What are Acceptable Limits for Gage R&R Results

When we conduct Measurement Sustem Analysis the important step is to conduct % Gauge R&R study.After conducting it what are the acceptable limits? Is there any min limit for it? Can we have some thing like 0.08% variation due to % G R&R and say 99.92% variation due to parts we have used.

Sean Kelley said:

When we conduct Measurement Sustem Analysis the important step is to conduct % Gauge R&R study.After conducting it what are the acceptable limits? Is there any min limit for it? Can we have some thing like 0.08% variation due to % G R&R and say 99.92% variation due to parts we have used.

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That's great! That's what you want to see. Actual Part variation should be the major contributor to total observed variation. Contribution of GRR error should be minimum. I trust you have taken samples of the 'same' part. If this is not the case, then observed variation is unduly inflated as compared to GR&R.

Usually, R&R error of 10% of Study variation is acceptable. The lower the better. If R&R is between 10 - 30%, the measurement system needs improvement and can be 'conditionally' accepted. Over 30% error is not acceptable.

You also have the choice of comparing the GRR with process variation and tolerance, in addition to the Study variation (TV).

I suggest you get hold of the AIAG MSA Manual (if you haven't already)..

R&R 10% - 30%

Gage R & R resullts of 10% - 30 % usually require Customer approval for use in production.
In the past I have found most will sign-off any R & R upto 15% .

Brian Greydanus

HELP,

I understand all about gauge R&R, nut need to know/ have been asked where the 0 - 30% limits have come from, are they from a standard somewhere, or have they been thought of out of the blue

Your help is really required

Lee01

Lee - Page 77 of MSA 3rd Edition refers to the 0-30% as "rule of thumb" indices. It also goes on to say "The final acceptance of a measurement system should not come down to a single set of indices. The long-term performance of the measurement system should also be reviewed using graphical analysis over time".

Hope this helps.

Dave

Thats a good one, I do use GRR all the time but really don't use the 0-20% okay, 21-30% acceptable but in need of a process overhaul, 30%+ not acceptable.

I simply use the theory that if its below 30% its okay, above its no good.

Thomas

Gage R&R

Hello all... please excuse my ignorance. I am conducting my first PPAP process and have only prior documentation to go off of at my new job. I am stuck at trying to figure out why the formula used in a previous excel spreadsheet was used.
My spreadsheet shows the following:
Gage R&R ..... =(5.15*D33)/1.19
where D33=average range (D33=.0004)

I have made sense of all the other doc's and spreadsheets archived here at my company with the exception of this. I have been told to just plug in a number and go with it... that is not my inclination and would rather try to understand where these formulas come from. I am pushing for implementation of Minitab software to assit me, but I still feel I need some type of understanding behind these formulas. Can anyone help?