javier garcia - verdugo sanchez - six sigma training - w1 failure mode and effect analysis (fmea)

FMEAFMEA

Week 1

Knorr-Bremse Group

About the FMEA

The FMEA is a structured method for:• Recognizing and rating of potential failures of a

product or processp p• Allocation and rating of various factors which

causes these failures• Rating of the possibility how bad or good a failure

or cause can be detected

• Furthermore the FMEA gives you the possibility to define and prioritize actions in order to reduce the occurrence of failures (causes) or improve the detection of fail res (ca ses) in others ords adetection of failures (causes), in others words a risk reduction of potential failures

Knorr-Bremse Group 09 BB W1 FMEA 06, D. Szemkus/H. Winkler Page 2/36

The Content of this Module

• Definition and historical backgroundg

• Areas for application

• Connection with other tools

• Preparation of a process FMEA• Preparation of a process FMEA

• Definition of improvements

• Application examples

P ti l i• Practical exercise

• Design FMEAg

• Summary


Definition FMEA

• FMEA stands for Failure-Mode and Effect-AnalysisAnalysis

• The FMEA is a formalized, analytical method for a systematic registration and avoidance of potential failures. It can be used for the development of new

d t d f l iproducts and for process planning

• The potential failure, the consequences for the p , qcustomer, the potential failure causes and the possible failure detection will be shown and quantitative rated.q

• Based on the rating, actions will be defined in order to avoid the potential failuresavoid the potential failures.

• Of course, this tool can be used for the investigation of


existing processes as well.

History

Developed in the 1960’s in the Aerospace industry during the Apollo missionsthe Apollo missions

In 1974 the US Navy developed MIL-STD-1629 with the use of FMEAuse of FMEA

In the late 1970’s, automotive applications driven by li bilit t b t i t th FMEA i t thliability costs, began to incorporate the FMEA into the management of their processes

Many companies involved in the management of hazardous materials and potentially dangerous

h d th i i l d l iprocesses, have used the same principals underlying FMEA in issues of risk management

The automotive industry requires the FMEA for all processes of suppliers since years


FMEA within the DMAIC Cycle

ControlMaintain

DefineMaintain

ImprovementsSPC

Control Plans

Project charter (SMART)

Business Score CardQFD VOC

D Documentation QFD + VOC

Strategic GoalsProject strategy

C M

MeasureB li A l iImprove

AIBaseline Analysis

Process MapC + E Matrix

M t S tAnalyze

ImproveAdjustment to the

Optimum

FMEA Measurement SystemProcess Capability

Definition of critical Inputs

FMEA

FMEAStatistical Tests

Simulation FMEAStatistical Tests

Multi-Vari StudiesRegression

Tolerancing


g

Purpose of the FMEA

The early rocognition of failure risks and the reduction y gof occurrence to a minimum.

The avoidance of the possibility of liability claimsThe avoidance of the possibility of liability claims.

The reduction of costs

• for a change caused due to the failures

• for additional work (non value added) due to rejects / scrap• for additional work (non value added) due to rejects / scrap or rework

• For warranty claims in external areas• For warranty claims in external areas

The FMEA is an efficient tool for preventive quality assurance


quality assurance

The FMEA Form Sheet

Process Potential Failure Mode Potential Failure Effects

SE Potential Causes

OC Current Controls

DE

RP

Step/FunctionPotential Failure Mode Potential Failure Effects E

VPotential Causes C

CCurrent Controls E

TPN

What is the process step/ function under

In what way could the process step/function potentially fail to meet

What is the impact on the Key Output Variables (Customer Requirements) or e

is t

he

t to

the

to

mer

? What are the causes of this Failure Mode? Typical failure cause result from process c

ause

oc

cur? What are the existing controls

and procedures (inspection and test) that prevent the cause or the an

you

or

FM

?

function under investigation?

potentially fail to meet process requirements or intent?

(Customer Requirements) or internal requirements?

How

Sev

ere

effe

ccu

s t cause result from process inputs.

How

oft

en d

oes

or F

M test) that prevent the cause or the

Failure Mode? Should include an SOP number.

How

wel

l cde

tect

cau

se o

H

RPN

Actions Recommended

Resp. Actions TakenSEV

OCC

DET

RPN

What are the actions for reducing the

occurrance of the Cause, or improving d t ti ? Sh ld

Whose Responsible

for the recommende

d ti ?

What are the completed actions taken with the recalculated RPN? Be

sure to include l tidetection? Should

have actions only on high RPN's or easy

fixes.

d action? completion month/year


Comparison of Theory and Praxis

The FMEA is a very helpful tool. However, the FMEA itself failed in several applications already. Why?

• The FMEA as a single “island” solution

In these cases, teams used the FMEA to investigate a product or service for potential risks. Very complex paper work is often the result, they are very difficult to maintain and to understand for people outside the actual teams.

• The external FMEA

These FMEA often stops with the rating of what the customer sees (e.g. after all control and inspection steps). The real risks will be not discovered. This gives a picture of fewer risks than there actually may befewer risks than there actually may be.


The Connection with other Tools

• Prüfergebnis• Regelkreisinfo an

SMD/Siebdruckggf. Linienstop

•Regelkarte•Lotpastenhöhe •Rüstkontrolldaten •Lötqualität

• Prüfergebnis• Regelkreisinfo an

SMD/Siebdruckggf. Linienstop

•Regelkarte•Lotpastenhöhe •Rüstkontrolldaten •Lötqualität•Regelkarte•Lotpastenhöhe •Rüstkontrolldaten •Lötqualität

Rating of Importance to Customer

9 9 7 10 10 9 3 2 6

C & E MatrixProcess Map

Lotpasten-druck

SMT-Bestückung

Reflow-Löten

SPC-Prüfung

M LeiterplatteS LP-MarkenM LotpasteA ArbeitsanweisungS SchabloneS Temperatur

M BauteileK BestückprogrammK BE NachversorgungA ArbeitsanweisungS DruckluftS Wartungszustand

K Lötprofil ProgrammS HilfsstoffeS WartungszustandS Ofenverschmutzung

S Regelkreis-information

A KontrollfolieA Prüfanweisung

G /

Lotpasten-druck

SMT-Bestückung

Reflow-Löten

SPC-Prüfung






G /

Lotpasten-druck

SMT-Bestückung

Reflow-Löten

SPC-Prüfung






G /

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Process Inputs Ge

l Tim

e

Vis

cosi

ty

Cle

an

line

ss

Co

lor

Ho

mo

ge

ne

ity

Co

nsi

ste

ncy

Dig

ets

Tim

e

Te

mp

era

ture

So

lids

Total

1Scales Accuracy

9 8 2 1 1 9 1 1 8 321

2Preheating DICY TK

1 1 1 1 1 1 1 1 1 65

THT-Bestückung

End-Prüfung

Schwall-Löten

M BauteileA Roy.- ProgrammA BestückanweisungS Training

A LötparameterM HilfsstoffeM LötmaskeS Wartungszustand

A PrüfprogrammS AdapterS Netzwerk

•Bestückqualität •Lotwellenparameter •Go / no go•Fehleranzahl•Fehlerzettel•DiagnoseTHT-

BestückungEnd-

PrüfungSchwall-

Löten




•Bestückqualität •Lotwellenparameter •Go / no go•Fehleranzahl•Fehlerzettel•DiagnoseTHT-

BestückungEnd-

PrüfungSchwall-

Löten




•Bestückqualität •Lotwellenparameter •Go / no go•Fehleranzahl•Fehlerzettel•Diagnose

3DMF Load Accuracy

3 8 1 1 1 8 1 3 8 255

4DMF Cleanliness

1 1 4 2 1 2 1 1 1 105

5DMF Raw Materials

1 1 1 1 1 2 1 1 1 74

6DICY Load Accuracy

9 7 1 1 1 9 1 1 2 269

7DICY Envir. Factors

8 5 3 1 1 8 1 1 2 247

8DICY Raw Materials

8 5 1 1 1 9 1 1 2 242

FMEA9DICY Mixer Speecd

1 1 1 1 7 1 1 1 1 125 FMEA

Process/Product Failure Modes and Effects Analysis

(FMEA)

Capability of Process and Measurement System

Process or Product Name:

Prepared by:

Responsible: FMEA Date (Orig) ______________ (Rev) ___

Process Step/Part Number Potential Failure Mode Potential Failure Effects

SEV Potential Causes

OCC Current Controls

DET

RPN

Spin Draw Process

Fiber Breakouts Undersized package, High SD panel-hours lost 2

Dirty Spinneret8

Visual Detection of Wraps and broken Filaments 9 144

Filament motion Visual Sight-glass

USLLSL

y

5Filament motion

2Visual Sight glass

8 80

8Polymer defects

2Fuzzball Light

9 144

0

33323130292827

ProzeßschrittErgebnis ( Output)

Spezifikation Faktor ( Input)

Control strategy

33323130292827 SpezifikationOSG

ZielUSG

FahigkeitCp

CpkMuster

AnzahlHäüfigkeit

Messmittel

Faktor ( Input)

SpezifikationOSG

ZielUSG

FahigkeitCp

CpkMuster

AnzahlHäüfigkeit

MaßnahmenWas

VerantwrtlichAbgeschlossen

Wirksamkeit


% R & R% P/T

HäüfigkeitMessmittel

% R & R% P/T Datum

Bewertet durch

FMEA Types

• System – used for analyzing systems or subsystems in early concept or design stages. Concentration on possible y p g g pfailure modes along with the function of the system caused by the design.

• Design – used to analyze a product design before production releaseproduction release.

Process used to analyze manufacturing and assemblyProcess – used to analyze manufacturing and assembly processes.

• In a modified form the FMEA will be applied for risk analysis in the area of health and safety and for important projects.


Process FMEA

In the product development process the design FMEA will be applied before the process FMEA.

We will turn the order and discuss the process FMEA first.

Then we will discuss the design FMEA.


Process FMEA

• Important tool for process engineering or teams looking at preventive process improvements (beforelooking at preventive process improvements (before a failure occurs).

• Will be used for the determination of priorities of• Will be used for the determination of priorities of process improvement efforts, to ensure that it is beneficial for the customer and raise attention.

• Will be used to document the finalization of projects and the resulting improvements of the risk gcalculation.

• It should be a live document, which requires a frequent review and updates.

• It is a key tool in the DMAIC cycle.


Process FMEA

Further applications

• Supports the analysis of new manufacturing processes

• Guides the development of a new manufacturing process by helping process design engineers in the

l d t di f th k f th tearly understanding of the weaknesses of the current process.

• Will help at the evaluation of risks due to process• Will help at the evaluation of risks due to process changes.

• Identification of gaps in the process control plan so• Identification of gaps in the process control plan, so that action for improvement can be taken.

• Identification of potential variables which can be• Identification of potential variables, which can be considered for further investigations with Mulitvari and DOE studies.


Process FMEA

• Initiation:

– Early in the process improvement investigation after aEarly in the process improvement investigation after a process map is available

– When a new process are being designedp g g

– When existing processes are being changed

– After process function are defined but before specificAfter process function are defined, but before specific hardware is selected or released to manufacturing

• Update/review:Update/review:

– Whenever a change is being considered to manufacturing / assembly processesassembly processes

– After review of action items completion

Recalculation of RPNs– Recalculation of RPNs

– To develop actions and assign responsibilities to the new highest ranking RPNs


highest ranking RPNs

Basic Definition of Defects

A product is defective if:− they differ from the determined condition due to the production

− they don’t fulfill the safety regulation due to design deficiencies, although they may be defect free.although they may be defect free.

− they don’t reach the specified performance level

− they are dangerous because warning notes and procedures are missing

Design defects:have an effect for the complete production line− have an effect for the complete production line

Manufacturing defects:raw materials have deficiencies− raw materials have deficiencies

− failures during the production itself

Service defects− service does not fulfill the criteria which have been defined by the

design and the customer


Failure Mode, Effect and Detection

Failure mode 1 Eff t 11

Failure mode 2

Effect 1

Failure mode Effect 11

Effect 2

F il dFailure mode 1

Failure mode 2

Effect 1Detection 1

Detection 22

Its getting very complex easily


Its getting very complex, easily…

Sources of the Complexity of a Product

Safety SOP`s− A high priority factor

Effect on the production stop and yield− What affects the production stop and the yield?

− Preventive maintenance - repairs while the process is still going on or when it is stoppedor when it is stopped

− Process control

− Actions to correct the programp g

Repair plan− repair time, ease of maintenance, repair costs and toolsp , , p

Access− Access difficulties to the repairing partp g p


The Risk Priority Number (RPN)

The result of a FMEA is the product of three quantitative ratings, in relation to failure effect, cause frequency and detection capability

Effect Cause Control RPNEffect

1.........10

Cause

1........10

Control

1........10

RPN

1.....1000

Capability to detect the failure

How often the cause occurs

How bad will it be for the customer

RPN= Importance x Occurrence x Detection


RPN= Importance x Occurrence x Detection

Definition of RPN Terms

• Severity (of Effect) - importance of possible effect on customer requirements - could also concern safety and q yother risks if a failure occurs (1=Not Severe, 10=Very Severe)

• Occurrence (of Cause) - frequency with which a given cause occurs and creates Failure Mode Cancause occurs and creates Failure Mode. Can sometimes refer to the frequency of a Failure Mode (1=Not Likely, 10=Very Likely)(1 Not Likely, 10 Very Likely)

• Detection (capability of Current Controls) - ability of current control scheme to detect: the causes beforecurrent control scheme to detect: the causes before creating failure mode and or the failure modes before causing effect (1=Likely to Detect 10=Not Likely to

D t il f th ti di f th d l

causing effect (1=Likely to Detect, 10=Not Likely to Detect)


Details for the rating see appendix of the module

Failure Mode, Effect and Detection

Example: Spraying of a wax layer

Process Step/Input

Potential Failure Mode Potential Failure EffectsSEV

Potential CausesOCC

Current ControlsDET

RPN

What is the In what ways does the Key What is the impact on the Key he

er? What causes the Key Input to se

ur

? What are the existing controls and ou

M?

process step/ Input under

investigation?

Input go wrong? Output Variables (Customer Requirements) or internal requirements?

How

Sev

ere

is th

to th

e cu

sotm

e go wrong?

ofte

n do

es c

aus

or F

M o

ccu

procedures (inspection and test) that prevent eith the cause or the Failure Mode? Should include an SOP number.

How

wel

l can

yo

ect c

ause

or

FM

Hef

fect

How

det

Apply wax layer Not enough wax low corrosion protection 7 Viscosity to high 5 5 175

Check spray pattern 1 /Apply wax layer Not enough wax low corrosion protection 7 Temperature to low 5 5 175

Apply wax layer Not enough wax low corrosion protection 7 Spray pressure to low 5 5 175

Check spray pattern 1 / layer, periodical spray

head cleaning

If a prepared process map and/or C&E matrix is available, you can start with the inputs (causes) which are responsible for thecan start with the inputs (causes) which are responsible for the failure modes. The start at the failure modes without pre-work is

more difficult and results in more complex FMEA.


p

Step by Step Create a FMEA

2. Define process flow

3. Define Inputs Outputs

4. Create C & E Matrix

1. Build Team for project p p

5. Identify the way for each input how it can change – these are the causes Note: one input may have several causes

p j

causes. Note: one input may have several causes.

6. Identify effects for each cause. This should come directly from the y yC & E matrix. Note: one cause may have several effects.

7 D fi th f il d f h bi ti f / ff t Th7. Define the failure mode for each combination of cause / effect. The failure mode, driven by the cause, will have an effect for the customer.

8. List the current controls for detection of failure mode or cause.

9. Rating of effect, occurrence and detection. Calculation of the risk priority number (RPN).


Step by Step Create a FMEA

10. Rank the all combinations creating the RPN

11. Define possible actions for combinations of RPN values >100

12. Calculate potential effects on the RPN for the defined actions

13. Start the actions with impact and / or quick to realize

14. Documentation of all conducted actions

15. Post rating of the RPN after the actions

A decision matrix is helpful to establish an action plan. The matrix includes the factors: effect on RPN, cost, time and resources.


, ,

Exercise

• For this assignment you need the results from the exercise process map and C&E matrix.

• Form the same teams.

• Create a FMEA for 3-5 cause – effect relations.

• What could be the actions to reduce the occurrence or to improve the possibility for p p ydetection. Recalculate the RPNs!

• Use the flipchart with “Post its” or the form sheetUse the flipchart with Post its or the form sheet FMEA.xls.

Present your results in 45 minutes


Design FMEA

• System – used for analyzing systems or subsystems in early concept or design y y p gphases. Concentration on possible failure modes, caused due to the design, in linkage with the function of the systemlinkage with the function of the system.

Design – used to analyze a productDesign – used to analyze a product design before production release

• Process – used to analyze manufacturing and production processes.

• In a modified form the FMEA will be• In a modified form the FMEA will be applied for the risk analysis in the area work safety and for important projects.


Purpose of the Design FMEA

Recognize functional failure modes of the product very early in the design phase.

Recognize potential safety and environment problems to eliminate doubts.p

Set priorities for design improvement.

Help with the development of a detailed test toHelp with the development of a detailed test to check the design.

Help with the identification of potential criticalHelp with the identification of potential critical inputs and outputs.


Philosophical Approach

Mainly concentrate on safety aspects and potential regress or complaint topicsregress or complaint topics

2 different points of view:

Suppose the material is perfect but the processSuppose the material is perfect, but the process is poor.

S th i f t b t th t i lSuppose the process is perfect, but the material is poor.


Inputs/Outputs of a Design FMEA

Inputs− customer requirements, safety regulations and legal

instructions

− Already known failure modes of the system

− list of the product functions

Outputs− Recommended design activities on product level

− Design controls or tests to rate design failure modes

− Potential failure modes converted into effects and transmitted to the process FMEAtransmitted to the process FMEA

− Potential causes converted into failure modes and transmitted to the process FMEAtransmitted to the process FMEA

− Potential critical variables


Design FMEA Form Sheet

Functional Potential Failure

SPotential Causes/

O Current Design D RProduct

RequirementPotential Failure Mode

Potential Failure Effects

EV

Potential Causes/ Mechanisms

CC

Evaluation or Control

ET

PN

fect

to

d th

at

ur?

dete

ct

mod

e?

mb

er

ET

)

What is the functional product requirement under

consideration?

In what ways could the functional product

requirement fail to be fully met?

What would be the impact of failure mode

on the customer (internal or external)?

ever

e is

the

eff

he c

usto

mer

?

What could cause the failure mode to occur?

s th

e lik

elih

ood

caus

e w

ill o

cc What methods, tools, or measures will

discover the cause before design

release? iffic

ult

is it

to d

use

of fa

ilure

m

Pri

ori

ty N

um

V X

OC

C X

DE

How

se th

Wha

t is

the

c

How

dth

e ca

u

Ris

k (S

EV


Design FMEA and Process FMEA

Design FMEA

F il d Eff t CFailure mode Effect Cause

One important t t i bl f

Effect on the customer -ti fi d RTY COPQ

One important i t i bloutput variable of

the product is not correct

unsatisfied, RTY, COPQ or C-P are being influenced

input variable is not correct.

Process FMEA

correct influenced

Process FMEA

Failure mode Effect CauseOne important input variable is not correct (further

One important output variable of the product is not correct (further

Cause of the KPIV problems

correct (further details will be added)

not correct (further details will be added)


)

Example: Oxidation Process

Design FMEA

F il d Eff t CFailure mode Effect Cause

Viscosity is on the t id f

Affects yield and it I t t

Flow rate is too hi h t loutside of

specificationcapacity. Important output of QFD

high or too low

Process FMEAProcess FMEA

Failure mode Effect CauseFlow rate is too high

Viscosity crosses the upper limit

Flow rate meter is not calibratedcalibrated


Summary

• Definition and historical backgroundg

• Areas for application

• Connection with other tools

• Preparation of a process FMEA• Preparation of a process FMEA

• Definition of improvements

• Application examples

P ti l i• Practical exercise

• Design FMEAg


Appendix for the Appendix for the

FMEAFMEA


Rating: Severity of the EffectConsequences

Effects Criteria: Meaning of the consequences

Rating number

Dangerous withoutCan endanger the operator or the equipment. Very high classification of the meaning, if possible

Dangerous withoutwarning

10failure consequences or failure to comply with regulations affects the safety during use/operation.Failure occurs without warning

9Dangerous with

warning

Can endanger the operator or the equipment. Very high classification of the meaning, if possible failure consequences or failure to comply with regulations affects the safety during use/operation

Very high

M i l di ti f th d ti P d t h t b t d t d tl d Th

Serious interruption of the production. 100% of the products have to be scrapped. Products or servicesare not functional. The customer is very unsatisfied and complaints usually

8

warning q p y g y g pFailure occurs with warning

HighMarginal disruption of the production. Products may have to be sorted out and partly scrapped. Theproduct or service is restricted functional. Customer unsatisfied 7

6MediumMarginal disruption of the production. Products may have to be sorted out and partly scrapped. Theproduct or service is restricted functional. Customer feels discomfort.

Low 5

Very low 4

Marginal disruption of the production. Products may have to be sorted and reworked. The product orservice is restricted functional. Customer feels discomfort.

Marginal disruption of the production. Products may have to be reworked. The product or service Very low 4

Minor 3

has defects which will be recognized by the customer in the most cases

Marginal disruption of the production. Products may have to be reworked during running production.The product or service has defects which will be recognized by the average customer.

Very Minor 2

None No

consequences

1

Marginal disruption of the production. Products may have to be reworked during running production.The product or service has defects which will be recognized by single customer.


q

Rating of the Occurrence

Failure probability Failure portionRating number

33% 9Very high, failure is almost inevitable

number

50% 10

5% 7

High, general similar to processes with high failureprobability

13% 8

Medium, general similar to processes with occasional failures but never in a higher degree 0,25% 2500ppm 5

1,30% 6

Low, sporadic failures at similar processes 50ppm 3

g g

0,05% 500ppm 4

5ppm 2

Minimal: in fact free of failure 0,5ppm 1

Very low, sporadic failures at constant processes


Rating of the Detection

DetectionCriteria: Probability that the existence of a failure before processing of delivery

can be detected due to appropriate measures

Absoluteimprobable

No controls for failure detection available. 10

Rating number

improbable

Very unlikely, that current controls will detect the possible failure. 9

Unlikely, that current controls will detect the possible failure. 8

Veryimprobable

Improbable

Very low Very low probability that the current controls will detect the possible failure. 7

Low 6

Moderate 5

Low probability that the current controls will detect the possible failure.

Moderate probability that the current controls will detect the possible failureModerate 5

4

3

Moderate probability that the current controls will detect the possible failure.

Moderate high Moderate high probability that the current controls will detect the possible failure.

High probability that the current controls will detect the possible failure.High

In every case 1

Very high 2Very high probability that the current controls will detect the possible failure.

Current controls will detect the possible failure in every case.


javier garcia - verdugo sanchez - six sigma training - w1 failure mode and effect analysis (fmea)

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