[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: http://www.cnczone.com/forums/showthread.php?t=6923
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: http://www.cnczone.com/forums/showthread.php?t=6923
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.

[accuratemike]

1/8" is not impossible. I get good results on 1/8". I use my smallest tip (000?) and reduced gas pressures. Consult your torch's manual for speed/tip/pressure settings. This
has alot of 1/8" in it. Front axle bracket, rear axle bearing brackets, F/N/R box mount, jack-shaft bracket, even the steering arms (less than 1/4" wide in spots). Do some test cuts first and adjust as you go. it is harder to get good results than the 3/4" stuff, be patient. I wasted some stock tuning.
While I'm showing off

and the tool path

This was 3/16, and alot of fun. Enjoy, MIKE

[massajamesb]

I cut quite a bit of 1/8 after the fact, and was never happy. I tried everything that Victor recommended, and just couldn't get satisfaction.
Now, I have a plasma setup specifically for 1/8 already loaded in Sheetcam No more problem, and about 3 times the cut speed.

Although, Mike, I must say I am jealous if you are having success with 1/8. I also flame cut a bit of 3/16, and had decent luck with it, though I prefer the results of plasma on it as well, as you can see in the pic above.

[byoung0454]

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!

Cost is not the big isue really, I just have a hard time letting go of 1500 to 1800 for a plasma cutter when I don't have a need for one other than just for a cnc setup. If I had more of a use for one I would be all for it. On the flip side I can invest a smaller amount of money on a machine torch , regulator and gas valve and the table set up and not be no were neer the cost and still fit my needs.

[byoung0454]

what are your guys thoughts on drive componets, belt, screw, or rack?

[massajamesb]

yes, I understand, and I feel your pain. I have had no less than 6 (or more) plasma cutters so far in my life, and I got into this cnc thing hoping to retrofit one.
Great idea, but I just couldn't justify spending the money at first. I wanted all my money to go into my table, and I didn't want to spend much at that.
The first build of the table wasn't beautiful, but I changed and modified it as time went on, and I have two larger tables in the works already.

If you want to save the money, oxyfuel is a viable option. It does cut slower than plasma, and it does and can warp material. Getting cutting speeds and tip sizes, gas pressure, preheat times, etc. takes a bit of practice, but in the end, it is well worth it. After listening to what you want to do, I think it will suit you fine. You can always try and make a little extra money with it so you can purchase a small plasma down the line, should you come to desire one.

If I were doing this all over again, I would consider
www.xylotex.com driver packages, the 280 ozin motors will be fine with some good gear reduction with belts and pulleys.
or www.Geckodrive.com, the G201 is top notch stuff. I love mine.
With that, www.kelinginc.net has some great motors and power supplies.

Any good CAD program, I use Dcad because the demo is free, and it is easy to use. There is a lot of others out there, look around.www.dcad.com

CAM. Well, I don't think (for low budget flame cutting) that I should bother mentioning anything besides www.sheetcam.com it is inexpensive, and designed for flame and plasma cutting. Les (the designer) has a free demo you can try before you buy. There are ways to get around using a CAM program such as coding by hand, but that can get to be a pain. CAM is one of those things that I never knew how much I wanted it until I got it, then I didn't want to go on without it.

Controller, well, you can go the really nice and professional route of Mach3, www.artofcnc.com
run under DOS like AccurateMike here by using Turbocnc www.dakeng.com (it doesn't show you what the part looks like since it runs under DOS, but it is inexpensive)
I personally use Quickstep4 with a pulse pacer,http://cpwojcik.home.att.net/Qstep/Quickstep_CNCx.html
which is inexpensive and really easy to use.

There are a variety of other programs out there that are good controllers, but those are three off the top of my head.

Does all that help? Or is it a bit confusing?

[massajamesb]

what are your guys thoughts on drive componets, belt, screw, or rack?

I use belts and pulleys for gear reduction, and rack for final drive.
I get really good and smooth cut speeds and rapids.
Originally I had chain drive, but as much as I liked it, I decided to change it. I wanted to try something different, so I went with rack.

[byoung0454]

First of all I want thank all who gave their input, it has been of great help.

I think I have a plan hammered out now. I plan on building a 5' x 5' table, for my rail system, I saw a link for a web site on hear that uses what looks like a 3/4 bar stock that sets on the top of the table frame with bearings guiding it on 3 sides. From what I see this looks to be a good set up and not to hard to do, I wouldlike to know what your thoughts are on this.

For my drive system I think I will go with a 1-5 acme rod with 2 steppers for my x, I have no idea on what size to use thoe, then single drive on my y. I want to go with a 3 hose torch but I am not sure about the valve to control the 3 o2 line. So far thats were I am at with this, it is going to be a little time before I get started I am adding a 40' x 40 addition on my shop and I need to get that done befor I can start this new idea. But the good news is that we stark framing the new shop this weekend.

Any other thoughts feel free to send them my way. I have noticed alot of you guys have started with a setup and then improve on you ideas, now do get me wrong thats great but I am the kind of guy build it once and leave it. So if you guys think I might be headed down the wrong path please let me know.

thanks for all the info

[massajamesb]

The linear guides sound feasible. I dont' see too many problems with that.

For a complete, all in one system, plug and play that would probably work for you, look at a Xylotex 3 axis board, use 2 of the axis outputs to drive X's leadscrews and the other axis for Y.
The 282 motors should work just fine. The bigger ones they sell will be overkill, at least for what you are doing.

For the third O2 input, I used a relay to turn on a 12 volt Parker air solenoid that was Teed into my oxygen regulator.
From the output of my regulator I had a 1/4" NPT nipple going into a 1/4"NPT T. On one end of the T I had the normal torch hose, going to the preheat side of the torch. On the other end of the T, I had the Parker solenoid. From there it went out of the solenoid to the cut oxygen port of the torch. Simple and clean.
I had 12 volts coming out of a small wall power supply going to a relay in my breakout board. Every time Pin 14 got a 5volt signal, my torch would turn on via that relay.

In my software, I would program for a preheat pause for X seconds, and then enter the M code to activate the pin controlling the torch relay.

For example, a preheat, cut, then torch off code would look like this in my code..
G04 sec=10 (10 second pause)
M07 (torch on)
G01 XwhateverYwherever
M09 (torch off)
Hope this makes sense. PM me if you need a solenoid, or anything of that nature, I have a few laying around.