15m Industrial Plasma Cutter

Jarman wrote:

The thinnest material to be cut is 8mm. The other is about 12mm.

???????
Those do not come in a roll ! Never.
If that is what you actually need to cut, at 15meters length, only the material for the table to carry that will cost you over 3000 plus work and welding.
You must mean 0.8 and 1.2mm, or ????

rodw wrote:

I don't think anyone said steppers. As Tommy said, keep the gantry as light as you can.

I did.
A 1.5 meter gantry can be made very light and sturdy and with reduction even some stronger Nema 17 motors on both sides can move it at over 18 meters/minute. Done that at 2.7 meters gantry and 22 m/m, gantry consisting of a 2mm thick metal bent to C shape with a single HGR25 and a single carriage, with floating head.

Now there is some contradicting info here so the answers are going all over the place.
Please check what exactly is needed and let us know.

Jarman wrote:

Sorry about that, my mistake.

You're right, the thicknesses are 0.8mm and 1.2mm.

Other than that I think the information is correct:


15m x 1.25m with a thickness of 0.8mm - 1.2mm.

Thanks for all of your help. I'll look into Mesa cards and THC.

That is more like it, thank you.
That brings us back to what some of us mentioned above and excludes some other.
To recap :
-Very light gantry made with a single square metal tube 80X80 or 100X100 mm, with a single square rail and a single carriage, HiWin HGR 15 or 20, 25 is the upper limit, belt driven preferably with some reduction, Nema 23 motor ( 17 will do just fine if above 1.2A ). Total weight with all motors should not exceed 50KG.
-Floating head, also as light as possible, screw driven with Nema 17 motor, all-thread M6 or M8 will do just fine but at slower speeds ( if you can budget it, use 1605 or 1204 ballscrews), drawer slides with ball bearings are very good for this, magnetic torch holder ( use magnets from old hard drives ), and very sensitive float switch so it triggers if it hits parts of material without breaking the torch.
-2 motors with reduction driving pinions on both sides of the gantry, Nema 23 2NM is more than enough. Ignore the 3:1 ratio, that will depend mostly on the pinion you use, so try to find the smallest pinion first, then calculate the reduction ratio to get 10 to 20mm per MOTOR revolution. You might end up needing 10:1 so buying 3:1 reduction might prove a bad investment.
-mounting the computer and controls and the plasma on the gantry is a very valid idea, but will greatly limit the maximum speed and acceleration.
-buy a small plasma, something like a Hypertherm 45, inverter as they are lighter, but do not buy a chinese one.
-Mesa 7i76E and THCAD
- supported round rails for the long axis on both sides, fi20mm are fine but use 3 carriages per side, 50 to 60cm total length for the carriages. You might want to use fi30 with 2 carriages per side but the price difference at 32 meters is quite big.
-you do need 31 to 32 meters of rails in total for the long axis, gantry will take the above mentioned 50 to 60 cm on both sides.
-Shielded cabling is a must.
-Drives, get Lam technologies DS1076 from mechapro.de at a significantly reduced price for the X and Y axis, DS1044 for the Z axis. 1076 work with higher voltage so you get much faster motor speed. They are indestructible.
-Metal work, that is for you to decide, and you have a lot of freedom on that part.

Thank you Rod, and sorry i forgot to mention that you do need at least 30A at 100%, as Rod mentioned. It would also help if it has current regulation, that way you can fine tune the best cutting at the fastest rate.
On a 15m machine every second counts, so some design ideas mentioned here will save you a lot of time and nerves later when using the machine.