Signal Detection-If Ppk>1, compare measurement system to process.


HI All,
The 4th MSA Manual (P.143) says if Ppk>1, compare measurement system to process.

now i understand if Ppk>1, then %GRR=d/5.15σ;

If understand this word correctly or not? pleas guide me how to understand the "process" here.

Bev D

Heretical Statistician
Super Moderator
I am not an expert on AIAG, but I assume that 'the process' means that you would compare the measurement error to the acttual variation of the process (study variation or historically observed variation). if you know that the Ppk value is greater than 1 then you know the process variation is less than the tolerance and the measurement study turns from focusing on the measurement system's ability to distinguish between 'in-tolerance' and 'out-of-tolerance' parts to the system's ability to detect changes (such as with SPC)...

If any AIAG experts out there can correct my interpretation or add insight it would be appreciated!
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