Advice on adding plasma torch height control
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@mawildoer said in Advice on adding plasma torch height control:
EMI Testing
Just a quick update on this one. I've done some testing very specifically on the EMI induced in a shielded wire taped adjacent and in very close proximity to the plasma cable. This test cable is a CAT 6 Ethernet cable, where each pair is foil shielded and the whole cable is braid shielded.
Also note that I didn't actually conduct everything in the following order, but I thought it made more sense to present it this way.
Test Setup
I got some interesting results (and way, way more noise than anticipated).
FWIW, I've been investigating making a plasma CNC as well, and have noticed
- VERY important not to use a HighFrequency arc starting machine, these DEFINITELY will fry CNC electronics, pilot arc start are the one to use
- Many cheaper Chinese plasmas have a s*** load of EMI noise, even one page goes directly to prohibit the use of certain plasmas (including the make of the one you are testing) with their CNC frame: http://www.langmuirsystems.com/plasma-cutters
by the way, their FAQ has a load of interesting info too
For my part, I'm also investigating an inductive probe to do the z-correction, instead of Torch Height Control, because I would prefer to completely isolate the CNC from the plasma (that said, would still need to attach the torch on/off M3....), but am also worried about EMI, but directly from the arc - if the inductive sensor is to be close enough to be useful to change height at the nozzle... if the sensor gets affected, it will incorrectly change the z-height... not convinced yet that it would work, probably THC would be better as is "spot-on" the nozzle...
Cheers!
Andy
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@andymidtf - Very interested in this topic. I'm doing a DIY CNC Plasma table and was planning to use a spare Mach3 controller. Now, I have 2x 3DPs with DuetWiFi (Duet 2 series) controllers and a spare controller. I recalled that some Duet users were using CNC router and CNC laser, so I did a quick search and found this. This post is a tad old and I'm wondering what progress you or other's have made. At the moment, I just upgraded my torch to a non-HF blowback model. Approx 4-5 years ago I tried the HF Arc Pilot torch with Mach3 and EMI was too much. So, giving this a go.. one more time.
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