Recommend a CNC/wallet-friendly plasma?

[Mud]

Hi all - I've got most of a CNC plasma setup together, but am struggling to convince myself which plasma cutter to buy. I'm looking for blowback start, which isn't the easiest thing to search for. The best compromise I have found so far is the GYS 35KF, which has the following spec:

10-35A
28A @100% duty
30A @ 60% duty
~£1,100
clean cut steel to 10mm

My build will be a 'nice' hobby machine, and will have a THC (likely the Proma), so signal ouputs to limit surgery on the plasma cutter wiring would be nice. Cheaper would be nice, but ultimately I'm after value - I don't like buying crap.

Thanks in advance

[Rodw]

I have not got any direct experience with it but the Herocut 55i is the cheapest unit I've seen anywhere that has all of the features required for CNC.


I'd much rather see you give Linuxcnc a go with USD $69 Mesa THCAD-10 board than the Proma. It will probably be cheaper and give better results.. You can use it on a parallel port but its much better if you spend another USD $119 on a Mesa 7i96e.

IN Europe, you can source Mesa hardware from EU Surplus. https://eusurplus.com/index.php?route=common/home

[Mud]

Interesting unit the Herocut - could be an opener whilst considering a nicer machine at a later date. Very light, which makes me wonder, and obviously Chinese so no support. I'm struggling to find a UK supplier though.

I could go LinuxCNC - I've already got a CNC router which I setup with it (using a £5 parallel breakout board). I've implemented tool height sensing and home debouncing on that one, so not fully useless with it. I haven't looked much into using it with external hardware, but I'll research the boards you mention - I wouldn't use a parallel port for the plasma (would really want a fairly decent PC rather than raiding a skip...). I've heard good things about LinuxCNC for plasma.

I have an ethernet PlanetCNC controller which I was going to use for noise resistance, but it's an expensive solution. I knew I would use it on either this machine or another I'm building, so I'm not married to it for the plasma.

[acourtjester]

There are a few things to consider besides price with a plasma unit. Many of the cheaper unit only come with hand torches not real bad but machine torches are easier to mount and setup to cut straight. Nozzle size is another thing, most cheaper plasma are sold for basic cutting and nozzle size is not important. If you plan on cutting art type projects you will want finer cut nozzle sizes. Consumable availability and life is another thing, the cheaper parts don't last as long. Torch design is another thing many torches do not have a way to use an Ohmic sensor, again needed for thinner metals and overall cutting.

[Mud]

I ended up with a GYS 40FV for a very nice price, which I think ticks most boxes...it is a hand torch, but for my use that may be an advantage (occasional manual use). They sell a machine torch which I may look at later.

I'm very tempted to go with the THCAD-10 and 7i96e, just trying to understand the complete model range. Too much choice frankly! Any reason not to go for those? They seem sufficiently specified, and were there less choice I would have bought them already!

[Mud]

I've ordered the 7i96 and THCAD-10 - thanks for the advice, I was being a bit lazy researching those prior (getting to the stage of wanting it done ). Between the tank, the cutter and the Mesa bits I'm feeling quite poor now!

[robertspark]

GYS are a French manufacturer and do some nice Tig welders, it would be good to get some feedback on the plasma cutter when you get it all going.

The Mesa hardware with linuxcnc + plasmac will be a good setup and at the moment starting fresh is one of the best setups.

[Rodw]

I've ordered the 7i96 and THCAD-10 - thanks for the advice, I was being a bit lazy researching those prior (getting to the stage of wanting it done ). Between the tank, the cutter and the Mesa bits I'm feeling quite poor now!

Great. If you get stuck, the Linuxcnc forum will provide good support. There are a couple of very helpful plasma guys in the UK and Europe.

And yes, I know the feeling about plasma poorness.

[Mud]

GYS are a French manufacturer and do some nice Tig welders, it would be good to get some feedback on the plasma cutter when you get it all going.

The Mesa hardware with linuxcnc + plasmac will be a good setup and at the moment starting fresh is one of the best setups.

Will do - it's not got the nicety of an exposed arc voltage signal, but it appears a well-made unit with good capability (amps, duty cycle) for its size.

I've ordered the 7i96 and THCAD-10 - thanks for the advice, I was being a bit lazy researching those prior (getting to the stage of wanting it done ). Between the tank, the cutter and the Mesa bits I'm feeling quite poor now!

Great. If you get stuck, the Linuxcnc forum will provide good support. There are a couple of very helpful plasma guys in the UK and Europe.

And yes, I know the feeling about plasma poorness.

I'll start exploring LinuxCNC on Debian stretch shortly - that's new to me. Googling around, it does seem to be a very small number of very capable folk advising.

[robertspark]

Will do - it's not got the nicety of an exposed arc voltage signal, but it appears a well-made unit with good capability (amps, duty cycle) for its size.

Most 30 Amp plasma cutters don't come with a cnc interface (I am not aware of one actually), hence you have to use the RAW voltage signal from the torch and generate the arcOK signal from the voltage being detected between the torch and the clamp.

You probably know this but plasma is opposite to what you may think, the torch is negative and the table is positive voltage with respect to each other.

The THCAD will be able to provide you with the sampled voltage and also allow you to determine the arcOK / transfer signal when it has occurred.

My own experience of a smaller plasma cutter was using a hypertherm powermax350 where I just bridged a couple of soldered connections / eyelets onto between the hand torch switch connections and the torch main current feed cables and the table clamp cable and it worked just fine.

The manual for your plasma cutter is here, with a basic schematic near the rear (pdf page 62 I think it is)
https://www.laboutiquedusoudeur.com/med ... 031043.pdf

there is a bit of reading for you here:
http://linuxcnc.org/docs/devel/html/pla ... guide.html

and there are a number of guys who will help you out with the setup on the plasmac thread on the linuxcnc forum.
https://forum.linuxcnc.org/plasmac

[Mud]

Going above and beyond finding my cutter manual

I think I'm fairly clear that it's a 'Mode 0' machine (analogue arc voltage input only), using a float switch (possibly ohmic with hypersensing later if changing to a machine torch). I am keen to use a sharpie (or similar) for a scribe - I haven't designed that hardware yet though.

I'll keep reading