Well, I tried a few more things this weekend. I found several postings suggesting that a set of parallel lines, each with a different cut speed would be a good way to check your settings. So I set (7) 3" lines. Cut at 110ipm through 170ipm (each one 10ipm more than the last). Then, I tried the same
test at 80 volts at the tip, then 85, 90, 95, 100, 105, 110. I tried the same test with 27 amps, 24 amps, 22 amps and 20 amps. The speed and the tip volts didn't seem to make hardly any difference, the cuts are all a bit on the poor side. Lowering the current made the most difference, but non of it good. It cut ok down to 24 amps, but below 24, it started to splatter all over the top. I did this with a brand new set of fine cut consumables (yep, hypertherm branded, not some third party consumables)
I am running out of ideas, I really wonder about my air quality (I live in Colorado so it's already very dry to start with). I am using all the settings that the manual for the cutter recommends to start with, and all the cuts are rough edged and poor. I have made sure to get a good ground (scratched down to bare metal with wire wheel and attached ground clamp to clean shiny metal).
I have never really seen anyone elses' plasma cuts... is plasma just not capable of making a smooth clean cut? I realize it won't cut like a laser, but i thought it would look better than a rat chewing through the metal...
I have included a top and bottom shot of the best settings I could find from the line tests. There isn't much dross, warpage no problem, but you can see the lines are not very smooth, and the corners are *very* rounded (the machine is not doing this, if you put a pen in it instead of torch, it draws beautiful sharp 90 degree corners). I also added a lead in and lead out to stop the corners from blowing out (like you see in the first post).
Anyone have any suggestions for me? Thanks.