What kind of controller to use for CNC plasma table

[drizzot]

Hi everyone, I have one question that I hope will solve my problem. Eight years ago, I built a very elementary plasma table. Then I used a Chinese CUT-50 and controller MACH3. The problem was that the g-code had to be edited every time. Each time I write in the code, when the plasma starts and when it stops. The speed with which to cut, as well as the arcs with which the cutting begins. It takes me a lot of work and time. Anyway, I've already built a really good table. So my question is: what kind of controller to use. When I place a DXF file, read it and start. I have already purchased a height controller as well HYPERTHERM 65. I have the old MACH3 controller, but I don't want to use it like I wrote above. I settled on this:

https://www.ebay.com/itm/SF-2100C-2-...QAAOSwZ65c0VsE

How do you think I can use this thing. I see it has two axes. Or recommend me another one to do my job, but in this price range.

Thank you for your time with my problems.

[Beefy]

A typical procedure for doing a cut goes as follows:

1) Draw your file in a CAD program, then export to DXF (or other suitable format).
2) Import that file into a CAM program. Sheetcam is excellent and powerful. Export your gcode file (normally a .TAP file) from the CAM program. The cam program generates the leadins, touch-off sequence, etc, etc, etc
3) Open the .TAP file in your CNC controller (e.g. Mach3)

There are some controllers that are "all-in-one", but I personally stay away from them because I like the independent control. Also any decent all-in-one seems to be expensive. I certainly wouldn't buy a Chinese controller with a Chinglish user manual and poor/zero support. Don't know if that applies to the controller you mentioned.

Check out this product from Cncdrive https://www.cncdrive.com/AXBB.html You can use it with Mach3 or use their own software called UCCNC, which is actively developed and growing in popularity. It also has an active user forum.

8 years of plasma cutting with such a basic frustrating setup. Reduce your pain and set yourself up with a real system. Go on a forum called Plasmaspider and ask about Torch Height Controllers. I've developed my own THC so don't have any experience with the cheaper off the shelf THC units, but many users there will have.

Based on what you said in your first post it's no wonder you gcode file was very basic. Relieve your pain and get set up properly. I don't know how much cutting you do but even if you took out a small loan to give yourself a complete system, I'm sure you'd be glad you did.

Mach3 has a problem when disabling THC during a cut, it momentarily pauses, causing a divot in the cut. UCCNC on the other hand has numerous "synchronous" M codes, two of which are THC ON and THC OFF. The synchronous M codes do not cause any motion pause so the cut is unaffected. If you don't know why/when you may want to turn THC on and off during a cut then I suggest you go to Plasmaspider and start learning.

If you don't already have it, I also recommend you set yourself up with a "floating head" on your Z axis so your gcode can command the Z to find top of material before each pierce.

[rodw]

So becasue of your eBay link I'm assuming you live in the UK.
I have to say Beefy is quite an expert with plasma cutting and has been very helpful in my journey. I just wish he was not so wedded to Windows!

You do not seem so wedded to Windows given your willingness to trial a stand alone Chinese controller. The fact its 2 axis is not really a concern because the Z axis is not something we need to worry about with plasma. So I am going to suggest you look at the Plasmac plasma config which is part of LinuxCNC V 2.8 and 2.9. The manual is here PlasmaC User Guide
There is also a Plasma Primer which is part of the linuxCNC documents which I wrote Plasma Cutting Primer for LinuxCNC Users

So for the same kind of money, you could purchase:

Mesa 7i96 ethernet card USD $119 See 7I96 picture
2 x Mesa THCAD (a THCAD10 and a THCAD5) USD $69 each THCAD picture
So by my calculations, that comes to about GBP 200 excluding VAT, duties and shipping so this in in your budget.
For that and a bit of work by you, you will end up with a kick ass controller that competes with those in the $20k price bracket and you will get kick ass support 24/7 from real users via the Linuxcnc forum. In fact there is a very experienced user there by the name of Clive S who visited me here in Australia in late November.to compare notes about plasma cutting and LinuxCNC.

There is a project underway entering final testing of control of Hypertherm plasma cutters via the RS485 interface from Plasmac so expect that will find it way into Plasmac during January all going well.

So how does all that hardware play together? Well the 7i96 is an ethernet controller board for Linuxcnc. One of the cool things about this board is that it has inbuilt relays on every output. The THCAD-10 is a robust voltage to frequency converter designed for plasma. The frequency is read by the 7i96 encoder and converted to a voltage in Linuxcnc. changing your Hypertherm divider board settings to 30:1 is a perfect match for the THCAD's 10-10 volt range.

The THCAD-5 is used for ohmic sensing in conjunction with an isolated 24 volt power supply. This is an invention developed between myself and Peter Wallace at Mesa. So we monitor the voltage as the plate is contacted and the THCAD-5 is sensitive enough to see the voltage ramp up as contact is made. A custom Linuxcnc component I wrote, turns on a probe signal at a certain threshold and keeps the logic side totally isolated at all times from the torch voltage. Very cool, very sensitive, very safe and very accurate!

So when it comes to the Gcode, I use Sheetcam and we have a post processor which eventually be rewritten by Les Newell, the Sheetcam developer and included in the Sheetcam distribution and there is also a post processor available for Fusion 360. But if you want to work with DXF files natively, thats OK too. You use gcode tools which is part of the Linuxcnc distribution. All you need to do then i to select the material in the Plasmac GUI and run the Gcode.

So plasmac includes a high performance PID based torch height control that just works perfectly, torch voltage sampling, corner lock, sheet severing, hole mode, pneumatic engravers, pneumatic drills, robust error recovery, and so may other features i belies belief. Thats becasue it had so much input from guys like Beefy and testing by hundreds of people around the globe,

Honestly, you need to look at it before you make a decision.