Consistently experiencing flashback with ProofGrade settings and material

I’ve had my Glowforge for a week and it seems like I keep getting a consistent amount of flashback on different proofgrade materials using the default proof grade settings. It’s happening on both acrylic and woods. I know I can manually tweak the settings to reduce it, but it seems like there shouldn’t be this much flashback using Glowforge-recommended materials and settings. Any ideas?

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First item i would check is your air assist fan, it should be blowing and keep the flame up from happening the majority of the time. Also, you may be cutting at too slow of a speed that will cause the flame up and burning…

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The issue with the first photo appears to be related to the Glowforge doing two passes on the inner cutouts. I have no idea why it’s doing this as there’s only one cut layer and it’s set to a single pass in the Glowforge settings. I’m using Affinity Designer if that helps.

If you are using Inkscape, go to View>outline or hot key Control+5 and zoom way in to see the path(s) and delete one. Not sure about AD.


Interesting! I opened the exported svg into Affinity, viewed in outline mode, and all seems fine except the inner triangles are listed as having a fill instead of a stroke. If I do the same thing in Inkscape (on a Windows VM because trying to run Inkscape on Mac is infuriatingly slow), sure enough there are two lines!

I tried a few experiments and converting the triangles to curves and then making sure their stroke settings (cap/join/align) were the same as the outer cut and it seems to be working properly. Weird bug and not sure of the exact cause, but flashback has been greatly reduced. Thanks!


You’re welcome, glad that worked for you! :sunglasses:

Thanks for the answer @PrintToLaser, that’s right. I’m going to close this thread - if you have another question, go ahead and post a new topic.

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