3/8 steel cut quality

[roberob2025]

Hello everyone. I am having a heck of a time trying to get a decent quality cut on some 3/8 steel and hoping to get some feed back to see what I can do to improve my cut quality. So I have a primeweld cut60 and crossfire pro with THC table and using fusion 360 for CAD/CAM. The first cut I did was with 60amp shielded nozzle 60amps @ 39.37IPM 70PSI cut height .030 pierce delay 1 sec pierce height .125 and it did not even cut all the way through the steel in some spots

cut1

and it got melted steel all over the tip. So I switched it to 60amp UN-shielded nozzle 60amps @ 23.62IPM 75PSI cut height .050 pierce delay 1.3 sec pierce height .150

cut2 top

cut2 top bevel

cut2 bottom

cut2 side

cut2 top middle

and I got a lot of dross and a really bad bevel and the holes are wider at the top then the bottom so I did a third cut with 60amp UN-shielded 60amps @ 26IPM 75PSI cut height .060 pierce delay 1 sec pierce height .150 and this is what I got the dross was knocked off with a hammer and what did not hammer off is what is still on the part in the photos

cut3 top

cut3 bottom

cut3 top dross knocked off

cut3 bottom dross knocked off

I hit the dross pretty good with a sledge hammer so what remains I will have to use a grinder on it. So what are some thoughts on these cuts? There has to be some settings that I am not inputting correctly. I went by what the manual says for primeweld and it did not want to cut all the way through so I used the settings for 1/2" and the third cut I just upped the IPM a little bit in between what the manual says for 2/5" and 1/2". I guess it could be my plasma cutter? Any help would be greatly appreciated and Thank you in advanced.
ROB

[acourtjester]

I would boost the air pressure to 90 or 100 PSI to the plasma unit, It also looks like your torch is not at 90 degrees to the surface see attached image.
With that much dross you are not moving fast enough bump it up about 5 IPM to see how that works. make the lead-in linger to remove the start notch. set pierce height to 0.150" and cut to 0.060" Hypertherm is about 45 IPM Shielded tip mild steel.
Images of 3/8" cuts with dross and after cleaning

[weldguy]

Take all of Tom's advice above and that will help.

Also go back to the shielded consumables, shields are very beneficial on 3/8 and thicker material. The shield will help prevent the molten metal that blows up at the torch prior to blowing a hole through the plate from damaging the cutting nozzle.

I am guessing your torch is square to the plate so the bevel on your cut edge is likely caused by a bad nozzle, possibly damaged from piercing blowback or moisture/oil in your air supply.

Do you have a GOOD air filter and drying system in place?