Uneven kerf

Hey everyone,

Does anyone have an idea how I can fix this problem? It looks like when its cutting material the kerf gets wider/bolder at certain points then goes back to cutting at hairline point. Is this a lens problem? (i’ve wiped all lenses too)

Welcome to the forum.

The width of the laser beam is unlikely to change in the course of a job, so my guess is that the material was warped or there was a double line in the file.


Definitlely no double line as the file was pulled straight from a box generator + this happens on multiple other projects. If it is warped material I’ll try anchor it down and see if the cut is more consistent.

Sometimes finished stuff “dances in the moonlight” and moves or appears to move in a direction after it is cut. Also anything sticking up (like a bed pin) can change the airflow a bit, or even going back instead of to the front. You get a different look at the top but I suspect a micrometer could not tell you the difference in width of cut below the surface.


I look forward to knowing the solution. This is a new one.

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So you think the cut only “looks” uneven? That is so smart. I bet you are right.


There is something strange going on there for sure never seen the kerf change like this in my experience.

You said that you cleaned all the lenses, did you also clean the mirror in the head? When is the last time you cleaned out your air assist fan and the one in the head? If you have a set of vernier calipers it might be worth cutting out a set of some squares and checking the dimensions of each one.


That can also be caused by inconsistencies in the material density/composition. If it’s not glued uniformly and has air pockets in it (inside) you will see wider kerf in some places. It burns hotter with more air around it.

I would run a test print of the Gift of Good Measure on Proofgrade material to see if the issue occurs there.

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Nothing gradual about that.

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Unless maybe that is the start stop point? in a pretty weird spot if it is tho.

I am dying of curiosity! Would you mind letting us know if this unusual behavior continued on another project, if you checked the mirror and found anything or if you measured the two pieces and found a significant difference in size. Inquiring minds need to know.

It would be most interesting to see the side of that cut and see how far down that difference went. :thinking:


I do love it when people see things I haven’t noticed.


I have a gift of hardly ever paying attention to what is important and riding the wave of things that irritate my ocd hehe.


Thank you for posting those photos. I’m so sorry that your print didn’t turn out as expected. The cut line in your picture looks unusually wide, which suggests that the laser beam is out of focus.

As @jules said, try printing the Gift of Good Measure on Proofgrade material. Or, if you aren’t using Proofgrade material, please use Set Focus to accurately measure the height of your material. If the material’s height is not accurately measured, that can affect the laser’s ability to cleanly cut.

If the test print doesn’t turn out as expected, post a photo of the print and the time (with time zone) and date the print was run.

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Depending on which box generator, that may be your problem. I found both the Inkscape one and one of the online ones to do duplicate lines sometimes… not every time, but sometimes. Check your file before you freak on your machine.


I wonder if the focus changed during the cut. Notice the circular shape at the widening of the char?

It’s been a little while since I’ve seen any replies on this thread so I’m going to close it. If you still need help with this please either start a new thread or email support@glowforge.com.