Re: Frequenty of R&R/ Measurement Uncertainty
As far as R&R, I would perform it often enough to determine if the process is stable. Do you hire new people? Do variables change in the process? Do you make improvements and such to possibly lower the variance? Or, did it go up?
Gage R& R really has no time function -
if it is performed correctly at the beginning - which means the parts and the operators cover the variety of possible levels the gage will see over time. If later you get operators less capable than your original operators, then that is significant enough to redo the gage R&R again. Some folks like to R&R every new operator. Again, that is academic (unless their gaging system has been shown to be so operator dependent that it should not likely be used anyway.)
If the gage is changed, or the
measurement process changed, then yes, it needs verified. Improvements can fix one thing, and break another. But, lacking any significant changes to the measurement system, redoing them at any frequency is, again, simply an academic exercise.
As far as stability, my preference is to use calibration data - if the same standards and enough measurement points to establish linearity are used -to establish stability over time. That way I can see measurement change not tainted by any measurement error (such as influenced by roundness, etc.)