Plasma cut quality

[ColinB]

I don't plasma cut frequently, but I have been recently, while modifying my workbench. I've narrowed the bench and was ready to cut down the 1/8" top, so I did a few test cuts to setup the machine. Air pressure is right in the middle green LED (Hypertherm T45). I tried currents from 25-35 and different travel speeds at each current, but my cuts aren't penetrating. Do I just need a new electrode and shield on the torch?

 

[Tom O]

I’d check for a good ground and maybe try increasing the amount of air

 

[FatherWes]

Why not up the amps to 45?
Personally, I’d try to start at an edge or a hole. If you have to start on a flat surface, angle the torch so the slag is blown away from the cut until you get full penetration. Once you’ve got full penetration and the slag is blowing out the bottom, the start moving, allowing full penetration all along the cut as you proceed.
I find cutting without full penetration just fouls up my tip pretty quickly.
Compare your electrode with a new one. If the old one has a much larger or elongated hole, replace and try a cut again.
EDIT
I agree with both of Tom O’s suggestions. Looking closer at your cut, it looks like the slag is not being blown out —> more air. And yeah, check the ground (It’s always a bad ground…). And I believe you can get a pretty nasty zap if you become the ground.

 

[Brent H]

Also make sure the air you are supplying is dry. Moisture in the air will make for poor cutting performance.

 

[fixerup]

I have a Lotos 40, with no pilot arc start. It uses the drag style castellated tip. The last time I used it, I was getting a lot of slag on the back side and inconsistent cutting. I tried different cutting speeds, currents and air pressure with no luck. After I replace the castellated tip I got a much better consistent cut.

 

[CWret]

I have a Hypertherm 45XP - I don’t know the 45T model you mentioned but my 45XP will cut through 1/2”or even 5/8” with ease and cleanly. I agree with all the comments and suggestions above.
Other than the obvious importance of using new consumables, a good ground and clean dry air is often overlooked.

 

[phaxtris]

looks like the main arc never started, thats what it often looks like when just the pilot arc is going, either ground or consumables

 

[ColinB]

Ground moved to a more bare area. I've got good compressor capacity (vertical 2hp, 10cfm, on 220v) which switches on at 90 psi, local regulator (set to 87) and trap (It's dry) and the T45 power supply (requires 80+ psi) built in regulator set so that the built in gauge is in the green (I've now also tried raising to the high end of that).

My cut has dross but going as steadily and not too slowly (makes a wide kerf), it's usable with a little angle grinder touch-up.



The electrode has a just visibly out of round orifice and quite a bit of wear on the castellated cap. I'm going to order a new set for future cutting.

 

[ColinB]

looks like the main arc never started, thats what it often looks like when just the pilot arc is going, either ground or consumables

It definitely kicks up from the pilot to a plasma jet. It does cut, but then tends to fill in behind the cut. The last inch of cut, before I stop, is always quite clean.

 

[phaxtris]

full power and new consumables i suppose

there are some pretty decent knock off consumables for the hypertherms, they are still expensive, but quite a bit less than genuine, makes it sting less to change them more often

 

[Tom O]

I’ve heard that some Hypertherm consumables have been discontinued favouring the newer torches.

 

[FatherWes]

I bought a bunch of consumables for my 45XP, T45v torch off of AliExpress. They work fine for a fraction of the cost.

 

[Tom O]

That’s good to know.
I’d have to look to make sure but I believe mine is an older 1250 model I even have the unused machine torch purchased in the 90’s.

 

[ColinB]

full power and new consumables i suppose

there are some pretty decent knock off consumables for the hypertherms, they are still expensive, but quite a bit less than genuine, makes it sting less to change them more often

Yes, I was thinking non OEM would be fine. I'm still working out the subtleties.

 

[Ironman]

That’s good to know.
I’d have to look to make sure but I believe mine is an older 1250 model I even have the unused machine torch purchased in the 90’s.

I have a 1250, and I upgraded the torch to the Duramax HRT. These give better performance and much longer life on consumables. They use a different electrode and tip, the old style tips will not fit the newer head unless you machine 10 thou out of it. Which I did to use up the old stock of 60 and 80 amp tips.
From my conversations with Jim Colt, I learned that you always set the air to the recommended max and the amperage also to the tip size. The reason for the correct pressure is laminar flow and cooling. Speed is the important thing to prevent ragged cuts and excess heating and melt back. As 90 of what I do with it is on a CNC table, I have learned the importance of speed and cutting height.

 

[Tom O]

I have a 1250, and I upgraded the torch to the Duramax HRT. These give better performance and much longer life on consumables. They use a different electrode and tip, the old style tips will not fit the newer head unless you machine 10 thou out of it. Which I did to use up the old stock of 60 and 80 amp tips.
From my conversations with Jim Colt, I learned that you always set the air to the recommended max and the amperage also to the tip size. The reason for the correct pressure is laminar flow and cooling. Speed is the important thing to prevent ragged cuts and excess heating and melt back. As 90 of what I do with it is on a CNC table, I have learned the importance of speed and cutting height.

It was disappointing hearing that they upgraded the torches I have a brand new 25’ one for a plasma table I bought in the early 90’s.

 

[Ironman]

It was disappointing hearing that they upgraded the torches I have a brand new 25’ one for a plasma table I bought in the early 90’s.

If you go with the new Duramax machine torch, and keep the hand torch you have, for hacking by hand, I think you will be happy. The price for a new hand held is $460, add another 100 for a machine head, but god, 50 ft leads are extreme, 25 is all you need. I bought when they first offered and it was somewhere in the 200 dollar range.