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?
steps I use for location and diameter of small arc/radius
At a recent users group meeting this topic was discussed and the following steps were given to achieve both the location and diameter of a small arc/radius
To measure a partial arc/radius:
1. create a "measured" circle
2. edit (F9) the circle and add additional hits and edit the "best fit math type" to "FIXED Radius", edit the NOMINAL DIAMETER, check box to "regenerate hits", when prompted "equal spacing" answer YES
3. ctrl E the feature to execute it and re-capture the measured hit points
4. dimension the "location only" of the fixed radius circle/arc
5. edit dimension tol's to print
6. create an alignment and set origin on fixed radius circle
7. (if using CAD skip this step) F10/Parameters>Probing> enable polar compensation for the active workplane
8. with joystick measure more individual/separate points on arc radius (if using CAD use "vector point" skipping step #7)
9. dimension individual points using the "PR" polar radius function
10. F10/Parameters>Probing> turn
off or disable polar compensation
steps I use for location and diameter of small arc/radius
At a recent users group meeting this topic was discussed and the following steps were given to achieve both the location and diameter of a small arc/radius
To measure a partial arc/radius:
1. create a "measured" circle
2. edit (F9) the circle and add additional hits and edit the "best fit math type" to "FIXED Radius", edit the NOMINAL DIAMETER, check box to "regenerate hits", when prompted "equal spacing" answer YES
3. ctrl E the feature to execute it and re-capture the measured hit points
4. dimension the "location only" of the fixed radius circle/arc
5. edit dimension tol's to print
6. create an alignment and set origin on fixed radius circle
7. (if using CAD skip this step) F10/Parameters>Probing> enable polar compensation for the active workplane
8. with joystick measure more individual/separate points on arc radius (if using CAD use "vector point" skipping step #7)
9. dimension individual points using the "PR" polar radius function
10. F10/Parameters>Probing> turn
off or disable polar compensation
