Thermal Dynamics - Cut Quality Questions

[herrmc]

I have a Thermal Dynamics Cutmaster A60 on my CNC table. I have acheived some pretty decent cut quality on most of my cuts... just using the manual to setup the speeds/feeds.... but overall I lack the experience to know how to tweak for better cuts.... or to understand and "read" the signs...

My first cutting was on 14 gauge... and I really had good luck with that.... then I cut up a sheet of 3/8 inch.... overall it went very well as well... but I did notice a couple of times some dross on the parts... but it always came off very easy.

Yesterday I cut some brackets (and a logo) out of 3/16" mild steel... The edge quality of the cuts was good, but there was a lot of dross collected on the back side of the material (some knocked off easily.... some was hard to knock off).... furthermore.... some sections of the cuts were nice and clean... then it would start leaving dross.

I am hoping that someone with experience can give me some pointers to be able to diagnose and correct my cutting problems.

On the 3/16" cut yesterday ... I was using a 40amp tip ... running at 40amps.

Initial Pierce Height = .18
Cut Height = .14 (I also later tried .12 and .11 might have been a little better)
Speed 55 IPM
Air Pressure 75psi

I am running a Motorguard (toilet paper?) filter.... and have another filter in line as well...

I will post some pictures with this post as well....

I labeled this thread about cut quality... but I also want to ask about consumable life.... seems like at time my tips don't last long.... what they do is I don't get a good pierce and the edges start having a lot of taper... I replace the tip and it seems to fix it (sometimes the tip don't look that bad though).... Yesterday I had to replace the tip every 5 parts.. (7 pierces per part) (6 - 3/8" holes .. and about 36 inch of line cutting)... last week I cut 432 holes though on one tip?

I also notice that when I take the tip off the electrode will have black stuff caked on it.... I usually wire brush it off. (I have a pic of this but it is a bit blurry).

[herrmc]

This piece is total 3" x 3" .... was just a one off part I was making... the actual part I was making several off was a "T" shaped bracket that was 12" x 12"

[binfordw]

I'm still in the learning curve of cut-quality myself. I cut alot of 3/16" with a 45amp Hypertherm, and actually just tonight fell into the right settings for a dross-free cut. I had been cutting too fast I guess, I slowed the feed to 72ipm and I got a part with zero dross. I had thought too much dross meant too slow of a cut, but apparently there is "too fast" as well. I just wish I could get the right setting for 16 gauge now :/

I can't comment on consumables, I have a TD 39 that I quite using because of that. I couldnt get through 5 parts before they needed to be changed. I bought the hypertherm and am still using the second pair of consumables weeks later, its great.

[Pure-Powder]

Try 40 amps , .o9 cut height, leave the pierce height the same and speed up to about 70 in/min Also now are you setting your air pressure, make sure you put the plasma unit in the purge setting to set your air pressure.