R&R Analysis for Destructive Measurements
Destructive vs. non-destructive tests:
With non-destructive measurements, data for GR&R
studies are collected by measuring the same part
or sample several times, using the same
measurement device, with measurements conducted
by the same appraiser.
With destructive measurements, we cannot use
the same part or sample again; by definition, it
is consumed or destroyed.
Since we cannot repeat measurements on the
same part or sample, we must use techniques to
separate sample-to-sample variation from actual
measurement system variation.
- The best approach, when possible, is to ensure
homogenous samples are used. If we can create
nearly homogenous samples, we can assume the
samples are essentially equal and perform the
analysis exactly the same way as it was done
with non-destructive measurements.
When you cannot create homogenous samples:
When homogenous samples cannot be created, the
repeatability inherent within the equipment used
to prepare the test specimen and the
repeatability (or variation) within the material
The use of ANOVA techniques allows us to
determine if the impact of test specimen
preparation is statistically significant.