Weird Doubling on Designs

Hi everyone,

I have a Glowforge Basic that is giving us strange behavior. When I upload designs to the software, everything looks normal:

but once the job starts, that’s where the weird behavior starts:



Keep in mind that these are only being done with 1 pass and 1 path (I made sure to check for any artifacts from previous designs). Also keep in mind that this only happens on engravings. No doubling behavior during cuts!

I tried turning everything off and on again - calibration works like normal
I tried uploading different file types - same behavior for both jpegs and svgs
It’s not the lens - that’s inserted the right way, and clean.
It’s not the mirrors or laser beam windows- those are also clean
We re-greased the x-gantry - still happens
We re-tightened the belt tension as far as it would go - could be a belt stretched loose over time but not sure how to confirm that
We tried different materials - same effect for different materials and different thicknesses
We tried moving the design to different areas of the bed - same behavior regardless of location

Please let me know if you’ve run into anything similar, or what you think?

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Do you get the same behavior when you use a known-good design like the Gift of Good Measure?

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Yup! Just tried it

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Well there goes the easy answer!

I would check for a mechanical issue first. With the machine off, very slowly roll the carriage plate back and forth. You’re feeling for catching/pulling. I would imagine there is either debris, residue, or a breaking tooth going on there.
If you can’t narrow it down to a specific spot while it’s still connected, I’d pull the whole thing off and check every tooth.
It’s also possible there is a crack in one of the wheels on the carriage plate, so check those too.

Both belts, and wheels, are user replaceable.

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Welcome to the forum.
I believe your belt tension may be incorrect. If you loosen the bolt when removing the carriage plate to clean the air assist fan, this is a common problem. I have never loosened the bolt, and have no had belt stretching in over 5 years of use. Also, there is never a need to grease the rails.

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@dklgood You hit the nail on the head! I had just removed the carriage plate to deep clean the air assist fan, and when I reassembled the machine, I didn’t realize that the belt tension wasn’t enough. It’s crazy, I was sure I had pulled that pulley reasonably tight, but the problem only went away when I applied an unreasonable amount of tensioning force on the pulley while tightening the allen key! Thanks so much everyone for your help!

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