Glowforge Material Keeps Catching Fire

Hello Everyone,

So recently, when my GF is cutting it is being followed by a 3 inch flame and I have to pause the print then resume every couple seconds. I tried turning up my air filter all the way up but it is still doing it.

I even tried using the internal fan as well as the external one both at once and it still caught on fire and cause even more smoke.

I wiped down inside of the machine.

What could the issue be?

What’s the material and settings you are using ?

It started with 1/8 in proof grade acrylic and I used the settings it pops up with.

Then I tried with 1/8 Baltic Birch Plywood with no masking with settings:

Speed: 270
Power: Full

Have you cleaned your air assist fan?


Is your filter full?

There is a little fan called the “air assist” that blows on the material as it’s being lasered and the fan helps keep the flames under control. Have you ever cleaned the fan? (It can get gunked up and slow down pretty quick.)


I’m surprised you are getting flames even at 270 speed on Baltic birch, unless it’s a very intricate design and the laser can’t get up to that speed (but it should be adjusting the power down when it has to slow down).

You might check the two windows on the bottom of the head as well that run the Auto focus measurement system. An out of focus beam can cause lots of flaming (just like a backwards lens can).

I’m so sorry to hear that you’re hitting this snag, but I appreciate you taking the time to send over these details. I’ve extracted the log files from your Glowforge, and compared them with the information you’ve posted.

Based on the logs, it looks like your Air Assist Fan is spinning a little slower than it should. I’d like to take a look at a photo of the Air Assist Fan. When you have a moment, could you work through the instructions here and send over a photo similar to the one below?:

Once we can review this image, we’ll send over any additional steps.


This is a picture of what my assist fan looked like.

Safe to say it was definitely in need of a cleaning.


Thank you for working through the steps I outlined, and sending over this photo!

I do see the heavy debris build up in the Air Assist Fan you noticed. I’ve extracted the log files from your Glowforge to review your most recent prints, and it looks like the Air Assist alert is no longer occurring while printing, and you’ve been able to successfully print since cleaning the fan.

This is great news! I’ll close this thread for now, but please don’t hesitate to reach out to us directly at if you happen to run into any of the same behavior. We’re here to help :slight_smile:

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