Upgrading from a P80 CNC torch

[mechcnc]

Hi,
I recently returned a torch that Ive been having problems. Its been very inconsistent with cutting angle, so much so that the bevel on a square cutout the four edges would be 90, 70, 90 and 110 degrees (roughly). Im more and more convinced that the cnc P80 torch for my Stahlwerk plasma cutter may not be made for precision cutting at all and more just trimming off material.

The plasma cutter is a 100 A HF pilot arc, and Im hoping that someone here may know about a quality plasma cutter that also uses HF ignition of the pilot arc. The plan is that if there is a lets say 100 amp Hypertherm torch with HF pilot arc then I could make it fit my existing equipment with maybe an adapter for the hose. That way Id get a quality torch with well fitting and performing consumables with my existing plasma source.

The easy solution given enough money is to buy a 100 amp Hypertherm, ESAB or equivalent, but I really cant justify that expense as a hobbyist... I do feel that this has to be possible, or did everyone abandon HF ignition past the P80 torch?
In that case I kind of want to buy a lathe instead and give a P80 "mk2" a try...

BR,
Mechcnc

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[acourtjester]

The Hypertherm torch are the Blow back type, which means they will not work with the HF start your plasma unit uses.
the Blow back is when the unit is triggered and current flows it triggers an air solenoid and the air causes the internal parts of the torch to separate. This causes an arc which starts the plasma flow from the torch. Hypertherm machine torches are not cheap, I just bought one and spent a total of $800. this was the torch and consumables for it.

[mechcnc]

Hmm thats disappointing and expected... I guess enough headache was generated by the HF to make BB the default strategy.
The HF ignition isnt impossible to make work though, even though I would not recommend it either. It was a huge pain (although enlightening) to make it work. Hypertherm among others had great advice on dealing with the EMI issues. If you anyone wants advice on this my experience could perhaps be of help.

Anyway, still hoping that anyone knows if a quality manufacturer of HF torches exists as its the path of least resistance for me right now. Ill continue my search as well and report my findings here if I stumble on anything.

[weldguy]

90, 70, 90, 110 bevel on the 4 sides doesn't sounds too far off from being near perfect. If your going to stick with the HF start machine I would experiment more with that torch before giving up on it.

Given that the 70 and 110 degree bevel is on 2 opposing sides it sounds as though the orifice in your nozzle may no longer be round. This could be from contaminated air, piercing while in contact with the material, touching the material while cutting, too long a pierce delay, etc.

I think you can make that torch cut closer to 90, 90, 90, 90 with some more work but I have no experience with what your working with.

[mechcnc]

I tried to eliminate the possible causes as you mentioned by using edge start and changing to new nozzle and electrode. I was experimenting with different current and air pressure levels as well, but when I rotated the torch 90 deg the square was going from 90, 70, 90 and 110 degrees to 70 90 110 90. So my conclusion was that there is some misalignment of the consumables. Ive returned it in hopes that it was a bad batch of torches, but I suspect it may be a bad design (loose fitting thread, no alignment geometry such as cones). They would get back to me later this week.

I saw that there was a torch named A140/A141 for a machine called Trafimet that could perhaps be an alternative also. That seems to use HF according to the ebay/ali sellers. I haven't yet looked into it at depth though.

[weldguy]

I would expect that rotating the torch 90 degrees would change your bevel to 70, 90, 110, 90. I would be curious if rotating just the nozzle 90 degrees would have had the same result indicating it is a nozzle issue. Regardless you have returned it so we will never know but good luck in your hunt for a torch to accomplish what you need

[PlasmaDon]

Hello,
dredging up an old thread.
I just put a p-80 torch on my new CNC plasma table, fed from a Hypertherm Max100.
Having never found any settings, (google search led me here BTW) I have been testing
and experimenting on my own.
Looks like 140-150 volts on the THC work best.
Any lower, and the THC wants to hit the plate.
I did have the torch on a Thermal Dynamics Pak-5xp at 55 amps and 1/4" plate was about all you could cut and not get terrible angle.
At 100 amps I'm at 1/2" plate, will load some pix later.

One question, is there supposed to be an O-ring up inside the electrode area ?
The main body has a groove right there, that looks like for an O-ring.

[mechcnc]

Hmm an o-ring wasnt included in either of the 4 different torches ive owned (manual and cnc). But it doesnt mean they didnt get it wrong since they copied it from Panasonic. Maybe the original had an o-ring. I gave up on the unit though and use it only for manual cutting now. I eventually caved and got a hypertherm unit for cnc use instead which is a huge difference in every way.
Br
mechcnc

[PlasmaDon]

Hmm an o-ring wasnt included in either of the 4 different torches ive owned (manual and cnc). But it doesnt mean they didnt get it wrong since they copied it from Panasonic. Maybe the original had an o-ring. I gave up on the unit though and use it only for manual cutting now. I eventually caved and got a hypertherm unit for cnc use instead which is a huge difference in every way.
Br
mechcnc

Thank you for the feedback.
FWIW I am getting it dialed in, and 1/2" plate cutting is acceptable, not powermax 65 quality, but good enough.
I did find some of my electrodes were not made concentric, so have ordered premium and they are concentric from what I can see.

[PlasmaDon]

I saw that there was a torch named A140/A141 for a machine called Trafimet that could perhaps be an alternative also. That seems to use HF according to the ebay/ali sellers. I haven't yet looked into it at depth though.

I have just purchased an A141 machine torch, and am testing it on my table.
It "seems" to cut better on 1/2" plate at 100 amps that did the p-80.
Holes are not too good just yet.

[mechcnc]

Awesome! Does it work well with thinner stuff too, like 1/8 or 1/4"? I found that to be the hardest for my torch to get right. Mine gave wildly different angles on either flank on a 90 deg corner.

Holes are tough to get right. I found the most important bits of it is pierce location, lead in, cut height and speed. I think its possible to counter the bevel with a slightly lower cut height so that the lag of the jet is balanced out with the shape of the jet at a lower cutting height.

But plasma hole cutting seems like there is as many theories as operators x number of brands of cnc. Trying different things (changing one thing at a time) is the best way to find out what works i think.