PDA

View Full Version : CNC Plasma State of Play



RustyArc
9th Aug 2020, 08:37 PM
Recently got me a new plasma cutter that does a respectable cut up to 20mm, and has a machine torch available as an option, which has started me thinking about CNC. Any experience out there with a kit or DIY setup?

OxxAndBert
9th Aug 2020, 09:16 PM
Watching with interest.
Which machine did you get?

Steve

RustyArc
10th Aug 2020, 02:39 PM
Which machine did you get?

One of these things:
https://swswelding.com.au/collections/best-selling-products/products/plasma-cutter-buy-online?variant=31806570070064

Only downside with it so far is that the cooling fan seems to come on based on a thermostat, but never turns off, even when the machine must have cooled off. And it's a noisy little bugger.

OxxAndBert
10th Aug 2020, 04:25 PM
One of these things:
https://swswelding.com.au/collections/best-selling-products/products/plasma-cutter-buy-online?variant=31806570070064

Only downside with it so far is that the cooling fan seems to come on based on a thermostat, but never turns off, even when the machine must have cooled off. And it's a noisy little bugger.

Thanks. I've seen those online recently and thought they looked good (and CNC ready).
Be interesting to hear what SWS have to say about the fan. I'd be surprised if that wasn't being controlled by firmware.
Might also be an opportunity to float CNC with them in case they have feedback from other users they can share.
Mate of mine has just ordered a TIG from them. He's mainly doing prototype work, but the guy who does any production alloy welding for him has one and is very happy with it.

I've no personal experience, but got excited a while back and had did quite a bit of online "investigation" into CNC plasma.
For my own situation I'd definitely want a water table or really good fume extraction, and think I'd probably get away with a 600x600 travel machine as long as it had the ability to overhang a larger sheet if necessary.
Seemed that torch height control was very desirable too.
The nature of plasma cutters (compared to routers etc) seems to cause a fair few interference issues that can drive you berserk trying to track down if haven't got good shielding and control boards etc.

Steve

elanjacobs
10th Aug 2020, 06:05 PM
The nature of plasma cutters (compared to routers etc) seems to cause a fair few interference issues that can drive you berserk trying to track down if haven't got good shielding and control boards etc.
When we first got our CNC router at my old work, the welder a couple of factories down on the same property (common supply) was wreaking havoc on it with power spikes. We installed a solar panel system shortly after and that fixed it (dunno what exactly it did, but it worked), but definitely worth looking into options for isolating/smoothing the power supply.

RustyArc
10th Aug 2020, 08:20 PM
Be interesting to hear what SWS have to say about the fan. I'd be surprised if that wasn't being controlled by firmware.

They reckon it should turn off after 10 minutes if it's cool enough, which could be true - I'll need to check that next time it's fired up.


Mate of mine has just ordered a TIG from them. He's mainly doing prototype work, but the guy who does any production alloy welding for him has one and is very happy with it.

If I hadn't already bought my Unimig, I'd have seriously considered their unit - I think I saw somewhere that they did firmware updates for it, which would be awesome if true.


For my own situation I'd definitely want a water table or really good fume extraction, and think I'd probably get away with a 600x600 travel machine as long as it had the ability to overhang a larger sheet if necessary.
Seemed that torch height control was very desirable too.

I was thinking 1200x1200 and similarly, with the ability to index/overhang a larger sheet. That said, hadn't actually worked out where that would fit... Nor how I'd handle and load a full, say, 12mm sheet...

CNC seems pretty straightforward these days with lots of essentially turnkey components - I have a 6040 CNC router where there's probably only a handful of custom components (i.e. the gantry ends).

I'll ask SWS about CNC options. There's also a local bunch who do CNC kits - 3dtek - but they didn't respond to my inquiry :(

OxxAndBert
31st Dec 2020, 04:32 PM
Hey Rusty - did you ever get any further with this?

Steve

RustyArc
31st Dec 2020, 09:15 PM
Hey Rusty - did you ever get any further with this?

No - and every time I see a CNC plasma fire up on a Youtube video it comes to mind again...

OxxAndBert
2nd Jan 2021, 02:43 PM
Haha - I know that feeling!
What surprises me a bit is the lack of DIY plasma table kits locally. Plenty of CNC routers, but I’ve only seen a couple of plasma ones.
Out of interest I did the online quote thing for a 1200x1200 PlasmaCAM setup. Around $28k...
I’m guessing even getting something like a Langmuir Crossfire ex USA would still run close to $5k
Below that there doesn’t seem to be much other than rolling your own from scratch. Less dollars, but LOTS more time.

Steve

grunto
8th Jan 2021, 09:14 AM
From my research it would seem that CNC plasma is not for the faint hearted! The plasma produces an enormous amount of electrical noise that causes havoc if effective shielding is not consider up front. Avid CNC makes a range of "roll your own" systems that appear to be popular in the US although I am not aware of an Australian distributor (I have bought some items from Avid CNC and their customer service is exceptional but even they bemoaned the cost of shipping to Australia). There are plenty of builds on YouTube but they generally lack the detail required (I do like Stefan Cymbaluk builds but he hasn't done any videos for about a year). Rod W (Brisbane based) has provided an excellent write up of his build - search for "rod's spaceship cnc plasma".

Greolt
11th Jan 2021, 09:25 AM
Here is a video I did just before Christmas showing file creation and cutting on my CNC plasma


.
https://www.youtube.com/watch?v=3dUm5VYdV1c

OxxAndBert
12th Jan 2021, 01:22 PM
Thanks Greolt. What machine do you have - a commercial one or did you build your own?

Steve

Greolt
12th Jan 2021, 01:58 PM
Thanks Greolt. What machine do you have - a commercial one or did you build your own?

I built my own It can cut 1200 x 1200. Or a full sheet hanging out one end.

Chinese pilot arc plasma cutter. Water table.

OxxAndBert
12th Jan 2021, 08:11 PM
I’d be really keen to see a few photos and hear your thoughts on the build. Things that worked well, or that you’d do differently with the benefit of hindsight.

Steve

KBs PensNmore
12th Jan 2021, 10:37 PM
:iagree:
Thanks for the Video Greg, was it built from scratch or come as a kit?? Also if it's not too personal, what did it set you back dollar wise??
Kryn

Greolt
13th Jan 2021, 05:15 PM
OK a few photos. The computer in the mobile control cabinet is shared between three machines. The bottom electrical cabinet is only for the plasma

As far as cost, I do not record how much it all ads up to. The boss might find out! And I was still working at the time. Now retired.

When I build a machine, purchases are spread over time. Always running out for some item or another. Or Ebay.

I have built a number of CNC machines over the last fifteen years. Tend to have a lot of bits and pieces laying around.

My guess would be about $2000 including the plasma. Got it for $275.

Would I do things differently? Can't think of anything. Maybe a coat of paint.

It really has performed pretty well for a home built machine.

.

OxxAndBert
13th Jan 2021, 06:43 PM
Thanks Greolt. I'm hearing you about adding up the costs ;)
That looks like a really practical build and mechanically simple with the v-rollers etc. Most builds I've seen online use linear bearings of some type and people seem to have a poor opinion of the v-rollers. I suspect a lot of that opinion is regurgitated - so good to know that the v-rollers work OK in the real world (or at least good enough for hobby use).

Couple of questions if I may...
- are you also using gear rack on your Y axis, or some other form of drive?
- are the X and Y just direct driven by the stepper motors or is there some gearing there?

I'm keen for a CNC project but at the moment the only CNC machine I've had anything to do with is my 3D printer and that just printed pretty much straight out of the box. I'm pretty comfortable with computers and electrickery so happy to do a scratch build.

I'm toying with the idea of making a small (maybe 600x600) plasma table to get my feet wet but still end up with something more useful to me than going down the road of a router build.The 1200x1200 size would be nice but its an order of magnitude bigger in space usage and just generally on the construction side (heavier materials etc).

I'd use something scalable in the control side - maybe LinuxCNC since I'm pretty familiar with Linux in general - and decent steppers and drivers. My thought being that down the track I could then build a 1200x1200 using any lessons learned and essentially just swap over the control side - fully realising that the effort on the drive/control side is the same as what it would be on the larger table.
Having seen the construction of yours I'm now pretty confident I've got enough "stuff" around here to make rails/frame/gantry for a smaller machine at very little cost :)

Steve

pippin88
13th Jan 2021, 06:54 PM
Re V rollers:

Needs of plasma (no cutting force) and routers are quite different. V rollers are a poor choice for a router but might be fine for plasma.

Cost of linear bearings has come down a lot in the last few years. V rollers were popular when they were a cheap but viable option.

Greolt
13th Jan 2021, 09:08 PM
I would never go past proper linear rails for a router or laser.

A lot of work to build these machines and you don't want to compromise the result by skimping on such an important component.

Having said that, a plasma cutter is a different beast. Operating in an extremely dirty environment.

If I built a big industrial machine to operate eight hours a day, five days a week, I might consider linear rails. But I doubt it.

Yes X and Y axis are gear rack, steppers running direct drive. V bearings on the Y axis. Cam follower bearings on the X axis.

Z axis has a Linear Stepper. It has a small linear rail for simplicity.

Like this. https://www.omc-stepperonline.com/linear-stepper-motor/nema-17-non-captive-48mm-stack-168a-lead-8mm031496-length-200mm-17ls19-1684n-200g.html

I am not linux person but there is a big contingent that use it for plasma together with some inexpensive Mesa components.

https://forum.linuxcnc.org/plasma-laser/36743-what-is-plasmac