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Danger, Danger, High Voltage - Laser Cutter Woes

cstanton

There are a number of hackspaces which try to go the cheap route when it comes to laser cutting and engraving, these machines are expensive, and unless you know what you're doing, they can be extremely dangerous.

 

One such repeated incident is with a 60watt laser cutter that my local hackspace has acquired, upgraded and attempted to fix over the years. With difficulties attaching cabling to the laser tube itself, through to the high voltage insulation or lack of it from the power supply unit to the rest of it itself.

 

However when you try to find guidance or assistance on ensuring insulation for high voltage, somewhat quite rightly, it's difficult to find. We're in the realms of trained professionals here, but still partial or low to no information is worse than the right information.

 

Recently, it's been arcing to the case, and that's not good. We guess that the power is 10-45kv and it has literally corroded it

 

image

 

What is a hackspace to do?

  • in reply to cstanton

    You might look into the literature and cabling used for Neon Signage - it's typically high voltage stuff that seems to last forever ... although if you get a guy who doesn't know what they're doing and puts sharp bends into things or nicks the insulation it's not any better ...

     

    - Gough

  • in reply to shabaz

    > The supply may not be regulated

     

    I suspect that it is, though this is something I will check with those who've worked on it.

     

    > Also I guess it came with those cable ties in place

     

    Oh no, definitely not, that was someone's attempt at maintenance.

     

    > I don't know the solution to repair that

     

    Replace the wiring, probably! and it's insulation along with it. A suggestion has also been to ensure that the cabling is stood off sufficiently from the enclosure.

  • From a long time ago when I used to repair TV's and other CRT devices, I seem to recall the HT cable was silicon rubber - which would have been operating at around 25kV max. Not sure how it would perform at 45kV though.

  • I'm still learning how to use a low-cost laser tube (blue laser diode), not going to power it up until it's all enclosed, but got some safety specs today.. I'll take some photos for a mini-review.

  • Hi Christopher,

     

    I wonder if that began occurring if someone powered up the supply without the laser attached (although there should be protection against that). The supply may not be regulated, and just relying on the laser tube to act as a load, i.e. without it, the voltage may rise high enough to self-damage itself or the cables.

    Also I guess it came with those cable ties in place, but that would make it worse, since it's better to have only slight bends and nothing crushed. I don't know the solution to repair that : ( Maybe the best thing is to mitigate any more discharge, with additional insulation until the tube/supply is replaced.

     

    I have an ancient HeNe (very low power - 10mW) laser tube that I got it second-hand about 10 years ago, and it's been unpowered for that long too! But I tried it a few weeks ago, worried that the years may have damaged the insulation, but surprisingly it still worked (also I can't believe the tube still functions, it's actual year of manufacture is stamped as 1980!). I'd like to place additional flexible conduit around the high voltage cable, but like in your photo, it is terminated with the large high voltage connector, so I don't want to modify that.