1. I.3 Philosophy and History
Some Goals of Manufacturing
Various Paradigms
Some Aspects of Taguchi’s Philosophy
On-Line and Off-Line Quality Control
Design Aspects
Service industry too

2. Some Goals The Quality Timeline
We have seen institutionalization since the late 1980’s (Six Sigma, etc)

3. Paradigms The Inspection Paradigm
Inspect Output To Remove Unsatisfactory Product
Inspection rules can be quite sophisticated

4. Paradigms Shewhart’s Paradigm
“Can’t Inspect Quality Into A Product”
Detect And Correct Quality Problems By Monitoring The Manufacturing Process
Two Types Of Variation In A Manufacturing Process
Moves quality upstream

5. Paradigms Shewhart’s Paradigm - Terminology
Shewhart: Assignable Cause Variation (ACV) and Chance Causes Of Variation (CCV)
Deming: ACV=Local Faults, Special Causes, CCV=Common Cause Variation
Juran: ACV=Sporadic Problems CCV=Chronic Problems

6. Paradigms Shewhart’s Paradigm Objective
Monitor The Process To Detect When ACV Is Present.
How Do You Detect ACV? Control Charts

7. Paradigms Shewhart’s Paradigm Two Ways To Improve Quality
Eliminate Assignable Causes To Bring Process Into Statistical Control
Improve The System By Reducing Common Cause Variation
Can’t experiment until process is in statistical control

8. Paradigms Tweaking The Variation Paradigm: The Variation/Complexity Paradigm
From a service industry perspective, we can contrast real real work vs complexity. Students can think of their own experiences here.

9. Paradigms The Variation/Complexity Paradigm
Paraphrase Deming - “Reduce Variation And Complexity And You Improve Quality”

10. Paradigms Deming and Juran
Originally Found That 80 to 85% Of The Quality Problems Required Management’s Input In Order To Correct.
Over The Years This Percentage Increased To Where They Found That 94 to 96% Of Quality Problems Were Systemic!

11. Paradigms Deming And Juran’s Extension
Need Management’s Involvement

12. Paradigms Definition of Quality
Customer Satisfaction is the Determining Factor in Product Design
Taguchi – “Loss to society”
Juran – “Fit for use”
Deming – “Continuous improvement”
Crosby – “Conformance to requirements”
Ishikawa – “Most economical, most useful and always satisfactory to the customer”
Crosby didn’t like vaguer definitions

13. Paradigms Deming, Juran and Taguchi
-Wring Out the Variation
Deming and Juran - Controlling the Process (On-Line QC)
Taguchi - Design Robust (Rugged) Processes and Products (Off-Line QC)
On-line vs off-line is an interesting distinction. Robust/rugged—think of Donald and Stella.

14. Paradigms Taguchi - Another Way To Improve Quality
Build Rugged/Robust Products And Processes By Making Things Insensitive To Unknown Or Uncontrollable Sources Of Variation
Donald and Stella again

15. Some Aspects of Taguchi’s Philosophy Prevention Rather Than Detection
Rather Than Detecting Defects, Let’s Design Quality Into The Product Right From The Beginning. “An Ounce of Prevention...”
Things are getting complicated…

16. Some Aspects Taguchi’s Approach
During the 50’s and 60’s Developed A Philosophy and Methodology Concerning Product Design and Production
Skim these next slides since we will be revisiting this in more detail in I.5; more context is needed first.

17. Some Aspects Design Aspects of Taguchi’s Philosophy
Robust Products And Processes Through “Engineering Design” (Statistical Design Of Experiments, DOE, Plays A Role Here)
Parameter Design
Choose Parameter (Factor) Levels To
Optimize Process or Product Performance
Mitigate Uncontrollable Factors
Cover only the bullet on optimizing process or product performance.

18. Some Aspects Design Aspects of Taguchi’s Philosophy: Factors
Control Factors
“Easily” controlled sources of variation
Noise
Uncontrollable
Internal – Wear out/aging
External - Environmental
Goal - Design Product to Be Insensitive to Noise Factors
Cover only the bullet on external noise