Suggestions for VTube-LASER GR&R Studies (Gage Repeatability and Reproducibility)

GR&R Definitions

GR&R = Gage Repeatability and Reproducibility
Repeatability = How well one operator repeats measurements.
Reproducibility =How well multiple operators repeat measurements between each other.

GR&R Requirements

GR&R studies require multiple operators to measure a batch of tube samples multiple times. If only one operator is used, the study is not a true GR&R study. (It would be a GR study without any way to measure reproducibility.)
You will use at least two operators with multiple samples of the same part.
Operators will measure the same part at least twice to calculate repeatability.
The study setup can vary widely for counts. However, every study has multiple operators and samples of the same part.

Basic Steps for a Study with VTube-LASER

Choose a representative part to measure.
Use one part shape.
Remember that, if you choose an unusually hard part to measure, then you will make passing GR&R much harder.
Choose the part type that you fabricate the most to get a good idea of what to expect for most parts.
Try to choose a part with fewer bends if possible. This will make the study go much faster.
Choose your users.
Choose users who are competent with the system.
Metrology systems are very precise instruments that can detect distances less than the thickness of paper.
Therefore, they always require intelligent and careful handling.
It is hard to pass GR&R studies with users who are not skilled and careful in handling the measuring system.
Set up VTube-LASER with the nominal data.
If part of the metric is the end lengths, we strongly urge you to use End Scan Flier Filters.
(LASER data will always have fliers. LASER data is generally only safe to use in groups of points. Solo LASER points should be considered fliers and discarded by the filter.)
Clear VTube-LASER Tube Data Storage. It is in the main toolbar at the top.
Select a batch of tubes with the same part number.
Your statistical process will need to dictate how many tubes to measure and how many operators measure in your study. Each part will be numbered (1, 2, 3, 4, etc.) so that each part's trend can be tracked uniquely in the data each time it is measured.
After each measure and alignment, VTube will store the new alignment in Tube Data Storage (TDS).
After each measure and alignment, enter TDS and give the measured aligned part a meaningful name.

Assuming your operators are John Smith, Theresa Sullivan, and Sam Johnson, we recommend a meaningful naming convention for each measure like this:

JS P1 M1 (John measured part 1, and it was the first time he measured it)
TS P2 M3 (Theresa measured part 2, and it was the third time she measured it)
SJ P20 M5 (Sam measured part 20, and it was the fifth time he measured it.)
The order in which you collect the data is not critical. What is critical is matching each alignment result with a person and a part number.
For some applications, it matters if you keep the placement of the parts reasonably close in orientation on the table.
Some tubes are different shapes when measured on opposite sides. If your tube shapes are like this, then take steps to handle this fact in your measurement process. For example, either use MTA (Measured Tube Averaging), or require users to place the tube on the table the same way for every measure. (You can include an image of the tube placement in VTube-LASER.)
Keep tight control of the process on every measure.
If a user's measure is poor based on all the indicators in VTube-LASER, don't use that measurement for your study. (Most operators should know how to see and handle indicators of wild fluctuation due to poor measurement or something not working properly.)
When all the measures and alignments are complete, enter Tube Data Storage and export whatever data you want to use in the statistical engine.
The data can be exported in different formats to XLS files.