Can a print cause gantry misalignment?

I was printing a file yesterday to make some face shields for a local facility, and the weirdest thing happened: at several points during the printing there was a clunk! that shook the whole glowforge, and after a few prints I noticed that my gantry was misaligned on the left (see picture).

The head passed through very similar coordinates without clunking, and I couldn’t find any mechanical obstruction, so I was wondering if it was possible that my file was tickling some bizarre bug in the motion-generating algorithm. The clunks always happened while the GF was cutting the little oval holes along the edge (but not, afaict, the circular one) . I was cutting the masks two-up, and the clunking happened on both copies. (This svg is a modified version of one derived from a dxf of the same shield slightly modified. I don’t know if there’s anything wonky about that.)

Also, I was holding the mylar down with big magnets, but none of them appeared to have moved after a print. So is it something mechanical I just haven’t found, or is there a chance that there’s some truly odd software thing happening?

Is your material overlapping the plastic edges of the honeycomb tray? That will knock the gantry off its tracks. I’d also check for any little bits that might have gotten onto the rails or belts that could be causing it.

EDIT: Also check that nothing has gotten into the divots in the bottom of the bed to make your honeycomb surface stick up in one corner.

I checked for little bits and didn’t see any, will check again. But the GF cut the outer perimeter fine first, so nothing could have been sticking out then. Only when it went to cut the tiny little ovals did it clunk. Which seems to me the confusing part.

I’m so sorry that you’re running into trouble. I appreciate you checking for any small debris that may have caused the Laser Arm to become skewed.

Could you check the tension of your belts for me?

When pressing lightly on one side of the belt, the other side should not move.

Like this:

(You should see an animated image above)

Let me know if the belt is loose and I will follow up with your next steps.

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At first glance, the belts weren’t loose, but they didn’t seem as taut – I could push down very lightly and they went down quite a bit, but I didn’t see actual slipping around the gear. I can go back today and check in more detail (the GF is in a building that’s closed to the public for the duration), but the tightening advice might be a good idea…


(PS this cut file could be particularly stressful because it’s got small-radius arcs followed by a dead stop at the end of that sub-path.)

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Thank you for checking in on those belts. If you feel a little more slack then you think you should, it may help to tighten them to see if this helps.

We’ve discovered that photos don’t always come through well in thread responses, so you can follow this link for instructions to adjust the tension of the side belt.

Let us know how it goes!

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