Early Life Failures
Bill Smith’s findings….
Bill Smith’s paper concluded that if product was found
defective and corrected in the process, some defects are
likely to be detected by customer in early usage.
Corrections and reworks in process
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
1
The six sigma metric:
Processes tend to
shift increasing the
chances of defects.
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
2
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
3
ATTACKING PROBLEMS: PRE-PROCESS
EXCELLENCE
PRACTICAL
PROBLEM
PRACTICAL
SOLUTION
NEXT
PROBLEM
In some cases, effective… But can result in perceptions of fire
fighting and in recurring problems.
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
4
The DMAI2C/Six Sigma Way to Attack
Problems
Define
PRACTICAL
PROBLEM
STATISTICAL
PROBLEM
Measure
Control
Innovative
Improvement
PRACTICAL
SOLUTION
STATISTICAL
SOLUTION
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
Analyze
5
The Six Sigma Funnel to reduce Process Variation
All possible Xs
Define
Measure
Analyze
Improve
Vital
Few
‘x’s
Control
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
6
Application Strategy
Define
Measure
Analyze
•
•
•
•
Define project scope
Validate measurement systems
Establish initial capability for Ys
Process exploration of all potential Xs
Characterize the response and analyze the raw data
Bimodal? Skewed? Is the problem with mu or sigma?
Use graphical analysis, regression, multivariate analysis,
hypothesis testing, and basic statistical tools to identify the
likely families of variability
Improve
Identify the likely Xs
Use the design of experiments to find
the critical few Xs
 Move the distribution (shift mu)
 Shrink the spread (decrease sigma)
 Confirm the results
Control
Mistake-proof the process
Tolerance the process
Measure the final capability
Place appropriate process controls on the critical Xs
Document the effort and results
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
7
Application Strategy
Phase 1: Product Measurement
YTP
X1 , , X N
Operation
Verify
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
Y1 , , YN
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Application Strategy
Phase 2: Product Performance Analysis
X2
X1 X 5 X
4
X3 X6
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
X1
X5
9
EMC Application Strategy
Phase 4: Process Control
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
10
The Process Six Sigma Roadmap
Define
Charter, Teaming
Measure
FMEA , Process Map,
C&E MSA Cpk
Analyze
Anova, Regression, Multivariate
analysis
Improve
Design of Experiments, Response
Surface Optimization, Poka Yoke
Control
SPC, Control Plans
All possible Xs
Few
‘x’s
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
11
Value Stream
Mapping
Define
Product Families
Product flow
Analysis
Measure
Analyze
Set-up
Reduction
Material
Replenishment
Workplace
Design
Improve
SIPOC
Detailed Process Map
Failure Modes Analysis
FMEA
Measurement System
MSA
T-Test, Chi Square,
ANOVA, COV
Design of Experiments
DOE
Regression Analysis
5S
Implementation
Control
Standard Work
Performance
Metrics
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
Control Strategies
Mistake Proofing
12
Six Sigma Performance Metrics
Individual
Parts per
million,
ppm
Process
capability
Cp Cpk
Pp,Ppk
Product
Defects per
Million
opportunities,
DPMO
First Time
Yield
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
13
Rolled Throughput Yield Example
The pedal sub-assembly process is outlined below. We have
identified the DPU associated with each process step.
Select R
and
L part #s
from bin
location
DPU = 0 02
Handtighten
L pedal
DPU = 0 01
Process step
Select part
Hand tighten L
Hand tighten R
Torque L
Torque R
Total
DPU
0.02
0.01
0.01
0.03
0.03
0.1
Handtighten
R pedal
DPU = 0 01
Actual
Yield
98%
99%
99%
97%
97%
Torque L
pedal to 5 ft
Lbs
DPU = 0 03
RTY  e
 dpu
e
0.1
Torque R
pedal to 5 ft
Lbs
DPU = 0.03
 90%
OR
RTY=0.98*0.99*0.99*0.97*0.97
=90%
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
14
Example Process Map for Assembly and Packaging
Process
Start boundary:
Assembly and Packaging
Run initiated per
production schedule
Bluing
Fitting
Suppliers:
•valve
manufacturers
(external & internal)
•body manufacturers
(external & internal)
•planing shop
•packaging materials
Suppliers
•turning shop
•production planning
Tightening
Inputs:
•valves
•bodies
•packaging
Materials
•miscellaneous
consumables
•production
schedules
Packaging
End boundary:
Packages released
for transfer to
warehouse
Leak
Test
Outputs:
•assembled and
packaged valves
•production
•materials
usage
reports
•leak test report
QA
Release
Customers:
•warehouse
(internal)
•end
users(external)
•production
scheduling
•purchasing
•QA
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
15
ORGANIZATION FOR SIX SIGMA
IMPLEMENTATION
CEO
Corporate Quality Council (Group of Champions)
Black Belts (Facilitators) (Corporation)
Green Belts
...
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
16
Six Sigma Steering Committee
CEO
Quality
Finance
Service
Manufacturing
H.R.
Marketing
Master Black Belt
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
17
Design for Six Sigma (DFSS)
Taking variability reduction upstream from manufacturing (or
operational six sigma) into product design and development
Every design decision is a business decision
Customer
CTQ’s
System
parameters
Subsystem
parameters
Component
parameters
Part
characteristics
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
18
Six-Sigma/DMAIC, lean, and DFSS: How they fit together
DFSS
Lean
Design
Predictive
Quality
into
products
Eliminate
Waste,
Improve
Cycle time
Robust
LeadTime
Design for six-sigma
Lean
Six
sigma/
DMAIC*
Eliminate
Defects,
Reduce
variability
Capable
Variation Reduction
The “I” in DMAIC may become DFSS
Prof. Indrajit Mukherjee, School of Management, IIT Bombay
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