[Scott Pancheau]

My gantry is set up with Mach 3 mill and runs DC servo motors via Gecko drives. I have the axis tuned so they travel the exact distance on a linear move. The problem
I have is circular pockets do not come out round. Is there somthing besides the linear tuning I can look at to improve the concentric result?
Thanks,
Scott

[ger21]

If you slow down the feedrate and the holes are more round, it's probably due to flex in the machine.

[Scott Pancheau]

Thanks for the suggestion. I will give that a try
Scott

[awerby]

It could also be due to backlash. That happens when a screw changes direction; there's a point where the threads shift from pressing on one side to pressing on the other. While it's doing that, the motor will turn but the axis won't move, so a circle will be distorted.