Some thoughts and some findings using PlasmaC

Oh goodie, where do i start ?
Well the torch on does work properly and had a huge impact on getting much less failed arcs , but also shed some light on proper setting of the minimum and maximum voltage for arcok when using mode 0 (arcok generated from the THCAD voltage), namely, setting narrow limits will result in lost arcok signal very often, so here are some tips:
--set the min voltage to 80 to 90V as that will ensure loosing the arcok if by any chance the torch gets very close to the material, this will prevent the older plasma sources from overloading,
--set the max voltage to 180 to 200V, make some quick tests by using F9 on some frequently used scrap material, lower that voltage until you get arc lost on at least 10 pierces, then set the voltage some 20V above that. This will prevent from torch moving to far from material if it runs over scrap or already cut parts, cutting the arcok and saving the material from going to the bin.
After using the arcok from the plasma source ( the reed switch mod found here at the very bottom linuxcnc.org/docs/2.8/html/plasma/plasmac-user-guide.html ), everything works perfectly, no misfires, no arc lost, just plain perfection.
## For anyone doing more than hobby cutting, please take the time to study and implement the above linked solution with a reed switch for ARCOK signal, it will save a lot of time in the long run> That is if the plasma source does not already have it.##
Thank you all.

Had a strange issue today that i could not reproduce any more, namely the probe height/speed where ignored for over 50 probes and after stopping with ESC and resuming with "run from here" it did work properly for some 300 more probes.
Beside that, it was a pleasure working and watching the machine work, no wonder my eyes are hurting !
More cutting tomorrow hunting gremlins ...
To make this topic happier, here are some of the parts cut today:

Ignored how? Like Rod had described?

Nope, it just moved fast at setup speed, not slowing down.

Tom is it possible that the material buckled up enough so the the top of the material was above the Probe Height. Remember that Probe Height is measured from the MIN_LIMIT rather than the material.

When cutting square tubing i set the probe height much higher, but yesterday i was cutting only 3mm and i did set the probe heigh just to make sure, but still it would just run full speed down.
Doing more cutting today so i will see if i can reproduce that and report back.

tommylight wrote:

When cutting square tubing i set the probe height much higher, but yesterday i was cutting only 3mm and i did set the probe heigh just to make sure, but still it would just run full speed down.
Doing more cutting today so i will see if i can reproduce that and report back.

Warning : Do not take any of this as de facto as i have two very fast machines that are set in many ways differently from what is normal setup.
This got to be more complicated than i thought, so here is some more:
As far as i could gather the ignoring probe height was happening as i had my heights set differently, i had the Z axis set as min at 0 and max at 180 or 200 on both machines and rarely had the issue of Z axis moving to far up and hitting the limit switch, but when i updated to 0.177 and later to 0.180 it got to the point of being unusable, so i set the Z axis as 0 max and -180 and -200 on both machines and that issue was gone .... until i started cutting some square tubing so the cut height was in the upper 50 to 80 mm of travel even when the safe travel height and probe height are set properly and both functioning it will still overrun and hit the switch.
Overruns will happen occasionally during normal work when everything is working properly and will not trigger the switch but will move past soft limit so resuming will not be possible without stopping the program execution and running from line after that it will run normally for quite some time or not repeat that again at all.
Checking the Z axis position in World and Joint mode shows the soft limit has been passed.
Writing this got me thinking, i must lower the setup speed as i did that before for testing and all these issues disappeared, but i like speed ! I have them set at a meagrely 4800mm/m!
Overall it is working magnificently and i am really enjoying using it all day every day, just the fact that i have not gone back to using "my" config should be enough proof that all of the issues i am having are mostly self caused.

phillc54 wrote:

Tom is it possible that the material buckled up enough so the the top of the material was above the Probe Height. Remember that Probe Height is measured from the MIN_LIMIT rather than the material.

Yes, yes it was as i had just changed the Z axis limits but was still using old heights.

DenkBrettl wrote:

Franklin wrote:

One more note for pierce/cut mode. When in the Gcode is present the spotting function and turn on the "Pierce only" mode the plasmac makes piercing instead of spotting.
It would be great to ignore spotting when "Pierce only" mode.

I had exactly the same problem today. So I fixed it

My fork can be found here: github.com/DenkBrettl/linuxcnc - I've opened a pull request as well.

Klaus

Thanks for the contribution, it looks good and has been merged.