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Six Sigma
Department of Mechanical Engineering, The Ohio State University
Sl. #1
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Six Sigma Revolution

Deming’s teaching about quality

Quality initiatives:
 SPC, Just-in-time, TQM

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Motorola in 1980’s
GE and AlliedSignal in 1990’s
 Radical Changes in products and services

Companies:
 TI, ABB, DuPont, Ford, Dow Chemical, Johnson Controls, BASF,
American Express, Nokia, Toshiba,
Department of Mechanical Engineering, The Ohio State University
Sl. #2
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What is Six Sigma?

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Vision
Philosophy
Company Strategy
Method
Culture
Tool
Department of Mechanical Engineering, The Ohio State University
Sl. #3
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The Cost of Poor Quality (COPQ)
Inspection
Scrap
Warranty
Rejects
Tangible Quality Costs
Rework
Lost sales
Lost Opportunities
Late delivery
More Setups
Hidden Factory
Expediting costs
Engineering change orders
Lost Customer Loyalty
Long cycle times
Excess inventory
Department of Mechanical Engineering, The Ohio State University
Sl. #4
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The Nature of the Process
Off-Target
xx
xx x
x xx
On-target,
less variation
Variation
x
xx
x
x
xxx
x
x
x x
x
x x
x
x
Six Sigma goal identifies and controls process variations and targets.
Six Sigma methodology identifies processes that are off-target,
Department of Mechanical Engineering, The Ohio State University
Sl. #5
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What is Six Sigma?

Integrates




Customer focus
Breakthrough improvement
Continuous improvement
People Involvement

Defines goals and performance metrics that
yield clear and measurable business results.

Applies statistical tools to achieve
breakthrough financial gains
Department of Mechanical Engineering, The Ohio State University
Sl. #6
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Six Sigma Focus





Meeting customer needs
Rapid breakthrough improvement
Process capability and improvement
Positive and deep culture change
Real financial results that impact the
bottom line
Department of Mechanical Engineering, The Ohio State University
Sl. #7
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Structure / Roles
Executive Management
Champion
Master Black Belt
Black Belt Black Belt
Green Belt Green Belt Green Belt
Department of Mechanical Engineering, The Ohio State University
Sl. #8
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Building the 6 Team

Executive Management:
 Set meaningful goals and propel implementation of six sigma in the organization

Champion:
 Create general scope and set strategic direction of the projects and teams
 Drive project success by removing obstacles and allocating sufficient resources

Master Black Belt
 Consults, trains and mentors the local organization on Six Sigma

Black Belt:
 Delivers successful projects (high corporate gains) using the Breakthrough Strategy

Green Belt:
 Delivers local projects (lower monetary gains) using the Breakthrough Strategy

Other key members:
 Process Owner: maintains system improvements at project completion
 Process Sponsor: provides resources, time, money and direction of your
project


Financial Analyst: verifies the financial gains of the project
Team members: implement the steps for six sigma success
Department of Mechanical Engineering, The Ohio State University
Sl. #9
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What is Sigma?



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
 (sigma) - A Greek letter
In statistics - the “standard” deviation from
the average/mean
Assumption of Gaussian/Normal distribution
Six Sigma Methodology uses  to define the
capability of a process
As the standard deviation of your process
decreases, the “sigma level” of your process
increases.
Department of Mechanical Engineering, The Ohio State University
Sl. #10
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Normal/Gaussian Distribution
34.13%
34.13%
13.06%
0.13%
13.06%
2.14%
-3
2.14%
2
1
m
1
2
3
68.26%
95.46%
99.73%
68.26% of the population is within +/-??1of the ?
Department of Mechanical Engineering, The Ohio State University
Sl. #11
0.13%
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Process Capability
6 process is to get acceptable results
through:
» Identification of variations
» Quantification of variations
» Elimination/control of variations
USL
LSL
Defects
Defects
Acceptable
Department of Mechanical Engineering, The Ohio State University
Sl. #12
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Six Sigma - Goal

1
2
3
4
5
6
Defects per
Million Opp.
691,462
308,537
66,807
6,210
233
3.4
Department of Mechanical Engineering, The Ohio State University
Sl. #13
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Six Sigma -- Practical Meaning
99% Good (3.8 Sigma)
99.99966% Good (6 Sigma)
16,000 lost articles of mail per hour
5.4 articles lost per hour
22,000 checks deducted from the
wrong bank account each hour
7.5 checks deducted from the
wrong bank account each hour
500 incorrect surgical operations per
week
1.7 incorrect operations per week
2 unsafe plane landings per day at
O’Hare International Airport in Chicago
1 unsafe plane landing every
four years
50 newborn babies dropped at birth
by doctors each day
1 newborn baby dropped at
birth by doctors every 2 months
Department of Mechanical Engineering, The Ohio State University
Sl. #14
** Source: Six Sigma Revolution, George Eckes
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Overall Approach
Define
Define Problem
Measure Practical Problem
Analyze
Statistical Problem
Improve Statistical Solution
Control Practical Solution
Department of Mechanical Engineering, The Ohio State University
Sl. #15
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The Strategy
USL
LSL
•
Characterize
•
Optimize
•
Breakthrough
T
USL
LSL
T
USL
LSL
T
LSL’
USL’
Department of Mechanical Engineering, The Ohio State University
Sl. #16
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The 6 Sigma Breakthrough Method
D
Characterization
M
A
I
Define
Measure
Analyze
Improve
1
Define project and scope
2
Establish process
3
Identify key input/outputs variables
4
Identify process capability/
measurement system
5
Establish Product Capability
6
Identify Variation Sources
7
Screen Potential Causes
8
Verify Variable Relationships
9
Validate Measurement System
Optimization
C
Control
10 Implement Process Controls
Department of Mechanical Engineering, The Ohio State University
Sl. #17
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Defining the Process

Team members who understand the
process

Put together a flow of the process
 An common foundation for team activity
 Identification of outputs for measurement
and capability studies
 Estimates of sigma levels at each step
Department of Mechanical Engineering, The Ohio State University
Sl. #18
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Project Scope
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Problem statement
Goals/objectives for the team
Measurable gains (monetary terms)
Milestone
Customer needs and requirements
Department of Mechanical Engineering, The Ohio State University
Sl. #19
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Process Mapping

What is process mapping?
 Graphical depiction of the ACTUAL
process

What will the tool identify?
 All value added and non-value added
process steps
 Process inputs (X’s)
 Process or product outputs (Y’s)
 Data collection points
Department of Mechanical Engineering, The Ohio State University
Sl. #20
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Basic Flowchart Symbols
Activity
Start / Stop
Flow Line
Decision Point
A
Connector
A
Department of Mechanical Engineering, The Ohio State University
Sl. #21
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Basic Structure
No
Start
Rework
Yes
•
•
•
•
A
What are the steps to capture?
What are the operational steps?
What are the decision points?
Where are the problem area?
Good
A
Finished
goods
Bad
Scrap
Department of Mechanical Engineering, The Ohio State University
Sl. #22
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Versions of a Process
What You Think It Is...
What It Actually Is...
What You Would Like
It To Be...
Start
Start
No
Yes
Start
Department of Mechanical Engineering, The Ohio State University
Sl. #23
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Preparing the Process Flowchart

Team Effort





Engineers
Line Operators
Line Supervisors
Maintenance Technicians
Inputs to Flowcharts

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Brainstorming
Operator Manuals (SOP’s, AOP’s, etc.)
Engineering Specifications
Operator Experience
5M’s and an E (Fishbone)
» Machine (Equipment), Method (Procedures), Measurement,
Materials, Manpower (People), Environment
Department of Mechanical Engineering, The Ohio State University
Sl. #24
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Measurement Phase

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
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The input/output variables
The capability of the process
The defects in the process
Sigma level
Department of Mechanical Engineering, The Ohio State University
Sl. #25
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Purpose of Measurement Phase


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Identify and define defects
Identify key input variables (X’s) and
key output variables (Y’s)
Document the existing process
Establish a data collection system for
your X’s and Y’s if one does not exist
Evaluate measurement system for
each key output variable using C&E,
FMEA, etc.
Department of Mechanical Engineering, The Ohio State University
Sl. #26
GATEWAY
The Importance of Defects
• Since Six-Sigma
focuses on reducing
defects, it is
necessary that each
project definition
clearly specifies the
defect(s) that will be
reduced
• Count the number of
times the letter f appears
in the following
statement:
The final information are
the results of years of
scientific studies and
were often combined with
years of experience.
We must often configure
the files for the final
report during the
conference.
Department of Mechanical Engineering, The Ohio State University
Sl. #27
Six Sigma Revolution, George Eckes, pg 2
GATEWAY
A simple test

What was your answer?
The final information are the results
of years of scientific studies and
were often combined with years of
experience. We must often
configure the files for the final
report during the conference.
Department of Mechanical Engineering, The Ohio State University
Sl. #28
GATEWAY
What Causes Defects?

Variation due to:
 Manufacturing processes
 Supplier (incoming) material
variation
 Unreasonably tight
specifications (beyond customer
needs)
 Unstable Parts and Materials
 Inadequate training
 Inadequate Design Margin
 Insufficient Process Capability
Department of Mechanical Engineering, The Ohio State University
Sl. #29
GATEWAY
How Do We Improve Capability
• Understand that the Outputs (Y’s) are determined by
Inputs (X’s).
Y = F (x1, x2, x3,…xn)
• If we know enough about our X’s we can accurately predict
Y without having to measure it.
• If we don’t know much about our X’s, then we have to
resort to inspection and test.
• If can control the X’s, then we reduce the variability in Y,
which decreases defects, and possibly, eliminates/reduces
inspection and test.
Department of Mechanical Engineering, The Ohio State University
Sl. #30
GATEWAY
Data Collection Plan
What to
measure
Type of
measurement
Type of
Data
Operational
Definition
Data
Collection
Form(s)
Sampling
Baseline
Six Sigma
Department of Mechanical Engineering, The Ohio State University
Sl. #31
Six Sigma Revolution, George Eckes, pg 72
GATEWAY
Data Collection Data

Type of Data
 Discrete
 Continuous

Sampling
Y-Axis
 Representative
 Random Sampling
X-Axis
Department of Mechanical Engineering, The Ohio State University
Sl. #32
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Metrics
Metrics: What to measure?


Defects per million
opportunities (DPMO) drives
plant-wide improvement
Sigma level allows for
benchmarking within and
across companies
Department of Mechanical Engineering, The Ohio State University
Sl. #33
GATEWAY
Calculating Sigma-Level
• Sigma level
• units: item produced or being serviced
• defect: event that does not meet the customer’s requirement
• opportunity: chance for a defect to occur
• Calculate Defects per Million Opportunities (DPMO):
DPMO =
Total # defects x 1,000,000
(# of Opportunities for Error) x (# of units)
• Go to a Sigma Chart and Estimate the Sigma Level
Department of Mechanical Engineering, The Ohio State University
Sl. #34
Six Sigma Revolution, George Eckes, pg 99
GATEWAY
DPMO and Sigma Level
DPMO
Sigma Level
DPMO
Sigma Level
1000000
-3.4
158655
2.5
999997
-3.0
66807
3.0
999968
-2.5
22750
3.5
999767
-2.0
6210
4.0
998650
-1.5
1350
4.5
993790
-1.0
233
5.0
977250
-0.5
32
5.5
933193
0.0
3.40
6.0
841345
0.5
0.29
6.5
691462
1.0
0.02
7.0
500000
1.5
0.00
7.5
308538
2.0
0.00
8.0
Department of Mechanical Engineering, The Ohio State University
Sl. #35
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Tracking Trends in Metrics
Our objective is to track the trends in the Metrics to establish,
based on fact, our improvements. These metrics can be
productivity, defects, time, yield, etc.
Department of Mechanical Engineering, The Ohio State University
Sl. #36
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Purpose of the Analysis Phase

Establish baseline capability for key output
variables (potential and overall)

Examine both the process and data for analysis

Determine and validate the root causation of
project problem

To reduce the number of process input
variables (x’s) to a manageable number

To determine the presence of and potential
elimination of uncontrolled variables
Department of Mechanical Engineering, The Ohio State University
Sl. #37
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Three Sigma Process
Centered
LSL
USL
1.5 Sigma Shift
LSL
USL
Department of Mechanical Engineering, The Ohio State University
Sl. #38
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Three Sigma Process
Centered
LSL
USL
1.5 Sigma Shift
LSL
USL
Department of Mechanical Engineering, The Ohio State University
Sl. #39
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Six Sigma Process
Centered
LSL
USL
1.5 Sigma Shift
LSL
USL
Department of Mechanical Engineering, The Ohio State University
Sl. #40
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Analysis Tools
Analyze
Capabilities
Hypothesis Testing
Multi-Vari
ANOVA
Cause/Effect
Root Cause
Histogram
Pareto
Department of Mechanical Engineering, The Ohio State University
Sl. #41
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Purpose of the Improvement Phase

Key variables are identified and validated
during this process .

Look to eliminate, reduce or neutralize the
effects of the input or root cause.

Design experiments to manipulate the key
input variables (X’s) to determine their
effect on the outputs (Y’s).

Select the solution that impacts the root
cause the most.
Department of Mechanical Engineering, The Ohio State University
Sl. #42
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Design of Experiment
• Full Factorials
• 2K Factorials
• Fractional Factorials
Department of Mechanical Engineering, The Ohio State University
Sl. #43
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DOE Example



Objective: To reduce consistency variation in Y
Output: Variation (Lower is Better)
Full Factorial Inputs:
 RPM
 Speed
 Time
(Lo, Hi)
(Lo, Hi)
(Lo, Hi)
Main Effects Plot
16
14
12
10
8
RPM
Time
Speed
Department of Mechanical Engineering, The Ohio State University
Sl. #44
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Purpose of the Control Phase

Develop and implement long-term control
methods to sustain the gains identified

Document the control plan with specific
roles identified

Monitor long-term delivered capability
and performance

Verify benefits and cost savings
Department of Mechanical Engineering, The Ohio State University
Sl. #45
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Control Tools
Control
• Control Plan
• SPC
• Mistake
Proofing
• Automated
Control
Department of Mechanical Engineering, The Ohio State University
Sl. #46
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Dynamics of Execution Strategy
40 - 50 Inputs
M
Process Map/C&E
15 - 20 X’s
A
Capability/Multi-Vari
8 - 10 X’s
I
DOE
3-5 Critical
X’s
C
Control Plan
Department of Mechanical Engineering, The Ohio State University
Sl. #47
GATEWAY
Who needs Six Sigma?
Service
Mfg.
Design
6
Method
QC
Sales
Admin.
Maint.
As long as there is a process that produces an output, we can apply the Six Sigma
Methodology. Every function has a customer and a deliverable.
Department of Mechanical Engineering, The Ohio State University
Sl. #48
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Six Sigma Project Consideration

Project is supportive of corporate objectives

Project is focused on an ongoing process /
recurring events that is causing defects

A 70% reduction in defects results

Customer (internal or external) will see or feel
the result

Takes 4-6 months to complete

Little or no capital required
Department of Mechanical Engineering, The Ohio State University
Sl. #49
GATEWAY
Possible Six Sigma Projects
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
Low yield rate
High operating costs
High customer
failure/complaints
High scrap/rework
High inventory/WIP
High maintenance costs
Supplier product quality
problems
Low productivity
Long cycle times
Low machine utilization






Inaccurate information
Missing information
Poor process control
Frequent set up requirements
Long set up time
Unpredictable product
performance
Department of Mechanical Engineering, The Ohio State University
Sl. #50
GATEWAY
Six Sigma Success
Visible top-down leadership and commitment
Education and training
Recognize and focus on customer needs
World-class quality
Establishing meaningful,
focused metrics
DMAIC - Define, Measure, Analyze, Improve & Control
Department of Mechanical Engineering, The Ohio State University
Sl. #51
GATEWAY
Credits

This module is intended as a supplement to design classes in
mechanical engineering. It was developed at The Ohio State
University under the NSF sponsored Gateway Coalition (grant
EEC-9109794). Contributing members include:

Gary Kinzel…………………………………. Project supervisors
Phuong Pham.……………. ………………... Primary authors
L. Pham ………………………………….….. Audio voice


Reference:
Six Sigma Revolution, George Eckes, John Wiley & Sons,
Inc., New York, 2001.
Department of Mechanical Engineering, The Ohio State University
Sl. #52
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Disclaimer
This information is provided “as is” for general educational purposes;
it can change over time and should be interpreted with regards to this
particular circumstance. While much effort is made to provide
complete information, Ohio State University and Gateway do not
guarantee the accuracy and reliability of any information contained or
displayed in the presentation. We disclaim any warranty, expressed or
implied, including the warranties of fitness for a particular purpose.
We do not assume any legal liability or responsibility for the accuracy,
completeness, reliability, timeliness or usefulness of any information,
or processes disclosed. Nor will Ohio State University or Gateway be
held liable for any improper or incorrect use of the information
described and/or contain herein and assumes no responsibility for
anyone’s use of the information. Reference to any specific commercial
product, process, or service by trade name, trademark, manufacture, or
otherwise does not necessarily constitute or imply its endorsement.
Department of Mechanical Engineering, The Ohio State University
Sl. #53