# taguchi s / n ratios

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• #32020

arun.s.kumar
Participant

I am a trainee in an automotive parts supplier company. I require guidance for calculation of S/N ratios in the taguchi method. Also recommend a good software for this. Please give a basic overview of the calculations (detailed version also invited) and guide me to any specific links that you would know.  The significance of the S / N ratios and the log transormation is also awaited.

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#85153

Manee
Participant

You can use rdExpert software for Taguchi experiments
Manee

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#85163

Mikel
Member

If you want to understand Taguchi’s S/N read his book on Quality Engineering.
Minitab does a good job with S/N although it is easy to prove that traditional analysis of mean and Box Myers analysis of variability done separately will allow you to learn much more.

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#133722

Benny
Participant

There are 3 Signal-to-Noise ratios of common interest; (I) SMALLER-THE-BETTER : n = -10 Log10 [ mean of sum of squares of measured data ] This is usually chosen for all undesirable characteristics like ” defects ” etc for which the ideal value is zero. Also, when an ideal value is finite and its maximum or minimum value is defined (like maximum purity is 100% or maximum Tc is 92K or minimum time for making a telephone connection is 1 sec) then the difference between measured data and ideal value is expected to be as small as possible. The generic form of S/N ratio then becomes, n = -10 Log10 [ mean of sum of sqaures of {measured – ideal} ] (II) LARGER-THE-BETTER : n = -10 Log10 [mean of sum squares of reciprocal of measured data] This case has been converted to SMALLER-THE-BETTER by taking the reciprocals of measured data and then taking the S/N ratio as in the smaller-the-better case.(III) NOMINAL-THE-BEST : n = 10 Log10 (square of mean / variance )This case arises when a specified value is MOST desired, meaning that neither a smaller nor a larger value is desirable. Examples are; (i) most parts in mechanical fittings have dimensions which are nominal-the-best type. (ii) Ratios of chemicals or mixtures are nominally the best type. e.g. Aqua regia 1:3 of HNO3:HCL Ratio of Sulphur, KNO3 and Carbon in gun powder (iii) Uniformity in deposition /growth /plating /etching thickness.

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#133723

Benny
Participant

There are 3 Signal-to-Noise ratios of common interest; (I) SMALLER-THE-BETTER : n = -10 Log10 [ mean of sum of squares of measured data ] This is usually chosen for all undesirable characteristics like ” defects ” etc for which the ideal value is zero. Also, when an ideal value is finite and its maximum or minimum value is defined (like maximum purity is 100% or maximum Tc is 92K or minimum time for making a telephone connection is 1 sec) then the difference between measured data and ideal value is expected to be as small as possible. The generic form of S/N ratio then becomes, n = -10 Log10 [ mean of sum of sqaures of {measured – ideal} ] (II) LARGER-THE-BETTER : n = -10 Log10 [mean of sum squares of reciprocal of measured data] This case has been converted to SMALLER-THE-BETTER by taking the reciprocals of measured data and then taking the S/N ratio as in the smaller-the-better case.(III) NOMINAL-THE-BEST : n = 10 Log10 (square of mean / variance )This case arises when a specified value is MOST desired, meaning that neither a smaller nor a larger value is desirable. Examples are; (i) most parts in mechanical fittings have dimensions which are nominal-the-best type. (ii) Ratios of chemicals or mixtures are nominally the best type. e.g. Aqua regia 1:3 of HNO3:HCL Ratio of Sulphur, KNO3 and Carbon in gun powder (iii) Uniformity in deposition /growth /plating /etching thickness.

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#133728

Damodaran
Member
#133729

Kev
Participant

One of office BB is doing a Tuguchi DOE.
What about the P values to keep?

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