Gage R&R failed, or did it really?

[Bev D]

The NDC should always be 5 or more, are your measurement results practically the same or low in variance?
If you could have more variation in results, to the max and the min dimensions, i think you should be fine.

You could test this by playing with the results in variance. Then decide if you should make parts with more variance.

No offense, but this is really just gamesmanship...and misses the point of the difference between SPC and acceptance sampling. Simple mathematical manipulation is not a substitute for insight and understanding of the process and it's measurement. While we should always try to select parts that span the range of natural variation, it isn't always possible. and we certainly should never create parts that don't yet naturally occur for the sake pf passing some arbitrary pulled out of their butts goal line...

and another thing: The NDC limit of 5 is also arbitrary. It has also been debunked as redundant at best even by the current living SPC master...

 

[Johnnymo62]

By the way,last year Ford eliminated the use of NDCs.

 

[Miner]

Process control would refer to SPC
Process analysis would refer to other statistical studies such as designed experiments and hypothesis testing. A bad measurement system could also have a detrimental effect on process capability if the process is marginal.

 

[Matt's Quality Handle]

No offense, but this is really just gamesmanship...

100% correct. However gamesmanship is sometimes easier than educating a Big 3 SQE.

 

[Bev D]

More’s the pity. Supporting ignorance only allows them to procreate

 

[bobdoering]

"From my understanding, study variation Gage R&R is more driven by SPC requirements while tolerance Gage R&R is more about the effectiveness of the measuring system to detect pass vs fail."

More practically, study variation Gage R&R (which should really be based on historical data rather than study data) is for process decisions, while tolerance Gage R&R is more about the effectiveness of the measuring system to detect pass vs fail - or product decisions.