Re: [CAD_CAM_EDM_DRO] plasma cutting table

dave_ace_me wrote:

> Hi all,
>
> My current desire is to make a plasma cutting table.

Awesome!

> I know that these are similar in design to router tables and I assume
> that there are a few in this group that have made these tables.

True, Similar, but can be much lighter duty if you are using it as a non commercial - hobby - fun type machine.

> If you have any pointers, I would greatly appreciate your input.
>
> My intention is to cut 1/8 and 0.08 aluminum sheets
>
> Some of the concerns I have are:
> how fast to I need to move the table,

You might want to be able to move as fast as 500ipm, but that is only necessary for really thin stuff.

>
> how messy the process is, does it create splatter like torch cutting.
> does it reak havoc on the slides ?

Messy, Very Messy and Yes, hard on the slides IF you use the real stuff. If you think you need the added accuracy of a REAL Linear Rail, I would probably suggest the common Bishop-Wisenheimer "V"
groove wheels and track. These will "scuff" off any garbage on the rail while it is in motion. Other options might be Frelon Lined bushings on round, supported linear rail with good wipers.

Because of the level of accuracy generally needed, because of the concept of the process itself, Some have been able to get by with simple Cold rolled steel for rails and generic Cam followers. Some
of this depends on how big of a machine you are building. I scoffed at this first, until I built a machine using the technique. Now that I see how messy this is, I am glad I do not have much mooola
invested in true linear technology. Cold rolled is cheap, and suprisingly straight enough for any Plasma Work I'd ever do. Laser ?? No, not accurate enough for that but Plasma ? Absolutely !

> How large of steppers should I plan on using ?
> and how you move the table, single center lead screw ? twin screws on
> the outside linked by a timing belt ?

I have one running 400ipm with dinky little 80oz motors. Non contact operation makes this possible. I would however shoot for something no less than 150, and target 220ish.

Leadscrews? No way, not unless you can spend a million protecting them. Otherwise they won't last long.
use cheapo rack and pinion, and because you are building from scratch, make sure you drive the pinion via a toothed belt setup so you can help yourself out later getting the most out of the particular
combination of Drivers and motors you end up using. Rack is plenty accurate for the process, just keep the "grooves" vertical so the Swarf falls out.

Also, Don't move the table for Plasma.... At least I wouldn't. Why move around a full and sometimes heavy sheet of goods when you could move a "known and calculated" gantry weight ? of course me and
moving tables have never seen eye to eye on gantry type machines.

If you are building it small enough, you might want to consider nuilding your "Gantry" in the shape of a large "T" square, driving the main axis from one side only, letting the other end ride free on
a roller. It's a fast and cheap way to do it, and I have yet to stumble across any higher accuracy needs for plasma use.
If you were doin a laser or water jet, It'd be a whole nuther story............. Or if it were a combo CNC Router.

> Also, if you do have one, do you make parts for people ?

Sorry, No. Too much goin on. (maybe too much time spent in NG's!)
Hope this gives a little insight as to what works for me in regards Plasma Cutting.

Chris L