Gage R&R is short for Gage Repeatability and Reproducibility which is a study that is a really useful way to understand the variation or error in a measurement process.
When doing a measurement, there are several factors that can affect the result and its precision.

  • Operator
  • Environment
  • Measurement equipment used
  • Calibration of measurement equipment

The more of these factors that varies, the more variation you will get in your measurements. The Gage R&R will provide visibility on the variation and provide information on how repeatable and reproducible the measurement system is.

When to use Gage R&R

A Gage R&R can be used in following situations

  • Before conducting a Process Capability Study or implementing Statistical Process Control (SPC) on a line, to ensure the measurement taken are reliable.
  • When looking to reduce common cause variation on control charts or potential special cause variation due to gage error.
  • To qualify operators to use specific measurement equipment.
  • When selecting measurement equipment, they can be compared with Gage R&R.

Conducting a Gage R&R

When conducting a Gage R&R, it is important to use production parts instead of reference samples. If not using production parts or preproduction samples, then you will not get a good indication of how precise your system will measure parts in production.
Gage R&R is not limited to mechanical measurement of parts, it can also be used for visual inspection or any other measurement system. Typically a study would be done conducting 3 trials using 10 parts and 3 operators. Different numbers can be used, but there need to be multiple trials and operators to estimate repeatability and reproducibility.

Calculating Repeatability and Reproducibility

There are several software packages around for calculating repeatability and reproducibility, but it is not needed to spend a lot of money on new software.
If you have Excel, then all the calculations can be done there. EQMS can provide you with a template that do all the calculations as your measurements are entered.

If you are interested in Gage R&R, then our 8D Problem Solving Training might be interesting for you.
It is a detailed training on how to effectively solve problems and prevent them from reoccurring, and covers how to conduct Gage R&R as part of the training.

Alternatively you can continue to our quality training page for an overview of other training we provide.

Go to Quality Training

Gage R&R Analysis