I have two cylinders on a part that need to be concentric within .002". I noticed that on some parts, not all, the concentricity reports out of tolerance at .0039 for example but then when I rotate the part 180 degrees, the concentricity is suddenly .002 or less.
I align the part by measuring a top plane, leveling to this and setting z origin. Then I measure a circle with 9 hits and make this the x and y origin. Im not locking rotation as I really dont think it matters in this case since its a circular part anyway. I then measure the datum as a 3 level cylinder with 9 hits each level, then measure the next cylinder 9 hits 3 levels.
I don't see how rotating it 180 degrees changes anything especially since I'm taking 9 hits at each level on diameters less than 2.5 inches I should be, in my mind, hitting enough spots to capture anything weird going on with the part. What am I doing wrong here? Thanks.
Need a visual here as rotating 180 has multiple means.....spinning the part ( around Z axis ) or fliping it over ( Z+ is now Z- ) ? This have something do to with leveling on the plane ? Wouldnt you level to the CYLINDER / DATUM ?
In this case 180 means spinning the part around the Z axis. I can try leveling to the cylinder although I cant think of a reason that changes things very much. As long as the cmm knows where the part is in space and then takes hits accordingly why would it matter which plane is used to level it?
In this case 180 means spinning the part around the Z axis. I can try leveling to the cylinder although I cant think of a reason that changes things very much. As long as the cmm knows where the part is in space and then takes hits accordingly why would it matter which plane is used to level it?