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Dust on the Laser Tube

PostPosted: Fri Jan 25, 2013 12:57 am
by nephertiti
Hi,

As you can see on the picture there is dust layer on the laser tube(maximum 3hrs worked). My system right now is naked and I'm sure there is electrical leakage(I will ground everything when I mount my electronics)

I just solder positive cable to laser tube and used heatshrink tubing tube.

So is this normal or I did all things wrong?

By the way my laser power looks low(used on %98 power). I'm not sure but on 2.x laser videos Plywood cutting looks easy. I tried to cut 6mm MDF but it didn't go very well (just maybe 2mm. %98power and about 5mm/s speed). Same for engraivings(not deepth enough).

So looking for your helps.

Re: Dust on the Laser Tube

PostPosted: Fri Jan 25, 2013 5:59 am
by macona
At the 20 to 25kv the tube works at you are going to build up a static charge on the tube. Thats is just the way it is going to be. The outside of the tube really does not matter, make sure it does not start building up on the output coupler though.

If you are getting that much build up (Cutting acrylic) you need a better smoke extractor.

Re: Dust on the Laser Tube

PostPosted: Fri Jan 25, 2013 5:04 pm
by TLHarrell
Is that on the inside or outside of the tube? Looks like deposits from electrical arcing.

Re: Dust on the Laser Tube

PostPosted: Fri Jan 25, 2013 8:30 pm
by nephertiti
TLHarrell wrote:Is that on the inside or outside of the tube? Looks like deposits from electrical arcing.


Outside, I can remove with my finger.

By the way heatshrink tubes looks lost the first shape. Is there any better way to connect power supply to laser tube then solder and heatshrink tube?

Thanks

Re: Dust on the Laser Tube

PostPosted: Sat Jan 26, 2013 12:40 am
by jv4779
I took the metal part out of a http://www.radioshack.com/product/index.jsp?productId=2103986 terminal strip, then covered with self adhesive silicone tape.

Re: Dust on the Laser Tube

PostPosted: Sat Jan 26, 2013 12:34 pm
by Techgraphix
You should not solder the pin that comes from the tube. You could crack the glass by applying heat.(even very small, invisible ones along the pin)
The pin is made from a kind of metal that can't be soldered very well. It is more for a good bond with the glass and has the same expansion-coefficient (i hope this is the right word)
Best way is to wrap the blank wire around the pin and seal it of with a tube filled with siliconkit. (take the one without acids..)
The metal clamp from the connectorstrip works fine too but take care not to apply too much force when you fasten the screws. If you can find headless-allenscrews that fit in the block (i expect something like M3), you can fasten them with minimal force and even cap it with a filled tube.
Ok, when you want to replace the tube you have to cut it. But if it cracks.... it need to be replaced anyway.

Kees