Feature Request

I know I've brought this up very briefly in the past, but it's a feature that I think is missing from Plasmac and might not be too terrible to introduce. I think we need a way to ignore Arc-OK signals (which I think would mean setting the arc-OK pin to true).

At least three reasons I can think of:
1. Cutting expanded metal in CPA mode
2. End of cut lead outs. Where you want the torch to continue to travel for the flame to catch up, and the piece of material might drop out and cause a flame-out (this happens most to me with holes, even though I use no lead-out).
3. Thin materials. I spend the most time "testing" () the paused motion features when I cut thin materials. Even though I don't have a lead-out, the torch usually has around 0.030" or so of travel to go, but it loses the arc, so it pauses. Which is really annoying when you're trying to let it run unattended.

In my mind it would work exactly like THC where you can:
1. turn it on and off permanently from the GUI
2. turn it on and off with the particular material recipe
3. turn it on and off with G-code

The last option would allow you to ignore the arc-OK signal say .1" from the end of the cut with a SheetCAM rule, etc.

One last thing regarding cutting expanded metal, while doing some research for this (to see how other vendors handle it), I read here where Jim Colt recommended not using CPA mode when cutting regular metals:

Make sure for normal cutting that your plasma is in the cutting mode. Normal cutting with the switch in the expanded metal position will cause shorter nozzle life, and may also affect cut quality.

Jim Colt Hypertherm

I think we need a way to ignore Arc-OK signals
Cutting expanded metal in CPA mode

It could be made automatic for machines with RS485 when CPA mode is selected.

End of cut lead outs. Where you want the torch to continue to travel for the flame to catch up

Don't you stop the travel to wait for the catchup, like Arc Dwell here:
linuxcnc.org/docs/2.8/html/plasma/plasma...#_hole_cutting_intro

Thin materials

I mainly cut 1.6mm (16 Gauge (what a wierd measurement)) and haven't seen the issue you noted.

Make sure for normal cutting that your plasma is in the cutting mode. Normal cutting with the switch in the expanded metal position will cause shorter nozzle life, and may also affect cut quality.
Jim Colt Hypertherm

I don't have a choice, that is how my machine (Powermax 30XP) is...

phillc54 wrote:

I think we need a way to ignore Arc-OK signals
Cutting expanded metal in CPA mode

It could be made automatic for machines with RS485 when CPA mode is selected.

I’m not sure I follow? I know it can select CPA mode for you, but the problem is you’ll lose the arc-ok signal after the first piece of expanded metal, and it’ll stop.

Even with the dwell feature, if it flames out while waiting for the dwell to complete, it’ll pause. Whereas if you had the option to force the arc-ok to true for that portion of the cut no matter what the plasma power source actually did, it would continue on its merry way.

I’m not sure I follow? I know it can select CPA mode for you, but the problem is you’ll lose the arc-ok signal after the first piece of expanded metal, and it’ll stop

What I meant was that I could make it so when it was in CPA mode it would automagically ignore a loss of Arc OK

Even with the dwell feature, if it flames out while waiting for the dwell to complete, it’ll pause. Whereas if you had the option to force the arc-ok to true for that portion of the cut no matter what the plasma power source actually did, it would continue on its merry way.

I understand what you mean. It is just that I have not seen this issue and I am surprised no-one else has mentioned it.

phillc54 wrote:

What I meant was that I could make it so when it was in CPA mode it would automagically ignore a loss of Arc OK

Ah ok! That’s a good thought for ignoring it altogether. Of course in its singularity it only benefits the hypertherm folks I guess.

I understand what you mean. It is just that I have not seen this issue and I am surprised no-one else has mentioned it.

Sorry just was making sure we were on the same page. Honestly I’m offended you’re even questioning my ability to break things

snowgoer540 wrote:

Sorry just was making sure we were on the same page. Honestly I’m offended you’re even questioning my ability to break things

I would never question that!

What size sheet are you seeing this on?

phillc54 wrote:

snowgoer540 wrote:

Sorry just was making sure we were on the same page. Honestly I’m offended you’re even questioning my ability to break things

I would never question that!

What size sheet are you seeing this on?

Most recently was on 1/8” material. But most holes I cut flame out before I get to the end of the cut. I did think I was cutting them the suggested way. And while they’re not perfect, they’re good otherwise and the little scrap piece drops out. But the arc ok gets lost and it pauses, literally with a tiny amount to go.

snowgoer540 wrote:

Most recently was on 1/8” material. But most holes I cut flame out before I get to the end of the cut. I did think I was cutting them the suggested way. And while they’re not perfect, they’re good otherwise and the little scrap piece drops out. But the arc ok gets lost and it pauses, literally with a tiny amount to go.

Can you post a bit of the code that shows this issue.

phillc54 wrote:

Can you post a bit of the code that shows this issue.

Of course, the cut file is attached below.

Have you tried perpendicular leadins on those internal features?