CNC Oxyfuel or Plasma

[byoung0454]

First post on here, great site

I am looking to build a CNC table for my shop, I am not looking to break the bank with this machine. I like the cost factor with the oxyfule and it fits more to my needs. The material I will be cutting is 1/4" and 3/8" it never changes, I dont plan on doing any sub work, I am trying to keep my work in house. I am not concerend with speed either. What ever maching I build will probley be only used maybe 6 hrs a month.

I am looking to build a maching with a cutting capicity of 4'x4', I plan to use round lineir rails for both of my X and Y axis not sure what the best drive system to go with rack,belt or screw. I would like to do a single side drive on my X just to keep cost down. Now the question shopuld I go with plasma for this set up or the oxyfule? I have the torch set up now I would have to get a machine head but other that that I am 1/3 of the way their.

Any advice would be of great help I am new to this but have been intresed ig doing something like this for a wile.

[massajamesb]

Welcome to Cnczone, good to have you.
Your question is a good one. When I started out, I wanted just plasma.
I then set a budget for my machine, and set off to building. Before long, I decided to just go with oxyfuel to keep costs low. I burned a number of parts on my 550 dollar machine with oxyfuel, and have now changed the machine up a number of ways. I now run Oxy or plasma, depending on the thickness of the material. I have a couple of pictures in my photo gallery of some plasma and oxy fuel cut pieces, from 3/16 to 1/2.

I have a build thread showing my original table, and some newer pics of it are on the way.

If you want, I can just post pictures here.
Do you know how and with what components you will build your table?
Are you only cutting mild steel, 1/4 and 3/8?
will cut edge bevel be a problem?
how big are the parts to be cut?

[byoung0454]

shure go ahead and post your pics I would love to see them.

as for the componets not really, the material is mild steel both small and large, the smaller ones are out of 3/8. I would rathe not have a bevel, it would make it easer the fit up parts and weld without it.

[massajamesb]

well, I have found that plasma will leave a noticeable bevel on anything 3/8 and thicker, and even some on 1/4, though not as noticeable.

here is some revised pics. These are fresh off the table, but I took them to work today, wire wheeled the edges and took some better pictures than the ones I had up yesterday.













These are 3/16, except the last three, which are 1/4. I will post some flame cut pics in a few minutes.

[accuratemike]

If you are using mild steel, 1/4"-3/8 thick", I'd go oxy/acetylene. I get great results and have cut some 3/4' & 1" stuff with the same machine too. If you need to do other metals or thin stuff plasma has to be, but for most bracketry oxy/acetylene works better. I used a hand held torch to make mine. I have less in the whole rig than a plasma machine would have cost. Mine is here: Homemade CNC Torch
It is only 30"x30", but it had to fit in my shop. Good luck! MIKE

[massajamesb]

If you are using mild steel, 1/4"-3/8 thick", I'd go oxy/acetylene. I get great results and have cut some 3/4' & 1" stuff with the same machine too. If you need to do other metals or thin stuff plasma has to be, but for most bracketry oxy/acetylene works better. I used a hand held torch to make mine. I have less in the whole rig than a plasma machine would have cost. Mine is here: Homemade CNC Torch
It is only 30"x30", but it had to fit in my shop. Good luck! MIKE

I agree.
Mike, how are you? haven't heard from you on here in a while.
I was going to post up a link to your lathe rest, if you didn't post up by now.
I have a couple of my own to post as well.

[accuratemike]

Hello! I read alot more than I post here. I almost chimed in on the "Dross" thread, but with all of that plasma technique stuff I didn't feel like I'd fit in. I get dross free cuts all of the time now. Mostly came from experience. I've been tuning tip height, speed, pressures and stuff for quite a while now. I do clean the metal and sometimes spray the no-stck stuff on the back side before I cut. (I don't know how much it helps, smokes alot though.) My rest pics are here: http://www.accuratepower.com/Rest/
That was 3/4 plate, no dross. Enjoy, MIKE

[massajamesb]

Here is some flame cut pieces





This was a axle tab I burned a while back, 1/4 thick. I ground the rust off the top to show the cut edge a little better, and just wire wheeled the cut edge for clarity. Hardly any dross.



This was my attempt at 1/8 flame cutting. Forget it. It warped so bad the cut edge was crap, and it had more slag than I care to remember.
You can at least tell it was the Superman logo, though.


A pair of ball joint mounts I burned out of 1/2 plate. The hole is 2" exactly.

[byoung0454]

Thats a great idea for a steady rest, I will have to show that to my father, he is a old school machinest. I would like to keep the cost down like you guys have, it all looks very interesting.

[byoung0454]

I like the plasma setups don't get me wrong, but I dont owen a plasma cutter as of now, I never had a use for one. I have plenty of cutting machines, power hacksaw, 14" cold saw, and a band saw that I plan on giving to my neightbor because I never use it. But for what I do the 2 saws fill my needs, I just have a void in my shop, and thats the need for a cnc setup. I have in the past used my cutting torch to cut my parts but that just takes to much time and no were neer the cut I would like to have for fit up and welding.

[massajamesb]

Well, if cost is a big issue, then it is oxyfuel for sure.
You can see the cut quality available with it.
I always thought oxyfuel would have a horrible cut edge, no matter what you did, until I saw a cnc torch cut edge. That did it for me!
Good luck with the build, any more questions, just post 'em up.
After all, that's what this place is for!

[massajamesb]

I like the plasma setups don't get me wrong, but I dont owen a plasma cutter as of now, I never had a use for one. I have plenty of cutting machines, power hacksaw, 14" cold saw, and a band saw that I plan on giving to my neightbor because I never use it. But for what I do the 2 saws fill my needs, I just have a void in my shop, and thats the need for a cnc setup. I have in the past used my cutting torch to cut my parts but that just takes to much time and no were neer the cut I would like to have for fit up and welding.

As long as you are not going to cut anything thinnner than 1/4, then I think you will be happy with oxyfuel.
Now, automated (cnc) cutting is generally faster than hand cutting ,(especially since grinding is pretty much a thing of the past, I generally acid dip and/or wire wheel my parts, that's it) but oxy fuel is still slow. I did most of my 1/4 plate cutting around 30 inches a minute. That's not bad when you think about it, but it still get tedious sometimes.
I suggest building a decent table for now that you can upgrade to include plasma later, should the need or desire arise.