Most detailed cuts with plasma

[slammedxonair]

What is the most detailed thing you have cut with cnc plasma, post pics with sizes please. Preferably a hypertherm with find cut consumables, but whatever works.

[jimcolt]

The key to cutting with accuracy and precision is not just within the plasma system. Plasma is an important part....at least 1/3 of the solution!

For excellent cut quality along with good accuracy.....and good consumable life....you must have a well designed torch height control that can sense the location of the plate surface acurately before each cut....which allows the pierce height to be set (1 bad pierce ruins the plasma nozzle...affecting cut quality)......and then indexes to cut height during the lead in portion of the cut....then quickly switches to arcvoltage control once the cut speed is achieved.

You also must have excellent x and y motion that can maintain the speed required by the plasma torch.....and should have acceleration in excess of 40 miligees.....this minimizes dross and ensures that the plasma gets up to its best cut speed quickly. There should be no jerkiness or roughness in the motion....any roughness in motion will show up in the cut.....any jerkiness (mechanical backlash) will create overshoots and divots in the cut.

Last, but not least.....the cut part program should pay careful attention to the shape and location of lead ins, lead outs, kerf width, as well as good resolution to make holes round instead of a series of connected straight lines.

Also....air plasma systems are the low end of plasma system capability! The Hypertherm FineCut consumable have a great reputation for cut quality on materials thinner than 3/16"......but for the best cut quality a high definition class HPR130xd plasma (also Hypertherm)....using oxygen as the plasma gas for steel...produces cut quality that will rival laser on materials thinner than 1/4", and is faster than laser on thicker materials.

Here's a few pieces cut with a Hypertherm Powermax45 air plasma with an entry level (low cost) PlasmaCam cutting machine...


Jim Colt

[slammedxonair]

You allways have the best looking plasma parts with your setup. I'm asking about detail because I had somebody ask me if I could make them some pretty detailed cut outs about the size of a business card. I told them they may be happier with the results having them laser cut.

[jimcolt]

I agree with you.....laser or water jet is probably the way to go. I do occasional small parts such as electrical box covers...the holes are fine for bolt holes....but not a lot of fine detail!

Jim

[jgramlich]

Yeah, business card...notsomuch. I've an HPR260, and granted we're kinda talking about sledgehammer vs. fly here, but the smallest detail I'd be comfortable with doing, even all the way down at 30 amps, is probably letters, text, more than 1" tall. Even then it might be tricky.

The biggest issue for plasma definition in small details is the kerf. You have to remember even at low amperages the plasma arc is fairly wide. Had I to guess I'd say at 30A my kerf is still 2-3 times wider than a bandsaw blade. When I'm doing 260A and very thick plate, that kerf can approach 1/4" (no matter what the computer or the spec sheet says).

Also, when the torch makes non-smooth direction changes, the corners of those turns tend to get a little more blasted and the kerf expands slightly on turns...not arcs, but where the torch must stop and change direction (may not be noticeable to the human eye, but the steel knows), say, the right angle corner of a rectangular piece.

That being said, you'd be surprised at what you can do. New consumables and ultra-clean rails to keep the motors from dragging or feeling any sort of resistance will definitely help your cut quality.

You *might* be able to get away with, say, a Christmas card sized piece with some small details, but it could take a lot of experimenting to get right. And text can be a huge pain anyways, no matter how small or large. You've got the middles dropping out of any character with an "O" shape, etc.

If you're set on the business cards, waterjet is the way to go. I got a little ingersol-rand promo years ago at a trade show that was a business card sized puzzle with several dozen pieces, cut on waterjet out of...I wanna say 3/16" plywood or something very similar. I've never used laser, but I'm pretty sure waterjet will not warp your material, and you can stack it, so if you wanted to make several at a time, waterjet will cut through many layers of material with no trouble...not melting them together like plasma (or laser?) would.

[BTA PLASMA]

I agree with Jim colt we have had cuts rival laser with just clean dry shop air. In my experience it has everything to do with consumables, material, air supply and amperage. You can really make some small thin aluminum parts with a water tray and a fine cut consumable.