Plasma cutting - how much air do I really need?

[gwdixon]

Thanks Steve.

Let me ask a dump question. Is the volume of air only required for the max cut? Example, the PM45 specs say like 6CFM. But if I am only cutting 1/8" or 1/4" can I assume it would need significantly less than 6CFM?

My experience is that the air stays the same. On my machine it is set at 80 psi and runs at 60 psi when the torch is open. The amps are the only variable to set when cutting different thickness.

 

[yomax4]

The torch needs a certain amount amount of air to keep it safe from melt down. Depends on Brand and quality. Turning the air up higher than 65-75 doesn't help anything. It actiually cools the arc if it's too high.

 

[yomax4]

You still need what ever the rating is. If it says 60, you will get an error code if you try to cut a t 40 and it will shut down to protect itself.

 

[BukitCase]

All true - look at it this way - just because you turn the air down (even if the machine would let you) doesn't change the air PATH thru your torch/consumables - so, unless you have enough CFM to maintain the PRESSURE the machine's sensor wants, it will shut you down.

In practice, I simply turn up the pressure on the external supply til the green light comes on, plus a little bit. I'll do one "dry fire", and if the light stays lit/fire keeps going, I'm good to go... Steve

 

[CNC Dan]

I have the Powermax30 and I can cut 1/2 steel with good results. Thats way over what it's rated for.
If you run the air down. it will stop cutting, so just use it till it stops and take a break.

I once cut a piece of old 24" X 1/2 wall pipe for a friend. He had a 120v air compressor and only one outlet. I would let the compressor fill and shut off, then cut 'till the compressor kicked in, wait for the compressor again an so on.

 

[BukitCase]

That's something I've not tried yet, I have one of those "double hot dog" Campbell Hausfield portables and an 8kw genny, and at least one "field" project that could use a plaz.

Forgot to mention another "benny" with the PM45 - if you decide to get into metal art, the 45 torch also accepts PM30 consumables. According to Hypertherm, using the smaller consumables can give a finer cut for thinner material. Just turn down the amps and swap consumables in the torch... Steve

(Did I mention that I like the PM45??!? :=)

 

[jgayman]

Does the length of the air hose have much effect on the pressure? I have 50-ft of 3/8" hose fed out of one of those spring loaded hose reels.

 

[BukitCase]

Not at that flow rate - I have 100 feet of 3/8 python air hose on a reel, might have had to turn up the external regulator just a tad initially, don't recall. Cutting 1/4 plate with the PM45 (as long as you get the travel speed right) looks like a laser cut to me... Steve

 

[crazyal]

Just throwing this out as an option but you could go with one of the Chinese plasmas sold by the venders here and with the money you would save be able to get a decent 5hp 60 gallon compressor.

 

[joshuabardwell]

Just throwing this out as an option but you could go with one of the Chinese plasmas sold by the venders here and with the money you would save be able to get a decent 5hp 60 gallon compressor.

I think he said a 220v compressor was not an option right now due to space.