I’ve been cutting mild steel for quite a while now with no problems. I thought I’d try some aluminum that I picked up cheap. It’s 0.195 thick so 5 GA I guess.
Piercing is leaving a LOT of splatter. To the point that cutouts are firmly welded in place. Most of the cut is ok wit very little dross except for start and finish.
I’m using Crossfire, Razorweld 45. I’ve tried various settings between 35A and 45A. 80IPM to 120IPM without much difference.
Cut height 0.065
Pierce height 0.15
Pierce time 0.4 to 1.2 (no change)
Pierce clearance 0.061
Lead-in Radius 0 to 0.2 (0.2 loses some cuts)
Lead-in distance 0 to 0.03
Lead-out none to same
Too fast, you should be between 55 ~70 ipm.
Make sure you have new consumables installed.
Put a film of Mig gun gel on the tip and nozzle.
This keeps the aluminum from sticking to the tip, causing the THC to rise up the torch.
Aluminum will never cut like steel. I cut aluminum every day, but I use nitrogen instead of air.
Aluminum melts at around 1100 degrees. The plasma stream is around 35000 degrees.
Thanks Bigdaddy but no joy.
60 ipm gives just the same result. I’m not getting pierce until after 1/2 inch travel. Tried pierce delay up to 1.5 sec. Still no pierce until after travel.
New consumables. Air tank drained. Dryers all blue.
Are you using THC? I assume you are. I am guessing you are using nominal voltage and THC eventually gets the height corrected for you. If you were using “Smart Voltage” more of the cut would be messed up.
So if my theory is right, you cut height is not really 0.065" like you hoped. I am guessing it is starting too high.
Run this test cut file. It will cycle the IHS and stop at the cut height of 0.06. Measure your distance from the plate to the torch tip with feeler guage. See what you get. cut height test.tap (224 Bytes)
Verify cut height with feeler gauges, Cut height, max out the amps, check your work clamp connections at the Au, and at the plasma, air pressure <75psi on the RW gauge during cutting.
I could be wrong here. But from the picture it is piercing fine. It looks like its running low/out of air before the finish of the cut. If the gauge drops below 70psi when cutting the regulator may be bad or the compressor just can’t keep up.
Except that would mean the cut is going the wrong direction, which is possible.
I now remember when I was cutting aluminum once, some flecks of aluminum got up in the torch shield. They bounced around and interfered with my cut of mild steel on my next project. Some of the cuts were great, then it would have a stretch where it didn’t cut. Check your consumables really well.
I tried a few test cuts to verify pierce height and cut height. I didn’t bother filling water table and noticed a huge improvement. Could it be that water was splashing up during pierce and solidifying the pierce? My water level is about 1.25 inches below top of slats.
So why the divot at the end of the cut, if its lead out it is to short. Lead in may also be to short also. 45 amps, pierce delay should be .05 to .07 sec., pierce height should be .15" , plunge rate 60ipm, cut speed about 75ipm. There is no reason you can’t pierce 3/16" aluminum with these settings unless the torch is not dropping down far enough or raising for some reason. With no metal on the table can you manually run the torch down to or just below the slats?
Yes, water has zero effect on your cuts. Water outside the torch is okay. It is the moisture in the air being turned into a plasma arc that will affect it.
And yes, it’s good practice to have water in the tray. Otherwise, your next thread will be about a leaking pan. You said you got a scrap piece of aluminum. If, by any chance, it is 75 series aluminum, it won’t cut or weld correctly. It is totally for machining aerospace parts. You could be chasing your tail if in fact it is 7075 aluminum.
