How does it lase?


#1

Here’s a technical question… I see a cool pink energy in the tube. Now that I see it in person, I was kind of expecting it to feed right into the laser, but the laser is connected via a ribbon cable. How does the plasma help the laser to lase? In my dreams I was expecting rays to shoot out of that tube. Silly me.


#2

The laser IS the tube. The ribbon connects the camera and other electronics in the head to the controller board. The rays are indeed shooting out of the tube, bent by mirrors, and focused though lens onto the work surface.


#3

Okay, any light you see is not laser light. C02 lasers produce laser light a bit out of our ability to see. Any purple light in the tube is waste and any white at the cut is incandescence.

So as @jjmacdougall said, it comes out the left side, as a beam about the size of a pencil, goes off two mirrors and I don’t know how many lenses to come back out and head to the head. The head has one more mirror and then the focus lens that makes it right around .5mm as it hits your material.

here is the last lens before it goes to the head.


#4

Oh. Right. I forgot about the lenses. Great explanation. Thanks!


#5

Yep, just like you thought, by its nature light travels in straight lines. At the end of the tube that energy is reflected off of a mirror at a 90 to another mirror that reflects it toward the head. The only part of the beam path that is exposed is between that window you see in the picture and the head, along with the distance to the material after the lens.
That differs from traditional design in that two of those mirrors are enclosed, and that frees the user from the maintenance of cleaning them. The round flat windows (lenses aren’t flat) are all we have to wipe, not the surface of a tuned mirror. The design can enclose that section of the path because the tube rides on the gantry.
As I understand it, there are mirrors, windows (in the case of the glowforge), and a lens. Your optics. It’s important to keep them clean.