[curtisturner]

I am having a problem I cannot seem to fix.
I have a heavy duty CNC Router I built (steel)
Running al AC Drives (Yaskawa and Automation Direct)
and Mach 3
The machine is dead on for every thing else so this is not a back lash issue.
When cutting out circles I seem to run into an issue with a diagnal elongation
basically a ovaling at 2:30 and 7:30 (or 40degrees and 210degrees) on every circle.

It seems worse or more noticable with smaller circles say 3/8" diameter
I am cutting G10 Fiberglass Sheets

I talked to Art from Artofcnc (Mach 3) and he thought it was a servo gain issue, or something like that.

Has anyone else had this problem or know how to fix it ?

Thanks
Curtis

[ironDigit]

though i can't help with the how's i have heard about servo's overshooting their intented position wich should be resolved by tuning the servo's and drives.

since you are dead on with everything else this could be an issue.

good luck.

[Al_The_Man]

If it is dead on in calibration on both axis and you do not get it on the quadrant points, (backlash). Then I would think you have a problem of one axis not perfectly perpendicular to the other. This would give you ovality.
Al.

[holger]

does the oval change if you change the direction (G02 G03)?

[elogicca]

Are your X and Y steps/inch and speed the same?