Calibration can not replace the need for Gage R&R
howste said:
In the past (on many occasions) I have submitted calibration certificates for tensile testers instead of R&R studies in PPAPs. I have never had a customer reject one. What do your customers say?
In calibration, we are estimating Bias. Bias and R&R are different errors. Bias is OK, does not mean that R&R should be OK.
Bias is Xbar - Referene value, if you have lot of variation in repeated measurements, the Bias many be still fine and Repeatability error will be high.
It is a good idea to check R&R destructive testing methods also. My experience is that the R&R values are generally more than 30% and with better maintenance & traning of operators the errors can be reduced.
For example, in one case of Hardness measurement, we found that different operators methods of sample preparation is quite different and hence the errors were also abnormal.