Post on 13-Nov-2014
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What is Six Sigma ?
Understanding Variation
When the Lord created the world and people to live in it - an enterprise which, according to modern science, took a very long time – I could well imagine that he reasoned with himself as follows:
“If I make everything predictable, these human beings, whom I have endowed with pretty good brains, will undoubtedly learn to predict everything,
and they will thereupon have no motive to do anything at all,
because they will recognize that the future is totally determined and cannot be influenced by any human action.
Understanding Variation
On the other hand, if I make everything unpredictable,
they will gradually discover that there is no rational basis for any decision whatsoever and, as in the first case, they will thereupon have no motive to do anything at all.
Neither scheme would make sense.
I must therefore create a mixture of the two.
Let some things be predictable and let others be unpredictable.
They will then, amongst many other things, have the very important task of finding out which is which.
Understanding Variation
Variation is inherent to a process……
Understanding Variation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Sum
Mean
S2
S1
X X–X (X-X)2
i 1
(Xi- X ) 2
n
n 1
(Xi- X ) 2
i 1
n
n 1
(Xi- X ) 2
n
130
166
178
131
140
125
127
145
110
184
161
194
171
125
163
2250
150
400
256
784
361
100
625
529
25
1600
1156
121
1936
441
625
169
9128
652
25.53
–20
16
28
–19
–10
–25
–23
–5
–40
34
11
44
21
–25
13
X
X =X
ii =1
n
nSample Mean
Sample Standard Deviation s =
(Xi- ) 2
i 1
n
n 1
Understanding Variation
If we take the height of all the people of India and draw a distributionOf frequencies it will tend to follow a normal distribution
Understanding Variation
MeanX-bar
Understanding Variation
MeanX-bar LSLUSL
LSL and USL are those specification limits beyond which your product doesn’t have a salable value in the market
Understanding Variation
MeanX-bar USLLSL
T
Cp = T/6σ
Cpk = {(Mean - LSL)/3σ ,(USL - Mean)/3σ }
Understanding Variation
-3s -2s -1s X +1s +2s +3s
68.26%
95.46%
99.73%
68.26% Fall Within +\- 1 Sigma
95.46% Fall Within +\- 2 Sigma
99.73% Fall Within +\- 3 Sigma
SIGMA
34.13% 34.13%
13.60% 13.60%2.14% 2.14%
0.13% 0.13%
Understanding Variation
0x
y
1SD= 68% DATA
2SD = 95% DATA
3SD = 99%DATA
Understanding Variation
Common Cause
Special Cause
Type of Variation Characteristics
Always Present Expected
PredictableNormal
Not Always Present
UnexpectedUnpredictable
Not NormalHas a surprise
element
Characteristics
Common vs. Special Cause
Understanding Variation
• 2 short or long landings at almost all major airports each day
• Unsafe drinking water almost 15 minutes each day
• No electricity for almost 7 hours each month
• 20000 lost articles of mail per hour
• 5000 incorrect surgical operations per week
• 200000 wrong drug prescriptions each year
Can you believe, all above correspond to a performance level of 99%!
• 50 Newborn Babies Dropped At Birth By Doctors Each Day
Understanding Variation
• Then We Would Have…• One Hour Of Unsafe Drinking Water Every Month• Two Unsafe Plane Landings Per Day At O’Hare International
Airport In Chicago
• 16,000 Pieces Of Mail Lost By The U.S. Postal Service Every Hour
• 500 Incorrect Surgical Operations Each Week• 50 Newborn Babies Dropped At Birth By Doctors Each Day• 22,000 Checks Deducted From The Wrong Bank Accounts Each
Hour• 32,000 Missed Heartbeats Per Person, Per Year
If We Accepted The Goal Of 99.9% Quality
Understanding Variation
The Sigma scale of measure is perfectly correlated to such characteristics as defects-per-unit, parts-per-million defective, and the probability of a failure/error.
Sigma Rating PPM2 308,5373 66,8074 6,2105 2336 3.4
Process Defects per Capability Million Opportunities
Understanding Variation
Higher σ = less variation = fewer defects
= better performance
Lower Specification
Limit (LSL)
Upper Specification Limit (USL)
6 σ process
Understanding Variation
SPECIFICATION WIDTH
Process Width
Cp = Specification width Process Width
Process variability
If the variability is well within the specified width then the process is capable
3-Sigma VS 6-Sigma Process
LSL USL LSL USL
-6 -5 -3 -2 -1 0 1 2 3 4 5 6 -6 -5 -3 -2 -1 0 1 2 3 4 5 6
Z- Scale Z- Scale
1.5 1.5
66,807 DPMO 3.4 DPMO
3-Sigma Process 6-Sigma Process
In every process it is observed that 1.5 Sigma long term drift takes place
6-= 99.99966%
3-= 99.73%
What is Six Sigma ?
A Measurement Scale Which Compares The Output
Of A Process To Customer Requirements
What is Six Sigma ?
93% 66,807 3.0
98% 22,750 3.5
99% 6,210 4.0
99.87% 1,350 4.5
99.9997% 3.4 6.0
DPMODPMOPercentPercent
Understanding Variation
IRS - Tax Advice (phone-in)
SIGMA (with ±1.5 Sigma Shift)
2 3 4 5 6 7
100K
10K
1K
100
10
1
(233 ppm)
Best in Class
Purchased Material Lot Reject Rate
Domestic AirlineFlight Fatality Rate
(0.43 ppm)
Payroll Processing
Journal VouchersWire Transfers
Air Line BaggageHandling
Order Write-upAverageCompany
Restaurant Bills Doctor Prescription Writing
(6210 ppm)
(3.4 ppm)
Benchmarking
(66810 ppm)
Understanding Variation
Sweet Fruit – 6 Design for Six Sigma (DFSS)
Bulk of Fruit – 4 to 5 Process Improvement Six Sigma Tools
Low Hanging Fruit – 3 to 4
Ground Fruit – Up to 2Logic and Intuition + Basic Quality Tools
Process Entitlement
DMAIC
DFSS
Kano Model
Satisfaction
+
–
Dissatisfaction
One-DimensionalDelighters
Must Be
InnovationCompetitive Priority
Critical Priority
FunctionalDysfunctional
Taguchi Model
Cos
t
Performance
Six Sigma
Six sigma is about reducing variations in a process
Customer Happy
Methodology
The methodology:
DMAIC
(define, measure, analyse, improve, control)
methodology to root out and eliminate the causes of defects
Methodology
Charter
Business Case
Problem Statement
Goal Statement
Project Scope
Milestones
Roles
Definitions:
– Units
– Defects
– Opportunity
– Process Sigma
Data Collection Plan
Data Display Tools
Process
Stratification Map Analysis C & E
Scatter Plots Regression DOE
Solution Summary
Cost/Benefit Analysis
Pilot
Standardizing
Response Plan
CPM Tree
S I P O CS
Monitoring
Documenting
Root Cause Analysis
Wk 2 Wk 4 Wk 8Wk 6 Wk 12Wk 10
AA
BB
C
D
G
H
I
J
E
Wk 1 Wk 3 Wk 5 Wk 7 Wk 9 Wk 11
F
Induce Statistical thinking
Practical problemPractical problem
Statistical problemStatistical problem
Statistical Statistical solutionsolution
Practical solutionPractical solution
DMAIC Methodology
Define
Measure
Clarify Customer RequirementsClarify Customer Requirements
Define Process (SIPOC)Define Process (SIPOC)
Charter A TeamCharter A Team
Define
Measure
Analyze
$ Identify And Quantify The Opportunity $
Clarify Customer Requirements
Define Process (SIPOC)
Output Measurement
Root Cause Analysis
Stratification
Scatter Plots Regression
Map Analysis C & E
Process Variation
DOE
Charter A Team
DMAIC Methodology
Improve
Implement
Control
Monitoring Standardizing Documenting
Generate Solutions
Select
Pilot
Response Plan
Different Faces
Plan 1 Charter/Theme Define
2 Data Collection Measure
3 Root Cause Analyze
Do 4 Solution ImprovePlanning AndImplementation
Check 5 ConfirmingSolution Works
6 Standardization Control
Act 7 Reflect NextSteps
PDCA 7 STEPS “DMAIC”
The Different Faces
Define The Customer, Their Requirements, The Team Charter And The Core Business Process• Team Charter Documented And Reviewed With Champion• Customer Requirements Derived And Documented• Validated High Level Process Map Completed
Deliverables
DefineDefine Measure Improve ControlAnalyze
Define
Measure The Core Business Process Performance • Identified Key Measures• Developed A Data Collection Plan For The Process• Executed The Plan And Document Results• Process Variation Displayed With Appropriate Charts
And Graphs• Calculated Baseline Sigma Performance
Deliverables
Define MeasureMeasure ImproveAnalyze Control
Measure
• Complete Detailed Process Map For At Least
One Subprocess
• Identify Process Streamlining Opportunities
• Identify, Verify And Quantify Root Causes
• Establish Improvement Targets
• Quantify Opportunity
Analyze (The Data And Map) To Determine Root Causes/Opportunities
AnalyzeAnalyzeMeasure Improve ControlDefine
Deliverables
Analyse
Generate, Select, Design And Implement Improvements • Solution Design Developed And Documented• Solution Validated And Cost/Benefit Proposal Presented
To Champion• Solutions Tested On A Small Scale Or Pilot Program• Implementation Plan Developed And Executed
AnalyzeMeasure ImproveImprove ControlDefine
Deliverables
Improve
Institutionalize The Improvement And ImplementOngoing Monitoring • Developed, Documented And Implemented An Ongoing Process/Monitoring Plan• Standardized The Process• Procedures Documented• Response Plan Developed And Displayed
Deliverables
Define Measure ImproveAnalyze ControlControl
Control
Six Sigma Organisation
Site LeaderSite Leader
Champion/SponsorChampion/Sponsor
Master Black BeltMaster Black Belt
Black BeltBlack Belt
Team MembersYellow Belt
Team MembersYellow Belt
Green BeltGreen Belt
Quality Leader/Six Sigma
Coordinator
Quality Leader/Six Sigma
Coordinator
Black BeltBlack Belt
Green BeltGreen Belt
Team MembersYellow Belt
Team MembersYellow BeltTeam Members
Yellow BeltTeam Members
Yellow BeltTeam Members
Yellow BeltTeam Members
Yellow Belt
External ConsultantExternal
Consultant
Six Sigma Project Example
Yield Improvement in PSF Plant