Imperfect squares, time for a new Glowforge?

Disclaimer: I’m writing this to vent as much as to get advice. Been a long day/week/month with my Glowforge.

I have a ~3 year old Glowforge Pro that I use heavily. It’s been a real champ, but it’s really not been a consistent worker for me for a while now.

First the power output started dropping. Customer support’s fix for this was to make my machine move slower for any given setting. So, I can get Proofgrade whatever to cut at the Proofgrade speed, but every job takes longer than it used to. And I just don’t feel like I have 45 watts available to me any more… most actual 1/4" thick material is impossible to consistently cut at any speed. I’m mostly working around that by carefully picking my suppliers so I get 0.21" thick material that’s a bit easier to cut.

New problem that started today: my laser arm isn’t staying squared. Squares sometimes don’t come out square, e.g. they’re slightly longer in one direction than the other. If I flip over something I just cut, it won’t fit back into the hole it was cut out from. And engravings when it’s lost its square don’t look quite right either, the edges of text looks more aliased than it should be for a given LPI.

So I checked that all the belts have the right tension and don’t see any cracks or chips in the wheels. I squared the laser arm with a square, the tool, and it seems alright for the next job. Then the next one after that isn’t quite square again, the start and end of the cut don’t line up perfectly. I restart the Glowforge, square the arm, let it re-center, and it’s cutting square again. I don’t know what’s going on, maybe it’s just so dirty or the belt is worn or something and it’s slipping somewhere during the jobs.

The fact that it’s not happening consistently means I don’t feel like taking this to customer support yet. If they ask me to print a square and measure it, it’ll probably come out right and I won’t be able to move forward. The inconsistency of the machine is what’s aggravating. If something were to break 100% of the way, at least then I could get a quote to repair or replace it.

As it is now, it seems like my only option is to keep running, and waste time and materials when something cuts wrong or doesn’t cut through the material, until it actually gets worse.

That, or buy a new Glowforge. I’m really tempted. Next time I get really fed up I might just pull the trigger on impulse. It just feels wasteful to abandon the one I already have. It’s just in this limbo state where it works, but not always, so I can’t easily get it fixed, nor in good conscience sell it to someone else.


which machine is it, and where do you live?
I ask these questions, because I am thinking about buying a ‘beater’ glowforge
to test things on, and not as a production unit.


What happens if you run a fast’ish score on a square big enough for the head to really accelerate and decelerate?

With the machine on, how does the holding power seem with different movements? Left, right on the head, pushing on the left side of the gantry, pushing on the right?

Steppers are pretty reliable but it’s not impossible for one to get weak, or even for a wiring issue to cause intermittent issues.


If you haven’t replaced the belts, and have only ever adjusted belt tension, I would recommend replacing all three belts with new. The need to adjust belt tension is an indication that the belt in question is stretching due to use. Eventually, stretched belts become unable to maintain not only tension, but they contribute to a loss of accuracy. When this happens, the results are exactly as you’ve described.

I know that Glowforge sells the lateral (carriage plate) belt and connecting block as a combo, priced around $30.00, but I don’t know if they do the same with the side (gantry) belts , contacting support should provide an answer .

If you have any issues ordering belts through support, I stock bulk belt material and can provide exact replacements at about half the cost if the ones Glowforge sells, without the connecting block, but you don’t need to replace them, just the belts.


@dan84 - I’m having a very similar issue. Every time I turn my :glowforge: on, it “calibrates” and the right side is visibly out of alignment with the right side. I use a square to align everything each time, but then my cuts are then off by about 1/2" from the camera. After a few cuts or a reboot, I need to resquare.
Additionally, I can’t seem to get it to cut all the way through 1/4" (0.23" actually) acrylic even with 3 passes. I’ve wiped all lenses and windows, and the mirror with ZIESS wipes, but it seems to either be out of focus or underpowered.

Were you able to resolve your issues?

The tube on that Glowforge started to go as well, at which point I contacted support again and they replaced the whole machine. So I don’t have a solution to the machine losing square. I think a new set of clean belts would probably have fixed it in mine, they were getting pretty worn and grody and probably losing steps.

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