Focus variants within one print job

Not sure if it is ground, as it has two broken ends, not just one disconnect from the screw, but I am going to look further, thanks for your image!!! Would a faulty ground be potentially causing these issues?

If it’s broken in the middle, it would have two loose ends… the obvious thing is to see if there’s a wire attached to that screw on your machine and if so is it the broken one. I didn’t see any other candidates, but I have a fat head and it’s hard to get inside the machine.

As for causing the issue, electrically I doubt it – but I’m not a laser engineer. Could be some mysterious static build-up, I don’t know. But it doesn’t have to be electrical. Perhaps the carriage is rolling over the wire or something.

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I like this theory… Could be what broke the plastic wheel to begin with (and why I am getting a replacement)… Will investigate further and report back shortly.

ok, you are correct… it is the grounding wire. Which would explain why the unit still runs, its not a “major” wire like, power to the camera or something.
Would an intermittent grounding issue theoretically cause the power fluctuations in the laser beam?

Depending on what part of the circuitry it could cause just about every problem you could think of. Everything from stopping static, keeping the metal parts of the system from shocking you, giving a reference for the power supply or a reference for signals to internal processor. Haven’t looked at a schematic.

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Given the voltages involved in firing that tube (typically 20kV), I’d be a little concerned about losing any ground connection to the gantry that it is housed on.

HEY ALL, just thought I would give an update, in case others have similar issues in the future. I was able to trace the problem back to a partial blockage in the air assist fan. I believe the blockage was acting somewhat like a flap, thus the inconsistent problem reproduction- sometimes it would block airflow, sometimes it would not. I cleaned out the unit based on these directions:

Despite the broken(temp repaired) wheel and the severed grounding wire, my machine is running full steam ahead today with no issues. My replacement machine arrives tomorrow, so hopefully all will be well soon.
I appreciate all of you for your help, insight, good questions, and ideas!


glowforge dot com /support/topic/cleaning-service-and-moving/clean-air-assist-fan


I appreciate you working so closely with everyone here, and following all of the instructions I sent over. I’m so glad to hear that you were able to narrow down the snag, and help to navigate what originally was causing the wheel on your unit to break. That is indeed the grounding wire, and its position points to it being caught in the rail as the unit was printing. I’m happy that we have a replacement unit coming quickly, and you are still able to get some projects done with your current unit.

I’ll close this thread for now, but please don’t hesitate to reach out to us directly at

Thank you :slight_smile:

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