6 risk prevention_fmeca_(mo hinh phong tranh rui ro)-

6. Quality Risk Prevention6. Quality Risk Prevention

FMECA Method

Process Control - 2013 - M.Brotto

Preliminary

Risk identification by inductive method (probability approach)

Cause Failure(s) Effect

Questions to ask : What can go wrong? What could be the consequences?

What is the likelihood (probability) it would go wrong?

Method :FMECA

22

Root cause of

failure or hazards

Final unwanted

effect :damageCombination and

sequence of events

Risk identification by deductive method (determinist approach)

Method : Fault Tree Analysis (FTA)

Questions to ask : What has gone wrong? What have been the consequences?

What is the likelihood it would go wrong once again?

FMECA

Failure Mode, Effects and Criticality Analysis

33

FMECA is a rigorous team working method applied to identify and remove failures,

defects or mistakes, revealed or not, of a system (process, product/service,

machine) before their occurrence (prevention). It’s based upon a risk evaluation.

The approach is :

• inductive : from potential failure identification to its effects

•

F.M.E.C.A. MethodFailure Mode, Effects and Criticality Analysis

1 - Description

44

•

• qualitative : no calculation, no specific knowledge

• exhaustive : performed on the whole components of the system

Questions to ask :

Mode of

potential failurePossible effects

Possible

causes

Detection

capacityRemediation

What could go

wrong?

What could be

the effects ?

What could be

the causes ?

What is the

control action plan?

What are the

measures to

take ?

2 – When to use

FMECA can be used for different purpose : both for product, machine or process,

in design or improvement phase, and always compared to the forecasted usage.

FMECA may be quality, environment, safety or security oriented, but the objectives

(risk prevention) and the method are the same.

F.M.E.C.A. MethodFailure Mode, Effects and Criticality Analysis

55

PROCESSPROCESSMACHINEMACHINEPRODUCTPRODUCT

Effective and eco-friendlySafe and reliableCompliant with customer specifications

Teamwork (5 to 10 people) led by a skilled person who will train the group

to the methodology and manage the progress of the FMECA study :

1. Realize a functional analysis

3 – Implementation

F.M.E.A. MethodFailure Mode, Effects and Criticality Analysis

66

1. Realize a functional analysis

2. Inventory all the potential defects or failures

3. Identify the effects and causes of these failures

4. Work out the criticality and rank the failures

5. Propose an action plan for removing them

6. After action plan implementation, re-work out the criticality

F.M.E.C.A. Method : Step 1

Step 1 : Functional Analysis : system components breaking down

Define first the limits of the system by asking what level of detail are you

interested in.

Break down the system (machine, product/service, process) into its

components (pieces or operations) with their related functions in order to

know why & how the system runs. A failure is always related to the function.

Answer the following questions :

77

System

component

« What’s that

for? »

«How does it run?»

« For which

recipient/task? »


Step 2 : Assessment of potential modes of failure

Failure mode = way in which the system may stop or run abnormally (go wrong)

Evaluate potential failures for the function of each element of the system.

Function failure mode

No function Function downgraded Function inopportune

88

Questions to ask :

• How could this component/piece fail to perform the assigned function

(FMECA Product or Machine)

• How could this operation/task compromise the mission/function

(FMECA Process)

Caution : The goal being to improve the reliability of the system, we must

question the components/operations, not the functions.!

Step 3 : Determination of their effects (consequences) and causes

• Effects of each failure on the function (but also on the whole system) and

consequences for the user, the customer…

• Cause of each failure : question to ask « what are the conditions likely to

generate the failure? » (use Ishikawa diagram with its 5 or 7 M).

• Besides, determination of the existing means to detect the failure :


99

• Besides, determination of the existing means to detect the failure :

alarm, gauge, preventive controls (ex. : Statistical Process Control (SPC),…)

Step 4 : Evaluation of potential failures and criticity calculation

For each failure, we provide :

• a mark “S” of Severity for the impact of the failure (effect).

• a mark “O” for the likelihood of Occurrence for the cause of failure

• a mark “D” for the likelihood of failure of non-Detection

These marks are defined in advance from specific grid of quotation built by the

group. They allow to clearly situate by a figure the importance of the criteria


1010

group. They allow to clearly situate by a figure the importance of the criteria

S, O, D

Criticity index “C” (or RPN) is obtained by the following formula :

C = S x O x D

Risk Priority Number = Severity X Occurrence X Detection

This index allows to rank the modes of failure : more the index is high, more the

failure is worrying or damaging.

Step 5 : Preventive and corrective actions

The highlighting of risks of critical failures allows to implement actions plan.

The value of the SOD allows to give direction for actions which may concern :

• means : ex. components, equipments, detection device…

• skills : ex. training to use correctly a machine, safety training…


1111

• skills : ex. training to use correctly a machine, safety training…

• methods : ex. instructions for preventive maintenance plan…

Action plan follow-up is essential. A new index C is worked out after every

change. The failure is corrected until the system be considered as acceptable.

FMECA analysis formalization

Failure Mode and Effects Analysis(Process FMECA)

Activity:

Area :

Sector :

Team :FMECA leader :

Target date :

FMECA number:

Page 1 of

Prepared by

FMECA date (orig.) (rev.)

Process

Function

Operation

Component

Potential

failure

mode

Potential

Effect of

failure

Potential

cause of

failure

Current

detection

Recomm

a-nded

actions

Response.

& target

completion

date

Actions results

Actions

takenS O D C S O D C

What is the function?

What couldbe the

severity?

What could be the

Index of detection Who,

Heading

System

Component

Function

1212

function?What is the

component?

What could be thefailure?

-no function-partial

function intermittent

-... What could be

the effects?-quality,

-Reliability-safety

problems-...

severity?

What could be the

causes?- technical- human

- management-...

be the occurrence?

Would it be detected?

How?

detection

INDEX OFRISK

ActionsTo be

implemented

Who,

what and

when?

Actions performedAnd

results

Functional analysisExample : process component change…

Failure Mode and Effects Analysis

(Process FMECA)Activity: Assemblage modules

MFG area:La Ciotat

Sector:

Team: Claude, Paul, Michelle,

Annie, Jean Pierre,Christine FMECA leader: Christine

Target date:Q2

FMECA number: XYZ 1/2001

Page 1 of 1

Prepared by: Christine

FMECA date (orig.) 10 fev 2001 (rev.)

Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

System

Component

Function

1313

Simple identification of component, task, operation or function to analyse

New resin

coating

for the

module

Failure modes (how the system can fail?)

New



MFG area:La Ciotat

Sector:



Target date:Q2


Page 1 of 1



Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

Coating not done

System

Component

Function

1414

New

resin

coating

for

module

Potential risksidentification ofdysfunction,non quality, non conformity…

not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

Effects of the failure

Coating



MFG area:La Ciotat

Sector:



Target date:Q2


Page 1 of 1



Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

Embedding

System

Component

Function

1515

Coating not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

New

resin

coating

for

module

What could be the consequences for the final customer or for the subsequent internal steps ?

Embeddingimpossible

Breakdown in use

Bad mechanickeeping

Filmunusable

Causes of the Failure

Coating Embedding



MFG area:La Ciotat

Sector:


Annie, Jean Pierre,ChristineFMECA leader: Christine

Target date:Q2


Page 1 of 1



Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

Pour head

System

Component

Function

1616

Coating not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

Embeddingimpossible

Breakdown in use

Bad mechanic keeping

Filmunusable

New

resin

coating

for

module

What are the causes at the origin of the failures?

Pour head blocked off

Air bubbles in the pour

head

Incorrect resinflow

adjustment

VariationsinT°and

hygrometry

Failure detection (possible detection in the current process)

Coating Embedding Pour head



MFG area:La Ciotat

Sector:



Target date:Q2


Page 1 of 1



Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

Visual

System

Component

Function

1717

Coating not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

Embeddingimpossible

Breakdown in use


Filmunusable


Air bubble in the pour

head

Incorrectresin flow

adjustment

VariationsIn T°&

hygrometry

New

resin

coating

for

module

What are the existing controls? Do they allow to detect the failures?or to anticipate them?

Visualinspection

None

None

Visual meters

FMECA analysis in short…

Component, operation, task / function,…

Failure Modes

Consequences (effects)

1818

Consequences (effects)

Causes

Detection

Prevention

Index of risk or Criticity

SEVERITY

X OCCURRENCE

X Non DETECTION

1919

= SODINDEX OF RISKor CRITICITY

•• Occurrence = frequency or probability of event emergence

• Severity = magnitude of the damage that depends both on the event

intensity and target vulnerability

Severity Index

5

New

Coating not done

Embeddingimpossible


Visualinspection



MFG area:La Ciotat

Sector:



Target date:Q2


Page 1 of 1



Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

S

System

Component

Function

O D

2020

5

4

4

New

resin

coating

for

module

not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

impossible

Breakdown in use


Filmunusable

blocked off


head

Incorrectresin flow

adjustment

VariationsIn T°&

hygrometry

inspection

None

None

Visual meters

Criteria cotation for Severity of Failure(qualitative & quantitative index examples for manufacturing process)

NoNo

perceivedperceived

effecteffect

1 = 1 point 2 = 3 pt 3 = 5 pt 4 = 8 pt 5 = 12 pt

Minor : Minor :

visual visual

defect defect

Major : Major :

disconfort disconfort

in use in use

Critical : Critical :

loss of loss of

performance performance

Total loss Total loss

of function of function

or unsafe or unsafe

CCUUSSTTOOMMEE

Product NC

(type,defect,

quantity…)

No No

perceivedperceivedPartial Partial

deliverydeliveryDelayDelay

<= 1 day <= 1 day

DelayDelay

< 7days < 7days

DelayDelay

> 7 days > 7 days

Impact on

time delivery

FAILURE

RANK

2121

EERR

IINNTTEERRNNAALL

perceivedperceived

effecteffectdeliverydelivery <= 1 day <= 1 day < 7days < 7days > 7 days > 7 days time delivery

Breaking

downStoppingStopping

< 3mn < 3mn < 1 hour < 1 hour < 8 hours < 8 hours < 3 days < 3 days > 3 days > 3 days

Workers

safety

Inoffensive Inoffensive

accident accident

Begnin body Begnin body

injury injury

Serious Serious accident accident

with leave with leave > > 1 day1 day

Cost Weak * Weak * NA NA Medium * Medium * Strong * Strong * Total loss of Total loss of

profitabilityprofitability

Irreversible Irreversible

effects/effects/

deathdeath

Body injury Body injury

With leave With leave

<< 1 day 1 day

Occurrence Index

5 4Coating not done

Embeddingimpossible


Visualinspection



MFG area:La Ciotat

Sector:



Target date:Q2


Page 1 of 1



Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

O

5

S

System

Component

Function

D

2222

5

4

4

4

3

2

2

New

resin

coating

for

module

not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

impossible

Breakdown in use


Filmunusable

blocked off


head

Incorrectresin flow

adjustment

VariationsIn T°&

hygrometry

inspection

None

None

Visual meters

5

4

4

Criteria cotation for Failure Occurrence (qualitative & quantitative index examples)

Very high :

almost inevitable

5

4

Probability

of failure

(qualitative)

F > 1 per 100

F > 10 000 PPM

Highly

probable

1 per 1000 < F < 1 /100

1000 PPM < F< 10 000 PPM

Frequency rate in PPM

(quantitative)

Frequency rate

(semi-qualitative

Regularly : several

times a year

Repeatedly : every

week

Rank

Almost

inevitable

2323

3

2

1

Probable

Hardly probable

Nothing recorded F = 0

probable 1000 PPM < F< 10 000 PPM

1/10 000 < F < 1/1000

100 PPM < F < 1000 PPM

F < 1 /10 000

F < 100 PPM

Unlikely Never

Rarely : less 1 time

a year

Intermittent : over 1

time a year

times a year

Detection (Likelihood of non-detection)

5 433

Coating not done

Embeddingimpossible


Visualinspectio



MFG area:La Ciotat

Sector:



Target date:Q2


Page 1 of 1



Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

S O D

System

Component

Function

2424

5

4

4

3

2

2

33

55

55

22

New

resin

coating

for

module

not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

impossible

Breakdown in use


Filmunusable

blocked off


head

Incorrectresin flow adjustment

VariationsIn T°&

hygrometry

inspectio

None

None

Visual meters

Detection example(Probability of non-detection)

Probability of failure detection

Detection impossible by current means

of control

Non reliable detection level

55

44

Detection level

Weak

Non detection

Value

2525

Detection at 1OO% definitely

33

22

11

High detection level (between 85 & 95%)

Very high detection level (over 97%)Very high

Absolute

High

5 43 6O

Criticity = SOD

New

Coating not done

Embeddingimpossible


Visualinspection



MFG area:La Ciotat

Sector:



Target date:Q2

Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

S O DC

System

Component

Function


Page 1 of 1



2626

5

4

4

3

2

2

5

5

2

75

40

16

New

resin

coating

for

module

not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

impossible

Breakdown in use


Filmunusable

blocked off


head


VariationsIn T°&

hygrometry

inspection

None

None

Visual meters

5 43 6O

New

Coating not done

Embeddingimpossible


Visualinspection



MFG area:La Ciotat

Sector:



Target date:Q2

Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

S O DC

System

Component

Function


Page 1 of 1



Implement preventive

Corrective actions

2727

5

4

4

3

2

2

5

5

2

75

40

16

New

resin

coating

for

module

not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

impossible

Breakdown in use


Filmunusable

blocked off


head


VariationsIn T°&

hygrometry

inspection

None

None

Visual meters

preventivemaintenance

Train operatorsTo the resin tank change (without making bubbles)

Train operators to the resin flow

adjustment

Put T°& hygrounder SPC

Actions Plan and Results (review)

Claude04/ 2001

PreventiveMaintenan.

planned5 2 2 205 4 3 6O

Coating not done

Embedding

impossiblePour head blocked off

Visualinspection

Implement preventive

maintenance

Failure Mode and Effects Analysis(Process FMECA)

Activity: Assemblage modules

MFG area:La Ciotat

Sector:


Annie, Jean Pierre,ChristineFMECA leader: Christine

Target date:Q2

Potential

failure

mode

Potential

effect of

failure

Potential

cause of

failure

Current

détection

Recommended

actions

Responsib.

& target

completion

date

Actions results

Actions

taken

S SDO DOC C

System

Component

Function


Page 1 of 1



2828

04/ 2001

Michelle05/2001

Christin06/ 2001

Annie08/ 2001

planned

Operators Trained

Operators Trained

SPCImplement

-ed

5 2 2 20

5 1 2 10

4 1 2 8

4 1 1 4

5

4

4

4

3

2

3

5

5

2

6O

60

32

242

New

resin

coating

for

module

not done

Coating incomplete

Coatingovermuch

Coatingfree-

running

impossible

Breakdown in use


Filmunusable

blocked off


head

Incorrectresin flow

adjustment

VariationsIn T°&

hygrometry

inspection

None

None

Visual meters

maintenance

Train operatto the resin tank change

Train operatto the resin

flow adjustment

Put T°/hygrounder SPC

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