Varying rotational axis max speed?

[ger21]

G94 is what all the code you've been running has been using. You're always either using G94, or G93.

G94 = Use standard feedrates
G93 = Use Inverse time mode

G90 has nothing to do with them.

[MRob]

Ah! Right, thanks for explaining. So unless it is explicitly stated, it is G94.

[ger21]

Not necessarily, but it's the default mode in UCCNC.

[cncdrive]

Interesting, unfortunately my gcode is outputting as G1 moves, no G94's in there. Also the files are 10+mb each, and I am regularly changing them around. Maybe I could find a way to use this as a workaround, but would really like to get the post outputting properly! Thanks for linking though, I do appreciate your taking the time to try and help me out. It might just be easier for me to downgrade to mach3 though, unless I can find a way to get proper G93 moves coded in. Have posted to the autodesk post processors forum, maybe someone there will be able to help me.

Mach3 handles it the same way, so downgrading to mach3 will not solve your issue.

[MRob]

Not such an issue regarding how mach3 or uccnc handle the code, although I am not sure how well mach handles g93 - the issue is with getting g93 from the post to begin with. If I mod the mach3 post to output g53 z0 rather than g28 etc, would that be sufficient to run it in uccnc? Or are there other critical differences in the gcode that mach uses that I should know about?

[ger21]

G93 code is completely different than G94.

In G94, a feedrate is specified, and the machine maintains that feedrate from move to move.
In G93 mode, each move has a time for the move to be completed, which determines the feedrate for each move.

[MRob]

Yes understood, G93 moves seem like an excellent solution. Guess I'll just try my bodged mach post, using g53 homing instead of g28, and see how it runs.

[ger21]

You keep bringing up G53 vs G28, but that has nothing to do with using G93 mode.

G53 is just a move in Machine Coordinates, where G28 is a move to the home position.

[MRob]

Yes, I am talking about changing the mach3 post to make it compatible with UCCNC, since the mach post from fusion outputs G93 and the UCCNC one does not. However the mach post also outputs G28 G91 Z0 // G90 code for homing Z, which doesnt play nicely with UCCNC for some reason. So to use the mach post, I need to change this, then the question is if there are any other mods I need to make to have it be compatible with UCCNC. This would seem much easier than trying to change the UCCNC post to add in G93, which is a more major change. Going to try it in the next hour or two, and see what happens.

[cncdrive]

G28 is return to reference point.
G90/G91 is absolute/relative movements mode.

These codes as far as I know work the same in both softwares.
Maybe the UCCNC does not like the syntax that there is another g-code between G28 and Z0, like G28 G91 Z0. When the Z0 belongs to the G28 as G91 has no parameter. That is not a good programming practise in the first place.
I'm not 100% sure now, but probably it is even a syntax problem which mach3 might find OK and the UCCNC does not.