1 failure mode and effect analysis. 2 learning objectives provide familiarization with fmea...
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Failure Mode and Effect Failure Mode and Effect AnalysisAnalysis
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Learning ObjectivesLearning 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
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Definition of FMEADefinition of FMEA
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.
FMEA is a systematic design evaluation procedure
whose purpose is to:
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FMEA is Function-drivenFMEA is Function-drivenFMEA begins with a definition of the FUNCTIONS an item is supposed to perform. The inputs must come from several sources to be effective:
ManufacturingEngineer
SupplierQuality Reliability
EngineerDesign
Engineer
ProgramManagement
Production
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BackgroundBackgroundDeveloped in early 60’s by NASA to “fail-proof” 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.
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NASA used FMEA to identify Single Point Failures on Apollo project (SPF = no redundancy & loss of mission). How many did they find?
420and we thought we had No problems!
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Types of FMEA’sTypes of FMEA’s
SYSTEM
DESIGN
PROCESS
System FMEA is used to analyze systems and subsystems in the early concept and design stages.
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
Design FMEA is used to analyze products before they are released to production
Process FMEA is used to analyze manufacturing, assembly and administrative processes
Process FMEA is used to analyze manufacturing, assembly and administrative processes
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When Is the FMEA Started?When Is the FMEA Started?
Do the best you can with what you have.
AS EARLY AS POSSIBLEGuideline:
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When to StartWhen 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
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Process FMEA FormProcess FMEA FormPRODUCT: FMEA NO.
PROCESS FMEA PROCESS/OPERATION: PAGE OF
PLANNING REFERENCE: DATE: BY:
Oklahoma City
PROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT D RPN ACTION CORRECTIVE RESPONSIBILITY ACTION RESULTINGFAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS PRIORITY ACTION & DATE DUE TAKEN
FUNCTION FAILURE FAILURE S O D RPN
DETECTIONOCCURRENCESEVERITY RPN = S x O x D
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Process Failure ModeProcess 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.
FAILUREMODE
EFFECT
PREVIOUSOPERATION
CAUSE
NEXTOPERATION
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Process CausesProcess Causes
Process FMEA considers process variability due to:
OPERATOR SET-UP MACHINE
METHOD ENVIRONMENT MEASUREMENT
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Current ControlsCurrent 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
SPC
Process Capability
Gage R&R
Sampling
Testing
DoE
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Typically, three items are scored:
Types of MeasuresTypes of Measures
SEVERITYAs it applies to the effects on the local system, next level, and end user
OCCURRENCELikelihood that a specific cause will occur and result in a specific failure mode
DETECTIONAbility of the current / proposed control mechanism to detect and identify the failure mode
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SeveritySeverityEffect Criteria: Severity of Effect Defined Ranking
Hazardous: Without Warning
May endanger operator. Failure mode affects safe vehicle operation and / or involves noncompliance with government regulation. Failure will occur WITHOUT warning.
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Hazardous: With Warning
May endanger operator. Failure mode affects safe vehicle operation and / or involves noncompliance with government regulation. Failure will occur WITH warning.
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Very HighMajor disruption to production line. 100% of product may have to be scrapped. Vehicle / item inoperable, loss of primary function. Customer very dissatisfied.
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HighMinor disruption to production line. Product may have to be sorted and a portion (less than 100%) scrapped. Vehicle operable, but at a reduced level of performance. Customer dissatisfied.
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ModerateMinor disruption to production line. A portion (less than 100%) may have to be scrapped (no sorting). Vehicle / item operable, but some comfort / convenience item(s) inoperable. Customers experience discomfort.
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LowMinor disruption to production line. 100% of product may have to be reworked. Vehicle / item operable, but some comfort / convenience item(s) operable at reduced level of performance. Customer experiences some dissatisfaction.
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Very LowMinor disruption to production line. The product may have to be sorted and a portion (less than 100%) reworked. Fit / finish / squeak / rattle item does not conform. Defect noticed by most customers.
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MinorMinor disruption to production line. A portion (less than 100%) of the product may have to be reworked on-line but out-of-station. Fit / finish / squeak / rattle item does not conform. Defect noticed by average customers.
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Very MinorMinor disruption to production line. A portion (less than 100%) of the product may have to be reworked on-line but in-station. Fit / finish / squeak / rattle item does not conform. Defect noticed by discriminating customers.
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None No effect. 1
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OccurrenceOccurrenceProbability of Failure Possible Failure Rates Cpk Ranking
Very High: 1 in 2 < 0.33 10
Failure is almost inevitable 1 in 3 0.33 9
High: Generally associated with processes similar to previous
1 in 8 0.51 8
processes that have often failed 1 in 20 0.67 7
Moderate: Generally associated with processes similar to
1 in 80 0.83 6
previous processes which have 1 in 400 1.00 5
experienced occasional failures, but not in major proportions
1 in 2,000 1.17 4
Low: Isolated failures associated with similar processes
1 in 15,000 1.33 3
Very Low: Only isolated failures associated with almost identical processes
1 in 150,000 1.5 2
Remote: Failure is unlikely. No failures ever associated with almost identical processes
1 in 1,500,000 1.67 1
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This is best thought of as Escape Potential - the higher thescore, the greater the problem
Detection (“Escape”)Detection (“Escape”)
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
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Risk Priority NumberRisk Priority Number
RPN = O x S x DOccurrence x Severity x Detection
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Basic StepsBasic Steps1. Develop a Strategy
– Form a FMEA teamST91260A
DRIVE
BASE SUB
SYSTEM & FIRMWARE
COVERMEDIA
DISC PACK
FINAL ARM
ARM SUB
ARM COIL
BOBBIN
ROT. ARM
SP. FLEX SPINDLE
STATOR
ROTOR
HDA ASSEMBLY
BASE DECK
RECIR FILTER
BREATH. FILTER
LABELS
PCB ASSEMBLY
DISC CLAMP
BAL. WT
SPACERS
MAG ASSY LATCH
ARM SUB
ARM SUB
BASE DECK
DAMPER
SEAL
MOTOR POLES, POLE SPACER
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..
FIRST PRIORITY
SECOND PRIORITY
THIRD PRIORITY
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1. Develop a Strategy
2. Review the design/process– Develop process map and
identify all process steps
Basic StepsBasic Steps
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Basic StepsBasic Steps1. Develop a Strategy2. Review the design /process
3. List functions– List all the value-added
process– For each process step,
list process inputs (process characteristics
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1. Develop a Strategy
2. Review the design /process
3. List functions
4. Brainstorm potential failure modes
Basic StepsBasic Steps
EFFECTCAUSES
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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
Basic StepsBasic Steps
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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) scorePRODUCT: FMEA NO.
PROCESS/OPERATION: PAGE OF
DESIGN (OR PROCESS) FMEAPLANNING REFERENCE: DATE: BY:
Oklahoma CityPOTENTIAL POTENTIAL S POTENTIAL O CURRENT D RPN ACTION CORRECTIVE RESPONSIBILITY ACTION RESULTING
FUNCTION FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS PRIORITY ACTION & DATE DUE TAKENFAILURE FAILURE S O D RPN
DETECTIONOCCURRENCESEVERITY RPN = S x O x D
Basic StepsBasic Steps
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1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. List the potential consequences of each failure
mode6. Assign severity (SEV) score
7. Identify the cause(s) of each failure mode.
Basic StepsBasic Steps
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1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. List the potential consequences (effect) of each
failure mode6. Assign severity (SEV) score7. Identify the cause(s) of each failure mode.
8. Assign occurrence (OCC) scores.
Basic StepsBasic Steps
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1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. List the potential consequences (effect) of each failure
mode6. Assign severity (SEV) score7. Identify the potential cause(s) of each failure mode.8. Assign occurrence (OCC) scores.
9. Identify current controls to detect the failure modes.
Basic StepsBasic Steps
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Basic StepsBasic Steps1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. List the potential consequences (effect) of each failure mode6. Assign severity (SEV) score7. 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.
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Basic StepsBasic Steps1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. List the potential consequences (effect) of each failure mode6. Assign severity (SEV) score7. 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.
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1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. List the potential consequences (effect) of each failure mode6. Assign severity (SEV) score7. 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.
Basic StepsBasic Steps
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1. Develop a Strategy2. Review the design /process3. List functions4. Brainstorm potential failure modes5. List the potential consequences (effect) of each failure mode6. Assign severity (SEV) score7. 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.
Basic StepsBasic Steps
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Shortcomings of RPNShortcomings of RPN
A 8 4 3 96
B 4 8 3 96
SAME RESULT
Failu
re M
ode
Seve
rity
Occ
urre
nce
Effect
iven
ess
RPN
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Action PriorityAction Priority
PRIORITY RPN RANGE
A Over 200
BCD
100-199
26-99
1-25
BUMP HEAD
WALK INTO DOOR
PAINCAN’T SEE
GET GLASSES WEAR HELMET
REMOVE DOORS
LIKELY
CAUSE
POTENTIAL
PROBLEM
LIKELY
EFFECT
ACTIONSPREVENTIVECONTINGENT
- ADAPTIVE
-CORRECTIVE
TRIGGER
INITIAL PROBLEM
BUMP HEAD
WALK INTO DOOR
PAINCAN’T SEE
GET GLASSES WEAR HELMET
REMOVE DOORS
LIKELY
CAUSE
POTENTIAL
PROBLEM
LIKELY
EFFECT
ACTIONSPREVENTIVECONTINGENT
- ADAPTIVE
-CORRECTIVE
TRIGGER
1st WHYCAUSE BECOMES
NEW PROBLEM
PROBLEM
BECOMES EFFECT
BUMP HEAD
WALK INTO DOOR AND
PAIN
CAN’T SEE
SURGERY
LIKELY
CAUSE
POTENTIAL
PROBLEM
LIKELY
EFFECT
ACTIONSPREVENTIVECONTINGENT
- ADAPTIVE
-CORRECTIVE
TRIGGER
1st WHY
GET GLASSES
NEARSIGHTED
BUMP HEAD
WALK INTO DOOR AND
PAIN
CAN’T SEE
SURGERY
LIKELY
CAUSE
POTENTIAL
PROBLEM
LIKELY
EFFECT
ACTIONSPREVENTIVECONTINGENT
- ADAPTIVE
-CORRECTIVE
TRIGGER
2ND WHY
GET GLASSES
NEARSIGHTED
BUMP HEAD
WALK INTO DOOR AND
PAIN
CAN’T SEE
SURGERY
LIKELY
CAUSE
POTENTIAL
PROBLEM
LIKELY
EFFECT
ACTIONSPREVENTIVECONTINGENT
- ADAPTIVE
-CORRECTIVE
TRIGGER
2ND WHYNEARSIGHTED
CUT OUTSTAR TREK
TOO MUCH T.V.
HAVE WE FOUND ROOT CAUSE?
BUMP HEAD
WALK INTO DOOR AND
PAIN
CAN’T SEE
SURGERY
LIKELY
CAUSE
POTENTIAL
PROBLEM
LIKELY
EFFECT
ACTIONSPREVENTIVECONTINGENT
- ADAPTIVE
-CORRECTIVE
TRIGGER
2ND WHYNEARSIGHTED
CUT OUTSTAR TREK
TOO MUCH T.V.
OR GONE TOO FAR !
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Determining Level of Determining Level of AnalysisAnalysis
PRODUCT: SEAGATE DRIVE STXXXXXSUBSYSTEMS SPINDLE MOTOR
DESIGN FMEADRAWING OR SPEC REFERENCE:
Oklahoma CityPROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT E RPN
FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS
FUNCTION FAILURE FAILURE
SPINDLE ROTATES MEDIA AT FIXED RPM
NO SPIN, OR DRIVE RUNS IN REVERSE
DRIVE INOPERABLE FAILURE OF FLEX SOLDER JOINT DUE TO INSUFFICIENT STRAIN RELIEF
RESISTANCE MEASUREMENT AT INCOMING INSPECTION
EFFECTIVENESSOCCURRENCESEVERITY
Handbook pg. 43Here’s a Seagate Example
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PRODUCT: SEAGATE DRIVE STXXXXXSUBSYSTEMS SPINDLE MOTOR
DESIGN FMEADRAWING OR SPEC REFERENCE:
Oklahoma CityPROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT E RPN
FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS
FUNCTION FAILURE FAILURE
SPINDLE ROTATES MEDIA AT FIXED RPM
NO SPIN, OR DRIVE RUNS IN REVERSE
DRIVE INOPERABLE FAILURE OF FLEX SOLDER JOINT DUE TO INSUFFICIENT STRAIN RELIEF
RESISTANCE MEASUREMENT AT INCOMING INSPECTION
EFFECTIVENESSOCCURRENCESEVERITY
Handbook pg. 43
Cause becomes Failure Mode
Determining Level of Determining Level of AnalysisAnalysis
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PRODUCT: SEAGATE DRIVE STXXXXXSUBSYSTEMS SPINDLE MOTOR
DESIGN FMEADRAWING OR SPEC REFERENCE:
Oklahoma CityPROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT E RPN
FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS
FUNCTION FAILURE FAILURE
SPINDLE ROTATES MEDIA AT FIXED RPM
NO SPIN, OR DRIVE RUNS IN REVERSE
DRIVE INOPERABLE FAILURE OF FLEX SOLDER JOINT DUE TO INSUFFICIENT STRAIN RELIEF
RESISTANCE MEASUREMENT AT INCOMING INSPECTION
EFFECTIVENESSOCCURRENCESEVERITY
Handbook pg. 43
Failure Mode becomes Effect
Determining Level of Determining Level of AnalysisAnalysis
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PROVIDES A DEEPER LEVEL OF ANALYSIS BY ASKINGYOU FOR THE DESIGN CAUSES AND VERIFICATIONOF INSUFFICIENT STRAIN RELIEF
PRODUCT: SEAGATE DRIVE STXXXXXSUBSYSTEMS SPINDLE MOTOR
DESIGN FMEADRAWING OR SPEC REFERENCE:
Oklahoma CityPROCESS DESCRIPTION POTENTIAL POTENTIAL S POTENTIAL O CURRENT E RPN
FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS
FUNCTION FAILURE FAILURE
SPINDLE ROTATES MEDIA AT FIXED RPM
FAILURE OF FLEX SOLDER JOINT DUE TO INSUFFICIENT STRAIN RELIEF
NO SPIN, OR DRIVE RUNS IN REVERSE CAUSING DRIVE TO BE INOPERABLE
EFFECTIVENESSOCCURRENCESEVERITY
Handbook pg. 43
WHY?
Determining Level of Determining Level of AnalysisAnalysis
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What’s Wrong With This What’s Wrong With This Picture?Picture?
NUMBER OF PROCESS FAILURE CAUSES
POWER
GAGE
DESIGN
HANDLING
SET-UP
CONTAMINATION
TOOLING
OPERATOR ERROR
0 5 10 15 20 25 30 35 40 45 50
POWER
GAGE
DESIGN
HANDLING
SET-UP
CONTAMINATION
TOOLING
OPERATOR ERROR
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ActionsActions
The design or process must be improved based on the results of the FMEA study.
A well-developed FMEA will be of limited value without positive and effective corrective actions.
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Elements of FMEAElements of FMEAFailure 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.
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It is conducted on a timely basisand
It is applied by a product teamand
Its results are documented
FMEA is most effective when FMEA is most effective when
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Example of how FMEA can be used in SCAR.
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 materialpurge 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 orcomplaint.
5.2.1.4 The concerned Departmental Manager or his designate or Supplier shall head and formthe 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, identifyand 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.
FOR REFERENCE
Section of SCAR procedure
FMEA can be used to identify the potential cause of failure and determine whether the current control is sufficient.
Integrating FMEA into SOPsIntegrating FMEA into SOPs
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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
Group 1 Tools
1 SCAR
Integrate FMEA into SCAR procedure/system
Mike 10-Dec-01 FMEA -15 Nov-01
Nick 15-Dec-01 31-Dec-01
Link Tools Integration Tasks to Work Link Tools Integration Tasks to Work Breakdown StructureBreakdown Structure
The effort to integrate FMEA into SCAR procedures should be translated into specific tasks in the Work Breakdown Structure.
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End of TopicEnd of Topic
Any Question ?