This has been a recent problem with my plasma cutter + CNC table combination. It was at the point that there was dross built up so much on both sides of the sheet metal, the cuts were wavy, and the nozzle was accumulating molten metal. I immediately thought it was the filter which I changed and there was actually a lot of improvement made. Still though when I cut 18G mild steel at 325in/min with a finecut nozzle it does not want to cut all the way through now, but just at some parts (about 85% of the lines are cut through all the way). Also, the nozzle is accumulating a lot of molten metal still. It’s to the point I have to take an angle grinder and finish the cuts with a cut off wheel. I reduced the speed and it’s the same outcome. Ive also tried re running the program where it recuts the same lines, but still no improvement.
Some context: I recently ordered fine cut consumables for more precise cutting. The setup was with a non shielded tip which cut great. I then researched that a shielded tip was better to increase the lifespan of the consumable so I swapped out for the shield. But ever since it just seems like the shield is collecting so much molten metal. I have to angle grind the metal off the shield with a sanding disc after a few cuts.
Any comments or suggestions would be very helpful and I am all ears at this point. Thanks in advance!
Plasma cutter: Hypertherm 45xp (running on 240V)
Table: Crossfire Pro
Filter: Devilbliss QC3
I’d add to your list that once consumables start accumulating molten metal, they’re getting damaged and should be replaced.
The cut height is probably too high with the shielded tip unless the tool definition was changed to reflect the additional standoff from the material the shielded nozzle has over a standard one.
I agree with both replies so far…
way …way…to fast…plasma does not have time to cut through the metal.
shielded tips add a lot of distance to the metal…you need to be around .06 from metal to actual hole in tip…you are most likely closer to .1
you stated your filter dryer…but what size of compressor are you running…you could also have an air VOLUME issue…not PSI…but volume.
top dross often nozel to high…
slag on tip…metal splatter…not cutting through and opushing metal down with air
wavy lines…looks like the arc is hunting to cut metal…
Thanks everyone. I’ll try replacing the consumables, and slowing down to 150ipm @ 40A. I was reading the “finecut” chart specs instead of the “finecut low speed” chart. My air compressor is a 60gal stationary.
From what I know so far, I am under the impression I just set the pierce clearance to whatever the chart gives under “initial pierce height” and then the THC will do the rest based on voltage levels. Do I have to compensate for the shield? How would I know what the measurement of that difference is if so?
Yes. IHS uses the contact of the tip to identify height and then the THC voltage is based on what the plasma cutter does at the cut height calculated from the IHS setting.
It can’t tell that there’s a .06" (might be different for fine tips - I don’t have any to check) gap between the nozzle and the material when using shielded consumables. The HT charts specify values for with & without the shielded cap. You can use the appropriate published values or just skip using the shielded ones.
great. I just went with unshielded for now until I can get a new shielded tip. I replaced my other consumables and the cuts are really clean now. The slow 150ipm really helped as well. Thanks fo the help everyone!