Warning as to MSA 3rd edition worksheets

[Howard Atkins]

Some of the worksheets that have been posted here which are based on the 3rd edition of the MSA book are not correct.
Some, including those posted by me, have had the constants changed but not properly converted.
Please see this thread MSA using tolerances - Page 116 of the AIAG MSA manual
Please treat all worksheets that are downloaded as suspicious.
A good example of the application of 7.6

When used in the monitoring and measurement of specified requirements, the ability of computer software to satisfy the intended application shall be confirmed. This shall be undertaken prior to initial use and reconfirmed as necessary.

 

[Marc]

If anyone finds a 'defective' MSA 3rd edition worksheet file, let me or a moderator know the thread and post it is in so we can delete it.

Howard - What will happen if someone inadvertantly uses a defective worksheet?

 

[Howard Atkins]

As far as I know the result will be slightly different, this could be good or bad depending on your point of view.
Please read the referenced thread to get an explanation

 

[dougvk]

This is an interesting note for me. I have been using the examples, notably pages 114-123 and appendix A to work through the examples. I am trying to develop a spreadsheet to take the ANOVA calculations from Minitab and turn the result into a GRR study. I have not been able to duplicate the results from the MSA. Table 8, p120 gives a MS value of .04598 for Equipment. The square root of that is .2144 Which according to the variance estimate formula on p187 (appendix A) should be the standard deviation. However, the tabulated value of standard dev in Table 19b on p 190 shows the sd as 0.199933, which is not .2144 ???

There is also not a clear description of the discussion comparing the result in the 5.15 sigma column of Table 19b which identifies the EV as 1.029656, and the result in table 9 which identifies the EV as .199933

I am sure that I am probaly missing a key point of the discussion... Can someone help me wiht what it is I am missing?

Thanks!

 

[Miner]

Sorry, I don't have time to run through the math right now, but I am bumping this post after the weekend, so others may see it and respond.

 

[Miner]

Any takers? Work has been too hectic lately to allow me time to investigate.

 

[prototyper]

This is an interesting note for me. I have been using the examples, notably pages 114-123 and appendix A to work through the examples. I am trying to develop a spreadsheet to take the ANOVA calculations from Minitab and turn the result into a GRR study. I have not been able to duplicate the results from the MSA. Table 8, p120 gives a MS value of .04598 for Equipment. The square root of that is .2144 Which according to the variance estimate formula on p187 (appendix A) should be the standard deviation. However, the tabulated value of standard dev in Table 19b on p 190 shows the sd as 0.199933, which is not .2144 ???

There is also not a clear description of the discussion comparing the result in the 5.15 sigma column of Table 19b which identifies the EV as 1.029656, and the result in table 9 which identifies the EV as .199933

I am sure that I am probaly missing a key point of the discussion... Can someone help me wiht what it is I am missing?

Thanks!

The 5.15 sigma calculation was factored out of the third edition by the AIAG, see the attached link from the AIAG website http://www.aiag.org/StaticContent/files/MSA_Changes.pdf

As a general rule, I would recommend using data from the MSA third edition manual to validate calculations and formulae where appropriate.