Post on 03-Jan-2016
© ABSL Power Solutions 2007© STM Quality Limited
STM Quality Limited
Failure Mode and Effect Analysis
TOTAL QUALITY MANAGEMENT
F.M.E.A.
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STM Quality Limited
What is an F.M.E.A.?
Why do we need it?
When do we do it?
What do we do when it’s finished?
Introduction
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What is aFailure Mode and Effect
Analysis?
F.M.E.A. is a simple way of predicting what might go wrong.
By using a structured method, results can be quantified and hence compared.
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How Does It Work?
Identifies critical and significant characteristics
Helps engineers prioritise and focus on eliminating product and process concerns and help prevent problems from occurring.
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Purpose
Utilise individuals’ knowledge and skills within a team environment
Identify potential failures at the earliest possible stage of new design/process
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Failure Mode and Effect Analysis
F.M.E.A.s can be done for any design, manufacturing or in-service activity
F.M.E.A.s are modular and can be carried out for single parts or large assemblies
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F.M.E.A. - Types
Component
DesignFMEA
DesignFMEA
System
Sub-System
ProcessFMEA
ProcessFMEA
Assembly
Manufacturing
System
Component
Sub-System
System
Component
Sub-System
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Benefits – Design F.M.E. A.
Aids in evaluating requirements and alternatives
Aids in initial Design for ManufactureIncreases probability of detecting
failure modes and their effectsProvides additional information for
testing requirementsHelps identify critical and significant
characteristicsHelps validate test methods
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Benefits – Process F.M.E. A.
Identifies potential process related failure modes which will effect internal/external customers
Reduces costs of repairs due to faulty process methodology
Increases efficiencyEstablishes a priority system for
considering corrective actionsIdentifies confirmed critical and
significant characteristics
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F.M.E. A. and Control Plans
F.M.E.A Identifies Risks
How Risks are ControlledControl Plan
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F.M.E.A. Model
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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STM Quality Limited
To meet Customer Requirements – A.P.Q.P.
To keep up with competition
To retain current business
Help obtain new business
Why Do A Failure Mode and Effect
Analysis?
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Generating F.M.E.A.s
Failure Mode and
Effects Analysis
Failure Mode and
Effects Analysis
Who initiates?Who initiates?
Who prepares?Who prepares?
Who updates?Who updates?
Who is FMEA customer?
Who is FMEA customer?
How is FMEA documented?
How is FMEA documented?
When started and updated?
When started and updated?
When is FMEA complete?
When is FMEA complete?
When to discard?
When to discard?
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FM.E.A.s are living documents and are updated when:
Modification to a component, process or system is planned;
Component is to be used in new environment;
Customer concern arises.
Managing F.M.E.A.s
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Process F.M.E.A.s
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Firstly, create a flow chart of operationsThen identify boundary for analysisNext, create a flow chart for one
operation
Process Flow Chart
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Transportraw
materials
Process Flow Chart of Operations
Op.10 Preparation Op.30 Weld
Op.40 assemble
Op.50 Trim to size
Op.60 Inspect & Pack
Store/Pack
Op.20 Mould
Boundary for analysis
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Place part on trim machine fixture
Boundary For Analysis
Press ‘Start’ button
Op.50.1
Remove from fixture when cycle complete
Op.50 Trim
Op.50.2
Op.50.3
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Process/Function Requirements
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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STM Quality Limited
From Process flow:
Enter a simple description of the process being analysed i.e. Place part on trim machine fixture;
Indicate the purpose of the process being analysed i.e. Fully seat part in correct orientation;
List separately other operations involved with that process;
Process function contains both product and process characteristics.
Process/Function Requirements
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What does the process do at this operation?
What is the process purpose?
What is its function?
Define the Process Purpose
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Place part on trim machine fixture
Process Purpose
Press ‘Start’ button
Op.50.1
Remove from fixture when cycle complete
Op.50 Trim
Op.50.2
Op.50.3
• Locate part on fixture - correct orientation - fully seated
• Start trimming programme
• Position in checking fixture - fully seated
• Remove waste before packing
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Determine What Can Go Wrong
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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Definition:
Potential failure mode is the manner in which the process could potentially fail to meet the process requirements and/or design intent.
It is a description of the non-conformance at that specific operation.
Failure Mode
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Examine process flow using:
No functionPartial functionIntermittent function
Failure Mode
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Effects Of Failure Mode
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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Definition:
The effects of the failure mode on the customer. The customer could be the next operation, subsequent operations or the final customer / user.
Effects of Failure Mode
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Identify potential effects on:next userdownstream userultimate customervehicle operationoperator safetyCompliance with government
regulationsmachines / equipment
Effects of Failure Mode
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Effects of Failure
Failure
mode
Nextuser
Downstream
users
Ultimatecustome
r
Vehicleoperatio
n
Operatorsafety
Governmentregulations
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Effects of Failure
Failure
mode
Nextuser
Downstream
users
Ultimatecustome
r
Vehicleoperatio
n
Operatorsafety
Governmentregulations
Failure mode: Incorrect Trim Programme
Incorrect to checking
fixture
Packaged in wrong stillage
Cannot fit to
vehicle.Stop
Production line
Cannot fit to
vehicleNone None
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STM Quality Limited
Severity
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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Definition:
An assessment of the seriousness of the effect of the potential failure mode on the customer.
Severity
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Hazardous without warning
Suggested Severity Scoring
Effect Criteria: Severity of Effect Ranking
10
Hazardous with
warning
9
Low Minor disruption to production line 100% of product may have to be reworked
5
None No Effect 1
May endanger machine or assembly operator…non compliance government regulation without warning
May endanger machine or assembly operator…non compliance government regulation without warning
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Critical or Special Characteristic
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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STM Quality Limited
Identify Special Characteristics
CRITICAL: Requirements that affect compliance with government regulations or safe vehicle / product function and require special controls (Score = 9 or 10)
SIGNIFICANT: Product and/or test requirements important for customer satisfaction, summarized on Control Plan and require special controls (Score = 5 to 8,)
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Cause
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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STM Quality Limited
Definition:
Potential cause of a failure is defined as how the failure could occur in terms of something that can be corrected or controlled.
Cause
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Only specific errors or malfunctions (eg. Operator fails to remove waste) should be listed.
Ambiguous phrases (e.g. Operator error, machine malfunction) should not be used.
Cause
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Occurrence
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
© STM Quality Limited
STM Quality LimitedHow frequently the cause is projected to
occur. Based on:
– Historical manufacturing/assembly failure rates with similar parts
– Statistical data from similar process– Existing process controls– Customer concern data– Rejects, PPM, Warranty data
Occurrence
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Very high
Suggested Occurrence Scoring
Probability Possible Failure Rates Ranking
10
Moderate 6
Remote Less than 1 in 500,000 1
About 1 in 2
About 1 in 80
About 1 in 3 9
About 1 in 400 5
About 1 in 2000 4
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Controls
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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STM Quality Limited
Increasing inspection is only a temporary measure. Permanent Corrective Action is required.
Emphasis must be placed on preventing defects rather than detecting them (e.g. S.P.C.)
Controls
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In Process Control column on FMEA:Prevention Controls
– Place a ‘P’ before each prevention control listed
Detection Controls– Place a ‘D’ before each detection
control listed
Controls
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Prevention: (Preferred option)
Prevent the cause / mechanism of failure or the failure mode occurring, or reduce their rate of occurrence
Prevention Controls
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Detection:
Detect the cause / mechanism of failure or the failure mode and lead to corrective actions
Detection Controls
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Engineering specification testsPoka-yoke or error proofingAudible or visual warning devicesIn Process / Final inspectionS.P.C.Process / Parameter audits
Process Control Examples
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Detection
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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Definition:Detection is an assessment of the probability that:
The process controls listed will detect a potential cause /mechanism (process weakness) , or
The process controls listed will detect a subsequent failure mode.
Detection
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Certain
Suggested Detection Scoring
Detection Likelihood of Detection Ranking
10
Moderate 4
Almost certain Process control will almost certainly detect a potential cause
1
Process control will not and/or cannot detect a potential cause … or there is no process control
Moderately high chance the process control will detect potential cause
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Severity
Select and Manage Actions
To Reduce Consider This Action To Accomplish
Eliminate failure modes
Occurrence Prevent cause(s), or reduce their rate ofoccurrence
Detection Add to or improve the control methods
Change the design ... or the process if operator safety is involved
Change the design or process
Improve ability to detect a failure mode
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Risk Priority Number (R.P.N.)
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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STM Quality Limited
Failure Mode and Effect Analysis
We have seen that the F.M.E.A. asks three questions:
What might go wrong?What effect would this have?What caused the problem?
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Failure Mode and Effect Analysis
From the answers to the three questions we can work out a risk priority number:
Risk Priority Number
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Failure Mode and Effect Analysis
How do we calculate the R.P.N.?We simply use the scoring criteria
easily remembered by:
Severity of the problem
Occurrence of the problem
Detection of the problem
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Failure Mode and Effect Analysis
Each is given a value from 1 to 10Let’s try this out for S, O & D
For Example,Severity = 1 2 3 4 5 6 7 8 9 10Occurrence = 1 2 3 4 5 6 7 8 9 10Detection = 1 2 3 4 5 6 7 8 9 10Each of these could be assessed in a rating from
1 to 10.
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Failure Mode and Effect Analysis
How can we use these values to give an overall risk?
We multiply the three figures together:e.g. 7 x 4 x 3 = 84. So the R.P.N. is 84.
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Failure Mode and Effect Analysis
From the R.P.N. we can now see the areas of greatest concern
i.e. Those failures with the highest risk priority numbers
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Failure Mode and Effect Analysis
We can now focus our attention on the worst problems – those with the highest R.P.N.
With limited resources, this must be a good idea
We can now eliminate or reduce the potential failure
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Recommended Actions
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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Recommended Actions
The intent of any Recommended Action is to reduce rankings in the following order:
SeverityOccurrenceDetection
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Responsibility & Target Date
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
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STM Quality Limited
Responsibility
Each action must be assigned to a specific individual and not a dept. / organisation
If the individual is not in the team a team member should be assigned responsibility for communication and feedback of action with a target date.
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Actions Taken
___ System
___ Subsystem
___ Component
Model Year / Vehicle(s):
Core Team:
PotentialFailure Mode and Effects Analysis
Design Responsibility:
Key Date:
FMEA Number:
Page 1 of 1
Prepared by:
FMEA Date ( Orig): (Rev)
Action Results
Potential
Failure
Mode
Potential
Effect(s)
of Failure
S
e
v
C
l
a
s
s
Potential
Cause(s)/
Mechanisms
Failure
O
c
c
u
r
Current
Design
Controls
D
e
t
e
c
R
P
N
Recommended
Action(s)
Responsibility &
Target
Completion Date
Actions
Taken
Se
v
Oc
c
De
t
RP
N
Item
Function
© STM Quality Limited
STM Quality Limited
Actions Taken
After the corrective action has been identified, estimate and record the resulting severity, occurrence and detection rankings
Calculate and record the resulting R.P.N.P.F.M.E.A. team must review the revised
R.P.N.s to determine if further action is necessary.
If no action write ‘None’.
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Actions Taken
Once the actions have been implemented, the estimated values, ‘the future’, becomes ‘the present’ and can be incorporated into the LHS of the form on the next F.M.E.A.
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Failure Mode and Effect Analysis
Advantages of F.M.E.A.s
Customer confidenceImproved quality & efficiencyImproved participation across
traditional boundaries
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STM Quality Limited
Failure Mode and Effect Analysis
More advantages of F.M.E.A.s
Uses extensive & untapped personnel/process knowledge to improve new & existing work
Provides a vehicle for continuous improvement
Supports product liability
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Failure Mode and Effect Analysis
There are drawbacks for F.M.E.A.s:
Must be adequate time & resources for F.M.E.A.s
Product LiabilityNeed for in-depth product &
process or design knowledge
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Failure Mode and Effect Analysis
Remember - F.M.E.A. is a practical activity and there will be differing interpretations regarding to the failure modes and rankings - this does not matter, provided that the team does not get bogged down in this way!
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STM Quality Limited
Failure Mode and Effect Analysis
Keep the meetings short and the tempo sharp!
Design F.M.E.A. team - Chairman, Production, Service, Quality Personnel
Process F.M.E.A. team - YOU CHOOSE!