Hi,

Has someone a R&R file ( Excel or any other format ) avaible in order to send it me?

Regards

I have one in spanish languaje, is it useful for you?

Arte::smokin:

Of course,

thank you Arte, please send it me.

here there is, sheet one is completely filled, and sheet 2 is to fill in the blank.

Regards

Arte:thedeal:

Dear Arte,

thank you very much.

Gracias

Hi,
In the GRR form, K2 is the constant used to calculate reproducibility,

reproducibility(raw)= (5.15*people variance)/d2

For 2 appraisers, d2 is 1.41,

May I know where does 1.41 come from?

Thank you very much.

The Square root of 2 is 1.41 (1.414213562²=2)
Therefore, with 3 appraisers d2 is 1.732, with 4 appraisers d2 is 2, and so on.

Ryan

The constant d2* (Dee-Two-Star) is read from the Table called "Values for the distribution of the Average Range" given in the MSA Manual.

The values of d2* for reproducibility are:

For 2 appraisers : d2* = 1.41; K2 = 5.15/1.41 = 3.65
For 3 appraisers : d2* = 1.91; K2 = 5.15/1.91 = 2.70

Similarly, d2* used in repeatability calculations depends on No of trials and (No of parts time no of appraisers). So for
3 appraisers, and 10 parts we have the following d2* values:

for 2 trials : d2* = 1.128; K1 = 5.15/1.16 = 4.56
for 3 trials : d2* = 1.693; K1 = 5.15/1.72 = 3.04

For R&R calculations,

For 5 parts, d2* = 2.48; K3 = 5.15/2.48 = 2.08
For 10 parts, d2* = 3.18; K3 = 5.15/3.18 = 1.62

For statistical explanation of these values you will have to refer
"Quality Control And Industrial Statistics" by AJ Duncan.
-Atul.

Thanks for the explanation Atul, you can find more information about in on MSA (measurement Systems Analysis) Febr. 1995 Ford Motor Comp., GM Corp and D.C, , the manual may obtained from AIAG at 810-358-3570, the values in this manual are on page 29


Regards
Arte:thedeal:

Arte,

Yes, the MSA manual has the table. MSA manual also mentions Duncan's book as reference.
I use the values on faith that someone out there would have a valid statistical explanation for them - much like we 'look up' the constants A2, D3, D4... in SPC.:)

-Atul.

here there is, sheet one is completely filled, and sheet 2 is to fill in the blank.

Regards

Arte:thedeal:

Could you please send me the password to unlock the operator names cells?

Thank you.

Sheet 2 is unprotected. Sheet 1 appears to be an example only.

Can you please send me the password, to unlock the operator names cells?fesparza2004, welcome to the Cove.

:caution: Please note that Arte's sheet was posted over 4 years ago. This has MSA 2nd edition constants. Also the sheet computes GRR as % of Tolerance only. You will have to correct the factors to match the 3rd edition. You also will have to add a few formulas if you need %TV or nDC etc.

If you search the forums you should be able to find many more worksheets conforming to the current MSA standard.

This link gives an explaination and formula to calculate d2 factors.

http://www.tau.ac.il/cc/pages/docs/sas8/qc/chapc/sect9.htm

Schilling, Ott, Neubauer "Process Quality Control" lists papers from Pearson (1932) as earliest reference. I do believe I was required to read those at one time. I'm sure you can imagine, it was enthralling to say the least. Wonder why I can't remember a dang thing about them. Hmmm. Maybe not so exciting stuff after all.