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Module-1
Six Sigma Introduction
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Established by Motorola in the 1980s and still being
developed. Seen as a cornerstone to the companys
culture.
Companies adopting 6 Sigma include General Electric,
Allied Signal, ABB, Sony, Lockheed Martin, Ford,Nissan and many others
It is essential for companies to take responsibility fortheir own (unique) programme.
History of Six Sigma
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A systematic approach to process
improvement. Processes can be related to design,
manufacturing or administrative functions.
It involves the use of statistical tools andtechniques to analyse & improve processes.
The relentless pursuit of variability reduction
and defect elimination.
LSL USL
LSL USL
What is Six Sigma?
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Where can Six Sigma be applied?
Six Sigma can be applied to all company processes A distinction is often made between:
Design applications (Design for Six Sigma)
Manufacturing applications (Operational Six Sigma) Administrative and Service applications (Transactional
Six Sigma)
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Used in statistics as a measure of variation
Sigma=
Standard Deviation
The central philosophy of 6 Sigma is the reductionof variation in all our work processes
The Six Sigma Metric
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The 3 Sigma mentality means 2700 defectives per million!
Lower
Spec.
Limit
Upper
Spec.
Limit
-1 +1
y 1 = 68.26%
+2-2
y 2 = 95.44%
-3 +3
y 3 = 99.73%
y
(Target)
The Normal Distribution
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-6 -5 -4 -3 -2 -1 y +1 +2 +3 +4 +5 +6
Lower
Specification
Limit
Upper
Specification
Limit
Normal DistributionCentred on Target
6 99.999999999 0.002
5 99.99994 0.6
4 99.9937 63
Specification
Limit
Percent within Specification
(Centred Distribution)
Defects Per Million
(Centred Distribution)
3 99.73 2700
The 6 Sigma Metric
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Lower
Spec.
Limit
Upper
Spec.
Limit
2700
Defects per Million
Lower
Spec.
Limit
Upper
Spec.
Limit
0.002
From 3 Sigma to 6 Sigma
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1.5 Shift
Lower
Spec.
Limit
Upper
Spec.
Limit
-6 -5 -4 -3 -2 -1 y +1 +2 +3 +4 +5 +6
Motorolas 6 Sigma Metric
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SpecificationLimit
Percent withinSpecification
(Centred)
Percent withinSpecification(1.5 shift)
Defectsper million(Centred)
Defectsper million(1.5 shift)
1 68.26 30.23 317400 697700
2 95.44 69.13 45600 308700
3 99.73 93.32 2700 66810
4 99.9937 99.38 63 6210
5 99.99994 99.98 0.6 233
6 99.9999998 99.9997 0.002 3.4
Motorolas definition of a 6 Sigma process is one
which achieves 3.4 defects per million or less.
Motorolas 6 Sigma Metric
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A Process with 10 Steps
Each Process Step has a 3 Quality Level = 93.32% Yield
The probability of success (non-defective) at each step = 0.9332
The probability of overall success = 0.933210 = 0.5008
Overall Process Yield = 50.08% (499200 dpm)
6 Sigma & Defect Rates
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Another Process with 10 Steps
Each Process Step has a 6 Quality Level = 99.99966% Yield
The probability of success (non-defective) at each step = 0.9999966
The probability of overall success = 0.999996610 = 0.999966
Overall Process Yield = 99.9966% (34 dpm)
6 Sigma & Defect Rates
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To produce a defect uses production time, production capacity,
energy, raw material.
It must be identified by testing and/or inspection,
transported, stored, re-tested.
It must be reworked and then checked or scrapped and disposed
of
Often this non-value added activity is not shown within the factorymetrics - the hidden factory
This all takes time, people, material, energy, floor space....
The Hidden Factory
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Raw
Materials Mixing Forming Cooling
Finished
Product
FinalInspection
100% Pass
0% FailThis process has 100% yield. Ourcustomers would be very pleased.
Should we be just as happy?
Process Yield
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RTY = 0.925 x 0.94 x 0.95 = 0.826 = 82.6%
0% Fail7.5% of Units
6% of Units
5% of Units
Raw
MaterialsMixing Forming Cooling
Finished
Product
Final
Inspection
100% Pass
0% Fail
Rework
& RepairRework
& Repair
Rework& Repair
Rolled Throughput Yield
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Define
Identify
Opportunity
Identify Key ys
(Outputs)
Measure
y = f(x)
Identify
Critical xs
(Inputs)
Analyse
Optimise
xs
Improve
Control
xs
Control
DMAIC Improvement Process
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Define ImproveMeasure Control Control Critical xs
Monitor ys
Validate ControlPlan
Close Project
1 5 10 15 20
10.2
10.0
9.8
9.6
Upper Control Limit
Lower Control Limit
y
Phase Review
Analyse Characterise xs
Optimise xs
Set Tolerances for xs
Verify Improvement
15 20 25 30 35
LSL USL
Phase Review
y=f(x1,x2,..)
y
x
. . .
. . .
. .. . .. . .
Identify Potential xs
Analyse xs
Select Critical xs
Phase Review
Run 1 2 3 4 5 6 7
1 1 1 1 1 1 1 12 1 1 1 2 2 2 23 1 2 2 1 1 2 2
4 1 2 2 2 2 1 15 2 1 2 1 2 1 26 2 1 2 2 1 2 17 2 2 1 1 2 2 18 2 2 1 2 1 1 2
Effect
C1 C2
C4
C3
C6C5
x
xx
xx
xx
xx
x
x
Select Project
Define ProjectObjective
Form the Team
Map the Process
Identify CustomerRequirements
Identify Priorities
Update Project File
Phase Review
Define Measures (ys)
Evaluate Measurement
System
Determine Process
Stability Determine Process
Capability
Set Targets forMeasures
15 20 25 30 35
LSL USL
Phase Review
DMAIC Improvement Process
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1. Define the Problem
2. Interim Actions
3. Acquire and Analyse Data
4. Determine Root Cause
5. Evaluate Possible Solutions
6. Action Plan and Implement
7. Verify the Results
8. Standardise and Future Actions
Problem Solving
Process
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ReviewTemplates
HistogramPareto
FlowChart
Effect
Man
Maint. Method
Machine
Cause & EffectDiagram
x
xxx
x
xx
xx
x
xx
ScatterDiagram
y=f(x)y
x
RegressionAnalysis
ProcessCapability
MeasurementSystemVariation Reproducibility
Repeatability
Accuracy
StabilityCalibration
Gauge R&R
FMEA
440 500 560 620 680 740
95% Confidence Interval for Mu
568 5 78 5 88 59 8 60 8
9 5 % Co n f id e n c e In te rv a l fo r M e d ia n
V a r i a b l e : S A T
A-Sq u a re d :P-Va lu e :
Me a nStDe vVarianceSk e wn e s sKu r to s isN
Min imu m1 s t Qu a r t i leMe d ia n3 rd Qu a r t i leMa x imu m
5 7 7 .3 2 3
57.159
5 7 0 .7 1 1
0.3290.512
5 9 0 .2 4 065.101
4 2 3 8 .0 82 .6 3 E-0 2-4 .0 E-0 1
100
4 2 6 .0 0 05 4 2 .2 5 05 9 8 .0 0 06 4 0 .0 0 07 4 0 .0 0 0
6 0 3 .1 5 7
75.626
6 0 5 .0 0 0
An d e rs o n -Da rl in g No rma l i ty T e s t
95% Confidence Interval for Mu
9 5 % Co n f id e n c e In te rv a l fo r Sig ma
95% Confidence Interval for Median
Descrip t ive S tat i s ti csMinitab Software
Run yA B C D E F G
1 1 1 1 1 1 1 1 y12 1 1 1 2 2 2 2 y23 1 2 2 1 1 2 2 y34 1 2 2 2 2 1 1 y45 2 1 2 1 2 1 2 y56 2 1 2 2 1 2 1 y67 2 2 1 1 2 2 1 y78 2 2 1 2 1 1 2 y8
Design of Experiments
A1 A2
Analysis of Variance
Robust DesignTolerance Design
CustomerFocus
MistakeProofing
MAIC
ProcessValidation
A Few of the Six Sigma Tools!