A "portable" CNC plasma table

[meincer]

I have limited space in my shop (who doesn't?). So a couple of months ago I got the idea of making a small (roughly 3' X 3') and light weight plasma table that could be moved, put on top of a large sheet of metal and/or over top of my small plasma cutting table.

Well it took me a while but I finished it. I am pleased with its performance(with one exception). I mostly cut 1/8th or thicker and therefore super fast speed was not necessary. Not counting the motors (from automation direct, 278 oz-in) and the driver board (Xylotex, 3 axis) and the software (TurboCNC and SheetCAM) I have under $150 in materials.

I actuate the plasma trigger by a small chain that presses the trigger when the z axis is lowered. The chain holder is spring loaded so going beyond the trigger point won't damage the trigger. After adjustment (easy with threaded height control) this works better than one might think it would.... flawlessly!

I skimped on the x axis linear bearings (skateboard bearings on an aluminum angle). It works adequately but the undriven side sometimes does not follow the driven side without shuddering a bit. I think I might go to two toothed belts driving both sides with the one x axis motor. This is the only performance issue, everything else works great!

The other two axis bearings are simply bronze sleeve bearings on ordinary steel rod, and the threaded rod just standard stuff all from the hardware store.

This setup probably doesn't match the precision of larger, more expensive tables but it does what I want it to.

[massajamesb]

I like the ingenuity! Good job!

I have seen quite a few of the "hardware store" variety router builds, but this is the first plasma one I have seen. Use what you have, and keep it cheap!

Looks like a winner!

[sailandoar]

That looks like what I will be building........... maybe this year?

[Weldtutor]

Nice work Meincer. Thanks for sharing.

Your post in the "other" forum also caught my attention.

What size threaded rod is used & what travel speeds do you obtain?

For the ingenious trigger activation, does the chain remain in a fixed position, & the torch move against it as mentioned?

You should be able to travel around the neighbourhood doing CNC plasma work!

[meincer]

I really haven't done much travel speed testing. I mostly cut rusted 1/4" to make rustic out door signs. My Hypertherm Powermax 600 works well at around 40 inches/min at that thickness and I have no trouble with that.

I am using standard threaded rod (1/2" for the X and 7/16" for the Y, standard threads/inch, I honestly can't remember the numbers). I just adjusted the scale factors in TurboCNC to get the correct scaling. I haven't really played with microstepping settings, etc.

The chain for the trigger is connected to the fixed backplate of the z axis. The other end is then held by the spring loaded holder, also attached to the fixed part of the z axis. The torch portion is inside of the chain and lowers into the chain when it goes from the 0.15" I have set for off to the 0.05" cutting position. The on/off action is amazing repeatable.

[meincer]

Actually I realize after looking at my own photo that I connected the back end of the chain to the moving portion of the zaxis (NOT the fixed portion) and the other end is connected to the fixed part. This still creates a situation where the torch lowers itself into the chain when it is lowered to the cutting position.

[Weldtutor]

Originally Posted by meincer The on/off action is amazing repeatable.

Thanks for the information.

Your table is a marvelous piece of KISS engineering!

WT

[DSL PWR]

Great job! I tend to over do things, and will have some pics of mine in the comming months. If you have an extra digital output go to your local surplus store and find an electric door lock solinoid (out of a car), and use that as a mechanism to trigger your torch. Even if your voltage is a little hi for the solinoid (over 14 vdc) it should work just fine.

[gromit68]

The trigger switch is low voltage, I'm curious as to why you don't just use a control output trigger a small relay to do this job.

[yudmikle]

Thanks for the information.
Good job!

[meincer]

I was aware I could have used a solenoid or a relay. What I ended up doing, though, didn't cost anything (literally NOTHING) and either of the other two solutions cost me something as I didn't have either of these components on hand. I also didn't want to open up my plasma cutter chassis and wire in there or splice wires anywhere else.

Besides......as hard as it is to believe it really works flawlessly!

[JEFFY]

Truley a very nice bit of work. I had something close to this but was smalller. The frame size was about about 20x20 and I would set my plate on a 55 gallon drum that was set up as a cutting table. Then lay the unit on top and cut my parts. Wish I still had this set up. My old employer ended up with it as he owned the plazma cutter and bougth my table when I left the buisness.
I like the way you made yours, very simple. Will have to remember this as I have been thinking about buying my own plasma cutter.