Plasma Problems

I've been trying to handle this offline, but I have to get some 11 ga steel cut before Monday, so I'm tossing this out to the group to see if it might be a simple problem, maybe something I've overlooked.

PP256 brand new, can't get plasma to work. Air pressure is OK, electrode and cap are tight. Torch (A81) produces a bright blue/white plasma flame when squeezed in mid air. But when I try to cut 1/8" mild steel I get all kinds of blowback that fouls the cap and very weak cutting. Plasma cut a shallow kerf into the metal, but wouldn't cut through. Today I tried again. Held the torch with roller standoff just off the edge of steel I need to cut (which was grounded back to the PP256 + terminal) and the plasma immediately stopped when it contacted the steel. Repeatedly. And I'm approaching the steel slow and there's less than 1/8" gap between the standoff and the cap on the A81.

So, first I got very weak cutting action and lots of stuff blown back on the cap. Now no cutting action and the flame goes out as soon as it touches the work. This is my first experience with a plasma torch, so I'm a little clueless.

Any thoughts?

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Originally Posted by Slartybartfa

I've been trying to handle this offline, but I have to get some 11 ga steel cut before Monday, so I'm tossing this out to the group to see if it might be a simple problem, maybe something I've overlooked.

PP256 brand new, can't get plasma to work. Air pressure is OK, electrode and cap are tight. Torch (A81) produces a bright blue/white plasma flame when squeezed in mid air. But when I try to cut 1/8" mild steel I get all kinds of blowback that fouls the cap and very weak cutting. Plasma cut a shallow kerf into the metal, but wouldn't cut through. Today I tried again. Held the torch with roller standoff just off the edge of steel I need to cut (which was grounded back to the PP256 + terminal) and the plasma immediately stopped when it contacted the steel. Repeatedly. And I'm approaching the steel slow and there's less than 1/8" gap between the standoff and the cap on the A81.

So, first I got very weak cutting action and lots of stuff blown back on the cap. Now no cutting action and the flame goes out as soon as it touches the work. This is my first experience with a plasma torch, so I'm a little clueless.

Any thoughts?

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Try to get rid of some obvious questions as those sometimes are the ones that are overlooked.

All connectors to the plasma unit inserted fully and tight
Work clamp on clean surface
Work clamp close to cutter

Make sure the swirl ring is in the torch head. Goes around the electrode (blown plastic looking ring, not plastic but best way to describe it).

Did you use the plastic tube with the ball inside to setup the air pressure (I think Duncan found it to be around 72PSI if you want to skip that part)?

Assuming good dry air, it should be working if you have a good ground. Ground in "+" or workpiece port.

You have pilot and get close and it blows out now?

Yes to all, torch is negative, ground clamp positive, etc. However I didn't see any plastic tube with ball in it that came with the torch, so I set it to 72 psi. Argon regulator has one, of course, but compressed air goes directly into air pressure regulator/moisture trap (set at 72 psi).

I've taken the torch head apart several times while replacing parts and compared the parts with the Trafimet A81 parts diagram and everything's there and assembled properly. I've also read extensively on this forum about common problems folks have had and this one doesn't seem to be like any of the others I've read about. I get a nice blue/white flame, but when it touches the edge of the metal to be cut, it simply goes out, and air continues to flow. Doesn't even try to cut now. Is that flame I'm seeing what you refer to as the pilot or is that the actual cutting flame? Not ever having done this before I'm in the dark.

Attached are some pics I shot. The shot of the face of the PP256 was taken after I turned off the air compressor, so the amber cut light is not on.

Attachment 7232Attachment 7233Attachment 7234Attachment 7235

Cut the air pressure back to around 55 psi and approx 40 amps,,,too much air is not always good,,,move very very slow and steady like a machine,,,watch for a rooster tail of sparks coming from the cut,,,try and keep that spark pattern steady,,,moving too fast will snuff the cut action and make it incomplete as shown in your photo's,,,the pilot arc you describe is as it should be...the cutting will take place when that stream touches the metal attached to the ground/earth clamp..

Getting a splash back is a sign that you are moving too fast for the cutting action...move slow and steady use a piece of angle iron for a guide until you get the hang of it..on 11 guage you could probably get away with out the stand off,,,just using a drag..

looks like you are touching work and way to close stand off . i run about a 1/4 inch from work when cutting saves on tip . the stand off you are using is not rite for your torch buy the rite one Attachment 7236

that stand off you are using is for a s45 not a a81 torch

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Originally Posted by Slartybartfa

However I didn't see any plastic tube with ball in it that came with the torch, so I set it to 72 psi

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Slarty,

See the following thread ... if you received a flow gauge it should like like the picture in this thread:

http://www.everlastgenerators.com/fo...st.php?p=17404

Also, have you checked the spark gap? I imagine that you wouldn't even get the pilot arc if they were way off, but it is something to look at.

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Originally Posted by Rodsmachineshop

that stand off you are using is for a s45 not a a81 torch

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My A81 standoff looks like the one in Slarty's picture.

Cheers
Mike

Quote:

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Originally Posted by Rodsmachineshop

that stand off you are using is for a s45 not a a81 torch

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I have used them a few times and they work fine (big problem is they eat the heck out of the retainer nozzle rim edge).

Now, the standoff from Plasmahelpers.com I have to reported back to them (no I get no kick backs on their stuff or the TIG finger). It is the better of all of them I have used, but the threaded rods are too close to the torch head again on the A81.

I like the s45 torch seems to work great for me .

A flow gauge came with the argon regulator. But none came with the compressed air moisture separator/pressure regulator, which was shipped without a pressure gauge, too, which Oleg took care of. The A81 standoff is, indeed, the wire one and holds the tip a little more than 1/16" off the work. I also purchased a roller standoff, expecting I'd be making some long cuts in 11 ga steel this weekend, but that didn't happen and I'm all gritty now and my skillsaw is smoking from cutting with the friction blade and I've got to sweep out the shop now, and I'm battling a bad attitude at the moment. I'm sort of done, I'm afraid.

1/8 or more is better saves on consumables and cuts cleaner 1/16 is to close

turn the start and end amp knobs to 0 I think the unit is in a ramp up mode and is not applying full amps at the start of the cut.

Now I do not know a thing about a plasma cutter... One thing I did notice from your picture... Not sure if it was just a front panel picture of the machine setting idle... The specification on the pp256 says... OK to cut indicator lights up when minimum air pressure is present The light on your machine is NOT on.

Just my 2 cents...

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Originally Posted by Brian Ski

Now I do not know a thing about a plasma cutter... One thing I did notice from your picture... Not sure if it was just a front panel picture of the machine setting idle... The specification on the pp256 says... OK to cut indicator lights up when minimum air pressure is present The light on your machine is NOT on.

Just my 2 cents...

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Post #4

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Attached are some pics I shot. The shot of the face of the PP256 was taken after I turned off the air compressor, so the amber cut light is not on.

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:)

Right. The light's not on because when I took that pic, I had shut off the air, so pressure was low and light was out.

Upslope and downlope are at 0, and Start amps and End amps are at 100%. Re: distance, Mark L at Everlast said, "Tip should be around 1/16th. You need to bend those stand off to make
the proper distance. Too far away is as bad as too close."

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Originally Posted by Slartybartfa

Right. The light's not on because when I took that pic, I had shut off the air, so pressure was low and light was out.

Upslope and downlope are at 0, and Start amps and End amps are at 100%. Re: distance, Mark L at Everlast said, "Tip should be around 1/16th. You need to bend those stand off to make
the proper distance. Too far away is as bad as too close."

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Forget about standoff distance at this junture,,,if you have it set to 2T ,,40 amps & 55 psi you can dragcut anything up to 1/8 inch no problem,,,it's a little tougher on tips and it has some dross on the cut,,,but you should be able to do it no problem,,,,just go slow and watch your sparks under the cut,,,the angle on them indicates too fast or slow,,I'm almost convinced it's an operator issue more than a machine issue,,,just takes some practice and a steady hand..give it another go and see if it improves..

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Originally Posted by geezer

Forget about standoff distance at this junture,,,if you have it set to 2T ,,40 amps & 55 psi you can dragcut anything up to 1/8 inch no problem,,,it's a little tougher on tips and it has some dross on the cut,,,but you should be able to do it no problem,,,,just go slow and watch your sparks under the cut,,,the angle on them indicates too fast or slow,,I'm almost convinced it's an operator issue more than a machine issue,,,just takes some practice and a steady hand..give it another go and see if it improves..

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Correct me if I'm wrong, but for thin material like that, if you just held the torch at 1/8" over the metal and pulled the trigger, shouldn't it be able to pierce that? If it does, then the machine is working, if the arc goes out, then something is wrong?
I'm just trying to take the operator out of the equation for troubleshooting.

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Originally Posted by Rambozo

Correct me if I'm wrong, but for thin material like that, if you just held the torch at 1/8" over the metal and pulled the trigger, shouldn't it be able to pierce that? If it does, then the machine is working, if the arc goes out, then something is wrong?
I'm just trying to take the operator out of the equation for troubleshooting.

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Yes whether you have the standoff on or are just pressing the tip down and then fireing it up you will pierce 1/8 material at those settings, after that move it and you are cutting.

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Originally Posted by Rodsmachineshop

looks like you are touching work and way to close stand off . i run about a 1/4 inch from work when cutting saves on tip . the stand off you are using is not rite for your torch buy the rite one Attachment 7236

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NO that is WAY too far. Standoff should be less than 1/8" and 1/16" if possible. The standoff is the one that comes with the torch if I remember right. This isn't oxy/acetylene. If you'll read any material related to Plasma, it will tell you keep stand off close for plasma. It lowers dross and reduces kerf...and it will actually reduce the wear on the consumable.

Having too great of standoff also hinders arc transfer and since it is a CC process can make the voltage spike somewhat on the unit which isn't great for the electronics.

The one thing we can't see is if the arc is transferring. Check your readout on the unit when you start your cut. See if amps drop in the display when you squeeze the trigger for the pilot arc, then see if it ramps up when you start to cut. Also you should notice a brighter flash in the arc when the arc transfers. It is possible you are trying to cut with the pilot arc only.

Mark, that's sort of the problem now. I can get a nice blue-white flame in mid-air. As I bring it into the work, very slowly, the moment the side of the flame contacts the metal, it goes out. No time to see if it's cutting. It isn't behaving the way it was earlier. It's no longer cutting weakly, it's simply going out. And though I haven't ever used a plasma torch myself, I've watched Jody and others' videos and I know what it should look like. The plasma flame is hotter than the surface of the sun and should go through 1/8" steel like a knife through warm butter. And it should make a clean cut, not a slaggy one, and the arc shouldn't go out.

Lets look at something different you say the PP256 is new have you done anythig with the unit then try plasma.
Will it stick weld, Tig AC/DC weld.

First thing I checked out was TIG (DCEN only). It did fine. Made a nice arc and I was able to draw a bead on mild steel. Then I tried the plasma torch and ran into difficulties, so haven't tried stick yet.
But what's bothering me is that, first I got some cutting action. Very weak and would barely go through 1/8" steel, and made a mess of the cut and the tip. Now it's not even doing that. Something has changed.

Adjust your air pressure down bit by bit and see if it will resolve the going out. Also when it does go out keep your trigger held and touch the metal and lift up quickly. Do you see a spark or an arc establish?

Do you mean actually touch the tip to the work? I thought there should be a HF arc that should jump that gap. When you talk of the pilot arc, is that the blue flame I'm seeing when I squeeze the trigger in mid air? If so, then when I bring it in to the metal, it's evidently not transferring to the work.

I'll do as you request this afternoon.

yes touch it to the metal. Yes, that is the pilot arc, which on your torch is Hf generated.

One thing I have noticed; if I run too much air pressure all the air leaks out the dryer, and very little air comes out of the torch. When I have the proper air pressure more air comes out of the torch. I would adjust the air pressure coming out of your air compressor, and not the adjustment on the plasma cutter. The other day I ran into the exact same problem, and it was because my air pressure was too high and going out of the water valve on the dryer. It would not arc properly because there was not enough air coming through the machine. If you hook your air line up the plasma cutter and it sounds like all your air is leaking out the pressure is too high.

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Originally Posted by SeanMurphy265

One thing I have noticed; if I run too much air pressure all the air leaks out the dryer, and very little air comes out of the torch. When I have the proper air pressure more air comes out of the torch. I would adjust the air pressure coming out of your air compressor, and not the adjustment on the plasma cutter. The other day I ran into the exact same problem, and it was because my air pressure was too high and going out of the water valve on the dryer. It would not arc properly because there was not enough air coming through the machine. If you hook your air line up the plasma cutter and it sounds like all your air is leaking out the pressure is too high.

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Sounds like you've got a bad seal on the check valve. I've used 60psi for everything so far (pp256 and pp60) I just set the amperage and go.
That's 60psi running... about 68psi static.

Something isn't right for sure, unless you have some crazy high pressure air system. Those standard regulator/dryer units are rated for up to 250psi input. Nothing should be leaking out.

Just got home from my day job. Reassembled everything, didn't change the settings at all, except for dialing the Amperage to max (65 indicated) and Success!

Attachment 7251

Set the pressure to 60 and 80 but didn't notice any difference in the way it cut.
Held the standoff on the edge of the work, angled the torch out away from the side and squeezed the trigger. A very small, bright white flame shot forth and went through the metal like it wasn't even there. No splashback, nothing like before.
Don't know what changed, but that confirms that the cutter really does work. Now I need to make some guides so I can cut against a straight edge.

Thanks for everyone's input. Sure wish I could say exactly what the cause of my problems was. Could it be the new welding cart fixed it?

Attachment 7252

It looks like your running too hot. You want to cut the metal and not melt it away. You probably could cut that material around 30 amps. I think 50psi is what I run.

Thanks, I think you're right. Went through a piece of 3/8" angle at the same setting and realized I probably could have dialed it back a lot. Having no frame of reference yet, I need to experiment and see what gives the best cut.

And re: your earlier comment about pressure, first thing I did when I put the parts together was to chase down all the air/argon leaks. Got all the connections sealed with teflon tape now and no air leaks. The water purge valve on the bottom of the water separator bowl was troublesome, so I took off the spring and now it seals perfectly. The spring was too stiff and was holding it open. And one thing about argon: once it's gone, it are gone!

It could have simply been the work clamp cable is loose in the dinse connector or there is some oxidation on the metal that was preventing a good connection of the work clamp.

Something simple, anyway. I was afraid it was the HF circuit not transferring the pilot to the work. That doesn't seem to be the case. However, I tried dialing back the power to see how low I could go. And lighting the arc just off the edge of the work, I can' go below 50A or the arc blows out just as it did yesterday. But when I squeeze the trigger with the tip over metal, even just the bare edge of the work, with the amperage set to 50, 40 and 30A the arc lights and I can cut. But below 30A and it just "pops" and the arc blows out. I'm wondering if the "points" gap inside might be set wrong. I understand about 0.030" is about right for this machine.

So I think part of my problem earlier was that I didn't have the amperage dialed up high enough to light the arc reliably.

And sure 'nuff, dialing the power back resulted in a much cleaner cut, less slag, etc.