Why/When is Taguchi Method Appropriate?

1. Why/When is Taguchi Method Appropriate? A new tip Every Friday Friday, 15th June 2001

2. Tip #9 Taguchi Method Identifies the “right” NoIsE factor(s) for Tolerance Design(next 8 slides) Friday, 15th June 2001

3. Taguchi MethodIdentifies the “right” NoIsE factor(s) for Tolerance Design OPTIMIZING A DESIGNMEANS DETERMINING : (A) THE BEST ARCHITECTURE ( " CONCEPT " DESIGN ) • USE "AVAILABLE" and "ASSURED DESIGN “ else “A NEW CONCEPT” (B) THE LEVELS OF CONTROL FACTORS ( " ROBUST " DESIGN ) • MAIN OBJECTIVE " OPTIMUM SETTINGS " , " NOISE INSENSITIVITY “ • ON " EXISTING / OLD " EQUIPMENT AND PROCESSES • NO COST FOR " NEW SETTINGS " ON " OLD EQUIPMENT (C) TOLERANCES OF CONTROL/ NoIsEFACTORS ("TOLERANCE" DESIGN ) • REDUCING THE " VARIATIONS " IMPLIES BETTER RAW MATERIAL / EQUIPMENT / LABOUR / USER ENVIRONMENT • EXPENSIVE AND HENCE IT IS TO BE AVOIDED

4. Taguchi MethodIdentifies the “right” NoIsE factor(s) for Tolerance Design OPTIMIZING A DESIGNMEANS DETERMINING : (A) THE BEST ARCHITECTURE ( " CONCEPT " DESIGN ) • BY USING "AVAILABLE" and "ASSURED DESIGN “ with certain modifications else • BY USING “A NEW CONCEPT” that works in a entirely different manner • In either of above concepts, the new implementation of the concept needs “parameter optimization”

5. Taguchi MethodIdentifies the “right” NoIsE factor(s) for Tolerance Design OPTIMIZING A DESIGNMEANS DETERMINING : (B) THE LEVELS OF CONTROL FACTORS ( " ROBUST " DESIGN ) • MAIN OBJECTIVES ARE TO • DETERMINE THE " OPTIMUM SETTINGS " • ACHIEVE " NOISE INSENSITIVITY “ • “BEST RESULTS” ON " EXISTING / OLD " EQUIPMENT AND PROCESSES • AT NO ADDITIONAL COST FOR " NEW SETTINGS " ON "OLD EQUIPMENT”

6. Taguchi MethodIdentifies the “right” NoIsE factor(s) for Tolerance Design OPTIMIZING A DESIGNMEANS DETERMINING : • TOLERANCES OF CONTROL and/or NoIsE FACTORS ("TOLERANCE" DESIGN ) • REDUCING THE " VARIATIONS " IMPLIES BETTER • RAW MATERIAL • EQUIPMENT • LABOUR • USER ENVIRONMENT • EXPENSIVE AND HENCE IT IS TO BE AVOIDED

7. Taguchi MethodIdentifies the “right” Control Factor(s) for Tolerance Design • A1  HIGHER SLOPE IMPLIES ‘VARIATIONS’ IN PARAMETER A AT A1 WILL AFFECT THE S/N RATIO ADVERSELY • THE FACTOR EFFECT PLOT INDICATES • THE RATE AT WHICH A PARTICULAR CONTROL FACTOR LEVEL AFFECTS THE S/N RATIO • C3  SIMILAR ADVERSE EFFECT ON S/N RATIO (AS FOR A1) • B2 ANDD2  HAVE THE LEAST EFFECT ON S/N RATIO S / N RATIO  A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3

8. Taguchi MethodIdentifies the “right” Control Factor(s) for Tolerance Design • THE FACTOR EFFECT PLOT INDICATES the effects of internal NoIsE (I.e. variations in the control factors themselves) • THE RATE AT WHICH A PARTICULAR CONTROL FACTOR LEVEL AFFECTS THE S/N RATIO Tolerance Design :  Priority #1 : Choose Control Factor A as it has a very steep slope near Level A1  Priority #2 : Choose Control Factor C as it has a substantial slope near Level C3 NOTE : Control Factors B and C ought not to be used for tolerance design

9. Taguchi MethodIdentifies the “right” NoIsE Factor(s) for Tolerance Design •  CONDUCT the experiment with best settings of Control Factors whereinNoIsEis included as • factorial combinations • or as noise-combinations based on orthogonal array •  THE effects of all externalNoIsEfactors can be calculated in a manner similar to the ANOVA analysis for Control Factors • From theNoIsEfactor effect plot • Choose the dominant noise factor(s) for Tolerance Design NOTE : Insensitivity may have been achieved for someNoIsE factor(s)

10. Taguchi MethodIdentifies the “right” NoIsEfor Tolerance Design CONCLUSIONS • REDUCING THE "VARIATIONS" IN “SELECTED” CONTROL / NoIsE FACTORS IS CALLED “TOLERANCE DESIGN” • “SELECTING”NoIsE FACTORS (FOR TOLERANCE DESIGN) • INTERNAL NoIsEFACTORS (FROM MAIN-ARRAY) • SETTABLE/ADJUSTABLE EQUIPMENT PARAMETERS • EXTERNALNoIsEFACTORS (FROM NOISE-ARRAY) • RAW MATERIAL • LABOUR SKILL • USER ENVIRONMENT Friday, 15th June 2001

11. Taguchi Method 1st Priority : Variance Reduction2nd Priority : Factor Effects 15.“inner” L9 array with “outer” L4 and L9 NoIsE arrays Taguchi Method “inner” L18 array with “outer” L4 and L9 NoIsE arrays Taguchi Method Why/When is TaguchiMethod not Appropriate? Friday, 3rd Aug 2001 Friday, 27th July 2001 Friday, 20th July 2001 Friday, 13th July 2001 More Tips Links below Tips 12, 11, 10 

12. Taguchi Method “inner” L8 array with “outer” L4 and L9 NoIsE arrays Taguchi Method Useful at ALL Life-stages of a Process or Product Taguchi Method Performs Process “centering” or “fine tuning” Friday, 6th July 2001 Friday, 29th June 2001 Friday, 22nd June 2001 More Tips Links below Tips 9, 8, 7 

13. Taguchi Method Identifies the “right”NoIsEfactor(s) for Tolerance Design Taguchi Method Finds best settings to optimizeTWO quality characteristics Simultaneously 7. Taguchi Method When to select a ‘Larger’ OA to perform “Factorial Experiments” Friday, 15th June 2001 Friday, 8th June 2001 Friday, 1st June 2001 More Tips Links below Tips 6, 5, 4 

14. Taguchi MethodUsing Orthogonal Arrays for Generating Balanced Combinations of NoIsE Factors Taguchi MethodSignal-to-Noise Ratio for Quality Characteristicsapproaching IDEAL value 4. Taguchi Methodimproves " quality “ at all the life stages atthe design stage itself Friday, 25th May 2001 Friday, 18th May 2001 Friday, 11th May 2001 More Tips Links below Tips 3, 2, 1 

15. 3. Taguchi MethodAppropriate forConcurrent Engineering 2. Taguchi Methodcan studyInteraction between Noise Factors and Control Factors 1. Taguchi’sSignal-to-Noise Ratiosare inLog form Friday, 4th May 2001 Friday, 27th April 2001 Friday, 6th April 2001 More Tips Links below

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