6σ标准差教材

A Rigorous Method for Measuring & Controlling Our Quality
6 Overview
What Does “Sigma” Mean?
Sigma is a Measure of the Consistency of a Process
It (is Also the 18th Letter in the Greek Alphabet!
Measuring & Eliminating Defects is the “Core” of Six Sigma
6 Overview
Measurement System
Some Sigma “Benchmarks”
SIGMA LEVEL

DEFECTS per MILLION
OPPORTUNITY
6 Overview
Why Does GE Need A Quality Initiative?
GE Raising The Bar • New Goal to be “Best in the World” vs. #1 or #2 • Customers are Expecting More, we Must Deliver • “Ship-and-fix” Approach no Longer Tolerated in the Market • Aim to Speed Past Traditional Competitors in 5 Years • Goal Consistent with Reduced Total Costs
6 Overview
Measurement System How Do We Arrive at Sigma?
Identify the CTQs
• “Critical to Quality” Characteristics or the Customer Requirements for a Product or Service
Unpredictable
X
X
XX X
X
X XX
X X
X
X X
Reduce Spread
6 Helps us Identify and Reduce VARIATION due to: - Insufficient Process Capability - Unstable Parts & Materials - Inadequate Design Margin
6 Overview
Problem Solving Approach
Off-Target
Target
Unpredictable
Target
LSL Defects
USL
Center Process
On-Target
Target
LSL
USL
Reduce Spread
“Lower Specification Limit”
Define Defect Opportunities
• Any step in the process where a Defect could occur in a CTQ
Look for Defects in Products or Services
• Count Defects or failures to meet CTQ requirements in all process steps
• Six Sigma Structure
• Key Concepts & Tools
• A Practical Example
An Overview....Not a lot of Details!!
6 Overview
“Six Sigma”
• If we can’t express what we know in the form of numbers, we really don’t know much about it.
We Must Acknowledge Our Vulnerabilities • Poor Quality That Impacts Customers • Problems with NPI • Too High Internal Costs
We Need a Major Initiative to Move From Where we Are to Where we Want to be
“...will bring GE to a whole new level of quality in a fraction of the
time it would have taken to climb the learning curve on our own.”
John F. Welch, Jr. 1995 GE Annual Report
Sigma Level

2 3 4 5 6
Defects per Million of Opportunity
PPM
308,537 66,807 6,210 233 3.4
Convert DPMO to Sigma
• Use the SIGMA TABLE
Arrive at DPMO
• Defects Per Million Opportunities
LSL
USL
“Upper Specification Limit”
Less Variation Means Fewer Defects & Higher Process Yields
6 Overview
PPM
{ IRS Tax Advice
2
308,537
{ Restaurant Bills Airline Baggage Doctor’s Prescription
3
66,807
{ GE Average Company
4
6,210
5
233
6
3.4
{ Best Companies Airline Safety
Deployment and Application of Six Sigma Concepts & Tools
Learning from Those Who Have had Success With 6Will Accelerate its Implementation at GE
6 Overview
• Proven Successful in “Quality-Demanding” Industries e.g., Motorola, Texas Instruments (many process steps in series)
• Proven Method to Reduce Costs • Highly Quantitative Method – Science and Logic Instead of Gut Feel • Includes Manufacturing & Service (close to customer) and Provides Bridge
2 1/2 Days per Century
5
1 Misspelled Word in
a set of Encyclopedias
$570 Indebtedness per $1 Billion in Assets
30 Minutes per Century
6
1 Misspelled Word in all
6 Overview
• Six Sigma: - A Definition - Applied to GE - GE Quality Initiative - Why This Approach? - Origin of Six Sigma - The “Breakthrough Strategy” - Arriving at Sigma
• If we don’t know much about it, we can’t control it.
• If we can’t control it, we are at the mercy of chance.
Mikel J. Harry President & CEO Six Sigma Academy, Inc.
Where Does “Six Sigma” Come From?
• Mikel J. Harry one of the Original Architects • Previously Headed Quality Function at ABB and Motorola • Now President/CEO of Six Sigma Academy in Phoenix, Arizona • Has Consulted for Texas Instruments, Allied Signal (and others) • Currently Retained by GE to Teach the Implementation,
to Design for Quality Concepts • Has Support and Commitment of Top Management
It Works!!!
6 Overview
Sigma: A Measure of Quality
Sigma 3
Spelling
1.5 Misspelled Words per Page in a Book
6 Overview
Why Does GE Need A Quality Initiative?