[Sanghera]

Hi all,
This might sound stupid, but what about a gas torch. If you have the right speed it should cut right without stopping.
Thanks.

[Al_The_Man]

There exists alot of CNC gas cutting tables, I just retrofitted one that uses 6 torches.
Al

[traveler]

Gas torches,I will assume you are refering to oxy/acetylene torches. they do a great job, especially on heavy plate. I change my plasma torch and oxy/acetylene back and forth on my table a lot depending on material thickness. One of the drawbacks to oxygen/acetylene cutting is that you are limited to mild steel. No stainless, aluminum, copper ect. It does a great job within it's limits.
Traveler

[Sanghera]

What about the preheating? And also, how do you guys start the cut? I know it's a little more difficult to start in the center than finding an edge and starting to cut.

Oh, yeah, is the cut nice and straight and smooth? I'm getting a little excited.
Thanks.

[Al_The_Man]

On a CNC machine, the gas is controlled by solenoid valves so after ignition, the preheat fuel solenoid is on for a the duration of the pre-heat timer,(this can also be manually overridden), then there is a creep time and creep speed after pierce option, before the torch goes into cut speed. It does a pretty decent job, it comes into its own on large material thickness.
Al

[Apples]

Is torch height control needed with an oxy. can i cut 1/4 steel an not use THC. also how intricate can you get with the work?

[Sanghera]

Good Question.
And also, what kind of software do you guys use for your solenoid valves, would the Xylotex board work for this? What kind of software for the toolpaths and what not?
Thanks.

[Al_The_Man]

I do not think automatic torch height control is as important on gas as with plasma, many of the machines I have converted have been older trace cutting machines where a trace head followed a full size drawing to control the machine, the conversion to CNC still allows for sharp corners and small curves. The system I have used so far is Acroloop's Acrocut (dos) software & motion card designed for plasma & gas cutting machines. programmed by G & M codes and will import DXF files and also has a library of size-definable shapes. Also has on screen graphic toolpath.
Al

[Sanghera]

Sounds perfect. Does any board work with this? Also, where did you get this software, and how much? Does it controll the solenoids?
Thanks.

[Klox]

Another question: How does plasma & oxy/acetylene compare price wise?

Klox

[Al_The_Man]

Originally posted by Sanghera
Sounds perfect. Does any board work with this? Also, where did you get this software, and how much? Does it controll the solenoids?
Thanks.

I purchased the s/w before Acroloop was taken over by Parker, It is a one time buy for the s/w, you have to use the Acroloop motion control card, I do not know if Parker are going to continue with the Acrocut for dos as they are bringing out a Win based s/w.
The thing I like about the Acroloop cards is they have all the I/O 24vdc isolated on board the card. i.e. all the control logic for the machine is done on board.
The Acrocut (DOS) mill package is not bad either, it has a couple of glitches, but does the job.
Al

[Sanghera]

So, the board is something like a parallel port that you plug your Xylotex in? Hmm... is it still even possible to get this software? How much (if you don't mind) did you pay?
Thanks.

[Al_The_Man]

No,it is a dedicated motion control card (like a Galil) , it is aimed at the comercial retrofit market, I purchased the software about 10 years ago for US$1,000.00. But you only purchase once. here is the present link. http://www.compumotor.com/products/C...80__30_80.html
Al

[Sanghera]

Oh, I was just looking at it as sort of a toy kind of thing. I wonder if you can just use turbocnc or Mach2, set the solenoids and striker as pumps or whatever, and run two paths, one for preheating and one for cutting. How does you software work when it makes a cut? How does the preheat work, and what if the torch stops cutting, does it have some sort of compensation?
Thanks.

[Al_The_Man]

The pre-heat works just like you would do it with a manual cutting torch, after you ignite the torch, the pre-heat fuel gas is held on together with the oxygen the torch is held in one place until the plate is heated through, the pre-heat fuel gas is then switched off and the torch remains on with almost a pure oxygen flame, this causes cut penetration and after a short delay the torch goes in to feed motion, on this software if the torch goes out, it has a reverse retrace feature, where the operator can back it up to the point of where it extinguished and relight and start at what point he choses.
Al

[Sanghera]

Is there a way to get around this without paying the $1000? I can sort of see a way of starting over. It would take a long time the way I would do it. I would either rewrite the G-Code or if my software allows it, to start from a specific G-Code near the stop point. Does TurboCNC Support this?
Thanks.

[Sanghera]

What software are all of you CNC Plasma and Gas Torch Guys using??
Thank you all very much for your help.
I really appreciate it.

[Sanghera]

What are you guys doing for preheat and what not other than paying the Big Bucks for the High End or even Medium End stuff.
Thanks.

[Sanghera]

Hello?
Thanks.

[Johnuk]

Remeber that oxy acetylene brings about some very serious fire risks.

A lot of commercial tables now feature flame management systems that actively watch the flame leaving the torch. Home users would probably not want to get involved with the added complexity and cost this would add to their table.

If you're not standing in the same room as your table, watching over it, there are a million and one horrible things that could happen. During piercing, the torch may blow back and start burning back along it's lines. Or flash back. This could turn the entire assembly into burning molten goo. It could also burn back into the tanks. Whilst flashback arrestors are designed to prevent this, they are not something you should be relying on to save the day. Even with them fitted, the flame will be able to burn into the mixing chamber of the torch.

Worst case, the flame could blow it's self out. Now you are left with the torch filling the room with an almost perfect combustion mixture. When it reignites, you loose your house and family.

In an industrial enviroment, there will always be at least one guy working somewhere near the machine. At home, you could get called away from it and forget it's running.

You absolutely must have a fire extinguisher and access to running water close to hand when working with gas cylinders. A hose with a misting gun is a good idea.

I have had first hand experience of using a fire extinguisher for real when my brother accidentally set his clothes on fire. He was making some extremely unpleasant sounds due to the shock of actually being on fire.

Unfortunately... the flames weren't quite hot enough to scar him, he survived and recovered 100%... :tired:

But seriously... gas cylinders... fire extinguishers!

The hand held size ones for cars and around the home are totally useless. Trust me.

Buy one of the waist height ones. CO2 or foam would be a good choice. The dry powder ones not only makes a lot of mess, but I don't like the way the powder dispenses. It's like slowly throwing talc at the flames. When the **** hits the fan, you want as much anti-fire stuff engulfing the flames as possible.

Also, read the instructions on the extinguisher a few times over, so you know precisely how to use it. Position it where you can reach out and have your hand on it - don't stack it behind anything. The burn from something like clothing that's on fire will go from nothing to deadly within a few seconds.

You might also want to consider running the table with natural gas from your mains. The gas company can fit a higher pressure line if you'd like to cut thicker material. Gas cutting is much easier than gas welding with natural gas. It's also much cheaper and you have a limitless supply of it on tap.