Process FMEA 071806
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Transcript of Process FMEA 071806
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Failure Mode Effects
Analysis(FMEA)
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Provide insight to the uses of FMEA
Define different types of FMEA
Learn the steps to develop a Process
FMEA
Review FMEA Audit Form
Practice creating an FMEA
Objectives
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What is an FMEA?
A structured approach to:
Identifying the ways in which a product or process can failEstimating the risk to the customer associated with specific causes
Prioritizing the actions that should be taken to reduce the risk to thecustomer
For Example, a process FMEA will:
Capture the critical process inputs
Identify the ways the product or process can fail because of these inputs
Facilitate the documentation of a recommended action plan to preventthose failures
Be used to initially evaluate the control plan
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Current standard is SAE J-1739
History of the FMEA
First used in the 1960s in the Aerospace
industry during the Apollo program to mitigaterisk during missions
In 1974 the U.S. Navy developed
MIL-STD-1629 regarding the use ofthe FMEA
In the late 1970s the automotive
industry began to incorporate FMEA intothe management of their processes dueto increasing liability costs
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Types of FMEAs
System
Used to analyze systems and sub-systems in the early conceptand design stages. Focuses on potential failure modes associatedwith the functions of a system caused by the design.
Design
Used to analyze product designs before they are released toproduction. A DFMEA should always be completed well in advanceof a prototype build. Focuses on product function.
Process
Used to analyze manufacturing, assembly, or any otherprocesses. Focuses on process inputs.
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Definition of FMEA Terms
Failure Mode
Effect
Cause
Current Controls
Severity, Occurrence, Detection
Risk Priority Number (RPN)
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Definition of Terms
EffectDefinition
Impact on customer requirements
Generally an external customer focus, but can alsoinclude downstream processes
Examples
Temperature too high: paint cracks
Incorrect PO number: accounts receivable traceabilityerrors
Surface contamination: poor adhesion
Dropped call: customer dissatisfaction
Paint too thin: poor coverage
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Definition of Terms
CauseDefinition
Sources of process variation that cause the failure mode tooccur
Identification of causes starts with failure modes
associated with the highest severity ratingsExamples
Temperature too high: thermocouple out of calibration
Incorrect PO number: typorgaphikal error
Surface contamination: overhead hoist systems
Dropped call: insufficient number of CS representatives
Paint too thin: high solvent content
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Definition of Terms
Current Controls
Definition
Systematized methods / devices in place to prevent ordetect failure modesor causes(before causing effects)
Prevention consists of failsafing, automated control andpreventive maintenance
Controls consist of audits, checklists, inspection,laboratory testing, training, SOPs, setup verifications, etc.
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Definition of Terms
Severity (of Effect)
(1=Not Severe, 10=Very Severe) Importance of effect on
customer requirements Could also be concerned
with safety and other risksif failure occurs
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Definition of Terms
Occurrence (of Cause)(1=Not Likely, 10=Very Likely)
Frequency with which a given cause occurs and createsfailure mode(s)
Can sometimes refer to the frequency of a failure mode
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Definition of TermsDetection (Capability of Current Controls)
(1=Likely to Detect, 10=Not Likely at all to Detect)
Ability of current control scheme to detect or prevent: the causes before creating failure mode the failure modes before causing effect
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Definition of Terms
Risk Priority Number (RPN)
Definition
The output of an FMEA
A calculated number based on information you provide,
regarding:
potential failure modes,
effects, and
current ability of the process to detect the failures beforereaching the customer
Calculated as the product of three quantitative ratings, each onerelated to the effects, causes, and controls:
RPN = Severity x Occurrence x Detection
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FMEA Form - Initial Assessment
Process
Step/InputPotential Failure Mode Potential Failure Effects
S
E
V
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
Actions
Recommended
What is the
process step/
Input under
investigation?
In what ways does the Key
Input go wrong?
What is the impact on the Key
Output Variables (Customer
Requirements) or internal
requirements?
How
Severeisthe
effecttothe
cusotmer?What causes the Key Input to
go wrong?
How
oftendoescause
orFMo
ccur?What are the existing controls and
procedures (inspection and test)
that prevent eith the cause or the
Failure Mode? Should include an
SOP number.
How
wellcanyou
de
tectcauseorFM? What are the actions
for reducing the
occurrance of the
Cause, or improving
detection? Should
have actions only on
high RPN's or easyfixes.
0
0
0
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FMEA Form - Long Term History
Current Controls
D
E
T
R
P
N
Actions
RecommendedResp. Actions Taken
S
E
V
O
C
C
D
E
T
R
P
N
What are the existing controls and
procedures (inspection and test)
that prevent eith the cause or the
Failure Mode? Should include anSOP number.
Howw
ellcanyou
detectcau
seorFM? What are the actions
for reducing the
occurrance of the
Cause, or improvingdetection? Should
have actions only on
high RPN's or easy
fixes.
Whose
Responsible
for the
recommendedaction?
What are the completed
actions taken with the
recalculated RPN? Be
sure to includecompletion month/year
0 0
0 0
0 0
0 0
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1. For each process input, determine the ways inwhich the input can go wrong (failure modes)
Process
Step
Key Process
Input
Failure Modes -What can go
wrong? Effects Causes
Paint Nozzle type Nozzle too large
Nozzle too small
Dirty nozzle
FMEA - Step by Step
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2. For each failure mode associated with the
inputs, determine effectsThese effects are internal requirements for the next processand / or to the final customer.
ProcessStep
Key ProcessInput
Failure Modes -
What can gowrong? Effects Causes
Paint Nozzle type Nozzle too largeToo much paint,
splatter
Nozzle too smallToo little paint,
low rate
Dirty nozzle
Uneven spray
pattern, too little
paint
FMEA - Step by Step
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Process
Step
Key Process
Input
Failure Modes -What can go
wrong? Effects Causes
Current
Controls
Paint Nozzle type Nozzle too large Too much paint,splatter
Incorrect nozzle inparts bin
Nozzles receivedbagged and tagged
Nozzle too smallToo little paint,
low rate
Incorrect P/N in
procedureSOP #XXXXX
Dirty nozzle
Uneven spray
pattern, too little
paint
Nozzle not kept in
solventNone
4. List the current controls for each cause
For each failure mode / cause, list how the cause is preventedor the
failure mode is detected.
Reference documented procedures and instructions where they exist.
This is how the FMEA identifies initial gaps in the current ControlPlan. Process teams can start working on these gaps right away.
FMEA - Step by Step
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Process
Step
Key Process
Input
Failure Modes -What can go
wrong? Effects Causes
Current
Controls
Paint Nozzle type Nozzle too largeToo much paint,
splatter
Incorrect nozzle in
parts bin
Nozzles received
bagged and tagged
Nozzle too smallToo little paint,
low rate
Incorrect P/N in
procedure
Paint set-up SOP
#XXXXX
Dirty nozzle
Uneven spray
pattern, too little
paint
Nozzle not kept in
solventNone
Paint Paint viscosity Viscosity too high
Paint spatter,
low rate, high
paint usage
Temperature too
low in booth
Closed loop HVAC
controls
Viscosity too lowThin paint, high
solvent usage
Incorrect solvent
loading
Mixing procedure
SOP #XXXXX
Heres the rest of the example
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5. Create severity, occurrence, and detection rating scales
Example Rating ScaleRating Severity of Effect Likelihood of Occurrence Ability to Detect
10 Hazardous without warningVery high:
Cannot detect
9 Hazardous with warningFailure is almost inevitable
Very remote chance of detection
8 Loss of primary functionHigh:
Remote chance of detection
7Reduced primary function
performance
Repeated failuresVery low chance of detection
6 Loss of secondary functionModerate:
Low chance of detection
5Reduced secondary function
performance
Occasional failuresModerate chance of detection
4Minor defect noticed by most
customers
Moderately high chance of
detection
3Minor defect noticed by some
customers Low:High chance of detection
2Minor defect noticed by
discriminating customers
Relatively few failuresVery high chance of detection
1 No effect Remote: Failure is unlikely Almost certain detection
FMEA - Step by Step
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6. Assign severity, occurrence and detection ratings to
each cause
Use only one severity value for each effect
Determine which effect has the highest associated severityand use that SEV value for ALL causes for the related
failure mode Example: If a failure mode could cause either a
scratched surface (SEV 3) or an incorrect dimension(SEV 9), then use a SEV of 9 for all lines in that failuremode
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6. Assign severity, occurrence and detectionratings to each cause
Process
Step/InputPotential Failure Mode Potential Failure Effects
S
E
V
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
Paint / Nozzle
type
Nozz le too large Too much paint, splatter
7
Incorrect nozzle in parts bin
4
Nozzles received bagged and
tagged 7 196
Nozzle too small Too little paint, low rate8
Incorrect P/N in procedure2
Paint set-up SOP #XXXXX5 80
Dirty nozzle Uneven spray pattern, too
little paint 7Nozzle not kept in solvent
8None
10 560
Paint / Paint
viscosity
Viscosity too high Paint spat ter, low rate, high
paint usage 7Temperature too low in booth
2Closed loop HVAC controls
2 28
Viscos ity too low Thin paint, high solvent
usage 8Incorrect solvent loading
6Mixing procedure SOP #XXXXX
4 192
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7. Calculate RPNs
Multiply the severity, occurrence, and detection values foreach line in the FMEA.
Sort all failure modes by RPN. Notice that all cells have to beidentified to carry the failure modes, effects, causes andcurrent controls along with the sort.
Process
Step/InputPotential Failure Mode Potential Failure Effects
S
E
V
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
Paint / Nozzle
type
Dirty nozzle Uneven spray pattern, too
little paint 7Nozzle not kept in solvent
8None
10 560
Paint / Nozzle
type
Nozzle too large Too much paint, splatter7
Incorrect nozzle in parts bin4
Nozzles received bagged and
tagged 7 196
Paint / Paint
viscosity
Viscosity too low Thin paint , high solvent
usage 8Incorrect solvent loading
6Mixing procedure SOP #XXXXX
4 192
Paint / Nozzle
type
Nozzle too small Too little paint, low rate8
Incorrect P/N in procedure2
Paint set-up SOP #XXXXX5 80
Paint / Paint
viscosity
Viscosity too high Paint spatter, low rate, high
paint usage 7Temperature too low in booth
2Closed loop HVAC controls
2 28
FMEA - Step by Step
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RPN Review
Calculate the RPN for each effect / cause / controlscombination and review the results, looking for insights
Do the gut check. Does the Pareto of items makesense?
If not, maybe the ratings given are varying.
Determine potential next steps:
Data collection
Experiments
Process improvements
Process control implementations
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8. Determine recommended actions to reduce
high RPNs
Now fill in recommended actions for top RPNs.
Actions are recommended for only the high RPNs.
The key is FOCUS!
Process
Step/Input
Potential Failure
ModePotential Failure Effects
S
E
V
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
Actions
RecommendedResp.
Paint / Nozzle
type
Dirty nozzle Uneven spray pattern, too
little paint 7Nozzle not kept in
solvent 8None
10 560Design nozzle storage
system
PTBNL
Paint / Nozzle
type
Nozzle too large Too much paint, splatter7
Incorrect nozzle in parts
bin 4Nozzles received bagged
and tagged 7 196Review and improve
part specifications
SQA
Paint / Paint
viscosity
Viscosity too low Thin paint, high solvent
usage 8
Incorrect solvent loading
6
Mixing procedure SOP
#XXXXX 4 192
Review and improve
training and mixing
methods
Paint / Nozzle
type
Nozzle too small Too little paint, low rate8
Incorrect P/N in
procedure 2Paint set-up SOP #XXXXX
5 80
Paint / Paint
viscosity
Viscosity too high Paint spatter, low rate,
high paint usage 7Temperature too low in
booth 2Closed loop HVAC
controls 2 28
FMEA - Step by Step
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9. Take appropriate actions and recalculate
RPNs
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
Actions
RecommendedResp. Actions Taken
S
E
V
O
C
C
D
E
T
R
P
N
Nozzle not kept in
solvent 8None
10 560Design nozzle storage
system
PTBNL Implemented automatic
nozzle 'parking' system 7 3 4 84
Incorrect nozzle in parts
bin 4Nozzles received bagged
and tagged 7 196Review and improve
part specifications
SQA Standardized on single
nozzle 7 2 7 98
Incorrect solvent loading
6
Mixing procedure SOP
#XXXXX 4 192
Review and improve
training and mixing
methods
XYZ Improved mixing
procedures and
equipment
8 4 4 128
Incorrect P/N in
procedure 2
Paint set-up SOP #XXXXX
5 80 0
Temperature too low in
booth 2Closed loop HVAC
controls 2 28
0
FMEA - Step by Step
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Summary
Process
Step/InputPotential Failure Mode Potential Failure Effects
S
E
V
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
Actions
Recommended
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
Whatis theInput
Whatcan gowrong
with theInput?
What can
be done?
What isthe Effect
on theOutputs?
What arethe
Causes?
How arethese found
orprevented?
HowBad?
HowOften?
Howwell?
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1 Does the Header Contain Adequate Information ?
Yes E
No
1aName of Program(s) included? N/A
1bName of Supplier included? N/A
1c Part Number and Description included? N/A
1d
Core Team includes all names with title or area? Note: Phone #'s recommended, but not mandatory for this audit. N/A
1eKey Date Shown is Cummins VPI Program Beta Build Date? N/A
1fFMEA Date (Orig.) is shown? N/A
1gFMEA "(Rev.)" date within past 60 days? Note: "N/A" if "(Orig.)" date is within 60 days. N/A
1hAll else ok (no other issues)? N/A
If all answers "Yes," check "Yes." If one or more "No," check "No." N/A
Note: "E" means only minor "E"xceptions, see comment section..
PFMEA Audit
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2 Is the Process Function/Requirements Column Adequate? Yes E No
2aEach operation is (briefly) described using a verb/noun (bend tube, apply primer, pierce hole, etc.), rather than justnumbered?
2bCharacteristics of part/process listed (hole diameter, tube length, etc.)? Note: Including specification tolerances (25mm. +/- 2) are recommended, but not required for this audit.
2cAll else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
3 Potential Failure Modes Column Adequate? Yes E No
3aFailure Modes written in terms of a characteristic (hole dia., surf. roughness)?
3bFailure Modes are specific ("hole dia. too small" rather than "hole out of spec.")?
3cAll else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
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4 Potential Effects of Failure Column Adequate? Yes E No
4aEffects written in terms of what customer (downstream process or end user) will notice/experience ("unable toassemble" do not use "scrap")?
4bAll else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
5 Severity Yes E No
5aSeverity rankings not underratedbased on AIAG Manual criteria? Note: Overrating not recommended, but notrequirement for this audit.
5bSeverity rankings identical for identical Potential Effects?
5cAll else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
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6 Class Yes E No
6aAre all Key, Major or Critical characteriustics identified?
6bAll else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
Supplier Process FMEA: Audit Summary-Page 2
7 Potential Causes Column Adequate? Yes E No7a
Descriptions specific? Note: 1) "Incorrect set-up", "improper cooling", etc. must be replaced by or include specificdescription of what was "incorrect" (temp. set too high) or "improper" (time too short). 2) Replace "operatorerror" with "operator installed widget upside down."
7b All else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
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8 Occurrence Yes E No
8a There is one Occurrence ranking for each cause ("worn/broken tool" must have two separate rankings)?
8b All else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
9 Current Controls Column Adequate? Yes E No
9a
Controls correctly identified as either Detection ("D") (Mistake Proof, 100% visual insp., etc.) or Prevention ("P")(visual aids, training, PM, etc.) controls? Note: 1) separate set-up process (P.) from 1st piece inspect. (D.). 2)
Error-Proofing is preventive (can't make), but may be listed as "P" or "D" or both.
9b Controls are adequately explained or easily referenced?
9c All else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
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10 Detection Yes E No
10a One Detection ranking for each Occurrence ranking?
10b
Detection ranking consistent with AIAG Manual (Visual Inspection=8, etc.)? Note: Detection ranking is no betterthan the best detection method (SPC + visual inspection + hourly audit=6 [SPC is best]).
10c All else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
11 Recommended Actions & Responsibility Columns Reasonable? Yes E No
11aDo all Severity rankings of 9 or 10 with a Detection ranking greater than 3 have a Recommended Action which will
lower the Detection? Notes: 1) "None" only to be used if Detection ranking is less than 4. 2) Justification for"None" in this column recommended, but not mandatory for this audit.
11b Recommended Actions are assigned to a specific person (not a department)?
11c Target Completion dates are shown and not past due?
11d All else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
PFMEA Audit
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12 Action Results Effectively Executed? Yes E No
12a Re-rankings affected Occurrence and/or Detection (not Severity)?
12b Occurrence and/or Detection re-rankings consistent with AIAG Manual?
12c All else ok (no other issues)?
If all answers "Yes," check "Yes." If one or more "No," check "No." Otherwise, check "E"
PFMEA Audit
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Lets Create a PFMEA
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FMEA Form - Initial AssessmentProcess
Step/InputPotential Failure Mode Potential Failure Effects
S
E
V
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
Actions
Recommended
What is the
process step/
Input under
investigation?
In what ways does the Key
Input go wrong?
What is the impact on the Key
Output Variables (Customer
Requirements) or internal
requirements?
How
Severeisthe
effecttothe
cusotmer?What causes the Key Input to
go wrong?
How
oftendoescause
orFMo
ccur?What are the existing controls and
procedures (inspection and test)
that prevent eith the cause or the
Failure Mode? Should include an
SOP number.
How
wellcanyou
detectcauseorFM? What are the actions
for reducing the
occurrance of the
Cause, or improving
detection? Should
have actions only on
high RPN's or easy
fixes.
0
0
0
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39
FMEA Form - Long Term History
Current Controls
D
E
T
R
P
N
Actions
RecommendedResp. Actions Taken
S
E
V
O
C
C
D
E
T
R
P
N
What are the existing controls and
procedures (inspection and test)
that prevent eith the cause or the
Failure Mode? Should include an
SOP number.
Howw
ellcanyou
detectca
useorFM? What are the actions
for reducing the
occurrance of the
Cause, or improving
detection? Should
have actions only on
high RPN's or easy
fixes.
Whose
Responsible
for the
recommended
action?
What are the completed
actions taken with the
recalculated RPN? Be
sure to include
completion month/year
0 0
0 0
0 0
0 0