of RPN
*
A
8
4
3
96
B
4
8
3
96
SAME RESULT
33
Action Priority
PRIORITY
RPN RANGE
A
B
C
D
Over 200
100-199
26-99
1-25
34
INITIAL PROBLEM
POTENTIAL
WALK INTO DOOR
PROBLEM
CAN’T SEE
LIKELY
CAUSE
LIKELY
PAIN
EFFECT
BUMP HEAD
TRIGGER
CONTINGENT
PREVENTIVE
ACTIONS
- ADAPTIVE
-CORRECTIVE
GET GLASSES
WEAR HELMET
REMOVE DOORS
1st WHY
CAUSE BECOMES
BECOMES EFFECT
POTENTIAL
NEW PROBLEM
CAN’T SEE
PROBLEM
WALK INTO DOOR
PROBLEM
LIKELY
CAUSE
LIKELY
PAIN
EFFECT
BUMP HEAD
TRIGGER
CONTINGENT
PREVENTIVE
ACTIONS
- ADAPTIVE
-CORRECTIVE
GET GLASSES
WEAR HELMET
REMOVE DOORS
1st WHY
POTENTIAL
CAN’T SEE
PROBLEM
NEAR
SIGHTED
LIKELY
CAUSE
LIKELY
PAIN
EFFECT
WALK INTO
DOOR AND
BUMP HEAD
TRIGGER
CONTINGENT
PREVENTIVE
ACTIONS
- ADAPTIVE
-CORRECTIVE
SURGERY
GET GLASSES
2ND WHY
POTENTIAL
CAN’T SEE
PROBLEM
NEAR
SIGHTED
LIKELY
CAUSE
LIKELY
PAIN
EFFECT
WALK INTO
DOOR AND
BUMP HEAD
TRIGGER
CONTINGENT
PREVENTIVE
ACTIONS
- ADAPTIVE
-CORRECTIVE
SURGERY
GET GLASSES
2ND WHY
POTENTIAL
NEAR
SIGHTED
PROBLEM
TOO MUCH T.V.
LIKELY
CAUSE
LIKELY
PAIN
EFFECT
CAN’T SEE
WALK INTO
DOOR AND
BUMP HEAD
TRIGGER
CONTINGENT
PREVENTIVE
ACTIONS
- ADAPTIVE
-CORRECTIVE
CUT OUT
STAR TREK
SURGERY
HAVE WE FOUND ROOT CAUSE?
2ND WHY
POTENTIAL
NEAR
SIGHTED
PROBLEM
TOO MUCH T.V.
LIKELY
CAUSE
LIKELY
PAIN
EFFECT
CAN’T SEE
WALK INTO
DOOR AND
BUMP HEAD
TRIGGER
CONTINGENT
PREVENTIVE
ACTIONS
- ADAPTIVE
-CORRECTIVE
CUT OUT
STAR TREK
SURGERY
OR GONE TOO FAR !
Determining Level of
Analysis
PRODUCT:
SUBSYSTEMS
SEAGATE DRIVE STXXXXX
SPINDLE MOTOR
DRAWING OR SPEC REFERENCE:
DESIGN FMEA
Oklahoma City
PROCESS DESCRIPTION
POTENTIAL
FAILURE MODE
FUNCTION
SPINDLE ROTATES
MEDIA AT FIXED RPM
NO SPIN, OR DRIVE RUNS
IN REVERSE
SEVERITY
POTENTIAL
S
OCCURRENCE
POTENTIAL
EFFECTS OF
CAUSE(S) OF
FAILURE
FAILURE
DRIVE INOPERABLE
FAILURE OF FLEX
SOLDER JOINT DUE
TO INSUFFICIENT
STRAIN RELIEF
O
EFFECTIVENESS
CURRENT
E
CONTROLS
RESISTANCE
MEASUREMENT
AT INCOMING
INSPECTION
Handbook pg. 43
41
RPN
Determining Level of
Analysis
PRODUCT:
SUBSYSTEMS
SEAGATE DRIVE STXXXXX
SPINDLE MOTOR
DRAWING OR SPEC REFERENCE:
DESIGN FMEA
Oklahoma City
PROCESS DESCRIPTION
POTENTIAL
FAILURE MODE
FUNCTION
SPINDLE ROTATES
MEDIA AT FIXED RPM
NO SPIN, OR DRIVE RUNS
IN REVERSE
SEVERITY
POTENTIAL
S
OCCURRENCE
POTENTIAL
EFFECTS OF
CAUSE(S) OF
FAILURE
FAILURE
DRIVE INOPERABLE
FAILURE OF FLEX
SOLDER JOINT DUE
TO INSUFFICIENT
STRAIN RELIEF
O
EFFECTIVENESS
CURRENT
E
CONTROLS
RESISTANCE
MEASUREMENT
AT INCOMING
INSPECTION
Cause becomes Failure Mode
Handbook pg. 43
42
RPN
Determining Level of
Analysis
PRODUCT:
SUBSYSTEMS
SEAGATE DRIVE STXXXXX
SPINDLE MOTOR
DRAWING OR SPEC REFERENCE:
DESIGN FMEA
Oklahoma City
PROCESS DESCRIPTION
POTENTIAL
FAILURE MODE
FUNCTION
SPINDLE ROTATES
MEDIA AT FIXED RPM
NO SPIN, OR DRIVE RUNS
IN REVERSE
SEVERITY
POTENTIAL
S
OCCURRENCE
POTENTIAL
EFFECTS OF
CAUSE(S) OF
FAILURE
FAILURE
DRIVE INOPERABLE
FAILURE OF FLEX
SOLDER JOINT DUE
TO INSUFFICIENT
STRAIN RELIEF
O
EFFECTIVENESS
CURRENT
E
CONTROLS
RESISTANCE
MEASUREMENT
AT INCOMING
INSPECTION
Failure Mode becomes Effect
Handbook pg. 43
43
RPN
Determining Level of
Analysis
PRODUCT:
SEAGATE DRIVE STXXXXX
SPINDLE MOTOR
SUBSYSTEMS
DRAWING OR SPEC REFERENCE:
DESIGN FMEA
Oklahoma City
PROCESS DESCRIPTION
POTENTIAL
FAILURE MODE
FUNCTION
SPINDLE ROTATES
MEDIA AT FIXED RPM
FAILURE OF FLEX SOLDER
JOINT DUE TO
INSUFFICIENT STRAIN
RELIEF
SEVERITY
POTENTIAL
S
OCCURRENCE
POTENTIAL
EFFECTS OF
CAUSE(S) OF
FAILURE
FAILURE
NO SPIN, OR DRIVE
RUNS IN REVERSE
CAUSING DRIVE TO
BE INOPERABLE
O
EFFECTIVENESS
CURRENT
E
CONTROLS
WHY?
PROVIDES A DEEPER LEVEL OF ANALYSIS BY ASKING
YOU FOR THE DESIGN CAUSES AND VERIFICATION
OF INSUFFICIENT STRAIN RELIEF
Handbook pg. 43
44
RPN
What’s Wrong With This
Picture?
*
NUMBER OF PROCESS FAILURE CAUSES
OPERATOR ERROR
TOOLING
CONTAMINATION
SET-UP
HANDLING
DESIGN
GAGE
POWER
0
5
10
15
20
25
30
35
40
45
50
45
Actions
*
A well-developed FMEA will be of
limited value without positive and
effective corrective actions.
The design or process must be
improved based on the results of
the FMEA study.
46
Elements of FMEA
Failure Mode
Any way in which a process could could fail to meet some
measurable expectation.
Effect
Assuming a failure does occur, describe the effects. List separately
each main effect on both a downstream operation and the end user.
Severity
Using a scale provided, rate the seriousness of the effect. 10
represents worst case, 1 represents least severe.
Causes
This is the list of causes and/or potential causes of the failure mode.
Occurrence
This is a ranking, on a scale provided, of the likelihood of the failure
occurring. 10 represents near certainty; 1 represents 6 sigma. In
the case of a Six Sigma project, occurrence is generally derived from
defect data.
Current Controls
All means of detecting the failure before product reaches the end
user are listed under current controls.
Effectiveness
The effectiveness of each current control method is rated on a
provided scale from 1 to 10. A 10 implies the control will not detect
the presence of a failure; a 1 suggests detection is nearly certain.
47
FMEA is most effective when
It is conducted on a timely basis
and
It is applied by a product
team
and
Its results are documented
48
Integrating FMEA into SOPs
Example of how FMEA can be used in SCAR.
Section of SCAR procedure
5.2.1.2 Quality Manager or his designate shall discuss with Customer for re-inspection of
finished product in the inventory. Only when the non-conformance is detected, a material
purge shall be initiated. If Customer does not agree, then a material purge will be initiated.
5.2.1.3 The designated Quality Engineer shall reply in writing or by phone to the Customer within
24 hours on the immediate containment plan implemented upon receiving the C.A.R or
complaint.
FOR REFERENCE
5.2.1.4 The concerned Departmental Manager or his designate or Supplier shall head and form
the investigation team. The team shall consists of the following :
a) Chairman
Responsible Departmental Manager or his appointed designate.
b) Members
Quality Manager / QA Engineer
Production / Manufacturing Engineer
Material Manager (if applicable)
5.2.1.5 The assigned Engineer from Production / Engineering will investigate, identify
and analyze the possible cause.
5.2.1.6 He/She will use any of the tools (e.g.7QC Tools, PSDM & DOE, etc.) to solve the problem.
FMEA can be used to identify the potential cause of failure and
determine whether the current control is sufficient.
49
Link Tools Integration Tasks to Work
Breakdown Structure
The effort to integrate FMEA into SCAR procedures
should be translated into specific tasks in the Work
Breakdown Structure.
S/N
Tasks
Task Owner
Target
Completion Date
Specific Training
needed for Task
Owner/ Date
Core Team
Member In
Charge
Internal Verified
Date
Group Phase
End Date
Mik e
10-Dec-01
FMEA
-15 Nov-01
Nick
15-Dec-01
31-Dec-01
Group 1 Tools
1
SCAR
Integrate FMEA into SCAR
procedure/system
50
End of Topic
Any Question ?
51