As part of a recent submission of a SIX SIGMA project, a dimensional measurement was identified as "critical to quality". GE's SIX SIGMA protocol requires a gauge R&R on all CTQ's. However, this piece was being measured via CMM, and as result I did not ask for a gauge R&R. Subsequently the project was rejected.

Is gauge R&R a standard practice on CMM measurements? I thought CMM calibration and referencing of the part relative to the appropriate axis prior to measurement was sufficient for the CMM measurement process. Can someone please provide information that would help me understand the finer points on this issue? Thank you.