Burning wood and acrylic

I have recently started having an issue where files that I have run tons of times with the same exact settings are now randomly flaming up and burning. I am using Glowforge proofgrade cherry wood and proof grade clear acrylic. I am randomly getting flames while cutting and other times while engraving. These particular photos of the burnt wood are from today. The latest one on the wood was ran around 7:15pm tonight. I have cleaned all 3 fans and all of the laser windows several times. This started to happen in the last few weeks. It happens random, even on the same piece of wood or acrylic on the same night. It will burn in one area and then cut and engrave cleanly in another, as you can see from the acrylic sheet. But it’s not consistent. It’s happening pretty constant now. I’m out of ideas on how to fix it. I even tried switching the lens on the laser head to see if that would resolve it. It did not. Can I get some help please?

This particular clover is a deeper wood engrave and then I set in a separate green acrylic clover. I’ve ran this particular file cleanly last week making about 60 pair with out an issue. Then I needed to restock and now they are burning and randomly cutting off center.

Just double checking that you also cleaned the mirror?

Yes, I forgot to mention that I’ve cleaned the mirror several times also. Thanks.

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Take off your carriage plate and check that when you cleaned the air assist fan that it stayed connected - that flame should be smaller and blowing straight forward - not high and to the side.

Attached are 2 photos of the mirror. I have noticed a scratch on the mirror. I’m not sure how it got there or if this could be the cause, but if so, please let me know either way.

Something’s up with your air assist fan. Make sure it’s spinning when your machine is on – you can see it if you lean over the machine far enough to see behind the gantry.


I cleaned my fan pretty good, I thought. The fan could easily spin and was spinning while my machine was on. I sprayed it with electronic degreaser and used the lens cleaning wipes to get all of the fine spots around the blades clean. I did this at least 4 times this week trying to figure out why I was getting flames.

After your comment about the fan I decided to google it. I found this video on cleaning the fan. After removing the silver plate off of the fan, it revealed that the airways were completely blocked. I never thought I had to take it apart, but I guess you do because no matter how clean it looks, between the fan and the silver plate can be hidden issues.

All better now. Thanks!


Oh no, I’m so sorry to hear you were experiencing larger than normal flames on your recent prints.

As a reminder per our manual:

A small, candle-like flame where the laser beam strikes the material is normal. This flame should move with the laser and should not remain lit when the laser has moved past

It appears the suggestions from @deidrebeth and @geek2nurse to clean the Air Assist Fan have got you back up and printing without trouble, that’s excellent news!

Would you let me know if you have any additional questions or concerns?

It’s been a few days since we’ve heard back from you, is there anything else we can assist you with?

Everything is working. Thanks

Thank you for the update. It’s great to hear that you’re back up and printing! If you run into trouble again, or have other questions, please post a new topic here on the forum or email us at support@glowforge.com. We’ll be happy to help!