Stuck Gantry

After a some time setting up the exhaust system, I have finally started to use my Glowforge Basic a couple of days ago. Unfortunately, it soon became clear that something about the gantry was off.

In brief, when printing even basic shapes such as squares, the left side of the gantry seem to get stuck when moving backwards (see attachments).

This of course leads to very low quality printings for more complex designs. I have tried all the alignments / perfect squares troubleshoots, thoroughly checked the rails for detritus and gently placed the head under the lid camera (as suggested in several related forums). Unfortunately nothing seems to work.

Is there anything I am missing? Any suggestions about how to fix this?


The only thing I can think of is kind of a long shot – make sure the white cable to the head is securely in place and the connector pins are all springing back like they should and making contact. Other than that, it sounds like you’ve done all the Things and need to wait until an official Support person gets here. Sorry! I know how frustrating it can be, especially when it’s brand new out of the box and you want to get started! :frowning:

Is there any chance you could take a couple more pics of what you are describing? or a video if it is not a hazard to use the machine

If it’s getting stuck while the gantry is moving backwards, there’s likely something that it is hanging up on, either in the track, or in the belt/pulley.

Turn off the machine. Slowly move the gantry to the front of the machine, then slowly move it towards the back, and see if you can feel it catch. If you do, look closely at that area with a flashlight and take pictures if you see anything amiss. (Sticky spot, missing teeth in the belt, debris in the pulley.)


The ultimate logic is irrefutable but I suspect that the description is a bit off as your cuts are incomplete and directly behind the designs. I would run the Calibration Program even if you did so before and see if that makes a difference. Especially if you can not sense a problem with @Jules proceedures

Try printing the Gift of Good Measure, take pics of the result and post here. Note the time as well. Support can then compare your results with the logs.

It looks like a problem with the Y-axis but there are two motors/drivers, and I assume the head is “parking” in the back left corner after a print?

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Have a really close look at the rails the gantry runs on. When I first started using mine I was astonished after a few weeks to find a rubber washer lying inside under the rails. It hadn’t caused any harm but where had it been hiding all that time? I finally figured out it came off one of the hold down bolts that kept it secure during shipment. That could have caused a problem such as yours had it fallen onto the rail.

I’m so sorry to hear about the trouble with your new Glowforge. I extracted the logs from these prints and agree that the gantry looks like it is having trouble moving smoothly.

This type of trouble can often be caused by a loose belt. 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.

Don’t know if it’s just me on safari on an iPad mini(fully up to date); I can’t see the image.

I can see it on my iPad.

Hours later, it’s there now.


Thank you very much for all of your comments. I really appreciate it.

I made a video of the Glowforge printing a simple pattern

in which you can see how the left side of the gantry lags when moving backwards. This leads to a heavily altered print

I also re-checked the rails and recorded the belt tension

and none of them seem to be the problem. So, I guess there might be something wrong with the left motor.

Any further questions or comments, please let me know.

Thanks again!

Looks like a bad stepper motor on the left side.

If it moves smoothly back and forth with the machine powered off, that’s almost certainly the problem.

Thank you for the additional information and videos. Unfortunately, it looks like your unit is experiencing an issue that we can’t resolve remotely. I want you to have a reliable unit, so I’m recommending we replace this one. I’ll be in touch via email to sort out the details. I’m so sorry about the bad news.