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CNC Router Convert to Plasma Questions
« on: March 12, 2018, 09:57:00 PM »
Ok so I've got a CNC router I built decades ago, recently rebuilt it with a Pokerys57CNC and Mach 4 to bring it up to modern times. I need to plasma cut some parts and figured I'd slide a water table onto it and cut away!!!

I know nothing about CNC plasma cutting or very little. So questions...

1. Any advise about using a nice cnc router with a plasma cutter so I don't screw anything up? I plan on using a slide on water table to capture all the bad stuff.
2. Do I need to modify anything or can I use it as is? I assume I'd only need a THC if I were cutting all the time on it and/or warped or multi level parts.
3. I assume Mach 4 Plasma works like Mach Mill and just runs the machine with coordinates and all the other stuff like torch cut width compensation and so forth is all adjusted in the CAM program.
4. Normally I use RhinoCAD and RhinoCAM to generate my GCode. What do I use for plasma, cause I assume it has special settings for width of the plasma stream (don't cross the streams), etc... I know people use sheetcam, but is there anything I can do in my current CAD/CAM?
5. If I'm not using A THC is there a specific height I use for all materials that the torch should be from the workpiece?
6. I assume I can just turn on my plasma torch with it's existing CNC port and a relay hooked up to my Pokeys57CNC? Do I need to do anything to protect the electronics from the plasma system?
7. Last question! I hope. Feeds and Speeds for plasma, is there a chart then just tweak from there?

Thanks in advance. I can guess and research most of this, but I like the opinions of you people as you know best.
Re: CNC Router Convert to Plasma Questions
« Reply #1 on: March 12, 2018, 11:13:04 PM »
Hi,

Quote
I assume I'd only need a THC if I were cutting all the time on it and/or warped or multi level parts.

No, thats not correct, THC is the single most important thing that you can do to make a plasma table work
properly. Does the 57CNC board support THC? Note that THC is rightly enacted by the motion controller not Mach,
the communication lag means Mach would be hopelessly behind the eight ball.

Quote
If I'm not using A THC is there a specific height I use for all materials that the torch should be from the workpiece?

A couple of mm is common UNTIL THC takes over and thereafter it will maintain whatever height to attain the cutting
voltage you set, 120-130V as a rule.

If you dont have THC then you set a height and hope.

Craig
My wife left with my best friend...
     and I miss him!
Re: CNC Router Convert to Plasma Questions
« Reply #2 on: March 13, 2018, 01:16:09 AM »
Ok, that's not hard. I've seen wiring diagrams I can just make a quick disconnect for the Z motor and the THC. Any inexpensive THCs you know of?
Re: CNC Router Convert to Plasma Questions
« Reply #3 on: March 13, 2018, 01:56:09 AM »
Hi,
I repair welding equipment for a living including plasma tables, one of the big ones well over $100,000 second hand. I've seen a few cheap ones,
say $1000US but I've had to become pretty adept at fixing them too.

The cheapest and best THC solution I'm aware of is a motion controller which supports it. Vital Systems Hicon is the one that comes to mind. PoKeys are
very flexible and it may well be that they have THC support also.

The Hicon controller is $600 for the basic unit and probably add another $200 to get THC activated. $800 might sound expensive but in the realm of pro
THC controllers its as cheap as chips.

Craig
My wife left with my best friend...
     and I miss him!
Re: CNC Router Convert to Plasma Questions
« Reply #4 on: March 13, 2018, 02:09:38 AM »
thanks. I sent a message to Pokeys to see if THC is supported.

Offline Davek0974

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Re: CNC Router Convert to Plasma Questions
« Reply #5 on: March 13, 2018, 03:22:32 AM »

1. Any advise about using a nice cnc router with a plasma cutter so I don't screw anything up? I plan on using a slide on water table to capture all the bad stuff.



One thing for sure - it will not be a nice router for long once you start plasma cutting :)

Don't forget fume extract - downdraught or water table will be needed, its not optional really.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: CNC Router Convert to Plasma Questions
« Reply #6 on: March 13, 2018, 06:42:13 PM »
Thanks. I won't be doing much on it and as I said in the first post I'll be using a water table that I slide on.
Re: CNC Router Convert to Plasma Questions
« Reply #7 on: March 14, 2018, 03:17:40 PM »
Pokeys support, which is great BTW, says that Mach 4 currently doesn't support THC, but NFS is working on it and Pokeys is working on implementing the plugin for that Mach update.

So if Mach 4 doesn't support THC, does Mach 3? Cause I have a mach 3 license from when I switched everything over to Mach 4 and I have a C10 BOB that I could use.

Offline Davek0974

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Re: CNC Router Convert to Plasma Questions
« Reply #8 on: March 14, 2018, 03:53:37 PM »
Mach3 supports THC movements of the Z axis, you need a THC controller like a Proma or higher.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: CNC Router Convert to Plasma Questions
« Reply #9 on: March 14, 2018, 03:54:03 PM »
Hi,
thats not quite correct, THC is a controller function not a Mach function. Mach may not have screens etc set up
but that does not prevent a controller from enacting THC.

Look at Vital Systems Hicon, it has THC with the appropriate screens for pierce height, anti dive parameters etc.

Almost all controllers support Mach3 THC functionality. That wide support is still developing with manufacturers
of Mach4 boards. Sounds like PoKeys is not there yet.

Craig
My wife left with my best friend...
     and I miss him!