What are Acceptable Limits for Gage R&R Results

[Sean Kelley]

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.

 

[Atul Khandekar]

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.

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)..

 

[Brian Greydanus]

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

 

[lee01]

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

 

[D.Scott]

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

 

[Thomas_Crown]

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

 

[jessia]

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?