My Glowforge has picked up a nasty smoking habit

I made a couple of short (~2 minute) cuts this evening, starting with proofgrade frosted acrylic followed by proofgrade draftboard. The acrylic had a stronger than usual odor and the draftboard released a ton of smoke. The oddest thing is that the smoke appears to be coming from the bottom of the Glowforge - well below the pass-through slot ( which is currently blocked by the metal piece which bolts in place).

Here is a video of the smoke.

  1. The name of the material you’re using:
    Proofgrade medium frosted acrylic and proofgrade medium draftboard

  2. A description of where the smoke/fumes are coming from: the door, lid, or hose
    See the video. It appears to be coming from below the Glowforge

  3. When you smell the fumes: during the print or after it has completed.
    During and after

  4. Photos of your Glowforge and your exhaust system
    See the video. Can upload additional photos of specific areas if you like.

Any ideas? I verified that the exhaust tube is clear and my seals appear to be intact. I have already followed the instructions at:

FWIW, mine’s never done that. Are the fans running when powered on and idling? Do you hear them pickup speed/get louder when cutting? It shouldn’t be doing that (obviously). It certainly appears that it’s not drafting /venting air.

Have you checked that you don’t have any obstructions on the underside (like a sheet of paper sucked flat against it)?

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Thanks for the suggestions! I hear the coolant pump while the glowforge is powered on and idling. The fan definitely turns on when the Glowforge is cutting and is running at what sounds like the same speed it has always run at.

I checked the underside just now and didn’t see any obvious obstructions.

It may be a pain, but I’d do a quick check outside to make sure the exhaust vent isn’t somehow obstructed/blocked up. That’s the only thing I can think of that would make this happen (complete blockage & stalled airflow out the exhaust).


There’s something blocking the exhaust. Could be the screen at the back of the unit where the vent hose attaches, that can collect gunk and slow the flow. Have you checked outside where the vent exits the building? If there is a damper or louvres at the end, make sure those are not stuck shut. Make sure there is no birds trying to nest there either.


As mpipes pointed out, you want to check the exhaust fan and vent for built-up gunk. Multiple people have reported smoke issues when that gets slowly blocked up.


Good suggestion @rusty.tracey and @mpipes!

I went outside and noticed that a metal “roof” that extends over the opening of my exhaust port seemed to be pressed up against the opening. I pulled this away and confirmed that I felt cool, freely-flowing air when I disconnected the exhaust hose from my Glowforge for yet another inspection. A subsequent print yielded far less smoke, but I’m still seeing some smoke outside the glowforge, especially near the bottom right side of the door, near the hinge where it attaches to the main unit.

I inspected the exhaust fan and vent and saw a bit of soot on the fan blades, but no obvious blockage. The fan is able to spin freely and the pathway looks clear.

I’m no longer smoked out of my “Bot Cave” where Hephaestus resides, but I will need to figure out how/why the last bit of smoke is coming out.


As others have said, build up on the exhaust will cause the smoke to find it’s way out elsewhere.
I know it’s major cleaning time when this happens to me. I also have a screened in-line lint trap on mine that gets clogged, especially when cutting or engraving acrylic.
I have a basic and the smoke usually finds it’s way out of the edge of the front door.


Is the in line line trap after the GF? Or did you manage to put it in the inside of the GF to keep from fouling the fan?

It’s after. It really catches a lot of sediment.
I put it on because my vent line is long and have an in-line fan, so I didn’t want the particals getting in to it.

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I apologize for our lack of reply – I’ve now replied to your email.