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

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

Taguchi Method Identifies the “right” NoIsE factor(s) for Tolerance Design OPTIMIZING A DESIGN MEANS 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/ NoIsE FACTORS ("TOLERANCE" DESIGN ) REDUCING THE " VARIATIONS " IMPLIES BETTER RAW MATERIAL / EQUIPMENT / LABOUR / USER ENVIRONMENT EXPENSIVE AND HENCE IT IS TO BE AVOIDED

Taguchi Method Identifies the “right” NoIsE factor(s) for Tolerance Design OPTIMIZING A DESIGN MEANS 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”

Taguchi Method Identifies the “right” NoIsE factor(s) for Tolerance Design OPTIMIZING A DESIGN MEANS 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”

Taguchi Method Identifies the “right” NoIsE factor(s) for Tolerance Design OPTIMIZING A DESIGN MEANS 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

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

Taguchi Method Identifies 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

Taguchi Method Identifies the “right” NoIsE Factor(s) for Tolerance Design  CONDUCT the experiment with best settings of Control Factors wherein NoIsE is included as factorial combinations or as noise-combinations based on orthogonal array  THE effects of all external NoIsE factors can be calculated in a manner similar to the ANOVA analysis for Control Factors From the NoIsE factor effect plot Choose the dominant noise factor(s) for Tolerance Design NOTE : Insensitivity may have been achieved for some NoIsE factor(s)

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

Earlier Tips Links below Friday, 27th July 2001 Friday, 20th July 2001 Friday, 13th July 2001 Taguchi Method “inner” L9 array with “outer” L4 and L9 NoIsE arrays “inner” L18 array with “outer” L4 and L9 NoIsE arrays Taguchi Method Why/When is Taguchi Method not Appropriate? Tips 12, 11, 10 

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

Earlier Tips Links below Taguchi Method Identifies the “right” NoIsE factor(s) for Tolerance Design Taguchi Method Finds best settings to optimize TWO 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 Tips 6, 5, 4 

Earlier Tips Links below Friday, 25th May 2001 Friday, 18th May 2001 Friday, 11th May 2001 Taguchi Method Using Orthogonal Arrays for Generating Balanced Combinations of NoIsE Factors Taguchi Method Signal-to-Noise Ratio for Quality Characteristics approaching IDEAL value 4. Taguchi Method improves " quality “ at all the life stages at the design stage itself Tips 3, 2, 1 

Earlier Tips Links below Friday, 4th May 2001 Friday, 27th April 2001 Friday, 6th April 2001 3. Taguchi Method Appropriate for Concurrent Engineering 2. Taguchi Method can study Interaction between Noise Factors and Control Factors 1. Taguchi’s Signal-to-Noise Ratios are in Log form

end