Method for Capturing Critical Failure Modes in FMEAs in Half the Time

Failure Mode & Effect Analysis (FMEA) in Half the Time

Howard C Cooper, MS, DFSS-BBMay 13th, 2014

INCOSE Michigan – May Dinner Meeting

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Introduction● Failure Mode & Effects Analysis (FMEA) is an

analytical tool and structured method to:– Recognize and evaluate the potential failure of

a product/process and its effects– Identify and prioritize actions which could

eliminate or reduce the chance of a potential failure

– Document the process

Before they are “baked” into a product

Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14

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Common Types of FMEA

● Design FMEA– Identify and mitigate potential design problems

early in the design cycle● Process / Manufacturing FMEA

– Improve quality and reliability, during set-up of initial manufacturing process

● Problem Solving / Six Sigma FMEA– Understand failure modes and effects to identify

and solve quality or reliability issues


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Where FMEA is Used

Customer

Reqmts:Vehicle

Tech Specs

Product Definitio

n:Key

product characteri

stics, Design FMEA

Process Definitio

n:Process

Flow Diagram (PFD)

ProcessFailure Mode

Analysis:Process FMEA

Control Strategy:

Control Plan, Error

proofing

Mfg: Work

Instructions &

Process MonitoringSix Sigma

FMEA

Common FMEA Usage


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Cause(What Failed)

LocalEffect

Next Level UpEffect

On Vehicle MissionSoldier(s) SEV

(physical or chemical

processes, design

defects, quality

defects, part misapplication

, or other).

PreventionDesign Controls

J1739OCC

Field FailureDetection Method

1629a

DVP&RDetection

J1739DET RPN

DFMEA FM

Problem Report #

Load Controller

locked up, or open output driver

1.No provisioning of power for vehicle start up

MRF = 1 - Combat Mission Failure on 100% of combat missions. [System Abort (SA)]

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1. Over Voltage, 2. Voltage Transients

43v Transients Clamps on all power supply inputs. MIL-STD-1275 CompliantRelay drivers and other higher current loads have transient protectoin.5 degree C Thermal Margin on PLCMs

3

PLCM Trip Status Reporting

PLCM Pass/ Fail Reprting

HALT testsEMI CS-101 & MIL-STD-1275Suseptability TestingMIL-STD-810g Environmental Life Test

3 45 SPR-00004339

Load Controller

PLCM Fault indicated

2. No distribution of power to hull and turret systems (SA Example; Generator Controller Dead)


5

1. Over Voltage2. Voltage Transients

43v Transients Clamps on all power supply inputs. MIL-STD-1275 CompliantRelay drivers and other higher current loads have transient protectoin.5 degree C Thermal Margin on PLCMs

3

PLCM Trip Status Reporting

PLCM Pass/ Fail Reprting


3 45 SPR-00004339

Load Controller

PLCM Fault indicated

1.No provisioning of power to vehicle start up


51. Over Voltage2. Voltage Transients

Transients Clamps on all power supply inputs. MIL-STD-1275 CompliantRelay drivers and other higher current loads have transient protectoin.5 degree C Thermal Margin on PLCMs

3

PDCM Trip Status Reporting

PDCM Pass/ Fail Reprting


3 45

SPR-00004200

Control Module

ePDCM Failure 2. No distribution of power to hull and turret systems


5 1. Over Voltage2. Voltage Transients

Transients Clamps on all power supply inputs. MIL-STD-1275 CompliantRelay drivers and other higher current loads have transient protectoin.

2 PDCM BIT Pass/ Fail Reporting

HALT testsEMI CS-101 & MIL-STD-1275Suseptability Testing

3 30

SPR-00004200

Failure Mode

Example Design FMEAPrioritize Failure Modes by Risk

Priority Number

SEV X OCC X DET = (RPN)

Items within the system being

analyzed

FM & Effects of each failure

mode

Severity

Root Cause

Relative Occurrence


Item

6

Item

Potential Failure Mode

Potential Effect(s) of Failure

SevPotential

Cause(s)/Mechanism(s) of Failure

Occur

Current Process Controls Detection

Detec

RPNProcess Function

3 - Front Door L.H.Manual application of chromate conversion coatings on exposed aluminum substrate(to retard corrosion)

Insufficient chromate coating over specified surface.

Deteriorated life of part leading to:- Unsatisfactory appearance due to rust through paint over time.- Impaired function of hardware.

5 Manually inserted spray head not inserted far enough.

3 Visual check each hour - 1/shift for film thickness (depth meter) and coverage.

5 75

Spray head clogged- Viscosity too high- Temperature too low- Pressure too low.


3 30

Spray head deformed due to impact.


2 20

Spray time insufficient. 1 Operator instructions and lot sampling (10 doors/shift) to check for coverage of critical areas.

2 10

Example Process FMEA

Steps within the process being

analyzed


7

Typical FMEA Process

1. Assemble team of people with diverse knowledge of process & product

2. Bound the problem3. Identify functions4. Identify potential failure modes5. Populate FMEA details6. Prioritize failure modes based on RPN7. Mitigate failure modes


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Mission to Improve FMEA Development

● ChallengeCurrent FMEA problems: Opportunity:

Time consuming Rapid (> 2x faster)

High rate of missed critical failure modes

Critical failure modes are given top-priority

Ad hoc identification of failure modes

Process-driven identification of all failure modes

Disjointed, undirected time-consuming discussion

Focused, efficient development effort

Allows prioritization only after FMEA development

Prioritization can happen before FMEA development


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Improved FMEA Process• In 2012, GDLS developed process to prepare

‘efficient’ and ‘effective’ FMEA at greatly reduced time and cost

• Process involves four primary tools:

Block / Process Diagram

p-Diagram Decomposition Table FMEA

Major innovation:

Decomposition Table identifies and prioritizes Failure Modes (FMs) into FMEA. Focuses analysis

on critical failure modesApproved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14

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Engine Seal / Flat

FlangeElbow

90 V-

Band

Exhaust Brake(valve)

V-Band

Flex Pipe

V-Band

Muf f ler V-Band

Exhaust Pipe

Mount

Mount

Exhaust Out

Vehicle Structure

Vehicle Structure

Insulation

Step 1: Bound the System

Identifies and verifies: 1. System functions: lines crossing the dotted boundary2. “Items” within the dotted line system boundary

What


Boundary Diagram / Process Flow

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Step 2: Characterize the Process

Green blocks, identify functions of the system (or process) Yellow blocks ~ Noise Factors, Blue block, Control Factors,

Pink blocks ~ Error States

Why


What (From Boundary Diagram)P-Diagram

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Outstanding Problem & Opportunity● Boundary or Process Flow Diagram

– Identifies “Items” for the FMEA, but not the Failure Modes (FM) of those “items”

● P-Diagram – Identifies system functions or requirements

(even noise factors) but not the function or FMs of the “items”

● Opportunity– Develop a table that will identify and link “items”

to their functions, and to their functional FMs


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Step 3: Map Functions to Failure Modes Function to Hardware Decomposition Table "Design" Functions:(Ideal Functions from P-Diagram / Functions (lines crossing boundary of B-Diagram "Design".)

2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Parti

ally

Res

trict

Exh

aust

Hardware:V-Band Clamps XExaust Pipe X XFlat Flange XSeals XMuffler X X XInsulation X XIsolation Mounts X XExaust Brake X X XFlex Pipe X XElbow X X

1. Transfer Exaust from Engine out of the Vehicle

System FunctionsP-Diagram

Boundary / Process Diagram


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2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Parti

ally

Res

trict

Exh

aust





Need to Identify Item / HW Functions

Secu

re

X

X

X


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2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Parti

ally

Res

trict

Exh

aust





Identify Functions


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2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Parti

ally

Res

trict

Exh

aust





Identify Functions


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2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Parti

ally

Res

trict

Exh

aust





Identify Functions


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Function to Hardware Decomposition Table "Design" Functions:(Ideal Functions from P-Diagram / Functions (lines crossing boundary of B-Diagram "Design".)

2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Parti

ally

Res

trict

Exh

aust



System Functions

Decomposition Table Structures FMEA

From B-Diagram or Pr-Flow Chart

3-4 FMs per Function

“X” indicates a Function (and 4

FMs in the FMEA)


functions translate to

FMs

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3 Purposes of the Decomposition Table

• Ensures all items are captured into the FMEA

• Ensures multiple function items and their potential failure modes are identified into the FMEA

• Provides opportunity to identify and prioritize by criticality of hardware or process functions before populating failure modes into the FMEA


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Function to Hardware Decomposition Table (with Maximum Criticality Scored)

"Design" Functions:(Ideal Functions from P-Diagram / Functions (lines crossing boundary of B-Diagram "Design".)

2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Rest

rict E

xhau

st

Hardware: Severity: 3 5 3 3 3 3V-Band Clamps 5 15Exaust Pipe 2 10 6Flat Flange 2 6Seals 2 10Muffler 4 20 12 12Insulation 1 3 3Isolation Mounts 3 9 9Exaust Brake 2 10 6 6Flex Pipe 2 10 6Elbow 1 5 3


Like

lyho

od o

f Fai

lure

: 1 -

5

System

Decomposition Table Prioritizes Functions

Criticality # rather than “X”


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Preparation Flow into Decomp Table

Engine Seal / Flat

FlangeElbow

90 V-

Band

Exhaust Brake(valve)

V-Band

Flex Pipe

V-Band

Muf f ler V-Band

Exhaust Pipe

Mount

Mount

Exhaust Out

Vehicle Structure

Vehicle Structure

Insulation

1. P-Diagram Ideal Functions – to Design Functions in F-H Decomp.

2. B-Diagram or Process Flow inner blocks go to Decomp. Table

3. Identify all ‘Item’ Functions needed to accomplish each System Function4. Mark with an “X” or with a “Criticality #”




2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Rest

rict E

xhau

st



Like

lyho

od o

f Fai

lure

: 1 -

5

System

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Step 4: Use Decomp Table to Fill FMEA

FMEA filled in from F-H Decomp Table

Function(measurable output, design requirement)

Item Potential Failure Mode LocalEffect

Next Level UpEffect

1. Transfer Exaust from Engine out of the

Vehicle V-Band Clamps Loss of Securing

Exhaust leak Loss of 1. Transfering Exhaust from Engine to out-side the Vehicle

Partial SecuringIntermittent Securing

1

1

2

2

3

3

4

4

1



2. Attenuate NVH

3. Limited thermal

transfer to vehicle

5. Exhaust Brake

Engine Slowing

Hardware Functions:

Secu

re

Cont

ain

Exha

ust

Prov

ide

Flow

Atte

nuat

e NV

H

Cont

ain

Heat

Rest

rict E

xhau

st



Like

lyho

od o

f Fai

lure

: 1 -

5

System


1

3

2

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Pareto Chart (80/20 Rule)

Benefits of Improved FMEA Development

Four Step FMEA Process:● Organizes and speeds FMEA failure

mode identification● Ensures all hardware-functions and

FMs are identified● Prioritizes critical hardware-functions

for FMEA analysis ● Provides power of 80/20 Rule on FMs

for best Reliability Growth● Focuses attention and time on

mitigation of “significant few” (the most critical failure modes (FMs)

F-H Decomp Table now being used on multiple GDLS Contracts: for DFR, to facilitate earlier diagnostics planning, to meet Weight and Testability RequirementsAddressing most critical FMs yields greatest reliability growth.


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Cost Savings Attributed to New ProcessBefore vs, After Facilitator Cost

Savings on Facilitator

Cost

Facilitator Savings X 3

for FMEA Team, X 3

Programs in 2013 = Total

Savings


Savings Calculation (savings to GDLS) Previous Programs doing DFMEA without 'F-H Decomp'

Start SFR End PDR Weeks Rel-Heads Hrs/Week Total Hrs. $Rate/Hr. Total $FCS 01-Mar-06 15-Dec-09 185 3 35 19,425 $77 $1,495,725Stryker-SMOD 01-Jan-10 15-Dec-10 50 4 35 7,000 $77 $539,000

Average: 117.5 3.5 Average: $1,017,363

2013 Programs using 'F-H Docomp Tool/Method' for DFMEAStart SFR End PDR Weeks Rel-Heads Hrs/Week Total Hrs. $Rate/Hr. Total $

Stryker+Tr 16-Oct-12 15-Mar-13 20 1 35 700 $77 $53,900Stryker-ECP 01-Oct-12 27-Sep-13 50 0.65 35 1,138 $77 $87,588Abrams ECP1 04-Feb-13 14-Aug-13 27.3 1 35 956 $77 $73,574

Average: 32.43 0.88 931 $77 $71,687

Savings$1,424,038 Savings over FCS - DFMEA Facilitator

$467,313 Savings over SMOD - DFMEA Facilitator$945,676 Savings over FCS & SMOD Average, for DFMEA Facilitator

X3 Facilitator labor Savings over SMOD baseline, for DFMEA Team (3-8)$1,401,939 Average 2013 FH-Decomp Program Savings over SMOD baseline - DFMEA Cost

X3 Three 2013 Programs: Stryker+Tr, Stryker-ECP and Abrams ECP1$4,205,817 Total 2013 Savings from using FH-Decomp to prepare DFMEA

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Questions?

Presenters: Howard C Cooper, MS, DFSS-BB

DFR Reliability [email protected]

Mark Petrotta, MS, DFSS-MBB Engineering Process Excellence

[email protected]

Method for Capturing Critical Failure Modes in FMEAs in Half the Time

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