Sudden drop in consumable life, HT2000 Plasma

We recently had a breakdown in our desecant air dryer connected to our Hypertherm HT2000 torch. That was bad news in that it pushed those little silica gel beads through my air lines up to the gas console on our torch. We traced the damage and repaired or replaced anything that was affected. It appeared the damage stopped at the gas console thanks to a small orifice on a needle valve flow control. We're back up and running now but we are now getting horrible life out of our electrodes. The only time I've seen this much damage is when water gets in the lines. We're running a brand new dryer with all new silica media. I'm pretty sure the air is good. The torch doesn't quite sound the same, I think. It seems like I don't hear as much pre-pierce shield air now. The arc seems weak, what little we've run the machine today we've had to reduce the pierce ht lower than normal. I'm attaching a couple pictures of new electrodes that didn't last 50 pierces. I'm wondering if any of you have some ideas?

Any of the recovered bead show signs of being damaged? Could have fractured enough pieces off that managed to get thru the needle valve and clogged things up downstream. The fact that you don't hear as much shield air probably indicates something is reducing the flow. It might take tearing down everything in the air system downstream of the needle valve to find it.

cvairwerks said:

Any of the recovered bead show signs of being damaged? Could have fractured enough pieces off that managed to get thru the needle valve and clogged things up downstream. The fact that you don't hear as much shield air probably indicates something is reducing the flow. It might take tearing down everything in the air system downstream of the needle valve to find it.

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I think you put your finger on it. This has been an absolute nightmare. I'm going to be dreaming about silica beads for a long time. There was in fact some pulverized remant of the desicant silica beads in the system down stream of the gas console. The gas console is the last stop for any relay signals to trip the safeties. After that anything between the gas consol and remote hi freq box or to the torch is all off the grid. We went through the system 3 different times. Eventually we found a single bead in a valve in the hi freq box. It was a narrow passage to begin with and that bead was enough to really reduce the flow. We are back running. So far so good. I'm going to run a few dozen pierces and then inspect the consumables. It won't take much to tell if we're in better shape.

What really surprised me though was how much the shield gas flow (air, not N2) affects the quality of the pierce / transfer arc. Without good shield air flow I can't pierce without being right up kissing the plate almost when I should be running a good 8mm away for pierce. I've run this machine for almost 10 years now and this was the biggest pain of break down yet. Maybe this will help some else down the road.

You know, it might be worth looking at installing a dry particulate filter pack at the air input. Something like these: Compressed Air Filters - Hankison
The Grade 6 unit is what you probably want. No idea on the cost for them, but could probably be offset by how much time you've had to mess with the unit. Down near the bottom, they have a link to a PDF on the filters. Glad you are back running and hopefully not going through the consumables as fast now.