Quote Originally Posted by Chaz View Post
On my concrete mill (Thor) I run CS Labs IPA with Panasonic servos. Ive always noticed that on circles and similar I get jerky movement, specifically where there are I and J type G Code involved.

I did a test last night, took the same code, ran it on my Bridgeport, running on Centroid Acorn, same Panasonic setup but in Step / Direction (Position mode) versus Speed move as per Thor. The same code was smooth.

Ive seen a lot of complaints about Mach 3's smoothness.

Is my issue a limitation with Mach 3 (or badly configured), related to not having good PID on the servos or something else?

I might try the new SimCNC software from CS Labs to see if its Mach 3 or not. A newer PC might also help.

Thoughts?
I think there is a setting tick box in Mach3 to use arcs CV mode