Fed my glowforge after midnight and now it uses two lasers while cutting

Per @Dan’s request…

Wednesday night I ran a project on a piece of maple hardwood- I happen to be watching closely and videoing while marveling at the new proofgrade engrave settings.

The engrave itself went more or less as expected, but as soon as it started the final cutting step, I noticed in addition to the usual bright white light where the laser hit the material, there was also a red, clearly laser, dot.

I think some people think I’m seeing things or some weird artifacting…

This image is :34 in the attached video, you can see the red-dot overhangs the edge and hits the floor of the engrave, behavior that can only occur if the light is coming from above, not sideways or some optical weirdness.


Nothing else seems to be out of the ordinary, other than some occasional weirdness with calibration last weekend but sounds like everyone else has had a touch of that.

Haven’t run anything since then, but will do some more experiments tonight.


Looks like the depth gauge laser is just mistakenly firing along with the CO2 laser. Probably not hurting your job, but we’ll let Support say for sure.
OR, we’re seeing the beginnings of continuous depth checking for use on uneven/curved materials. Wouldn’t that be something!




Wasn’t much concerned about it hurting anything, actually assumed it was an early implementation of moving autofocus… but since Dan doesn’t know about it and nobody else has able to replicate it, probably should let support know.


I would be surprised if they can simultaneously measure distance and engrave because the flare from the engraving is so bright and smokey it must obscure where the red dot hits the material.

Perhaps when combined with other sensor data (head cam, etc.).

Yes the head cam looks at the spot to work out depth but I don’t see how it isn’t obscured by the bright flare of the laser.

Well that’s why I said “etc.” :wink:
I don’t know how they’ll do it. It’s not even something I’d care to guess about since there’s no gain for me. Just speculating. Or, more-specifically, mock-speculating. :wink:


Would you please take two photos for me?

  1. Turn off your Glowforge
  2. Gently use both hands to move the Laser Arm and Printer Head so that you can take two photos:
  • A photo of the window on the side of the Printer Head
  • A photo of the window just over the left rail of your Glowforge
  1. Post your photos here, or email support@glowforge.com

The below pictures show what I need pictures of, but it would help if yours are much more zoomed in. Thanks!


I 've seen glows like that a lot when I have two cuts near each other. I’ve always assumed that it’s either a little bit of backsplash or else light/burning shining through the wood.

1 Like

It will be interesting if it does it again and I look forward to hearing how the next cuts go. I agree with paulw, it does look similar to the glow you can sometimes see with cuts right next to each other, but it looks like just one cut in the video. It’s a total longshot and not likely, but maybe check the file for any hidden lines or maybe post it for others to check @cbarker ?

Does it switch on and off in step with the beam or is it on during moves as well?


Here are the photos you requested and some extras.

And one attempt of a picture of the bottom lens.


I’ve done two cuts since the one in question, one with draftboard- no red light, and another run of maple.
Now this time I was running the GF during the day and getting much more natural light. I am willing to admit, it does look like an optical effect of the material rather than a second laser, but it does look exactly like a 650nm wavelength laser pointer when in lower light conditions like the other night. I was going to post a second video but the difference is not perceptible between the two runs using my phone camera, but very perceptible in person.


Thanks - those pictures look great and I’m glad to hear you’ve printed successfully. Would you take one more picture? Unfortunately, I don’t have a sample of this one, but here’s how to get it:

  1. Turn off your Glowforge
  2. Take off the very top of your printer head (it’s just the top quarter inch, and will come off easily if you pull straight up)
  3. Pull the little handle to pick up the mirror, and take a picture of it
  4. Set the mirror back down with the handle up, and replace the lid
  5. Turn your Glowforge back on and carry on!

Here are the pics - first the mirror…



Then the lens on the bottom,

Both of which look like they need cleaning.


Thanks so much for providing these photos. Everything looks good!

I’d recommend cleaning everything including the mirror according to these instructions.

Please let us know if you run into anything else.