5 axis CNC Router/3d printer

[George Butty]

Hi Tom:

"It isn't entirely clear what you are trying to do or what is happening, but there does seem to be a bug in the what G28 does with the ABCUV Axes. G28 performs 2 moves. The Programmed move and then a move to the G28 programmed position. You didn't tell us what the programmed position is. By default it is zero. Currently the G28 should perform the programmed move then move only XYZ to the G28 programmed position, but doesn't move the ABCUV axes and leaves them in an indeterminate state.

G28 G91 Z0

Should first perform an incremental move in Z of 0 so should do nothing. Then move all axes simultaneously from wherever they are to zero."

Still not sure how to handle the G28 code. As stated by you the G28 G91 Z0 does as you described about. I have a zeroing
routine when I start the machine. I set X0 and Y0 in the first quadrant of the Cartesian Coordinate system. Z0 is set at the highest point
of the Z axis. This is my machine zero. Once this is complete I set a new work coordinate system on the part to be machined. The work coordinate
system will have +x,+y and -z values once set relative to the machine zero. When G28 91 Z0 is activated in the program, all 3 axis heads to machine zero at the same time. I would like the machine to first go to Z0 then X0,Y0. I have two other mills and both of them first go to machine zero then X0,Y0 with the same G28 G91 Z0 code. My assumption is that G28 is relative to the machine zero therefore the machine should move from a -Z value to 0 before X0,Y0 proceeds. Also the G28 G91 Z0 code was generated by Fusion 360 so I am not clear on why this is not so.

Thanks
George

[TomKerekes]

Hi George,

I have two other mills and both of them first go to machine zero then X0,Y0 with the same G28 G91 Z0 code.

What kind of mills are these? Do they run KMotionCNC?

Again since:

G91 Z0

commands an incremental move of 0 distance nothing will happen.

To move to an absolute position of 0 use

G90 Z0

So try:

G28 G90 Z0

[George Butty]

Hi Tom, not having much luck with the G28 so I started working with G53. That is working nicely. Once G53 is triggered, ZAxis moves to
Z0 on return and then I also programed a head rotation position x,y which it gets to nicely. Then I noticed when RTCP was active in the
program attached , the head would move to the first tool path and then return to the head orientation position (Z0 first then X0Y0). The next move would rotate B56.31,-C45 and then the head would move to the proper cutting position. Once finished, G53 gives a Z0 command. At this point
Z moves up but stops short of zero. The Z machine value has changed from the original zero position (reads zero but is short by the Z RTCP correction value). That changed value looks to be the z the value that was used to run the RTCP position of the last move. Head reorients to next RTCP position where the Z axis moves even lower then the last ( again machine value reads zero but actual position is nowhere near the proper position) position and then proceeds to machine the last surface. Seems to be in right position relative to G54. Once complete head starts going up but only reaches the Z height that was set by the last RTCP rotate. Machine Z value reads Zero but not even close to the Zero set at startup of machine. Once head gets back to head orientation position, (X and Y value good, Z is short by 20") head RTCP's back to B0 Z0 and the and all the other axis X,Y and Z go back to the proper head orientation position.(the correct machine zero) If I run with RTCP disabled (G49 active) then machine does every thing correctly but without the RTCP movement.

Thanks
George

[TomKerekes]

Hi George,

Sorry I can't really follow that.

Could you come up with a simple example with just several lines of GCode where one thing doesn't work as you expect.

Also include any Fixture or Tool offsets that are involved.

[George Butty]

Hi Tom, sorry for that long winded nonsense. I thought about how your logic works and it is correct. For some reason
I thought the machine would have to work in RTCP mode all the time. Then I realized that I only turn RTCP on when needed
and when I do the return to head orient position I use G49 command to cancel the RTCP mode. This works nicely so far.
Thanks
George

[TomKerekes]

Hi George,

Ok great. Thanks for posting back.

[George Butty]

Hi Tom, things are working quit good at this time. Still working on some issues but it is getting close to where
things are quite reliable. Getting very nice 5 axis moves with very large file sizes.
The software lost the help feature in KmotionCNC ( window comes up but no information) and I am getting a script error when I go into help in Kmotion. I noticed you have new updates for your software. Would it be wise to load new updates or just reload 4.35h? I do recall at one time I could run two different versions in my computer. Is that still the case?
Thanks
George

[George Butty]

Also can you confirm which files I need to copy over to new version if I update?
Thanks
George

[TomKerekes]

Hi George,

Sorry for the delay. Turns out several Versions have issues with the local help that we weren't aware of.

Here is a zip file of our latest Help files. Replace the \KMotion\Help folder in any Version to use it.

Let us know if you have any issues.

[George Butty]

Hi Tom, loaded your sent Help file. Works in Kmotion but it seems to go to the
help on line files when running Kmotion Cnc. Is that correct?
Also question about RTCP. Does RTCP get disabled when program runs in G0?
Also, I am having motor fault problems with a program I am trying to run.
I have attached a snippet of a program that seems to cause axis run away.
The program gets to around line 9150 and the B and Z axis makes a very fast movement
and then it trips a motor fault. Not sure why things make a sudden jump. I played
with velocity settings in both kmotion and KmotionCNC. Ran simple test program to make sure
that none of the axis can be over driven. Still get this sudden high speed jump. Not sure
if this is a posting problem or something in the RTCP setup. I have ran large programs with beautiful
5 axis motion with no problems prier to this.
George