Best way to cut 304 stainless?

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Tristar500
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Best way to cut 304 stainless?

Post by Tristar500 »

I've got a few relatively small parts I'd like to cut from 304 stainless. I'm getting a lot of dross and generally poor cut quality.

Any tips on cutting 304?
Use a gas other than air? amperage settings?

I'm using a PrimeWeld Cut 60 on a own design CNC.

Thanks all!
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Re: Best way to cut 304 stainless?

Post by weldguy »

Typically you will want to close up the gap between the tip and the material by around 30% from what you would use on mild steel. Do some test straight line cuts at the new height and increase the speed until you find the maximum speed you can cut before it's going too fast and not cutting through, then back it off 10ipm or so. Nitrogen gas may help with a cleaner, more colorless edge but hardly worth the trouble and expense for a few small parts, clean dry compressed air is all I ever use.
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Tristar500
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Re: Best way to cut 304 stainless?

Post by Tristar500 »

Material is .100 304 stainless. I can cut at anywhere between 20 and 60 amps.
Any speed recommendations?

I'm getting a lot of dross that is basically welded to the piece.
I was thinking of raising the water in the table so that the piece is in full contact with the water below to stop the material from getting so hot.
5X7, 6x11 plasma own design
Mach3,4 SheetCam, CorelDRAW 2020 Inkscape .0.92
Homebuilt 3 axis mill
Homebuilt 5 axis mill
PrimeWeld cut 60
Hypertherm 350
Miller Symchrowave 250 DX
Several mig welders

You are only as old as the woman you feel.
weldguy
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Re: Best way to cut 304 stainless?

Post by weldguy »

I would do a test straight line cut at 40 amps, start slow and speed it up until it is going too fast, them back it off a bit to be sure it cuts through.

Do the same thing at 60 amps and compare the cut quality and dross formation at the point where you had the ideal speed set and then make your decision as to which setup provided the best results and use that.

Not sure if raising the water up will help or make things worse but curious to see your cuts.
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Re: Best way to cut 304 stainless?

Post by Deezl Smoke »

Give raising the water level a try. It really makes a difference for my setup. But as weldguy mentions, speed up the cut speed as best you can. If you look at the kerf width of a stock tool setting vs a sped up one, you should see the reason for so much dross. The slower travel speed makes a wider kerf which is what is causing the dross. It's like the difference between using a sharp, high end nibble vs. a 1/4" wide grinder wheel as a cutoff wheel.
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Re: Best way to cut 304 stainless?

Post by ben de lappe »

Plasma cutting stainless steel is a little different. In my experience the edge finishing process is as critical as the cut and speed settings. Even a good cut will often need to be broken/separated due to dross weld back. The granular 'sugar' dross can be dealt with but it's not a quick and easy process. Maybe this thread from a while back will help.


https://www.plasmaspider.com/viewtopic. ... ss#p166558
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Re: Best way to cut 304 stainless?

Post by TJS »

The last stainless job I did were letters for a sign. I made some test cuts first with compressed air. The result was not so good. Then I used nitrogen and a nitrogen regulator. Cuts were much better and the dross much less; and minimized the discolored edges were much better than the compressed air. I incorporated the large bottle of nitrogen into the job. Customer was happy.
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Tristar500
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Re: Best way to cut 304 stainless?

Post by Tristar500 »

Hmmm, I don't have nitrogen in the shop but do have straight argon and co2/Ar mix.
anybody tried either?
5X7, 6x11 plasma own design
Mach3,4 SheetCam, CorelDRAW 2020 Inkscape .0.92
Homebuilt 3 axis mill
Homebuilt 5 axis mill
PrimeWeld cut 60
Hypertherm 350
Miller Symchrowave 250 DX
Several mig welders

You are only as old as the woman you feel.
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Re: Best way to cut 304 stainless?

Post by arnegrant »

That's pretty thin.

I would get it with air and not mess around with other gas.

Stainless moves more, might want to stand on the sheet when cutting or put weight on it

+1 on the test cut lines mentioned above.

Turn the thc off and turn up the machine amperage and pressure and keep cutting faster until you find where you can't cut through anymore then slow it down a bit leaving the air pressure and amperage high.

After that I get the edge square by adjusting voltage.

I run higher voltage than the tables show by 10 or 15 to start.

Good luck!
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Re: Best way to cut 304 stainless?

Post by jimcolt »

If a Hypertherm Powermax45 or larger is used....there are specs in the operator manual for cutting stainless using F5 (premixed 5% hydrogen, 95% nitrogen) for 10 gauge through 1/2" with nice cut quality. Jim Colt
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Re: Best way to cut 304 stainless?

Post by jimcolt »

If a Hypertherm Powermax45 or larger is used....there are specs in the operator manual for cutting stainless using F5 (premixed 5% hydrogen, 95% nitrogen) for 10 gauge through 1/2" with nice cut quality. Jim Colt
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Re: Best way to cut 304 stainless?

Post by Gogo »

I tried nitrogen bottle gas, cut was less black but not as less black as my bank account was way more red. Not at all worth it.but I was fitting thin. I have no problem with 1/4” plate and straight air.
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