China HF-start plasma CNC design!

[gcafonso]

Thanks for the reply. I think that what you made is exactky the same thing that Longevity plasma did. They claim to have a pilot arc plasma, and indeed they have, just like your machine they use a wire to ground the Tip ( not shown, but think its it). The price is very like a chinese price. They claim to work with CNC as well, but there is a video in their forum showing how to install their machines in a Torchmate CNC table. Seems to be a lot of problem with the HF, as they show how to properly ground the system because of the HF interference issues. Will try this on my CNC and CUT40 just like you did. Lets see if I get interference like they had or if your tip ground eliminates the HF just like in your machine. Again, thank you for sharing your ideas.

[hdoug5]

I tried this on my cut50D and still have HF interference, must have some wires touching inside of case but using it free hand the plasma works great.  any suggestions ?

[MachinistSF]

The arc itself still radiates plenty of RF interference, like any arc. Also there is high current flowing in the cables at dozens of amperes of arc current, run by some inverter. The control electronics must be properly shielded and grounded with any plasma cutting.

However, this interference seems to be a lot less than the interference from the sparks from HF start when the cutting arc (from torch to piece to be cut) doesn't start immediately. The interference from the "pilot arc" (of grounded tip HF start torch) is somewhere between those two - less than HF start, but more than just the plasma arc. Also the arc transfer happens much faster with the "pilot arc" as the pilot plasma stream hits the piece to be cut and heats it and destroys any coatings, so there is less time for interference problems before real plasma cutting starts. It works nicely for manual plasma cutting too - much easier to start cut with painted plate!

[TSOffroad]

Just purchased a burntables unit, should be here in a few weeks.  I've also purchased a machine torch for my simadre cheap chinese "Cut50" unit.  I'm going to try and use it to get buy until I can get my hands on a larger hypertherm unit.  With that said....you talked about grounding the torch head.  I can see where you have the alligator clip...but where does it go to to get grounded ?  Do you have it specifically to the grounding rods or just to the ground on the plasma cutter.  Any help is appreciated. 

[MachinistSF]

Just purchased a burntables unit, should be here in a few weeks.  I've also purchased a machine torch for my simadre cheap chinese "Cut50" unit.  I'm going to try and use it to get buy until I can get my hands on a larger hypertherm unit.  With that said....you talked about grounding the torch head.  I can see where you have the alligator clip...but where does it go to to get grounded ?  Do you have it specifically to the grounding rods or just to the ground on the plasma cutter.  Any help is appreciated.  

The wire is connected to the plasma ground (where ground clamp (connected to piece to be cut) is also connected already).

I connected the wire to the connector that attaches the ground clamp thick black wire to the plasma cutter plasma ground connector. When you pull the black rubber away there is an allen key connection inside. Just slide extra wire there.

[TSOffroad]

My next questions would be....

How's it holding up ?
Are you using AVHC ?
How long do your tips last ? (piercings ?)


Thanks again for the reply's....helps alot ! 

[TSOffroad]

I would also ask,

Do you have any info on how you wired up the cutter ?  I've been working for days to get some info with no success...

[MachinistSF]

How's it holding up ?
Are you using AVHC ?
How long do your tips last ? (piercings ?)

To be honest, I wanted to get more cutting depth and recently bought a new plasma with 25mm cutting capability. For this, I found Everlast powerplasma 60, which is a pilot-arc plasma and has 3-phase input so I don't need large fuses. Plasma cutter works fine, Everlast is a funny company though. Had lots of trouble finding who really sells the plasma cutter (official importer just said they'll have more in future, maybe next month, maybe later), and after buying the plasma cutter (from another company that apparently had bought it from official importer as it had their sticker) they didn't give me access to their official forum but banned me from the forum - just for registering. Really strange. However, the plasma works fine, and was really reasonable price. I'm using a modified WSD-60P torch.

As long as I used the "tuned" chinese HF start plasma, the consumable lifetime was about the same as using it with manual torch. Not that good but the consumables are cheap.

I have been happy with performance without height control so I have not implemented it.

Do you have any info on how you wired up the cutter ?  I've been working for days to get some info with no success...

What do you mean, how to wire the cutter? Power in, plasma on/off with relay (to torch "start switch" wires).

[dwdw]

Plasma cutter works fine, Everlast is a funny company though. Had lots of trouble finding who really sells the plasma cutter (official importer just said they'll have more in future, maybe next month, maybe later), and after buying the plasma cutter (from another company that apparently had bought it from official importer as it had their sticker) they didn't give me access to their official forum but banned me from the forum - just for registering. Really strange. However, the plasma works fine, and was really reasonable price. I'm using a modified WSD-60P torch.

As long as I used the "tuned" chinese HF start plasma, the consumable lifetime was about the same as using it with manual torch. Not that good but the consumables are cheap.

I have been happy with performance without height control so I have not implemented it.
What do you mean by the Tuned Chinese HF start? is it in their plasma cutter or an external device? Can you explain it?
Thank You
dwdw

[MachinistSF]

What do you mean by the Tuned Chinese HF start? is it in their plasma cutter or an external device? Can you explain it?
Thank You
dwdw

Please, read the start of this thread to see how I "tuned" the chinese HF plasma (not everlast) to get it to work like pilot-arc plasma, by adding ground wire to tip of the plasma torch..