PlasmaC torch starting problem (Solved with help from the famous three)

tommylight wrote:

Clive wrote:

tommylight wrote:

Actual cuts, the pilot is working, but to know if the transfer is working, actual cuts have to be made.

Do you mean jog the z down to height then press the button and keep it down then jog to do a cut say about 50mm

Yes, at least 2 or 3 consecutive cuts of 10 to 20mm, or 50mm.

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Yes. Just tested. I can jog the Z down to cut height press the button (and keep it pressed) it will pierce and then I jogged for 150mm several times.

It will even pierce from 4mm above the 3mm steel and cut

tommylight wrote:

Were those cuts or just pierces ?

Yes as I said above 150mm cuts

tommylight wrote:

Thank you.
Did you also fix the pierce and cut height, as Phill noted they were reversed.
Pierce height 2 to 3mm, cut height 1 to 1.5mm.

No. but I will cut height is 1.12mm for 3mm steel that give me a good cut with very little dross and a sq. edge.
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I will make the pierce height 2.5mm.

Do you think that could make a difference.

Clive wrote:

rodw wrote:

Clive wrote:

I have noticed that when the button is pressed it stops the air purge briefly

I'm not sure that firing a torch in the air without cutting something proves anything. Its the arc transfer is the issue.

Does this interruption of the air flow happen when the CNC triggers it with a relay? If not, what is different about your switch and the relay?

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OK the switch is wired across the relay contacts so it is doing what the relay should do.
Its hard to see with the relay as it drops out to quick.
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When it probes for the fail cut (ie the second one) I can press the button and hold it for about 1sec then release and the cut will continue.

Sounds like the air is halted to allow the pilot arc to fire when you press the button.

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Yes it does But if we could get the relay to stop on longer it should work

So I went back and read the first few posts. Seems like we have been around the world.

So the original problem was the relay was turning off prematurely.
So we've since confirmed that Plasmac is working correctly.
It wasn't initially clear that a lot of testing was just on piercing, It needs to be based on a complete cut as Tommy says.
We are fairly certain that the issue is that the arc is not transferring to the material because the voltage is up around 230 volts.

But the relay is still turning of prematurely.

So does that state the situation?

So are you using a gcode file to do your testing? Write one by hand that does a single cut about 75 mm long

Seems to me with the software confirmed working and if a switch works and a relay doesn't, the issue must be related to HF noise. I'm not sure there is a solution other than waiting 15secs between cuts

phillc54 wrote:

From the plots on this post the torch is being turned off because PlasmaC sees a voltage within its set window and then that voltage drops out of the window. It appears the voltage is from the pilot arc and not the cutting arc.
I think your best solution would be a current sensor either similar to this post or at the bottom of this post and this would avoid the pilot arc being used by PlasmaC as the arc ok source.

I take it you saw the vid of the torch firing with the button. and the manual cuts of 150mm with using the button and jogging worked fine even with the air running.

Yes I have found a reed switch from an alarm contact. I will try and make 3 tight turns on the earth clamp cable to see if it will close the switch. if it does I could wire it through a relay coil and use the contacts to fire the torch.

Would I have to change any mode in PlasmaC etc