advanced pfmea
Post on 13-Sep-2014
894 views
DESCRIPTION
TRANSCRIPT
Process Failure Mode Effect
Analysis
Northrop Grumman CorporationIntegrated Systems
CA/PA-RCA : Advanced Tool
2
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.
3
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
4
Agenda 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?
5
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.
Now adopted by many other industries.
For all automotive suppliers.
Potential serious & frequent safety issues or loyalty issues.
6
What is FMEA ?
Cause & effect, Root Cause Analysis, Fishbone Diagram Etc
Failure Mode Effect Analysis
7
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.
8
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.
9
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.
10
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.
11
The FMEA Team Roles
FMEA Core Team4 – 6 Members
Expertise in Product / ProcessCross functional
Honest CommunicationActive participation
Positive attitudeRespects other opinions
Participates in team decisions
FMEA Core Team4 – 6 Members
Expertise in Product / ProcessCross functional
Honest CommunicationActive participation
Positive attitudeRespects other opinions
Participates in team decisions
Champion / SponsorProvides resources & support
Attends some meetingsPromotes team efforts
Shares authority / power with teamKicks off team
Implements recommendations
Champion / SponsorProvides resources & support
Attends some meetingsPromotes team efforts
Shares authority / power with teamKicks off team
Implements recommendations
RecorderKeeps documentation of teams efforts
FMEA chart keeperCoordinates meeting rooms/time
Distributes meeting rooms & agendas
RecorderKeeps documentation of teams efforts
FMEA chart keeperCoordinates meeting rooms/time
Distributes meeting rooms & agendas
Facilitator“Watchdog“ of the process
Keeps team on trackFMEA Process expertise
Encourages / develops team dynamicsCommunicates assertively
Ensures everyone participates
Team Leader“Watchdog” of the project
Good leadership skillsRespected & relaxed
Leads but doesn’t dominateMaintains full team participation
Typically lead engineer
12
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 thenumerical 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 processdeficiency (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 failureModes have more than one Cause.
13
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..
14
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.
15
Determine“Controls”
Detection Rating
Determine“Effects” ofThe Failure
ModeSeverity Rating
Getting Started on FMEA
What Must be done before FMEA Begins!
Determine“Causes” ofThe Failure
ModeOccurrence Rating
DetermineProduct or Process
Functions
Determine Failure Modes
of Function
Understand yourCustomer
Needs
Develop & EvaluateProduct/Process
Concepts
Create an Effective FMEA Team
Develop andDrive
Action Plan
Ready?
1
3
2 4 6
=QFD
=Brain Storming
=4 to 6 Consensus Based MultiLevel Experts
= What we are and are not working
Define the FMEAScope
5Calculate &Assess Risk
6
7
16
The FMEA Worksheet
Product or
Process
Failure Mode
Failure Effects
SEV
CausesOCC
ControlsDET
RPN
Actions / Plans
Resp. & Target
Complete Date
pSEV
pOCC
pDET
pRPN
1 62 3 4 5 7
DetermineProduct or Process
Functions
Determine Failure Modes
of Function
Determine“Effects” ofThe Failure
ModeSeverity Rating
Determine“Causes” ofThe Failure
ModeOccurrence
Rating
Determine“Controls”Detection
Rating
Calculate &
Assess Risk
Develop and
DriveAction Plan
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
17
FMEA ScoringSeverity
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 8
Reduced primary function performance. Product requires repair or Major Variance. Noticeable loss of Takt Time 7
Medium disruption of production. Possible scrap. Noticeable loss of takt time. Loss of secondary function performance. Requires repair or Minor Variance 6
Minor disruption to production. Product must be repaired. Reduced secondary function performance. 5
Minor defect, product repaired or "Use-As-Is" disposition. 4Fit & Finish item. Minor defect, may be reprocessed on-line. 3
Minor Nonconformance, may be reprocessed on-line. 2
Non
e
No effect 1
Ext
rem
eH
igh
Mod
erat
eL
ow
18
FMEA ScoringOccurrence
Likelihood of OccurrenceFailureRate
Capability(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
Process is in statistical control. 1 in 15k > 1.33 3
Low Process is in statistical control. Only isolated
failures associated with almost identical processes.1 in 150k > 1.50 2
Rem
ote
Failure is unlikely. No known failures associatedwith almost identical processes. 1 in 1.5M > 1.67 1
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.
Ver
y H
igh
Hig
hM
oder
ate
19
FMEA ScoringDetection
Likelihood that control will detect failure RatingV
ery
Low
No known control(s) available to detect failure mode. 10
9
8
7
6
5
4
3
2
1
The process automatically detects failure.Controls will almost certainly detect the existence ofa failure.
Controls have a good chance of detecting the existenceof a failure
Low
Mod
erat
eH
igh
Ver
y H
igh
Controls have a remote chance of detecting the failure.
Controls may detect the existence of a failure
20
FMEA ScoringRPN or Risk Priority Number
Severity x Occurrence x Detection=
RPN
The Calculation !
21
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
ImprovementsProduct
or Process
Failure Mode
Failure Effects
SEV
CausesOCC
ControlsDET
RPN
Actions / Plans
Resp. & Target
Complete Date
pSEV
pOCC
pDET
pRPN
Hole Drilling
Oversize Hole
Unable toInstall BPFastener
WrongDrill Bit
Used
Ball GageVisual Insp5 8 3
120 Kit Drill
Bits010103 5 11 5
22
Failure Modes & Effect Analysis
Questions?Call or e-mail:
Kevin M. Treanor Bob Ollerton310-863-4182 310-332-1972/[email protected] [email protected]