The following definitions describe the terms used in
a gage R&R study.
- any device used to obtain measurements, for example,
a micrometer or a gasket thickness gage.
- typically an operator, but can be
thought of more generically as any condition affecting the
measurements. For example, with an automated process,
might be a set-up procedure or an environmental condition such
as temperature. For the remainder of this appendix,
condition is referred to as operator.
- a set of measurements on all parts taken
by one operator. Multiple trials help separate
the gage variability (repeatability) from the variability
contributed by operators (reproducibility).
- the item that is measured, for example, a gasket.
The parts selected
should represent the entire operating range
(variability) of the process.
- Measurement System
the complete process used to obtain
measurements. This includes people, gages, operations, and
the variation resulting from repeated
measurements taken on the same part with the same gage
by the same operator. Repeatability is the gage or equipment
the variation in the average
of the measurements resulting when different
operators using the same gage take measurements on the same part.
Reproducibility is the operator-to-operator variability.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.