[Turbo911]

I have a Feeler VM40-SA with a Fanuc Oi-MC control. Problems with cutting round circles and following 3d math data. We had Fanuc in here yesterday to tune servos, they were just fine. Ball bar tests shows out of round, but no backlash. Thinking we have parameter problems. Does anyone out there have one of these machines. I need to compare parameters. Next is to get the machine lasered for pitch errors in the x, y and z. Don't know what else to do.

Thanks

[underthetire]

Many reasons for a ballbar to show out of round. Don't assume its parameters right off the bat until you get a proper diagnosis of the ballbar reading.

[barbter]

I'm asuming fanuc used the laptop and connected to the front card for diagnosis?
If they did and their software says hunky dorey, when does the machine do this?
Ie, is it just on 3d data or if you did simple mill a square, would it round the corners?
If you spiral a bore would it show out of round?
Or is it just 3d tool paths that you have the problem?
If it is, is your program outputing R values or IJK? On the mastercam forum people have had probs with R as it is an approximations, where IJK is absolute figures?