failure modes effects analysis (fmea) six sigma continuous improvement training six sigma continuous...
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Failure Modes Effects Analysis (FMEA)Failure Modes Effects Analysis (FMEA)Six Sigma Continuous Improvement TrainingSix Sigma Continuous Improvement Training
Six Sigma Simplicity
ObjectivesObjectives
s Discuss what FMEA is fors Review how to use FMEAs Address steps involved in
constructing an FMEAs Using FMEA for risk assessment
s Discuss what FMEA is fors Review how to use FMEAs Address steps involved in
constructing an FMEAs Using FMEA for risk assessment
3
What is FMEA?What is FMEA?s FMEA: Failure Modes Effects Analysis. A proactive,
preventative evaluation. s What does it do?
s Helps to evaluate how a process or design can fails Helps to quantify risk factors assisting in prioritizing
current or future potential projectss Can act as a forum for process or design
improvements and preventative actionss Assists in identifying weaknesses in current control
plans May lead to reduction in manufacturing costs to
improved design or set-up processes
s FMEA: Failure Modes Effects Analysis. A proactive, preventative evaluation.
s What does it do?s Helps to evaluate how a process or design can fails Helps to quantify risk factors assisting in prioritizing
current or future potential projectss Can act as a forum for process or design
improvements and preventative actionss Assists in identifying weaknesses in current control
plans May lead to reduction in manufacturing costs to
improved design or set-up processes
Some Sources of Risk?Some Sources of Risk?
D. H. Stamatis, FMEA:FMEA from Theory to Practice, Quality Press,
1995
Total RiskVague
Workmanship Standards
Poor control plans & SOP’s
Raw Material Variation
Poorly developed Specification
LimitsMeasurement Variation (On- Floor and QC)
Machine Reliability/Poor
Process Capability
Potential Safety Hazards
Unclear Customer Expectations
Types of FMEA?Types of FMEA?
s PFMEA --- Process or Potential Failure Modes Effects Analysis. May be used where a process needs to be evaluated for potential failures. May be a manufacturing or transactional process
s DFMEA --- Design Failure Modes Effects Analysis. Generally used in Research/Development where designs are analyzed for potential weaknesses
s SFMEA --- System Failure Modes Effects Analysis. Used to evaluate system issues that cross corporate functions
Where Can FMEA Fit In?Where Can FMEA Fit In?
Process Mapping / Brown Paper
Project: Housing Welding
Date: 12/20/96
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Len
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Dim
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Nu
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Fla
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All
We
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Pre
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Rank 5 7 9 8 10Inputs
1 Width Bracket 1 10
2 Length Bracket 1 7
3 Housing Width 7
4 Housing Length 10
5 All SOPs 9 9 9 6
6 Weld Schedule 10 10
7 Air Pressure 5 5 5
8 Line Voltage 5 5 5
9 H20 Circulation 5 5 5
10 Width Bracket 2 10
11 Length Bracket 2 7
12 Daily Tip Dressing 10 8
13
14
15
View Results
Delete
Instructions
DEMO
X-Y Matrix
350345340335330325320
USLLSL
Process Capability Analysis for Volume
PPM Total
PPM > USL
PPM < LSL
PPM Total
PPM > USL
PPM < LSL
PPM Total
PPM > USL
PPM < LSL
Ppk
PPL
PPU
Pp
Cpm
Cpk
CPL
CPU
Cp
StDev (Overall)
StDev (Within)
Sample N
Mean
LSL
Target
USL
452293.06
237546.24
214746.82
414406.23
218970.95
195435.28
450000.00
233333.33
216666.67
0.24
0.26
0.24
0.25
*
0.26
0.29
0.26
0.27
5.31817
4.89682
120
334.202
330.000
*
338.000
Exp. "Overall" PerformanceExp. "Within" PerformanceObserved PerformanceOverall Capability
Potential (Within) Capability
Process Data
Within
Overall
Initial Capability Study
#Process Function
(Step)
Potential Failure Modes (Process
Defects)
Potential Failure Effects (KPOVs)
SEV
Clas
Potential Causes of Failure (KPIVs)
OCC
Current Process Controls
DET
RPN
1 Load Bracket 1 and housing into Fixture A
Parts do not fit Delay in process 2 Incoming component dimensions out of print
3 Receiving inspection (1% dimentional audit)
6 36
2 Part is loaded incorrectly
Final assembly width/length out of print
8 Operator error 5 100% final dim gauge/100% visual inspection
4 160
3 Fixture A: Initiate cycle start
Machine will not cycle
Delay in process 2 Power off, sensor out
2 1/month PM 7 28
4 Fixture A: Clamps Machine will not clamp
Delay in process 2 Air pressure low, sensor out
2 1/month PM 7 28
5 Delay in process 2 Part not loaded properly
2 Sensor installed (poke yoke)
2 8
6 Fixture A: Welds Machine will not weld
Delay in process 2 Not enough voltage supplied
1 Voltage regulator and visual alarm
2 4
7 Welds appear small or "light"
Airbag housing will not sustain deployment
10 Weld schedule out of adjustment
5 100% visual inspection, 2/shift destructive testing
4 200
8 Fixture A: Unclamps
Machine will not unclamp
Delay in process 2 Air pressure release valve broken
2 1/month PM 7 28
9 Remove and transport subassembly
Dropped/ damaged subassembly
Final assembly width/length out of print
8 Operator error 2 100% final dim gauge/100% visual inspection
4 64
FMEA
When Do I Do an FMEA?When Do I Do an FMEA?
s They can begin as soon as a project is selected for a certain process, system or design
s First one usually started no later than Measure Phase, or beginning of the Analysis Phase
s FMEA document is a dynamic document
s Should be revised as improvements or changes made to a process
Who Does an FMEA?Who Does an FMEA?s This is a team process. Team sizes may
vary, but recommended size is approximately 5-7 members.
s Depending upon the type of FMEA being done, members may come from:
s Research and Design Engineerss Manufacturing Supervisors, Manufacturing
Engineers, Manufacturing Operators (very important members)
s Quality Department Memberss Saless Marketings Testing or Validation Departments Human Resourcess Maintenances Supplier
How to Do an FMEAHow to Do an FMEA1. For each Process Input, determine the ways in which the
input can fail (these are failure modes)2. For each failure mode associated with the inputs,
determine effects3. Identify potential causes of each failure mode4. List the current controls for each cause5. Define or adapt definitions of Severity, Occurrence and
Detection appropriate to what is being evaluated6. Assign Severity, Occurrence and Detection ratings to
each cause7. Calculate RPN (spreadsheet does it automatically)8. Determine recommended actions to reduce high RPN’s9. Take appropriate actions and document10. Update FMEA documents as appropriate11. Recalculate RPN’s
FMEA DocumentFMEA Document
FMEA: Step 1FMEA: Step 1s Process Function (or step) --- Refers to the function of a
process or step within a process. A manufacturing example might be “Drilling Holes,” and a transactional example, “Create Sales Orders.”
Sales creates quote/orders
FMEA: Step 1 (cont’d)FMEA: Step 1 (cont’d)s Failure Mode --- the way a process input may fail. Can be
associated with a defect (in manufacturing) or a process input within a transactional process. A manufacturing example would be: “Wrong Hole Size” or a transactional example being, “Incorrect Information.”
Incorrect infoSales creates quote/order
FMEA: Step 2FMEA: Step 2s Effect --- The impact on process or customer requirements.
This impact or result may be on a downstream process, the system, design or end-user customer. A manufacturing example may be, “Parts scrapped” and a transactional example could be, “Wrong person gets benefits”:
Customer does not receive product
Sales creates quote/order
Incorrect info
Customer receives incorrect product
Order cancelled
FMEA: Step 3FMEA: Step 3s Cause --- Source of the failure mode.
Customer does not receive product
Sales creates quote/order
Incorrect info
Customer receives incorrect product
Customer changes mind
Type/operator
Customer gave wrong info
Customer gave wrong info
Part deviation
FMEA: Step 4FMEA: Step 4s Current Process Controls --- Methods/devices in place to prevent
or detect failure modes or causes. Prevention consists of mistake-proofing, automated controls and set-up verifications. Controls consists of audits, checklists, Inspection, laboratory testing, training, SOP’s, preventive maintenance, etc.
Customer gave wrong info
Repeat/verify info with customer (shipping vs
billing address)
Quality review by random sampling
FMEA Step 5: SeverityFMEA Step 5: Severitys Addresses how severe the failure mode and effect is to the
customer. Also may address safety concerns. See below:
• Also refer to the AIAG guidebook: Potential Failure Mode and Effects Analysis (FMEA), Reference Manual,
1995. Page 35. Chrysler Corporation, Ford Motor Company, General Motors Corporation.
Effect Criteria: Severity of Effect Defined Ranking
Hazardous: Without Warning
GRAVE SAFETY concern/ violation, Possible Injury/ Death to customer or employee10
Hazardous: With Warning Major Safety/ / Health/ Environmental concern and/ or may be illegal
9
Very High Render the product or service unfit for use
8
HighCause extreme Customer dissatisfaction.
7
ModerateResult in partial malfunction, major customer dissatisfaction i
6
LowCause a loss of performance likely to result in a complaint
5
Very Low Cause minor performance loss.
4
MinorCause a minor nuisance, can be overcome with no loss
3
Very MinorBe unnoticed, minor effect on performance
2
None Be unnoticed and not effect performance. 1
FMEA Step 5: OccurrenceFMEA Step 5: Occurrences Addresses the frequency the failure mode occurs. See below:
* Also refer to the AIAG guidebook Potential Failure Mode and Effects Analysis (FMEA), Reference Manual, 1995. Page 39. Chrysler Corporation, Ford Motor Company, General Motors Corporation.
Guidelines for Failure Possible Failure Rates Probability Ranking
Very High: Failure is almost inevitable
> 30% 10
9
High: Generally associated with processes similar to previous
processes that have often failed.
£ 30%
£ 5% 8
£ 1% 7
Moderate: Generally associated with processes similar to previous processes that have experienced
occasional failures but not in major proportions
:
£ .03% 6
5
, . £ 6 per 10,000 4
Low: Isolated failures associated with similar processes.
£ 6 per million 3
Very Low: Only isolated failures associated with almost identical
processes £ 3 per 10 million 2
Remote: Failure is highly unlikely. No failures ever associated with
almost identical processes.
More than one per day
Once every 3 to 4 days
Once per week
Once per Month
Once every 3 months
Once every 6 months
Once a year
Once every 1 – 3 years
Once every 3 – 6 years
Once every 6 – 50 years £ 2 per billion 1
£ 1 per 10,000
FMEA Step 5: DetectionFMEA Step 5: Detections Addresses the ability of methods or systems in place to detect the
failure if it occurs. See guidelines below:
* Also refer to AIAG guidebook Potential Failure Mode and Effects Analysis (FMEA), Reference Manual, 1995. Page 39. Chrysler Corporation, Ford Motor Company, General Motors Corporation.
Almost Impossible
Detection Criteria: Ranking
Defect caused by failure is not detectable. 10
Very Remote Occasional units are checked for defects. 9
Remote Units are systematically sampled and inspected. 8
Very Low All units are manually inspected. 7
Low Manual inspections with mistake-proofing. 6
Moderate Process is monitored (SPC) and manually inspected. 5
Moderately High SPC utilized with immediate reaction to out-of-control (OOC) condition.
4
High SPC (above) with 100% inspection (for OOC condition). 3
Very High All units are automatically inspected/ tested/ verified. 2
Almost Certain Defect is obvious and kept from affecting Customer. 1
FMEA Step 5: Additional InformationFMEA Step 5: Additional Information
s One thing that will save a lot of time is if the Black Belt defines the scales and definitions previous to the FMEA meeting
s Scales do not have to be 1-10. They may also be 1, 3, 7, 10 or similar scale
s Additional characteristics may be factored into the RPN. For example, one Black Belt added an “Impact” characteristic. The intent was to quantify the impact to the process
FMEA: Step 6FMEA: Step 6s We could put the following scores for the
information we had below:
Customer does not receive product
Type/operator
Customer gave wrong info
Customer gave wrong info
34
4
4
2
2
2
4
2Repeat/verify info with customer (shipping vs
billing address)
Quality review by random sampling
Repeat/verify info with customer (shipping vs
billing address)
FMEA: Step 7FMEA: Step 7
s Risk Priority Number (RPN) --- The risk priority number allows the team to quantify various failure modes to assist in prioritizing the team’s improvement efforts. The RPN is the product of:
Severity x Occurrence x Detection The value of each of these characteristics is determined by the team.
s The higher the RPN, the higher priority the potential failure mode becomes. Prevention becomes the focus of the team
s Risk Priority Number (RPN) --- The risk priority number allows the team to quantify various failure modes to assist in prioritizing the team’s improvement efforts. The RPN is the product of:
Severity x Occurrence x Detection The value of each of these characteristics is determined by the team.
s The higher the RPN, the higher priority the potential failure mode becomes. Prevention becomes the focus of the team
Let’s Look at Each Characteristic
FMEA: Step 7FMEA: Step 7s We could put the following scores for the
information we had below:
Customer does not receive product
Type/operator
Customer gave wrong info
Customer gave wrong info
34
4
4
2
2
2
4
2Repeat/verify info with customer (shipping vs
billing address)
Quality review by random sampling
16
32
24
We Get An RPN =4X2X2= 16
Repeat/verify info with customer (shipping vs
billing address)
FMEA: Before ActionsFMEA: Before Actions
122Repeat/verify info with customer (shipping vs billing
address)
3Operator error2
82Repeat/verify info with customer (shipping vs billing
address)
2Customer gave wrong info
(credit card)
2Order delayed
162Repeat/verify info with customer (shipping vs billing address)
2Wrong address4Order not deliverable
605Pre-production report4Part has EOL/leadtime
increased
3Order cancelled
41Call customer1Part deviation4
605Verify order with customer3Customer changes mind
4Customer receives incorrect
product
484Quality review by random sampling
3Type/operator4
24Repeat/verify info with customer (shipping vs billing address)
23Type/operator4
324Quality review by random sampling
2Customer gave wrong info
4
162Repeat/verify info with customer (shipping vs billing
address)
2Customer gave wrong info
4Customer does not receive
product
Incorrect info
Sales creates
quote/order
RPNDET
Current Controls
OCC
Causes of Failure (X’s)
SEV
Failure Effects
Failure Mode
Process Function
FMEA: Step 8FMEA: Step 8s Recommended Actions --- Actions that are decided on by the
team that will eliminate, reduce the impact or prevent the failure mode from occurring.
Customer gave wrong info 2 4Quality review by
random sampling 32 Confirm Customer Requirement
before issue order
FMEA: Step 9FMEA: Step 9s Responsible Person & Target Date --- Actions have a much better
rate of completion when they are assigned a person with an expected date of completion. Once completed, update the FMEA form and fill out the “Taken Action” field.
R. Day 12-Dec-02
Customer gave wrong info 2 4Quality review by
random sampling 32Confirm Customer
Requirement before issue order
FMEA: Step 10 and 11FMEA: Step 10 and 11
10. Update FMEA documents as appropriate11. Re-assign the re-assign Severity, Occurrence and
Detection ratings. Then Recalculate RPN’s
R. Day 12-Dec-02
4Quality review by random sampling 32 Confirm Customer
Requirement before issue order
As recommend Actions 4 1 2 8
s Break into your designated groups. s Use the XY matrix created during the last
module.s Using the methodology you have learned today,
create a preliminary FMEA for two steps from the in-class project.
s You have 30 minutes for this exercise.s Be prepared to report your results to the class.
In Class ExerciseIn Class Exercise
Failure Modes Effects Analysis (FMEA)Failure Modes Effects Analysis (FMEA)Six Sigma Continuous Improvement TrainingSix Sigma Continuous Improvement Training