Transcript Process Failure Mode Effect Analysis

Process Failure
Mode Effect
Analysis
CA/PA-RCA : Advanced Tool
Northrop Grumman Corporation
Integrated Systems
Overview Objective
 Failure Mode Effect Analysis (FMEA) – Provide a Basic
familiarization with a tool that aids in quantifying
severity, occurrences and detection of failures, and
guides the creation of corrective action, process
improvement and risk mitigation plans.
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Agenda
 FMEA History
 What IS FMEA
 Definitions
 What it Can Do For You
 Types of FMEA
 Team Members Roles
 FMEA Terminology
 Getting Started with an FMEA
 The Worksheet
 FMEA Scoring
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Agenda
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Why does it always
seem we have plenty of
time to fix our
problems, but never
enough time to prevent
the problems by doing
it right the first time?
FMEA History
This “type” of thinking has been around for
hundreds of years. It was first formalized in
the aerospace industry during the Apollo
program in the 1960’s.
 Initial automotive adoption in the 1970’s.
 Potential serious & frequent safety issues.
 Required by QS-9000 & Advanced Product Quality Planning Process
in 1994.
 For all automotive suppliers.
 Now adopted by many other industries.
 Potential serious & frequent safety issues or loyalty issues.
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What is FMEA ?
Cause & effect, Root Cause Analysis,
Fishbone Diagram Etc
Failure Mode Effect Analysis
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What is FMEA ?
Definition: FMEA is an Engineering “Reliability Tool” That:
 Helps define, identify, prioritize, and eliminate known and/or
potential failures of the system, design, or manufacturing process
before they reach the customer. The goal is to eliminate the Failure
Modes and reduce their risks.
 Provides structure for a Cross Functional Critique of a design or a
Process
 Facilitates inter-departmental dialog.
 Is a mental discipline “great” engineering teams go through, when
critiquing what might go wrong with the product or process.
 Is a living document which ultimately helps prevent, and not react
to problems.
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What is FMEA ?
What it can do for you!
1.) Identifies Design or process related Failure Modes before they
happen.
2.) Determines the Effect & Severity of these failure modes.
3.) Identifies the Causes and probability of Occurrence of the
Failure Modes.
4.) Identifies the Controls and their Effectiveness.
5.) Quantifies and prioritizes the Risks associated with
the Failure Modes.
6.) Develops & documents Action Plans that will occur to
reduce risk.
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Types of FMEAs ?
System/Concept “S/CFMEA”- (Driven by System functions) A
system is a organized set of parts or subsystems to accomplish one
or more functions. System FMEAs are typically very early, before
specific hardware has been determined.
Design “DFMEA”- (Driven by part or component functions) A
Design / Part is a unit of physical hardware that is considered a
single replaceable part with respect to repair. Design FMEAs are
typically done later in the development process when specific
hardware has been determined.
Process “PFMEA”- (Driven by process functions & part
characteristics) A Process is a sequence of tasks that is
organized to produce a product or provide a service. A
Process FMEA can involve fabrication, assembly, transactions
or services.
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Types of FMEAs ?
System/Concept “S/CFMEA”- (Driven by System functions) A
system is a organized set of parts or subsystems to accomplish one
or more functions. System FMEAs are typically very early, before
specific hardware has been determined.
Design “DFMEA”- (Driven by part or component functions) A
Design / Part is a unit of physical hardware that is considered a
single replaceable part with respect to repair. Design FMEAs are
typically done later in the development process when specific
hardware has been determined.
Process “PFMEA”- (Driven by process functions & part
characteristics) A Process is a sequence of tasks that is
organized to produce a product or provide a service. A
Process FMEA can involve fabrication, assembly, transactions
or services.
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The FMEA Team Roles
Champion / Sponsor
Provides resources & support
Attends some meetings
Promotes team efforts
Shares authority / power with team
Kicks off team
Implements recommendations
Team Leader
“Watchdog” of the project
Good leadership skills
Respected & relaxed
Leads but doesn’t dominate
Maintains full team participation
Typically lead engineer
FMEA Core Team
4 – 6 Members
Expertise in Product / Process
Cross functional
Honest Communication
Active participation
Positive attitude
Respects other opinions
Participates in team decisions
Recorder
Keeps documentation of teams efforts
FMEA chart keeper
Coordinates meeting rooms/time
Distributes meeting rooms & agendas
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Facilitator
“Watchdog“ of the process
Keeps team on track
FMEA Process expertise
Encourages / develops team dynamics
Communicates assertively
Ensures everyone participates
FMEA Terminology
1.) Failure Modes: (Specific loss of a function) is a concise
description of how a part , system, or manufacturing process may
potentially fail to perform its functions.
2.) Failure Mode“Effect”: A description of the consequence or
Ramification of a system or part failure. A typical failure mode may
have several “effects” depending on which customer you consider.
3.) Severity Rating: (Seriousness of the Effect) Severity is the
numerical rating of the impact on customers.
 When multiple effects exist for a given failure mode, enter the worst
case severity on the worksheet to calculate risk.
4.) Failure Mode“Causes”: A description of the design or process
deficiency (global cause or root level cause) that results
in the failure mode .
You must look at the causes not the symptoms of the failure. Most failure
Modes have more than one Cause.
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FMEA Terminology (continued)
5.) Occurrence Rating: Is an estimate number of frequencies or
cumulative number of failures (based on experience) that will
occur (in our design concept) for a given cause over the intended
“life of the design”.
6.) Failure Mode“Controls”: The mechanisms, methods, tests,
procedures, or controls that we have in place to PREVENT the
Cause of the Failure Mode or DETECT the Failure Mode or Cause
should it occur .
Design Controls prevent or detect the Failure Mode prior to engineering
release
7.) Detection Rating: A numerical rating of the probability that a given
set of controls WILL DISCOVER a specific Cause of Failure Mode to
prevent bad parts leaving the facility or getting to the ultimate customer.
Assuming that the cause of the failure did occur, assess the capabilities of the
controls to find the design flaw..
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FMEA Terminology (continued)
8.) Risk Priority Number (RPN): Is the product of Severity,
Occurrence, & Detection. Risk= RPN= S x O x D
Often the RPN’s are sorted from high to low for consideration in the action planning
step (Caution, RPN’s can be misleading- you must look for patterns).
9.) Action Planning: A thoroughly thought out and well developed
FMEA With High Risk Patterns that is not followed with corrective
actions has little or no value, other than having a chart for an audit
Action plans should be taken very seriously.
If ignored, you have probably wasted much of your valuable time.
Based on the FMEA analysis, strategies to reduce risk are focused on:
Reducing the Severity Rating.
Reducing the Occurrence Rating.
Reducing the detection Rating.
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Getting Started on FMEA
What Must be done before FMEA Begins!
Understand your
Customer
Needs
Develop & Evaluate
Product/Process
Concepts
Create
an Effective
FMEA Team
=QFD
=Brain Storming
=4 to 6 Consensus Based Multi
Level Experts
= What we
Define the FMEA are and are
Scope
not working
Determine1
Product or
Process
Functions
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Ready?
Determine2
Failure Modes
of Function
Determine
“Effects” of3
The Failure
Mode
Develop and
Drive
7
Action Plan
Severity Rating
Determine 4
“Causes” of
The Failure
Mode
Occurrence Rating
Determine5
“Controls”
Detection Rating
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Calculate &
Assess Risk
The FMEA Worksheet
Product
or
Process
Failure
Mode
Failure
Effects
1
2
3
Determine
Product or
Process
Functions
Determine
“Effects” of
The Failure
Mode
Determine
Failure
Modes
of Function
Severity
Rating
S
O
E Causes C Controls
V
C
4
5
D R
Actions
E P
/ Plans
T N
6
p
O
C
C
p p
D R
E P
T N
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Develop
and
Drive
Action Plan
Determine
“Controls”
Determine
“Causes” of
The Failure
Mode
Occurrence
Rating
Resp. &
p
Target
S
Complete E
Date
V
Detection
Rating
Calculate
&
Assess
Risk
If an FMEA was created during the Design Phase of the Program, USE IT!
Create an Action Plan for YOUR ROOT CAUSE
and Re-Evaluate the RPN Accordingly
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FMEA Scoring
None
Low
Moderate
High
Extreme
Severity
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Severity of Effect
Rating
May endanger machine or operator. Hazardous without warning
10
May endanger machine or operator. Hazardous with warning
9
Major disruption to production line. Loss of primary function, 100% scrap. Possible jig lock and
Major loss of Takt Time
Reduced primary function performance. Product requires repair or Major Variance.
Noticeable loss of Takt Time
Medium disruption of production. Possible scrap. Noticeable loss of takt time.
Loss of secondary function performance. Requires repair or Minor Variance
Minor disruption to production. Product must be repaired.
Reduced secondary function performance.
Minor defect, product repaired or "Use-As-Is" disposition.
Fit & Finish item. Minor defect, may be reprocessed on-line.
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7
6
5
4
3
Minor Nonconformance, may be reprocessed on-line.
2
No effect
1
FMEA Scoring
Occurrence
Moderate
High
Very High
Likelihood of Occurrence
Failure is almost inevitable
Process is not in statistical control.
Similar processes have experienced problems.
Process is in statistical control but with isolated failures.
Previous processes have experienced occasional
failures or out-of-control conditions.
Remote
Low
Process is in statistical control.
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Failure Capability
Rate
(Cpk) Rating
1 in 2
< .33
10
1 in 3
> .33
9
1 in 8
> .51
8
1 in 20
> .67
7
1 in 80
> .83
6
1 in 400
> 1.00
5
1 in 2000
> 1.17
4
1 in 15k
> 1.33
3
> 1.50
2
> 1.67
1
Process is in statistical control. Only isolated
failures associated with almost identical processes. 1 in 150k
Failure is unlikely. No known failures associated
with almost identical processes.
1 in 1.5M
FMEA Scoring
Detection
Very Low
Controls have a remote chance of detecting the failure.
Moderate
No known control(s) available to detect failure mode.
Low
Likelihood that control will detect failure
Rating
10
9
8
7
Controls may detect the existence of a failure
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Very High
High
5
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Controls have a good chance of detecting the existence
of a failure
The process automatically detects failure.
Controls will almost certainly detect the existence of
a failure.
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3
2
1
FMEA Scoring
RPN or Risk Priority Number
The Calculation !
Severity x Occurrence x Detection= RPN
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Failure Modes & Effect Analysis
(FMEA) Part or Process Improvement
 FMEA is a technique utilized to define, identify, and eliminate known or
potential failures or errors from a product or a process.
 Identify each candidate Part or Process, list likely failure mode, causes,
and current controls
 Prioritize risk by using a ranking scale for severity, occurrence, and
detection
 Mitigate risk – Can controls be added to reduce risk? Recalculate RPN.
 Characteristics with high Risk Priority Numbers should be selected for
Improvement and Action Plans Created
 Recalculate RPN After Completion of Action Plans to Validate
Improvements
Failure
Mode
Failure
Effects
S
O
E Causes C Controls
V
C
Hole
Oversize Unable to
Drilling
Hole Install BP 5
Fastener
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Wrong
Drill Bit
Used
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Ball Gage
Visual Insp
D R
E P
T N
Actions
/ Plans
Resp. &
Target
Complete
Date
120
Product
or
Process
Kit Drill
Bits
010103
3
p
S
E
V
p
O
C
C
p p
D R
E P
T N
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Failure Modes & Effect Analysis
Questions?
Call or e-mail:
Kevin M. Treanor
310-863-4182
[email protected]
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Bob Ollerton
310-332-1972/310-350-9121
[email protected]