Craig,
“ m62/m63 are for lasers. It turns the laser on, but ONLY when the machine has started to move, otherwise the laser would burn a spot right at the start.” 

I’m with you on this. But there is no reason m62/m63 would not work for Plasma as long as g4p2 dwell is included,  I have manually put a two second dwell before any x or y axis  movement
And the it did  operate properly.

I am really not into macros/programming so I think I’m going to simply use Mach3 for my plasma cutting and wait for somebody to develop a plasma cutting post processor for Mach4.

Thanks for all your input,
Chuck

Hi,

Mach3 for my plasma cutting and wait for somebody to develop a plasma cutting post processor for Mach4.

I think you'll be waiting a long time....what you want is not done by a post processor, what you require is to set up your machine with a compliant m3()
which is a function of your machine, and that is not a post process at all.

What you are actually saying really 'I want someone to write some magic code so I don't have to', and that tends to take a long time.

Craig

OK, Craig, sounds like I’m gonna have to learn how to do macros which I’ve been avoiding.

Thanks for all your input,

Chuck.

Hi,
this one is really simple, or at least can be simplified down to a couple of lines.

A more sophisticated macro would be bigger and take more effort.

Lets say for the moment you ignore all Z axis movement, that is to say you jog the machine to the start point and set it to the correct cutting height.
Then all you have to do is say Turn the Arc On, wait for 2 seconds and return. That would be enough, two, three maybe four lines.

A slightly more complex start routine would be Turn the Arc ON, wait until the ArcOK signal is received and return. If the plasma refuses to fire then the ArcOk signal
will never happen, ie the arc did not start so there is no point moving to cutting stuff because there is no arc.

A more complex one again would be to go to some safe height before starting the arc, the Start the Arc, wait until ArcOk signal, drop to pierce height, wait 2 seconds to pierce,
drop to cut height and return.

So you can see that you can start very simple and add nuances to match your requirement, but the simplest is about three or four lines.

What signal have you used to control the Arc relay? Have you hooked up the ArcOK signal from the plasma and to what input did you hook it to?

Craig

Hi,
I've just been experimenting with the Mach4 Plasma screenset and it appears like m3 is already coded and working. Is there a reason you don't use it?

Craig

Craig,
“ Is there a reason you don't use it?”

The reason I didn’t use it was  because I have been looking for a Plasma post processor for Mach4 like the one Artsoft has for Mach3.

If I had used the Mach4 Plasma screenset, what post processer in fusion 360 would I use for my “plasma cutting”tool paths?

Chuck

Hi,

If I had used the Mach4 Plasma screenset, what post processer in fusion 360 would I use for my “plasma cutting”tool paths?

The same one, it seems the Mach3Plasma post.

You seem to be fixated on the post....and the post has got ZERO to do with it. The post generates Gcode , but Gcode does not start or stop the torch,
that is m3 or m5.

The machine behaviour in response to m3 or m5 is where you need to concentrate. You have already proven that you can get perfectly good tool paths from Fusion and
the Mach3Plasma post.....but what you can't do is turn the torch on or off.....and that's got nothing to do with Fusion or the post.

The Mach4Plasma screenset already has a sophisticated m3 routine built in....there is no need for you to code it.

It first touches off the material surface. Note this procedure is optional, although you'll certainly want it if you are using different thickness plate. Anyway once the machine
touches off the plate and effectively determines where Z zero is then in raises to the torch start height....whatever you program in. Then it fires the torch and waits for the
ARC_OK signal. If it doesn't get an ARC_OK signal after about three seconds it faults, ie the torch has been told to fire but it fails for whatever reason.

Assuming the torch does fire and Mach receives the ARC_OK signal then the torch lowers to the pierce height, whatever you set. After a pierce delay of so many seconds, whatever you set,
then it starts to decsend to its target cut height, agin whatever you specify and starts the tool path.

What you really need, as a minimum, is a circuit to activate to turn the arc on and an ACR_OK signal. Ideally you'd have a probe input so the torch can touch off too.

Do you have those?

Craig

Craig
OK, I understand what you’re saying.

“What you really need, as a minimum, is a circuit to activate to turn the arc on and an ACR_OK signal. Ideally you'd have a probe input so the torch can touch off too.

Do you have those?”


To activate the arc, I’m using output number 2, which is a pin16 of port2.


Not sure about the “ ACR_OK signal” and “probe input”.
I will look into these.

Thanks,
Chuck

Hi,
so what plasma machine do you have?.

There are three things that ALL plasmas have that are intended for machine use.

The first is an input to start the arc, it replicates the trigger on a handheld torch. The best solution is s set of isolated relay contacts with the relay
under control of  Mach. Sounds like that's what you've got.

The second is ARC_OK. When a plasma arc first starts the tip is energised and the nozzle is earthed. The plasma current is usually limited to 20A
or so otherwise the nozzle will be wrecked. If the arc in in reach of the plate the arc will 'transfer' to the earthed plate, and the plasma machine will recognise this
and release the earth on the nozzle thereby preventing further excessive wear while the arc is now formed between the tip and the plate. Now the plasma current will ramp up
to whatever you have set the machine at. The 'transfer' and current ramp up signal that the machine is ready to cut and it will close a set of relay contacts (typically)
and that is the ARC_OK signal. Mach would use this to determine that the plasma has established an arc and that it has successfully transferred to the plate. It will now
assume the correct pierce height and the cutting will begin.

The ARC_OK signal is critical. If the m3() macro in Mach4Hobby Plasma screenset does not recieve an ARC_OK signal after a few seconds it will fault out.

I noted in a previous post that you start the plasma and wait for a fixed delay, two second or whatever. That might be how you'd do it manually but a machine plasma uses
the ARC_OK signal.

I worked for seven years for a company that sold and serviced welding equipment. I was an electronic repair tech, and used to repair plasmas and plasma tables.
Our premier brand was Hypertherm, but over the years I worked with  Kaliburn, ESAB, Lincoln, Miller, Thermal Dynamics and who knows how many Chinese machines.
All of the good ones had an ARC_OK signal.

The last feature that is required for machine use is a arc voltage output. Hypertherm have a 50:1 voltage divider, while some of the other brands copied that same 50:1,
others were 20:1, 25: 1, 30:1 etc. This voltage is used by the THC module to monitor the arc voltage.

One other feature you'll need is a probe input.  When you put a piece of plate in the machine the torch needs to descend and touch off the plate to know where the top surface is.
Without knowing that then your Pierce Height or Cut Height  don't really mean much do they? And what happens if you take a 3mm plate out and put in a 12mm plate for the next part?
If you don't have some routine to tell where the new surface level is the machine will drive to '3mm off the plate being pierce height' only to find that is still below the surface
of the piece of 12mm plate you just put in. The traditional way to do this is to use a g31 probing move. The torch descends from some safe height until the nozzle touches the
plate and Mach detects that touch or probe event and stops. It latches the Z axis location so it knows where the surface of the plate is. Many plasmas have a connection on the plasma
machine which is hooked to the nozzle of the torch to facilitate this touch off. Its sometimes also called Ohmic probing.

Craig

Craig,
Thanks for all the detailed information on Plasma Cutters.

I have an thermodynamics cutmaster 52

I do not have a THC module and my set up is pretty basic. I have the plasma torch  mounted on my milling machine which has a 28 inch X travel and a 15 inch y travel.

A Couple years ago, I worked with Arturo, CNC4PC,  trying to get a THC module set up on my machine and we could not do it, machine compatibility issues.

For the small parts that I cut I really don’t need the THC.

I have had good success with Mach3 Plasma.

Hopefully I can get Mach4 Plasma working correctly.

Thanks again for all your input.
Chuck.