Potential Failure Mode & Effects...

Version 2010.1 FMEA Manual 1

Heribert NuhnQMS

Qualitäts-Management-Systeme

Heribert NuhnQMSQualitäts-Management-SystemeGermanyD-56587 StrassenhausDeutschlandTel.: ++ 49 2634 9560 71Fax.: ++ 49 2634 9560 72Mobil: + 49 171 315 7768eMail: [email protected]

Key Points Regarding

Potential Failure Mode & Effects AnalysisDesign and Process FMEA

If you have further questions let us know.We are ready to help.

ISO/ TS 16 949

RGA/ APQP

Internal AuditorVDA 2/ PPAP

FMEA DVP

5-

Why8D


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Reference Material

• Potential Failure Mode and Effects Analysis Reference-Manual (Fourth Edition, June 2008)

• VDA 4.2 (Second Edition, 2009/ 2010)

• APQP & CP Reference Manual Second Edition (2008)

• APQP Status Reporting Process (Ford, Checklist)

• PPAP Fourth Edition (2006)


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FMEA

History• developed mid-1960s in the US• for aerospace industry (Apollo-Program)

Present• essential part of QM-Systems

• aerospace• nuclear energy• automotive industry


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Introduction

This manual introduces the topic of Potential Failure Mode and Effects Analysis (FMEA) and gives general guidance in the application of the technique.


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FMEA Process (1)• APQP: FMEA is an analytical methodology

used to ensure that potential problems have been considered and addressed throughout the product and process development process

• Its most visible result is the documentation of the collective knowledge of cross-functional teams

Introduction


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FMEA Process (2)• evaluation and analysis to assess risk• conduct discussion regarding

• product and process design• review of functions• changes in application• resulting risk of potential failure

Introduction


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FMEA Process (3)• attention on every component within product or

assembly• critical or safety related components or

processes should be given a higher priority• importance of timeliness of FMEA-Process

• "before-the-event"• not "after-the-fact"

Introduction


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FMEA Process (4)• Design FMEA in the early stages of design• Process FMEA before tooling or

manufacturing equipment is developed or purchased

• FMEA evolves throughout each stage of design and each stage of the manufacturing development process

• may be used in problem solving

Introduction


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Purpose of Manual (1)• describes basic principles and implementation

of FMEA process• covers FMECA: Failure Mode Effects

Criticality Analysis quantifying risks• shows integration into product and process

development cycle• includes documentation of this process

Introduction


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Purpose of Manual (4)

There are three basic cases for which FMEA process is to be applied:

• new design, new technology or new processes• modification to existing design or process• use of an existing design or process in a new

environment, location, application or duty cycle

Introduction


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Scope of Manual• The analytical methods presented in this

manual are applicable to any product or process.

• However, this manual will focus on those applications prevalent within the automotive industry and its suppliers.

Introduction


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Impact on Organization and Mgmt.

FMEA • is an important activity within any company• must be well planned as a multi-disciplined

activity• must have a process owner and• senior management commitment


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Impact on Organization and Mgmt.

Comprehensive trainings program including• management overview• training for

• user• supplier• facilitator

Ultimately, management has the responsibility and ownership for development and maintenance of the FMEAs


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Follow-up & Continuous Improvement

Taking effective preventive/ corrective action• action should be communicated to all affected

parties• team leadership is responsible that

recommended actions are addressed• as a living document the FMEA reflects the

latest level• team leader should use appropriate means to

assure implementation of recommended action (reviews, Control Plans etc.)


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Strategy, Planning, Implementation

Approach (1)• no single or unique process for FMEAs,

however there are common elements• identify the team

• multi-disciplinary or cross-functional team• represent subject matter • facilitation expertise and knowledge of FMEA

process• experience and • necessary authority


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Component

Subsystem


Product/ System

Powertrain


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Approach (3)• define the customer, there are four (4) major

customers• End user• OEM assembly and manufacturing centres/ plants• supply chain manufacturing• regulators/ government agencies

• identify functions, requirements, and specifications

• clarify design intent or • process purpose


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Approach (6)• identify potential causes

• potential cause of failure is defined as an indication of how the failure could occur, described in terms of something that can be corrected or can be controlled

• potential cause of failure may be an indication of a design weakness, the consequence of which is the failure mode


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Approach (10)• recommended actions and results

• the intent of the recommended action is to reduce overall risk and the likelihood that the failure mode will occur

• the recommended action will reduce severity and occurrence and

• improve detection• responsibility and timing for recommended actions

should be recorded• once actions are completed updated ratings should

be recorded


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Management Responsibility• management owns the FMEA process• management has the ultimate responsibility of

• selecting and applying resources• ensuring an effective risk management process and• ensuring adequate timing

• management responsibility also includes providing direct support to the team through

• on-going reviews• eliminating road blocks and• incorporating lessons learned



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DFMEA supports the design process in (1) reducing the risk of failures by:

• objective evaluation of the design, functional requirements and design alternatives

• evaluating the initial design requirements for• manufacturing• assembly• service• recycling

Design FMEA Introduction


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DFMEA is a living document• initiated before design concept finalization• updated as

• changes occur• additional information is obtained throughout the

phases of product development• fundamentally completed before the production

design is released• a source for lessons learned for future design

iterations



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Processes

Considerations manufacturing, assy, service (1)• DFMEA should include any potential failure

modes and causes that can occur as a result of design during the processes of

• manufacturing• assembly• customer usage or• service and recycling

• failure modes may be mitigated (design change, i.e. error-proofed) or

• transferred (action plan) to be covered by PFMEA



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Considerations manufacturing, assy, service (3)• The DFMEA can also take into consideration the

technical and physical limits of product serviceability and recycling such as

• tool access• diagnostic capability• material classification symbols• materials/ chemicals used in the manufacturing

process



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Prerequisites (2)• understand system, subsystem or component

• What processes, mating components or systems does the product interface with?

• Are there functions or features of the product that affect other components or systems?

• Are there inputs provided from other components or subsystems that are needed to perform intended functions of the product?

• Do the products function include the prevention or detection of a possible failure mode in a linked component or system?

• Tools: Block Diagram or Parameter Diagram

Development of the Design FMEA


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Block Diagram (2)

Flip GlassBall Studs

Hinges

Environment

MFG Plant

Service

Weather Strips

FlipGlass

Flip GlassStriker

LatchAssembly

WiperAssembly

Flip GlassAppliquéAssembly

Customer

Lift GateBall Studs

Lift Gate

WiringHarness

Flip GlassBall Struts

3

2

3

45

1

Numbers relate to detail on interface analysis

One way interaction/ function

Two way interaction/ function

Boundary Line

Critical interface focus

Critical assembly focus

Key:



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Parameter Diagram (3)

Control Factors

ChemicalWash coat technologyPrecious Metal Loading/ Ratio

Mechanicalshell design and materialmount material/ wire/ sealsSubstrate• geometry contour & length)• cell density• wall thicknesspackaging location and volumeflow distribution (pipe & core geometry

SignalMass• exhaust gas

compositionEnergy• Thermal• mechanical• chemical• pressure

Noise Factors

Piece to piece variationmaterial variationsubstrate wash compositioncanning forces• clamping force• wrap lightness• crimping forcesassembly process• misbuild/ mislabels• orientation and centrality• mount gapwelding process

Changes over time/ mileageblockage/ restrictionweld deteriorationsubstrate retention (mount degradation)substrate erosion/ breakagecatalyst chemical agingcorrosion of shellloosening of heat shield

External environmentambient temperatureroad load/ vibrationoff road - debris/ rocksroad salt/ mud/ water

Customer usageshort, low speed tripshigh speed with trailer towfuel type & quality/ sulphur levelservice damageshipping mishandlingdriving with engine errors

System interactionsheat shield/ NVH pads pressurewelded exhaust manifold leaksengine misfire, excessive heatpower train load vibrationdynamic load (engine induced)

Input

Error states:Functional• output gases do not

meet emission requirementsnon-functional• odour/ smell• noise/ rattle• power loss• excessive heat (internal)

Error states:Functional• output gases do not

meet emission requirementsnon-functional (cont.)• excessive heat (external)• exhaust leak• inadvertent "Check Engine" signal

Response:Y1 = regulated emission (HC, CO, NOx) gms/ mileY2 = non-regulated emission (H2S) ppm/ test

Output



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RPN

Current Design Controls Action Results

RPN

DOSActions Taken& Completion

DateFunctionDDe-

tectionOPre-vention

Respon-sibility

andTargetDate

Recom-mendedAction

Poten-tial

Causes of

Failure

Class

S

Poten-tial

Effects of

Failure

Poten-tial

FailureMode

Re-quire-ment

Item

Core Team:

FMEA Date (Orig.):Key Date:Model Year(s)/ Program:

Prepared by:Design Responsibility:Component:

Page: of:Subsystem:

FMEA Number:PotentialFailure Mode and Effect(s) Analysis

Design FMEA

System:

Alphanumeric string to identify the

FMEA, used fordocument control

Identify, what isbeing analysed.

Identify thescope of the

FMEA as System, Subsystem or

Component

Enter who is responsible for the design: OEM, the organisation by department or group or supplier

Design FMEA

Enter the initial design due date, not

to exceed the scheduled production design release date

Completion date or revision

date

Responsible engineer:

name & contact information

Name, organisation and other contact

information of team members

Use consistentterminology for FMEA and

supporting tools!


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RPN

Current Design Controls Action Results

RPN


DateFunctionDDe-

tectionOPre-vention

Respon-sibility

andTargetDate

Recom-mendedAction

Poten-tial

Causes of

Failure

Class

S

Poten-tial

Effects of

Failure

Poten-tial

FailureMode

Re-quire-ment

Item

Core Team:


Prepared by:Design Responsibility:Component:

Page: of:Subsystem:


Design FMEA

System:

Design FMEACurrent Design Controls are those activities conducted as part of the

design process that have been completed or committed to and that will assure the design adequacy for the design functional and reliability requirements under consideration.

The Risk Priority Number (RPN) assists in action prioritization using:

RPN = S x O x DThe use of RPN threshold is not

recommended practice for determining the need for actions!

Detection (D) is the rank associated with best detection control listed in the Current Design Controls. The

ranking value of one (1) is reserved for failure prevention through

proven design solutions

Prevention:Eliminate (prevent) the cause of the mechanism of failure or the failure mode from occurring or reduce its rate of occurrence.

Detection:Identify (detect) the existence of a cause, the resulting mechanism of failure or the failure mode, either by analytical or physical methods, before the item is released for production.

Occurrence (O) is the likelihood that a specific cause/ mechanism will occur resulting in the

Failure Mode within the design life.


supporting tools!


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Risk evaluation• initial focus should be oriented towards failure modes with highest

severity rankings• when severity is 9 or 10, it is imperative that the risk is being

addressed through design controls or recommended actions• for failure modes with severities 8 or below consider causes with

highest occurrence or detection rankings• use of RPN threshold is not a recommended practice

example:

Determining Risk Priorities

126792C112447B

90529A

RPNDetectionOccurrenceSeverityItem


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VDAAIAGAIAGVDAFailure Rate

199,99%Almost certain

Failure is eliminated through preventive

control1 ppmVery low

No discernable effect.

299,9%Very high0,001 per 1.0001 ppm50 ppm

Appearance or audible noise, vehicle operable, item does not conform and defect is noticed by discriminating customers (> 25%).

399,9%High0,01 per 1.00010 ppm100 ppm

Low

Appearance or audible noise, vehicle operable, item does not conform and defect is noticed by many customers (> 50%).

499,9%Moderately high

0,1 per 1.000100 ppm500 ppm

Appearance or audible noise, vehicle operable, item does not conform and defect is noticed by most customers (> 75%).

599,7%Moderate0,5 per 1.000500 ppm1.000 ppm

Degradation of secondary function (vehicle operable, but comfort/ convenience functions at reduced level of performance).

699,7%Low2 per 1.0002.000 ppm5.000 ppm

Moderate

Loss of secondary function (vehicle operable, but comfort/ convenience functions inoperable).

799,7%Very low10 per 1.00010.000 ppm10.000 ppm

Degradation of primary function (vehicle/ item is operable but at reduced level of performance).

898%Remote20 per 1.00020.000 ppm50.000 ppm

Loss of primary function (vehicle inoperable, does not affect safe vehicle operation).

990%Very remote50 per 1.00050.000 ppm100.000 ppm

High

Potential failure mode affects safe vehicle operation and/ or involves non-compliance with government regulation with warning.

1090%Almost impossible

≥ 100 per 1.000100.000 ppm500.000 ppmVery high

Potential failure mode affects safe vehicle operation and/ or involves non-compliance with government regulation without warning.

FactorDetection (D)Occurrence (O)

Severity (S)

Evaluation Criteria for Design FMEA


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Special CharacteristicsD FMEA

Classi-fication

Memo Rating Control

potential CCin P FMEA

YC S: 9 or 10 n.a.

potential SCin P FMEA

YS S: 5 - 8O: 4 - 10

n.a.

CC or SCnone S: < 5 n.a.


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DFMEA is a living document• should be reviewed whenever there is a design change and• should be updated as required• updates of recommended actions should be included into a

subsequent FMEA• along with final results of actions taken• periodic review of rankings used in the FMEA, specific focus

should be given to occurrence (O) and detection (D)• this should reflect

• product changes• improvements in design controls• feedback from field issues

Maintaining Design FMEAs


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Design Verification Plan


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Design Verification Plan

D FMEA

DVP

Testing

& SOR

final risk:reactiondocumentation

result

acceptancecriteria

potential failure mode

revised product/ risk


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Prototype Build Control PlanXXXX


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Design FMEA Linkages

DFMEA

- Boundary/ Bock Diagram- Parameter/ P Diagram- Schematics/ Drawings- Bill of Material

- Design Verification Plan &Sign-off Report (DVP&SOR)

- Prototype Build Control Plan- Final Drawings- PFMEA


supporting tools!


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Process Flow Diagram (2)

Development of the Process FMEA

Startinput

Step 1 Step 2 Step n

High Level Process Map

Detailed Process Flow Diagram

endoutput


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Process Flow Diagram (3)


no damage

LD1, ID5locate centrelineOD1, RO1, MI1no surface damageall nonconforming parts

Drill & 20.3Mill 30.1

Grind 40.1

Inspect 50.2

Spillage, rough handlingMaterial hardness, structure and

dimensionsCoolant contamination and

pressureTool setup by presetDirty/ oily parts

DeliverablesProcess FlowSources of Variation

Date:ID Number:Product/ Service:

Page: ofDepartment:

OperationActivity

100%Inspection Storage

Operation withInspection

Trans-portation

Operator full timeOperator part time


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Interrelationship (Characteristic) Matrix (1)• indicates relationship of product and process as

well as product to product• identify all process steps, that may have an

influence on producing the product characteristic


a final product characteristic has a strong influence on an other one-A

characteristic is automatically checked-M

a common tool produces more than one characteristic-T

characteristic is used for positioning-L

charectristic will be used for set-up-C

characteristic is produced or changed-X

Key


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Interrelationship (Characteristic) Matrix (2)


Mtesting/ gauge

Xgrinding

Aclamping

50.240.130.120.3Product Characteristic

Cmilling notch

Xdrilling

Apositioning of part

Acorrect positioning of part

Operation


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RPN

Current Process Controls Action Results

RPN


DateFunction

DDe-tectionOPre-

vention

Respon-sibility

andTargetDate

Recom-mendedAction

Poten-tial

Causes of

Failure

Class

S

Poten-tial

Effects of

Failure

Poten-tial

FailureMode

Re-quire-ment

ProcessStep

Core Team:


Prepared by:Process Responsibility:Item:

Page: of:


Process FMEA

Process FMEA


supporting tools!

Alphanumeric string to identify the

FMEA, used fordocument control

Enter the name and number of the System, Subsystem or

Component for which the process is being analyzed

Enter who is responsible for the process design: OEM, the organisation by department or group or supplier

Enter the initial Process FMEA due date, not to exceed the scheduled

production date

Completion date or revision

dateResponsible

engineer:name & contact

information

Name, organisation and other contact

information of team members


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Risk evaluation• initial focus should be oriented towards failure modes with highest

severity rankings• when severity is 9 or 10, it is imperative that the risk is being

addressed through design controls or recommended actions• for failure modes with severities 8 or below consider causes with

highest occurrence or detection rankings• use of RPN threshold is not a recommended practice

example:


126792C112447B

90529A

RPNDetectionOccurrenceSeverityItem


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VDAAIAGAIAGVDAFailure Rate

199,99%Almost certain


control1 ppmVery low


299,9%Very high0,001 per 1.0001 ppm50 ppm


399,9%High0,01 per 1.00010 ppm100 ppm

Low


499,9%Moderately high

0,1 per 1.000100 ppm500 ppm


599,7%Moderate0,5 per 1.000500 ppm1.000 ppm


699,7%Low2 per 1.0002.000 ppm5.000 ppm

Moderate


799,7%Very low10 per 1.00010.000 ppm10.000 ppm


898%Remote20 per 1.00020.000 ppm50.000 ppm


990%Very remote50 per 1.00050.000 ppm100.000 ppm

High


1090%Almost impossible

≥ 100 per 1.000100.000 ppm500.000 ppmVery high


FactorDetection (D)Occurrence (O)

Severity (S)

Evaluation Criteria for Process FMEA


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cannot passdiscrepant part

select installverify

set-up or first-piece check

100% Go/ No go gauging

charting (SPC)

double visual inspection

visual inspection

indirect or random checks

cannot/ is notchecked

Gauging/ Man. Inspection

Inspection Types

Error-proofed

Likeli-hood of

DetectionIncidentsCpkFailure Rate

1error-

proofeddesign

Almost certain


control≥ 1,67Very low


2

automaticgauging,

stopfeature

Very high0,001 per 1.0001 ppm≥ 1,50


3detection in

station multiple

High0,01 per 1.00010 ppm≥ 1,33

Low


4detection in subsequent

station

Moderately high

0,1 per 1.000100 ppm≥ 1,17


5Moderate0,5 per 1.000500 ppm≥ 1,00


6Low2 per 1.0002.000 ppm≥ 0,83

Moderate


7Very low10 per 1.00010.000 ppm≥ 0,67


8Remote20 per 1.00020.000 ppm≥ 0,51


9Very remote50 per 1.00050.000 ppm≥ 0,33

High


10Almost impossible

≥ 100 per 1.000100.000 ppm< 0,33Very high


FOccurrence (O)

Severity (S)

Evaluation Criteria for Process FMEA


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Special CharacteristicsP FMEA

Classi-fication

Memo Rating Control

critical characteristicCC S: 9 or 10 Control Plan

significantcharacteristic

SC S: 5 - 8;O: 4 - 10

Control Plan

high impact(capable processes)

HI S: 5 - 8;O: 4 - 10

specialcare


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Special CharacteristicsP FMEA

Classi-fication

Memo Rating Control

operator safetyOS S: 9 or 10 approvalby SafetyEngineer

notCC or SCHI or OS

none other n.a.


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Special Characteristics

• Note:• special characteristics are confirmed after

completion of D FMEA and P FMEA

• include special characteristics in Design Review with customer ISO TS 16 949 and Customer Specific Requirements)

• Control Plan and FMEAs must be signed(Ford: CC, for all Control Item Parts (∇))


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P-FMEA is a living document• should be reviewed whenever there is a product or process design

change and• should be updated as required• periodic review of rankings used in the FMEA, specifically

occurrence (O) and detection (D)• this should reflect

• product or process changes• improvements in process controls• feedback from field issues or production issues

Maintaining Process FMEAs


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Control PlanXXXX


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Process FMEA Linkages

PFMEA

- Design FMEA- Process Flow Diagram- Interrelationship (Characteristic) Matrix - Final Drawings

- Pre-Launch Control Plan- Production Control Plan- Set-up Instructions- Work Instructions


supporting tools!


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Alternative Approach (Appendix C)• primary approach may be on severity and occurrence rankings only

(S and O as a non-arithmetic combination!)• depending on the organisation and product or process focusing on

severity and detection may be chosen (S and D)• most common risk evaluation is RPN: S x O x D• each approach will set different risk priorities, example:


37377147773C

B

A

Item

7

7

Severity

7773714777

7377314733

SDSODRPNDetectionOccurrence

Potential Failure Mode & Effects...

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