Why/When is Taguchi Method Appropriate?

Why/When is Taguchi Method Appropriate? A new tip Every Friday Friday, 22nd June 2001

Tip #10 Taguchi Method Performs Process “centering” or “fine tuning”(next 6 slides) Friday, 22nd June 2001

Taguchi MethodPerforms Process “centering” or “fine tuning” “centering” or “fine tuning” of a process MEANS DETERMINING : THE CENTRAL VALUES OF CONTROL FACTORS TO ACHIEVE REPEATABLE PERFORMANCE even when THE LEVELS OF CONTROL FACTORS HAVE SOME “VARIATIONS” AROUND ITS CENTRAL VALUES Please note that this is different than making the process ROBUST againstNoIsEin general ”Centering” or “Fine Tuning” covers only the CONTROL FACTORS

INTERNAL NOISE Taguchi Method Effect of Internal/External noise on the output Y Noise FactorsX EXTERNAL NOISES Process / Product Diagram Y VARIATIONS Z Control Factors

THE FACTOR EFFECT PLOT using S/N RATIO INDICATES • THE RATE AT WHICH A PARTICULAR CONTROL FACTOR LEVEL AFFECTS THE S/N RATIO i.e. VARIANCE • BEST SETTINGSARE SELECTED (AS SHOWN BT ) • FOR EACH CONTROL FACTOR • EACH SELECTED SETTING IMPLIES reduced VARIANCE S / N RATIO  A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3

Mean  A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3 • THE FACTOR EFFECT PLOT using Mean INDICATES • THE RATE AT WHICH A PARTICULAR CONTROL FACTOR LEVEL AFFECTS THE Mean (AS INDICATED BY SLOPE) • BEST SETTINGSARE SELECTED (AS SHOWN BY ) • BY using S/N RATIO PLOT • EACH SELECTED SETTING IMPLIES reduced VARIANCE • BUT COULD AFFECT THE Mean SIGNIFICANTLY • SLOPE AT A1 IS LARGE • SLOPE AT B2 IS MEDIUM • SLOPES AT C3 AND D2 ARE SMALL

Mean  S / N RATIO  A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3 • THE FACTOR EFFECT PLOTS (S/N RATIO AND Mean) • CLEARLY INDICATE THAT • CONTROL FACTOR ‘B’ HAS small EFFECT ON S/N RATIO • and A LARGE EFFECT ON Mean • ‘B’ IS AN ADJUSTMENT FACTOR AND CAN BE USED FOR ADJUSTING MEAN-ON-TARGET

Shape of this curve depends on the control factor settings Y – Large variation in Y Nominal Settings Y Y Increasing S/N ratios Y – small variation in Y Y Y Best Settings B B – Variation in B B Taguchi Method Internal noise in control factor B and its effect on output Y

Taguchi Method “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, 27th July 2001 Friday, 20th July 2001 Friday, 13th July 2001 Earlier Tips Links below Tips 12, 11, 10 

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 Earlier Tips Links below Tips 9, 8, 7 

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 Earlier Tips Links below Tips 6, 5, 4 

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 Earlier Tips Links below Tips 3, 2, 1 

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 Earlier Tips Links below

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Why/When is Taguchi Method Appropriate?