is there any Criteria to choose samples for R&R study?

i had taken samples with least variations which resulted higher R & R value.

Thankyou

is there any Criteria to choose samples for R&R study?

i had taken samples with least variations which resulted higher R & R value.

Thankyou
According to the AIAG MSA manual 3rd Edition), samples for an average-and-range study should "...represent the actual or expected range of process variation." (Page 99)

Selecting samples with least variation will give poor R & R and not a good R & R.

R & R is a ratio of variation in measurement system divided by variation between the parts. By reducing part to part variation, you are reducing the denominator which will result poor ratio.

We perform gage R & R to make sure that process capability what we want to measure is from the process itself and not due to the measurement system.

We donot do R & R to show that it is good. In fact, when you improve aprocess capability, R & R must deteriorate (if your measurement system is stable before and after improvements).

In fact poor R & R after process improvement by itself becomes a justification for asking money from management for new or improved measurement system.

Thanks mr. Jsw05 & Mr. Arvind for guidence.

Vinay