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Carol Stopforth
07-06-2013, 10:58 AM
I seem to have plain old bad luck with my engraving machines. The plug which goes from the power supply to the beam is sparking. Nothing was changed on the engraver, except we replaced the water chiller for a bigger one. The plug gives off sparks and makes a noise. I have immediately switched off the machine. Does anyone have any idea what could be causing this? We have checked the plug to make sure the wires are connected correctly. The engraver has worked fine up to now. And it would happen over a weekend. Any possibly advice would be appreciated.

Dave Sheldrake
07-06-2013, 12:16 PM
What kind of machine Carol? RF /DC? western made or Chinese etc?

Arcing is usually a product of insulation breakdown or tube failure in a DC system. It *could* also be loose connections on the controller or tube clamps. "Stitching" is usually cased by a lose wire into the laser control card...lots of possibles but without more information impossible to say which.

best wishes

Dave

Carol Stopforth
07-06-2013, 1:30 PM
It's a CO2 laser, Chinese make. 60w. If a possible tube failure, would the machine still engrave? It is still engraving.

Dave Sheldrake
07-06-2013, 2:31 PM
Hi Carol,

Engraving is usually done at a lower power, tubes tend to fail when subjected to high power (the arc jumps to the nearest point of lowest resistance)

I have a *gut feeling* it may be a lose wire,

Keep the machine off for 24 hours to ensure power is discharged.

On the control inside the machine are a number of connectors for wires held by screws, (usually green blocks with brass screws in them)

Check to ensure each one of these is tight (don't murder them up but a good connection is essential) the "control" will look something similar to this

http://www.ebay.co.uk/itm/CO2-Laser-Engraving-Cutter-Motion-Control-System-/160536360845?pt=LH_DefaultDomain_0&hash=item2560b6778d check the screws in the green blocks.

Yours may look a little different but will be similar.

If that isn't the problem then I'd suspect a failing tube, when you say "sparking" do you mean tiny blue dots like you would get from a battery or long bright blue arcs (like miniature lightning)?

If Mini Lightning then it's likely your tube is close to dead (DON'T run the machine, those arcs are VERY high voltage and you will damage your power supply as well as possibly injure yourself). If tiny blue spots then it's stitching and will be a loose wire somewhere.

I just have a strange feeling the arcs and lack of power are stitching.....ergo loose wires

best wishes

Dave

ps: is there a power meter on the machine? (usually in Ma)

Carol Stopforth
07-06-2013, 4:41 PM
Hi Dave, it's short bright sparks - they look white or yellow in colour. The machine has been doing some heavy work of late, but it's a brand new tube, probably doesn't have more than about 10 hours work on it. I will check the connections first and let you know. Thanks for your advice.

walter hofmann
07-07-2013, 5:36 AM
hi carol
make a picture from your tube connection both sides. if you want you can send it directly to my PM then I can send you more info and eventually some picture from solving the problem.
my PM a542002@hotmail.com
greetings
waltfl

Carol Stopforth
07-08-2013, 3:29 AM
Hi there, we eventually managed to solve the problem. There was indeed a lose connection and when we tightened this the sparking stopped. Thanks so much everyone for your help.

Dave Sheldrake
07-08-2013, 4:51 AM
Good news Carol,

It crossed my mind that it would be a lose wire as I saw the exact same thing on a large flatbed laser last week :)

best wishes

Dave