# Points to Establish Maximum Inscribed Diameter
# Points to Establish Maximum Inscribed Diameter
(OP)
Hell All: I am going to conduct a Gage R&R study on CMM touch probe machine (software is PC-DIMS). The feature that will be measured is maximum inscribed diameter, which is tricky depending on the spots on the circle where the points are obtained. How do you determine a sufficient/adequate number of points to establish a maximum inscribed diameter so that I won't flunk the Gage R&R study?





RE: # Points to Establish Maximum Inscribed Diameter
The second "R" is repeatability. I hope that there are at least 2 Operators measuring the same parts two or three time and, hopefully, the same points.
Usually one uses 10 parts, measured either 2X or 3X by the same Operator and either 2 or 3 different Operators.
Anytime one is measuring a diameter, the higher the number of points, the more confident one is in the results. Make sure that you are over 12 points to achieve a reasonable value.
Dave D.
www.qmsi.ca