PRINCIPLES OF SIX SIGMA

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PRINCIPLES OF SIX SIGMA

• ISE 412/512
• LECTURE 1-2
• THOMAS E. SCOTT, PhD

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Six Sigma Non-technical Definition

• The relentless and rigorous pursuit of the
  reduction of variation in all critical processes
  to achieve breakthrough improvements that impact
  the bottom line, and increase customer
  satisfaction.

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6s Problem Solving Methodology
Existing Business Processes
Supplier
Inputs
Processes
Outputs
Customer

• Six Sigma Methodology
• Define
• Measure
• Analyze
• Improve
• Control

DMAIC
Quality Productivity Cost Profitability
Improved Business Performance
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Six Sigma Technical Definition

• Assume that process variability behaves as a
  normal distribution
• NOTE This may be an incorrect assumption
• We can compute mean and standard deviation and
  plot the data in terms of frequency versus the
  variation from the mean

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NORMAL DISTRIBUTION /- 3s
GOALPOST VIEW OF QUALITY
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• BALL BEARINGS
• µ DIA 25mm
• Tolerance /- 5mm
• VoC Any dia between 20 and 30mm is acceptable
• For every 1 Million bearings, 2700 bearings would
  be outside the allowable range
• This is the VoP

20mm 25mm 30mm
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Six Sigma Premise

• The variation of the process
• (Voice of the Process)
• can use up no more than
• HALF
• of the specification limit
• (Voice of the Customer)

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VoC
VoC VoP
VoP
LSL
USL
6s
-6s
20mm 25mm 30mm
20mm 22.5 25mm 27.5 30mm
SIX SIGMA METHODOLOGY
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• BALL BEARINGS
• µ DIA 25mm
• Tolerance /- 5mm
• VoC Any dia between 20 and 30mm is acceptable
• The NEW VoP means
• For every 1 Billion bearings, 2 bearings would be
  outside the allowable range

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Six Sigma

• The process is designed to be
• TWICE AS GOOD
• as the customer specification?
• YES

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SIX SIGMA

• METHODOLOGY IS THE KEY
• FOLLOW THE ROADMAP
• NOT MBO(Management by Objectives)
• NOT about Quality(Often improves quality)
• NOT about Training (is necessary)
• NOT about Statistics (means to an end)
• NOT an Art (but experience helps)

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SIX SIGMA

• ABOUT BUSINESS IMPROVEMENT
• TARGETS BREAKTHROUGH PERFORMANCE
• PROJECTS LOOK FOR 40 to 50 CHANGE
• TIMELINE LESS THAN 4-6 MONTHS
• EXPECT BOTTOM LINE IMPACT
• 6s CHANGES CULTURE THROUGH RESULTS

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Six Sigma Problem Solving Methodology
Existing Business Processes
What is important?
DEFINE
MEASURE
How are we doing?
What is wrong?
ANALYZE
What needs to be done?
IMPROVE
How do we guarantee performance?
CONTROL
IMPROVED BUSINESS PERFORMANCE
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6s BASIC ASSUMPTION

• OUTPUT IS
• DEPENDENT
• ON THE PROCESS INPUTS
• Y f(X1, X2, X3,., Xk,)

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DMAIC Define

• All about the OUTPUT
• What is important to the customer?
• DEFINE
• Scope and boundary
• Specify Measurable Defects
• Estimate the impact

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DMAIC Define

• Business case with a project objective
• SIPOC analysis
• Voice of Customer analysis

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DMAIC Measure

• All about the INPUT
• What things can we control?
• MEASURE
• Map process
• Identify inputs and outputs
• Cause and Effects Matrix
• Preliminary FMEA
• Establish Measurement System Capability
• Establish Process Capability Baseline

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DMAIC Measure

• Operationally define each CTQ characteristic
• Understand the measurement system for each CTQ
  characteristic
• Understand the current capability of each CTQ
  characteristic

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DMAIC Measure

• Interesting plots
• Table 5.7 page 125

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DMAIC Analyze

• All about ROOT CAUSE
• Define the CRITICAL inputs
• ANALYZE
• Complete FMEA
• Perform multi-variate analysis
• Identify potential critical inputs
• Develop plan for improvement

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DMAIC Analyze

• Develop a more detailed process map
• Identify and prioritize the inputs that impact
  the CTQ
• Reduce the number of inputs for consideration to
  the most significant
• Identify the relationships between the
  significant inputs and the CTQ
• Develop hypotheses for improvement

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DMAIC Analyze

• Interesting charts
• FMEA format Table 6.3

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DMAIC Improve

• All about the SOLUTION
• IMPROVE
• Verify critical inputs
• Optimize critical inputs
• Consider mistake proofing
• Complete final FMEA

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DMAIC Improve

• Designing and executing experiments to clarify
  functional dependency and optimize inputs
• Identify and mitigate risks involved with
  optimized settings
• Identify actions to formalize the optimized
  process

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DMAIC Control

• Lock and load to achieve and maintain gains
• CONTROL
• Implement control plan
• Verify long term capability
• Continuously improve process

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DMAIC Control

• Ensuring that the optimized settings are locked
  in place
• Hand the process over to the process owner