Rotary Axis speed control

[srracer]

I've searched and found a couple of other people mentioning this without any obvious follow up or conclusions.

I just setup a 4th axis rotary on my mill. I have the settings configured as rotary and the units are configured as degrees.
I was expecting to use G93 (inverse time) to control the speed of cuts. I have essentially only 1 job destined for this rotary axis which is to machine a barrel cam into a tube. There is a portion of the cam profile where *only* the rotary axis should be turning.

Unfortunately, G93 does not work when only the rotary axis is engaged. I wrote a simple program to test:

Code: Select all

(rotary test)
G90
G54
G0 a45 x.594   <- Behaves as expected - Full Axis speed
g93
g1 f20 a0 x.5945 <- Behaves as expected - completes in 3 seconds
g1 f5 a30 x.5945 <- Does not behave as expected - moves full speed
g1 f10 a45 x.595 <- Behaves as expected - completes in 6 seconds
g0 a0 x.594  <- Behaves as expected - Full Axis speed
g94
g1 f1 a45 <- Behaves as expected - Full Axis speed (G94 + F1 doesn't work for rotary as expected)
g0 a0 <- Behaves as expected - Full Axis speed
M30

I really am not fond of introducing some small error in the cam program just to get it to work right.
Can someone please clarify:
1. Is this recognized as a bug and CNCdrive has it on the list to get fixed eventually?
2. Is this actually expected behavior? That there is no way to control speed for rotary axis only moves?
3. Am I doing something wrong?

Thanks!
Chris

[srracer]

Sorry - a few more details:
running version 2.2116
Axis is rotary is checked
Rollover on 360 is not checked

[TReischl]

I am following your thread to see if there is ever a response. . . . .

There seem to be folks who tout that UCCNC is controlling rotary axis. I sure would like to know how. I have spent the last two days trying everything I can think of to make it go. No luck. I am not a newcomer to cnc, been working with it since 1974.

Seems pretty ridiculous to me, I converted over from Mach3 which we all know is antique software, which actually controls a rotary axis correctly. I was even led to believe that updating to the latest Vectric software would fix the issue. $400 down the drain. I did not need the latest version for anything.

This has become very irritating. Hope we hear something soon.

Methinks there is no solution, or someone would have happily shown us the error of our ways.

[cncdrive]

We will test this soon.

[Greolt]

I was even led to believe that updating to the latest Vectric software would fix the issue. $400 down the drain. I did not need the latest version for anything.

I am fairly certain that version 4 did not have G93 output capability.

Not saying that would make any difference to your problem.

[TReischl]

Greolt, see my replies over on the Vectric forum to your posts. Thanx!

[TReischl]

We will test this soon.

You might want to start following this thread over on the Vectric forum:

https://forum.vectric.com/viewtopic.php?f=38&t=43357&p=314393#p314393

[TReischl]

The help manual has this twisted sister paragraph about this issue. It is about as clear as mud. Furthermore, if a user is in fact setting up a rotary axis and a check box says "Axis is Rotary" then that checkbox should be checked. Period. Full Stop.

That is not the case here, instead, checking that box results in the axis not running correctly for the vast majority of people running a rotary axis. Some of them never notice it because they primarily cut along the linear axis and do not see that the rotary is not rotating under feed rate control.

Like I have posted elsewhere, this miserably labeled checkbox cost me 2.5 days and $400. And yea, I read that stupid paragraph in the manual a dozen times, it is so twisted it is virtually incomprehensible.

[Greolt]

G1 means it should move at the specified feedrate.

G0 means it should move at rapid rate.

I fail to understand the logic that says it should be otherwise.

Perhaps someone with more experience could set me straight.

[srracer]

G1 means it should move at the specified feedrate.

G0 means it should move at rapid rate.

I fail to understand the logic that says it should be otherwise.

Perhaps someone with more experience could set me straight.

For rotary, G1 is tough (impossible) because the speed of the bit along the material depends upon the radius of the material where the tool is. So I sympathize with anybody who has to write a controller to interpret what is meant by the G-code.

That's why G93 does make a LOT of sense to me for any moves that utilize a rotary axis. That said, it should work when the rotary axis is the only axis to move. Currently UCCNC does not do that. Any rotary only movement is only at max rapid speed. And I agree, this should be fixed.