Six Sigma Quality
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Understand total quality management.
Describe how quality is measured and be
aware of the different dimensions of quality.
Understand the meaning of six sigma and be
able to explain the define, measure, analyze,
improve, and control (DMAIC) quality
improvement process.
Understand what ISO certification means.
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Critical to quality: attributes most important to
the customer
Defect: failing to deliver what customer wants
Process capability: what your process can deliver
Variation: what customer sees and feels
Stable operations: ensuring consistent,
predictable processes to improve what the
customer sees and feels
Design for six-sigma: designing to meet
customer needs and process capability
LO 1
Total quality management: managing the
entire organization so that it excels on all
dimensions of products and services that are
important to the customer
Two fundamental operational goals:
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1. Careful design of the product or service
2. Ensuring that the organization’s systems can
consistently produce the design
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LO 1
TQM was a response to the Japanese
superiority in quality
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Established in 1987 by Department of
Commerce
Goal is to help companies review and
structure their quality programs
Has requirement that suppliers demonstrate
they are measuring and documenting their
quality practices
LO 1
Three Quality Gurus Define
Quality
Crosby: conformance to requirements
Deming: A predictable degree of
uniformity and dependability at low
cost and suited to the market
Juran: fitness for use (satisfies
customer’s needs)
LO 1
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LO 1
Create consistency of purpose
Lead to promote change
Build quality into the products
Build long term relationships
Continuously improve product, quality,
and service
Start training
Emphasize leadership
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LO 1
Drive out fear
Break down barriers between departments
Stop haranguing workers
Support, help, improve
Remove barriers to pride in work
Institute a vigorous program of education
and self-improvement
Put everybody in the company to work on
the transformation
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Design quality: inherent value of the product
in the marketplace
Conformance quality: degree to which the
product or service design specifications are
met
Quality at the source: the person who does
the work takes responsibility for making sure
it meets specifications
LO 1
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Performance: primary product or service
characteristics
Features: added touches, bells and whistles,
secondary characteristics
Reliability/durability: consistency of
performance over time
Serviceability: ease of repair
Aesthetics: sensory characteristics
Perceived quality: past performance and
reputation
LO 2
Basic cost assumptions
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1. Failures are caused
2. Prevention is cheaper
3. Performance can be measured
Cost of quality
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LO 2
Appraisal cost
Prevention cost
Internal failure cost
External failure cost
4.Act
1.Plan
3.Check
2.Do
Implement Identify the
improvement and
the plan
make a plan
Is the plan
working
LO 3
Test the plan
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LO 3
A philosophy and set
of methods companies
use to eliminate
defects in their
products and
processes
Seeks to reduce
variation in the
processes that lead to
product defects
The name, “six sigma”
refers to the variation
that exists within plus
or minus three
standard deviations of
the process outputs
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Six Sigma allows managers to readily
describe process performance using a
common metric: Defects Per Million
Opportunities (DPMO)
DPMO 
Number of defects
 Number of 
 opportunit ies 
 for error per  x No. of units
 unit
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LO 3
x 1,000,000
Example of Defects Per Million
Opportunities (DPMO) calculation.
Suppose we observe 200 letters
delivered incorrectly to the wrong
addresses in a small city during a
single day when a total of 200,000
letters were delivered. What is the
DPMO in this situation?
DPMO 
200
 1  x 200,000
So, for every one
million letters
delivered this
city’s postal
managers can
expect to have
1,000 letters
incorrectly sent
to the wrong
address.
x 1,000,000  1, 000
Cost of Quality: What might that DPMO mean in terms of overtime employment to correct the errors?
LO 3
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LO 3
Define, Measure, Analyze, Improve,
and Control (DMAIC)
Developed by General Electric as a
means of focusing effort on quality
using a methodological approach
Overall focus of the methodology is to
understand and achieve what the
customer wants
A 6-sigma program seeks to reduce
the variation in the processes that lead
to these defects
DMAIC consists of five steps….
Define
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Identify customers and their priorities
Identify a project
Identify critical-to-quality characteristics
Measure
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Determine how to measure the process
Identify key internal processes
Analyze
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LO 3
Determine most likely causes of defects
Understand why key defects are generated
Improve
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Identify means to remove causes of defects
Confirm the key variables
Identify the maximum acceptance ranges
Modify process to stay within acceptable range
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Determine how to maintain improvements
Put tools in place to track key variables
Control
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LO 3
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Uses many of the same statistical tools as
other quality movements
◦ Used in a systematic project-oriented fashion
through define, measure, analyze, improve, and
control (DMAIC) cycle
 More detailed version of Deming PDCA cycle
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Continuous improvement: seeks continual
improvement in all aspects of operations
◦ Also uses scientific method
LO 2
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LO 3
We are the maker of this cereal.
Consumer Reports has just published an
article that shows that we frequently
have less than 15 ounces of cereal in a
box.
What should we do?
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LO 3
What is the critical-to-quality
characteristic?
The CTQ (critical-to-quality)
characteristic in this case is the weight
of the cereal in the box.
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LO 3
How would we measure to evaluate the
extent of the problem?
What are acceptable limits on this
measure?
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LO 3
Let’s assume that the government says
that we must be within ± 5 percent of
the weight advertised on the box.
Upper Tolerance Limit = 16 + .05(16) =
16.8 ounces
Lower Tolerance Limit = 16 – .05(16) =
15.2 ounces
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LO 3
We go out and buy 1,000 boxes of
cereal and find that they weight an
average of 15.875 ounces with a
standard deviation of .529 ounces.
What percentage of boxes are outside
the tolerance limits?
Lower Tolerance
= 15.2
Process
Mean = 15.875
Std. Dev. = .529
Upper Tolerance
= 16.8
What percentage of boxes are defective (i.e. less than 15.2 oz)?
Z = (x – Mean)/Std. Dev. = (15.2 – 15.875)/.529 = -1.276
NORMSDIST(Z) = NORMSDIST(-1.276) = .100978
Approximately, 10 percent of the boxes have less than 15.2
Ounces of cereal in them!
LO 3
◦ Worker error
◦ Machine issues
◦ Raw material mix
◦. . .
LO 3
◦ 6s minimum from process
center to nearest spec
12s
6s
3
LO 3
2
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Implies 2 ppB “bad” with no process
shift
With 1.5s shift in either direction from
center (process will move), implies 3.4
ppm “bad”.
12s
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LO 3
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What changes are to be made to reduce
variation?
Center process
Change process specifications
LO 3
 Statistical
(SPC)
Process Control
◦ Use data from the actual process
◦ Estimate distributions
◦ Look at capability - is good
quality possible
◦ Statistically monitor the process
over time
LO 3
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Flowcharts
Run charts
Pareto charts
Checksheets
Cause-and-effect diagrams
Opportunity flow diagrams
Control charts
LO 2
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LO 2
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Failure mode and effect analysis (DMEA): a
structured approach to identify, estimate,
prioritize, and evaluate risk of possible
failures at each stage in the process
Design of experiments (DOE): a statistical test
to determine cause-and-effect relationships
between process variables and output
LO 3
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LO 3
Executive leaders must champion the
process of improvement
Corporation-wide training in Six Sigma
concepts and tools
Setting stretch objectives for improvement
Continuous reinforcement and rewards
Shingo’s argument:
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SQC methods do not prevent defects
Defects arise when people make errors
Defects can be prevented by providing workers with
feedback on errors
1. Successive check
2. Self-check
3. Source inspection
Poka-Yoke includes:
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LO 3
Checklists
Special tooling that prevents workers from making
errors
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Series of standards agreed upon by the
International Organization for Standardization
(ISO)
◦ Adopted in 1987
◦ More than 160 countries
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A prerequisite for global competition?
ISO 9000 an international reference for
quality, ISO 14000 is primarily concerned
with environmental management
LO 4
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LO 4
First party: A firm audits itself against ISO
9000 standards
Second party: A customer audits its supplier
Third party: A "qualified" national or
international standards or certifying agency
serves as auditor
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LO 4
Identify those processes needing
improvement
Identify a firm that is the world leader in
performing the process
Contact the managers of that company and
make a personal visit to interview managers
and workers
Analyze data