I need to measure a dimension to the centerline of a radius, but the radius is 2" and only covers an arc of about 25 degrees. Measured on the optical comparator, the radius is nearly nominal, but on the CMM it measures 2.117". This throws my centerline over .100" out of position. How can I create a centerline from points on the radius using the nominal radius? Can I force PC-DMIS to best fit a 2" radius to points on the surface?
You might have one shot at making this work... the problem is, that as prev. stated, the measurement algorithm breaks down on small arcs, but also due to that breakdown should give you nonrepeatable results. As the error is a "normal" error, it is subject to statistical analysis. So, if you do get such "nonrepeatable" measurements, run the part twenty or thirty times and look for the x-bars on size and position. I have successfully used this method on other systems.
You might have one shot at making this work... the problem is, that as prev. stated, the measurement algorithm breaks down on small arcs, but also due to that breakdown should give you nonrepeatable results. As the error is a "normal" error, it is subject to statistical analysis. So, if you do get such "nonrepeatable" measurements, run the part twenty or thirty times and look for the x-bars on size and position. I have successfully used this method on other systems.
