Plasma cutting AL

[BarnBurner]

We build parts out of 1/4 and 3/8" Flat bar 6061 Aluminum, and are currently building them one at a time on Taig CNC mills. The machines work perfectly, but it is slow doing a part at a time. We are considering either a 4 x 4' Router or Plasma as the parts average 4" square.

My question is what sort of finish does Plasma leave, and how bad are the burrs? Also, will the parts warp at all? Speeding up the production would not work well if the deburring increases. The parts need to remain flat and without major burrs.

I have been sort of looking into Torchmate and Techno CNC

[xjdubber]

if your just going to do alluminum get yourself a good router, it will make much nicer parts. Plasmacut alluming has a very rough edge and usually not to square. I'm sure that someone can post up some pics of some cut alluminum.

[mc-motorsports]

plasma will make those parts look like a dog chewed them out of plate. I second a CNC mill or router. Plus if your going to have a chance, I think you would have to use a helium/nitrogen mix? Anyway, shop air will cut aluminum but gas would be better and then that's just more money. CNC Mill

[DSL PWR]

One other problem with plasma cutting aluminum is hydrogen get introduced in the cut area, which will cause cracking. The only time I plasma cut alum is to rough it out and then slap it on the mill.

[jimcolt]

Attached is a picture of High Definition cut samples....On the left is thin stainless cut with 5% Hydrogen/95% nitrogen as plasma gas and nitrogen shield. Next is 5/8" carbon steel cut with oxygen plasma, air shield....next 3/8" carbon steel cut with oxygen plasma, air shield, then 1/2" aluminum cut with air plasma, air shield. These parts are all cut with a Hypertherm HPR130....which is a high definition class plasma.

There have been many different processes developed over the years for producing the best metalurgy on the cut face....each type of material of course has different results. The above gas mixtures are engineered to work with a rather complex gas delivery system that is micro-processor controlled...in the HPR130 plasma system.

I don't recommend using any gases that your plasma system is not designed to use. Most air plasma systems use an air cooled torch....and introduction of anything but air or nitrogen in these torches can cause internal arcing, explosion and fire!

The only issue with Hydrogen production when cutting aluminum is if the cut is being done with water present.....when water breaks down some hydrogen is produced....and further, when aluminum oxide particles sink in a water table....they absorb oxygen, which will cause some hydrogen bubbles to rise to the surface. Cutting aluminum dry does not produce hydrogen....to my knowledge anyway!

Jim colt

[xjdubber]

the hpr-130 is also worth $35,000 to &45,000 depending on options. but yes it cuts nice, alluminum still looks and feels like sandpaper when cut though. It looks so nice when cut on a router or mill. My vote goes to a nice sturdy router the bigger the better, you can nest all your parts and get some really nice quality work done.