I’ve been having trouble with my laser for a little while but I haven’t had the time to work on it. I went to take another run at a beam alignment today, and now the laser won’t seem to fire. when I press the pulse button, I can see the pink light in the tube (see video) but the beam doesn’t burn the tape on mirror 1 (yes I have some paper bahind the tape so as to not et adhesive on the mirror )
The bubbles in the tube are new. I’m not sure if that would affect the beam emitting from the tube. I tried the pinching the inlet hose several times and it doesn’t seem to get rid of the bubbles. I also turned off the laser and lifted the tube on one end so the air would exit the tube. Both solutions get rid of the bubbles momentarily, but they come back.
I’ve never seen that and I would not be firing the laser with those bubbles in the tube since there would be almost no cooling going on and the glass could break.
What kind of water is in there? How recent was it changed and have you checked for places where air can get into the line? There seems to be no correlation with bubble and laser firing and it looks like some really high flow rate.
Not sure I like seeing the laser excitation beam on the OUTSIDE of the water jacket… It’s supposed to be down the center of the inner most closed space. Our CO2 tubes are made of 3 compartments. Outer air gap, middle water jacket, inner gas filled firing chamber.
If you loop through the first few seconds of the video, the inner tube isn’t emitting the pinkish glow we like.
It looks like the voltage is jumping around where it should go. I saw something similar to this on Reddit and I think the tube has an issue. The inside of this area where it’s arching is usually where the gas mixture is and is at a very high impedance that’s generally unlikely to conduct.
I’d suggest a good examination of the tube for exterior issues.
Bubbles are OK if they don’t stick to the inner wall where it’s lasing. Large bubbles stuck to the center will allow uneven heating and likely crack the tube.
Has it always been operated with distilled water flowing? Those metal ends will get hot and if cooling water is not flowing heat can build up and uneven heating can crack glass.
Or maybe just a defect. Interestingly it looks like a burned through hole as if there’s been lots and lots of arcing and heating.
Yeah it was working before. I haven’t had it very long and it was second hand. It was running distilled water the whole time. I don’t know what caused the bubbles but I guess that may have been what caused the uneven cooling.
)
