1. Design Failure Mode & Effect Analysis,
Design Review & Design Validation Plan
(DFMEA, DR & DVP)
Dr K C Vora
Deputy Director & Head,
ARAI Academy, ARAI
2. New Product Development (NPD)
Concept
Phase
Feasibility
studies
Formulate
development
policy
Definition
Phase
Draft
several
scheduling
proposals
Design
Phase
General
design
Jigs, tools &
equipment
Make
tradeoffs
Define system
specifications
Solicit bids
(when using
subcontractors)
Production
process
design
Detailed design
Make prototypes
List
operational
requirements
Production
Phase
Prototype
testing
Qualification
testing
Pilot
production
Pilot evaluation
Full
production
startup
Product launch
Market
stage
3. House of Quality
QUALITY ELEMENTS
Q-CHARACTERSTIC
CUSTOMER
IMPORTENCE
VOC
CUSTOMER
REQUIRE
MENTS
OR
CR
QUALITY ELEMENTS CONFLICT
IDENTIFICATION TABLE
CUSTOMER
COMPLAINT
DATA
RELATIONSHIP
MATRIX
OR
QFD TABLE- 1
OR
QUALITY TABLE-1
TECHNICAL
BENCHMARKING
PRODUCT PLANNING.
TECHNICAL
STUDY
ITEMS
SUBSYSTEM
DESIGN TARGETS.
RELIABILITY
TARGETS
BOTTLENECK TECHNOLOGY
ISSUES
MECHANISM
- AA
BENCHMARKING
BY CUSTOMER
IMPACTED
COMPONENTS
A , B ,C
QUALITY
PLANNING
CONCEPT
DEVELOPMENTTABLE
BNE ISSUES
COST ISSUE
FUNCTION & SERVICE CONCERNS
FT DIAGRAM
FMEA table
ACTION PLAN TABLE
5. FMEA
• FAILURE MODES & EFFECTS ANALYSIS (FMEA)
is a paper-and-pencil analysis method used in engineering
to document and explore ways that a product design
might fail in real-world use.
• Failure Mode & Effects Analysis is an advanced quality
improvement tool.
• FMEA is a technique used to identify, prioritize and
eliminate potential failures from the system, design or
process before they reach the customer.
• It provides a discipline for documenting this analysis for
future use and continuous process improvement.
6. History of FMEA
• Historically, FMEA was one of the first systematic
techniques for failure analysis developed by the U.S.
Military on 9th November, 1949. FMEA was implemented
in the 1960’s and refined in the 70’s. It was used by
reliability engineers working in the aerospace industry.
• Then the Automotive Industry Action Group formed by
Chrsyler, Ford & GM restructured the FMEA techniques
which found a lot of importance in the automotive
industry.
• Since then FMEA has been instrumental in producing
quality goods in the automotive sector.
7. Types of FMEAs
• Design
–Analyzes product design before release to
production, with a focus on product function.
–Analyzes systems and subsystems in early
concept and design stages.
• Process
–Used to analyze manufacturing and assembly
processes after they are implemented.
8. Types of DFMEA
• SYSTEM
FMEA
- Chassis system
- Engine system
- Transmission
• COMPONENT FMEA
- Piston
- Crankshaft
9. FMEA Timeline
DFMEA: Starts early in process. It is complete by the time
preliminary drawings are done but before any tooling is initiated.
PFMEA: Starts as soon as the basic manufacturing methods have
been discussed. It is completed prior to finalizing production
plans and releasing for production.
10. Standards
MIL-STD 1629, “Procedures for Performing a Failure Mode and Effect
Analysis”
IEC 60812, “Procedures for Failure Mode and Effect Analysis (FMEA)”
BS 5760-5, “Guide to failure modes, effects and criticality analysis
(FMEA and FMECA)”
SAE ARP 5580, “Recommended Failure Modes and Effects Analysis
(FMEA) Practices for Non-Automobile Applications”
SAE J1739, “Potential Failure Mode and Effects Analysis in Design
(Design FMEA)”
SEMATECH (1992,) “Failure Modes and Effects Analysis (FMEA): A
Guide for Continuous Improvement for the Semiconductor Equipment
Industry”
11. Limitations of FMEA
• They can only be used to identify single failures
and not combinations of failures
• Failures which result from multiple simultaneous
faults are not identified by this
• Unless adequately controlled and focused, the
studies can be time consuming
• They can be difficult and tedious for complex
multi-layered systems
• They are not suitable for quantification of system
reliability
12. Responsibility and scope of DFMEA
• The DFMEA is a team function
– All team members must participate
– Multi-disciplinary expertise and input is beneficial
• Input from all engineering fields is desirable
• Representatives from all areas (not just technical
disciplines) are generally included as team members
• The DFMEA is not a one meeting activity
– The DFMEA will be refined and evolve with the product
– Numerous revisions are required to obtain the full benefit of
the DFMEA
• The DFMEA must include all systems, sub-systems and
components in the product design
13. Steps to conduct DFMEA
• Form the cross functional team.
• Call FMEA Meeting with advance intimation.
• Complete the top of the form
– Project, year, team members, date, and DFMEA iteration
– There will be many iterations
• List items and functions
– Start with the system, then subsystems and finally components
• Document potential failure modes
– How could the design potentially fail to meet the design intent?
– Consider all types of failure
• Document the potential effects of failure
– How would design potentially fail to meet the design intent?
14. •
•
Rate the severity of the failure effect
– See ranking guidelines
– Severity ranking is linked to the effect of the failure
Document potential causes and mechanisms of failure
– Failure causes and mechanisms are an indication of design
weaknesses
– Potential failure modes are the consequences of the failure causes
– A single failure mode may have multiple failure mechanisms
– Use group brainstorming sessions to identify possible failure
mechanisms
– Don’t be afraid to identify as many potential causes as you can
– This section of the DFMEA will help guide you in necessary design
changes
– The output of the DFMEA will indicate on which item to focus
design efforts
15. •
•
Rate the occurrence
– See attached page for ranking guidelines
– Things that may help you rate the occurrence
• Are any elements of the design related to a previous device
or design?
• How significant are the changes from a previous design?
• Is the design entirely new?
List the design controls
– Design controls are intended to:
• Prevent the cause of the failure mode (1st choice solution)
• Detect the cause of the failure mode (2nd choice solution)
• Detect the failure mode directly (3rd choice solution)
16. – Applicable design controls include
• Predictive code analysis, simulation, and modeling
• Tolerance “stack-up” studies
• Prototype test results (acceptance tests, DOE’s, limit tests)
• Proven designs, parts, and materials
•
List any critical or special characteristics
–
–
•
Critical characteristics: Severity > 8 and Occurrence >1
Special characteristics: Severity > 6 and Occurrence >2
Detection rate
–
•
See attached page for ranking guidelines
Calculate the RPN of each potential failure effect
–
–
•
RPN = (Severity) x (Occurrence) x (Detection)
What are the highest RPN items?
Define recommended actions
–
What tests and/or analysis can be used to better understand the
problem to guide necessary design changes ?
17. • Assign action items
– Assemble team
– Partition work among different team members
– Assign completion dates for action items
– Agree on next team meeting date
• Complete “Action Results” Section of DFMEA
– Note any work not accomplished (and the justification
for incomplete work) in the “actions taken” section of
the DFMEA.
• Why was nothing done?
18. – Change ratings if action results justify adjustment, but
the rules are:
• Severity: May only be reduced through elimination
of the failure effect
• Occurrence: May only be reduced through a design
change
• Detection: May only be reduced through
improvement and additions in design control (i.e. a
new detection method, better test methodology,
better codes, etc.)
– Include test and analysis results with DFMEA to
validate changes.
19. __ System
__ Subsystem
__ Component
Model Year/Vehicle(s):
Core Team:
Potential
Failure Mode and Effects Analysis
(Design FMEA)
Design Responsibility
Key Date:
FMEA Number:
Page 1 or 1
Prepared by:
FMEA Date (Orig.):
Responsibil Action Results
Potential
Current D
O Current
Potential Potential S C
ity
L Cause(s)/ C Design
Design E R. Recommend
Failure Effect(s) of
& Target Actions S O D R.
C
T P.
ed
E AMechanism(s) U Controls Controls E N.
P.
Mode
Failure
S
Action(s) Completion Taken E C E
Of Failure R Prevention Detection C
V C T N.
VS
Function
Date
Item
19
20. The FMEA Form
Identify failure modes
and their effects
Identify causes of the
failure modes
and controls
Prioritize
Determine and assess
actions
21. FMEA Sequence
Subsystem
Potential Potential S C Potential O Current Controls
failure Effect(s) E L Cause(s) C
mode
of
V A Mechanism C
Failure
S
(s) of
U
S
Failure
R
Function
Requires
What are the
effect(s)?
How bad
is it?
What are the
Functions,
Features or
Requirements?
What can go
wrong?
- No function
- Partial/ over/
degraded
function
- Intermittent
function
- Unintended
function
What are
the
cause(s)?
How often
does it
happen?
How can this
be prevented
and
detected?
D R Recommen Respons
E P
ded
ibility &
T N Action(s)
Target
E
completi
C
on date
T
I
O
N
What can be done?
- Design changes
- Process
changes
- Special controls
- Changes to
standards,
procedures, or
guides
How good is this
method at
detecting it?
Action
results
Act- S O D R
ion E C E .
s V CT P
take
.
n
N
.
22. FMEA Procedure
List all Function &
requirements
List all conceivable
failure modes
Consider effects, if above
failure mode happens
Look possible causes &
mechanism for
failures mode
Assess the frequency of
occurrence of
failure modes (O)
Re- evaluate
(New RPN )
Define Responsibility
& Time- frame
Recommend
improvements
Calculate the Risk
Priority Number (RPN)
Assess the possibility of
Failure being
detected ( D )
Assess the Severity of effect (s)
24. Function & Function Tree
Function means what the product does, and is normally
considered in a dynamic sense, expressed as
Verb + object - (There could be a number of functions for a
product or its sub assy. Or part.)
Example –
• Can drive with stability,
• Generates electricity,
• Propels airplane,
• Some time cd be given as static expression by noun +
adjective–
• Easy handling, good look, quite sound,
• Also expressed as adverb –
• Rotate smoothly
• Basic functions are expressed by verb + Object
25. Motivation
• Analyze the vehicle / engine / system / components
and summarize various functions and failure modes.
• Conduct DFMEA various components/systems.
•These components & systems all had failure modes
and a corresponding Risk Priority Number (RPN) to
be calculated using severity, occurrence & detection
rankings.
•The idea is to reduce this RPN value so that the
components/systems are designed more towards
reliability and safety. These reductions are to be done
through design changes.
27. Failure Definitions
Failure: (Noun)
1a- Omission of occurrence or performance,
specifically a failing to perform a duty or expected
action
1b- A state of inability to perform a normal function
1c- A fracturing or giving away under stress
2.- A lack of success
3.- A falling short or deficiency
Deterioration or decay
28. Failure Definitions
Fail: (Noun)
(a) To lose strength: Weaken
To fade or die away
To stop functioning
To fall short
To be absent or inadequate
To be unsuccessful
( b) To miss performing an expected service or function
To be deficient in: Lack
To leave undone: Neglect
To be unsuccessful in passing (like a test)
30. How We Call a Failure ?
1. Unsuccessful (Not meeting design intent)
2. Deteriorating (Not to standards)
3. Defective (Imperfection, flaw)
4. Decaying (Gradual or sudden decline)
5. Deficient (Impaired or inferior; weak)
6. Incomplete (Inadequate)
7. Non-Functional (Doesn’t work)
8. Omission (Overlooked, neglected, missed)
31. Examples
Unsuccessful: A required function is wrong
Example: Wrong firing sequence in engine
Deteriorating: A measured value does not meet an
established level
Example: Engine power does not qualify to a defined
level
Defective: A part has a physical flaw
Example: Crack in the engine casting
Decaying: A measured value has changed from
an initial baseline level
Example: Head lamp light lux level reduction over
time
32. Examples
Deficient: A material or product is not capable of
meeting requirements
Example: Strength of con-rod deficient due to selected
material grade.
Incomplete: One or more expected functions or
outputs are missing
Example: Kombi –switch does not provide for night light
dipping. (not considered by development)
Non-Functional: The component is not working or
responding to commands
Example: Kombi –switch does not function for command for
night light dipping ( considered in dev, but not performing )
Omission: A required characteristic has not been
designed or measured
Example: Water pressure in radiator not considered in design
33. Failures & Failure Modes
Failures modes –
• Concept of failure mode is fundamental to FMEA
• A failure mode is not a failure in itself, it is a class of
undesirable phenomena that can result in failure.
• Failure mode is also not a actual cause of failure.
• Wire break, short circuit, adhesion, surface
roughness, leakage,
detachment, slackness,
blockage, deformation, snapping,
cracking, loss are
few examples of failure mode.
CAUSE
Cause of failure mode
FAILURE-MODE
FAILURE
Effect of failure mode
34. Failures & Failure Modes
CAUSE
CAUSE • Wrong oil selection
• Wrong gasket
• wrong workmanship
• Over filling
• Wrong breather
• Deflection
Leakage
( Oil / Gas )
Oil leakage
FAILURE
• FAIURES • Engine stalling
• Over Heating
• Air entrapping
• Others
35. Severity, Occurrence & Detection
• Severity
– Importance of the effect on customer
requirements
• Occurrence
– Frequency with which a given cause occurs and
creates failure modes
• Detection
– The ability of the current control scheme to detect
or prevent a given cause
35
36. Occurrence (O) Table
Probability of Failure
Very High : Persistent
failures
Possible Failure Rates
> 100 per thousand vehicles/ items
50per thousand vehicles/ items
Ranking
10
9
High : Frequent failures
20 per thousand vehicles/ items
8
10 per thousand vehicles/ items
7
5 per thousand vehicles/ items
6
2 per thousand vehicles/ items
5
1 per thousand vehicles/ items
4
Low : Relatively few
failures
0.5 per thousand vehicles/ items
3
0.1 per thousand vehicles/ items
2
Remote : Failure is
unlikely
< 0.010 per thousand vehicles/ items
1
Moderate : Occasional
failures
37. Severity (S) Table
Effect
Hazardous
without
warning
Criteria : severity of Effect
Ranking
Very high severity ranking when a potential failure mode affects safe
10
vehicle operation and/or involves noncompliance with government
regulation without warning.
Hazardous
with warning
Very high severity ranking when a potential failure mode affects
safe vehicle operation and/or involves noncompliance with
government regulation with warning.
9
Very High
High
Vehicle/ item inoperable (loss of primary function).
Vehicle/ item operable but at reduced level of performance.
Customer very dissatisfied.
8
7
Moderate
Vehicle/ item operable, but Comfort/ Convenience item(s)
inoperable. Customer dissatisfied.
6
Low
Vehicle/ item operable, but Comfort/ convenience item(s) operable
at a reduced level of performance. Customer somewhat dissatisfied.
5
Very Low
Fit & Finish/ Squeak & Rattle item does not conform. Defect noticed
by most customers (greater than 75%).
4
Minor
Fit & Finish/ Squeak & Rattle item does not conform. Defect noticed
by 50% of customers.
3
Very Minor
Fit & Finish/ Squeak & rattle item does not conform. Defect noticed
by discriminating customer (less than 25%).
2
None
No discernible effect.
1
38. Detection (D) Table
Detection
Absolute
Uncertainty
Very Remote
Remote
Very Low
Low
Moderate
Moderate High
High
Very High
Almost Certain
Criteria : Likelihood of Detection by Design Control
Design control will not and/or can not detect a potential cause/
mechanism an subsequent failure mode; or there is no Design
control
Very remote chance the Design control will detect a potential
cause/ mechanism and subsequent failure mode.
Remote chance the Design control will detect a potential cause/
mechanism and subsequent failure mode.
Very low chance the Design control will detect a potential cause/
mechanism and subsequent failure mode.
Low chance the Design control will detect a potential cause/
mechanism and subsequent failure mode.
Moderate chance the Design control will detect a potential cause/
mechanism and subsequent failure mode.
Moderate high chance the Design control will detect a potential
cause/ mechanism and subsequent failure mode.
High chance the Design control will detect a potential cause/
mechanism and subsequent failure mode.
Very high chance the Design control will detect a potential cause/
mechanism and subsequent failure mode.
Design control will almost certainly detect a potential cause/
mechanism an subsequent failure mode.
Ranking
10
9
8
7
6
5
4
3
2
1
39. Risk Priority Number (RPN)
RPN is the product of the severity, occurrence, and
detection scores.
Severity
X
Occurrence
X
Detection
=
RPN
40. RPN / Risk Priority Number
Top 20% of Failure
Modes by RPN
R
P
N
Failure Modes
41. Example of Significant / Critical Threshold
Special Characteristics Matrix
S
E
V
E
R
I
T
Y
POTENTIAL CRITICAL
10
CHARACTERISTICS Safety/Regulatory
9
8
POTENTIAL
SIGNIFICANT
7
CHARACTERISTICS
6
Customer Dissatisfaction
5
4
ANOYANCE
ALL OTHER
ZONE
3
CHARACTERISTICS
2 Appropriate actions /
1 controls already in place
1 2 3 4 5 6 7 8 9 10
OCCURRENCE
42. FMEA Inputs and Outputs
Inputs
a
Brainstorming
Process Map
Process History
Procedures
Knowledge
Experience
Outputs
FMEA
List of actions to prevent
causes or detect failure
modes
History of actions taken
43. Action
• Recommend Action, wherever RPN is high through
- Design Controls
- Design changes
- Process changes
- Special controls changes to
standards/procedures/guidelines
• Decide Responsibilities
• Decide Target date of completion.
44. What Next?
Repeat: undertake the next revision of the DFMEA
The DFMEA is an evolving document!
Revise the DFMEA frequently & keep on reducing RPN!
Diligence will eliminate design risk!
Include documentation of your results!
46. Steps for NPD
?
PRODUCT CONCEPT
CONCEPTUAL DESIGN
DR1
DR2
DR3
DR4
DR5
OUTLINE DESIGN
DETAILED DESIGN
PROTOTYPE MAKE
TRIL RUN
INITIAL PRODUCTION
MASS PRODUCTION
PRODUCTION
PREPARATION
SUPPLIER
PREPARATION
48. Participants for Design Review
Design Engineer; System Engineer, System
Experts, Process Engineer; Product Planner,
Manufacturing Engineer, Sourcing Engineer;
Reliability Engineer; Service Engineer;
Contribution by Participants:
Participants should come to the meeting along
with the data worked out and results relevant to
their roles/expertise required under "preparation
list" and leading to "deliverables ".
49. Preparation for Design Review
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Intent & concept definition of project
Application details & translated to Technical requirements
Design Inputs
Customer Requirements - VOC; RWUP translated to technical
requirements
Deliverables- performance & endurance; Reliability goals
Benchmark & competition data
Information of failures /successes of similar products, competitor
product
Metallurgical data
Cost data
Design calculations of performance, endurance, strength
requirements of system/ components
Homologation requirements
Legal regulation
Layout & detail drawings of system
Operational ergonomic requirement data
Assembly build variation analysis.
50. Deliverables of Design Review
Conformance of design to the intent & concept for
performance, endurance & warranty.
Conformance of design to strength
Conformance to regulations & homologation
Manufacturability aspects
Serviceability aspects
Identification of special/ stranger technology
Use of standard products
Use of standard materials
Identification of patent issues- a) use of present- legal matters;
b) patentable features
Identification of overlapping & interdependent areas between
Interfacing systems
Identification of environmental issues
Operational ergonomic conformance.
52. Design Validation Plan (DVP)
• Design Validation is next step to DFMEA.
• Depending upon RPN in DFMEA, the components
are arranged in DVP.
• It contains all the information regarding the
acceptance criteria, responsible person or team,
type of test and start & finish dates.
53. Why Design Validation?
• ‘Are we building it right?’
• Major costs of projects are incurred in early design
stages.
• The cost of fixing a design and faulty decisions at later
stages is exponentially greater than at an earlier
stage.
• Early Validation/Verification:
reduces risk early in the program
provides feedback to designers before delivery
proves that requirements are met
saves costs
reduces complexity of fault detection
54. Validation Definition
The documented act of proving that any
procedure, process, equipment, material, activity
or system, actually leads to the expected results.
Design Validation means establishing by
objective evidence that device specifications
conform to user needs and intended uses.
56. Design Verification Catalogue (DVC)
The Design Verification Catalogue (DVC) allows the System
Engineers to verify that the vehicle / system / sub-system /
component meets the design specifications appearing in
corresponding VDS / SDS / CDS.
• DVC serves to,
describe appropriate Design Verification Methods (DVM)
associate one or more verification methods with each
SDS requirement
capture facility and prototype requirements to conduct
planned verifications.
DVC includes the operating conditions, accuracy and
uncertainty of the test.
56
57. Requirements of
Design Validation
• Design validation shall be performed under defined
operating conditions on initial production units, lots or
batches, or their equivalents.
• It includes testing of production units under actual or
simulated use conditions.
• It includes software validation and risk analysis.
• The Validation must be documented in Design
Validation Plan.
60. Validation Methods
• Testing ( Static as well as Dynamic)
• Analysis ( Using software's and simulations)
• Inspection Methods(Visual or with Test Rigs)
• Compilation of relevant scientific literature
• Study of historical evidences of similar design
61. Examples of validation methods &
activities
•
•
•
•
•
•
Worst case analysis of an assembly.
Fault tree analysis of a process or design.
Failure modes and effects analysis (FMEA).
Package integrity tests.
Testing of materials.
Comparison of a design to previous vehicles having
an established history of successful use.
62. Conclusion
For design of high performance products / systems /
components, quality tools like DFMEA plays an
important role to achieve desirable performance and
durability requirements. If this is done right from
concept stage, the risk of failures substantially
reduces and lot of time, energy and cost is saved.
Design Review is a continuous process of
conforming that the design to the intent & concept
for performance, endurance & warranty is foolproof.
Design Validation Plan is a systematic plan to
confirm that the design meets the desired target
after verification.
