Hypertherm 1250 Plasma advice

M. Moore · Sep 24, 2020

Just picked up a used 1250 and have no experience using a plasma.
I have been cutting with gas on my small Koike CNC torch and would like to use the plasma for thinner materials and maybe some aluminum.

I will have to get a machine torch but need to use it and get good before I invest in a new torch. I am sure I could cobble up a holder to use the hand torch to get started with the CNC but I need some practice just with hand cutting.

So some tips and info setting up would be great, things like amps in relation to thickness and any tips/tricks that might help a newbie. I do know a little bit about plasma and I have excellent quality clean dry air.

Ziggy2 · Sep 24, 2020

M. Moore said:
Just picked up a used 1250 and have no experience using a plasma.
I have been cutting with gas on my small Koike CNC torch and would like to use the plasma for thinner materials and maybe some aluminum.

I will have to get a machine torch but need to use it and get good before I invest in a new torch. I am sure I could cobble up a holder to use the hand torch to get started with the CNC but I need some practice just with hand cutting.

So some tips and info setting up would be great, things like amps in relation to thickness and any tips/tricks that might help a newbie. I do know a little bit about plasma and I have excellent quality clean dry air.

Do not waste your time trying to cobble up a holder for your CNC table.

Your hand torch has the trigger to start/stop the cutting action and the power supply needs no interface. The hand torch also has a built in angle to the head to make it ergonomically friendly to the user.

The machine torch will be a straight torch head and need to be mounted 90 deg to the work surface. It would also be good to have a torch height control for CNC applications if you want to have decent kerf quality and control. The hand torch is rather forgiving in this aspect but a perfect kerf is usually not the primary goal, easy of use is.

The Hypertherm chart is usually the best place to start for tips, heat, and flow. They pretty much have that figured out

dkmc · Sep 25, 2020

You can see on the internet and Youtube, dozens of setups where a hand torch is being used on a CNC table. No better or worse than a machine torch, only hundreds of dollars cheaper. Well worth the time invested to make a holder for the hand torch.

M. Moore · Sep 25, 2020

Thanks for the replies guys, even if you disagree!

I have turned it on to test but not made any cuts yet as I have to get the power supply wired properly. I will be running it on 480 volts three phase and need to get that all wired to the transformer.

DDoug · Sep 25, 2020

If you look at the hypertherm exploded views for each torch, you may find the only difference is a bent handle.

some torch bodies are straight inside, and the handle is the "bend" portion.

as far as amperage....Turn it to 11 !

Seriously, the only time we turn them down is for very thin work.

Again consult the charts in the book, they are very good, however
I find going slower that listed gives a straighter, more accurate part (which is what I am after, not production)

M. Moore · Sep 27, 2020

Digger,

I assumed that the settings would be similar to gas cutting. In other words the gas pressures are directly related to the quality of the cut.
I am surprised that you can just turn it up to max and get good results. I am not surprised that going slower gives a better cut. From the plasma cut parts that I have worked on I have seen some slightly out of square cuts and some way out of square cuts.
Square cuts of high quality are what I am after not production speed. If I can achieve that on 3/8" steel plate I will likely cut a lot of parts with the plasma and time will tell if my cost per cut goes down or not. Consumable life will be the real test, with gas it gets consumed no matter what happens and even gets consumed when you are not cutting sometimes.

snowshooze · Sep 27, 2020

Most important thing to extend the electrode life is to dry the air.
I chain up 3 water-separators and it makes a huge difference.
A proper air drier would be even better.
You wouldn't believe the difference, it comes to money in a hurry.

M. Moore · Sep 27, 2020

Snow,
Did you skip over this part in my first post?
I have a 20hp compressor and matching Kaiser air dryer with filters etc, so I think the air will be fine but it is good to know that it will improve consumable life.

M. Moore said:
I do know a little bit about plasma and I have excellent quality clean dry air.

DDoug · Sep 27, 2020

M. Moore said:
Digger,

I assumed that the settings would be similar to gas cutting. In other words the gas pressures are directly related to the quality of the cut.
I am surprised that you can just turn it up to max and get good results. I am not surprised that going slower gives a better cut. From the plasma cut parts that I have worked on I have seen some slightly out of square cuts and some way out of square cuts.
Square cuts of high quality are what I am after not production speed. If I can achieve that on 3/8" steel plate I will likely cut a lot of parts with the plasma and time will tell if my cost per cut goes down or not. Consumable life will be the real test, with gas it gets consumed no matter what happens and even gets consumed when you are not cutting sometimes.

Well, I do both with cnc machines (my table at home has oxy/propane, and I also run a plasma one for the employer)

Settings not exactly ,You don't drop air pressure on a plasma based on thickness.
For the hypertherm, follow the setting chart exactly, as far as air pressure, torch height, etc.

Except the speed, I drop that down. The Hypertherm numbers for speed are a compromise between cut economy & accuracy.

Oxy & plasma are similar in the speed aspect, if you go too slow, you lose the cut. Have done it with plasma as well, testing for the best accuracy.

M. Moore · Sep 27, 2020

My experience with gas cutting on my CNC table is that if I go too fast I lose the cut. I am always trying to push the speed. Going slow just makes a wider messy kerf, I have never lost the cut going too slowly when gas cutting.

So now you say follow the chart but slow down to improve cut quality, your earlier post said crank it to 11?

DDoug · Sep 27, 2020

M. Moore said:
My experience with gas cutting on my CNC table is that if I go too fast I lose the cut. I am always trying to push the speed. Going slow just makes a wider messy kerf, I have never lost the cut going too slowly when gas cutting.

So now you say follow the chart but slow down to improve cut quality, your earlier post said crank it to 11?

"Crank it to 11" was a joke about the power level (amperage)

I have never seen anyone turn one down, walk into any fab shop and they are all turned up to max.

When troubleshooting a problem on the little torchmate 4x4 table, the 65 amp setting was causing torch height sensing problems on a nearby cut (making thin slots) I did turn that one down, for that particular job, to make the THC
work properly.

snowman · Sep 27, 2020

Everything digger has told you....plus, you need the best ground you can get.

You should be able to cut 3/8” all day long with a 1250.

I had a 1650 and found that I used 60 amps for almost everything from 1/8 to 3/8”.

I’m pretty sure it adjusts pressure automatically.

Sent from my iPhone using Tapatalk

DDoug · Sep 28, 2020

M. Moore said:
My experience with gas cutting on my CNC table is that if I go too fast I lose the cut. I am always trying to push the speed. Going slow just makes a wider messy kerf, I have never lost the cut going too slowly when gas cutting.

If your gas cutting gets a "wider messy kerf" when you slow down, your doing something wrong.

I suspect way too much preheat, and way, way too slow.

When I say "Slow down for accuracy" I mean, watch the cut so the jet is almost straight down.
Trailing behind too much makes a less accurate part, especially on corners.

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