My fan is making some weird sounds. Advice, please

When I begin a cut, my fan starts off really low pitched (different than it used to) and kind of sounds like it is dragging and then about 15 seconds later it jumps into a much higher pitch and the fan sounds like it is moving much faster. Is this normal? I have cleaned the duct and the grate in the exhaust as best I can. Thoughts?

Take the hose off and shine a light in the port. If you have been doing a lot of cuts with lots of particulate matter in the exhaust, it could quite likely have built up on the fan or the exhaust port.

I’m betting that a periodic attack with a shop vac will help quite a bit, though I’m also concerned about the longevity of this particular part.


And if you use a shop vac on it, make sure you have it set to suction and not to “blow all the crap right back into the machine”.

Thank you, thank you very much.


Sounds like a lesson learned from experience.


Another thing to keep in mind is that sometimes the fan speed changes as a result of a software update. I know when I had the PRU Glowforge, the fan sound went through a few changes over the course of the months that I had it.


I have cleaned the grate in the exhaust as best as I can, but it still sounds weird and smoke comes out of the front of the machine. It also hasn’t been cutting all the way through even proofgrade material. I have to do 2 or 3 runs before it will cut all the way through. I clean the lens every other day or so. Is this normal? Is this a warranty issue?

You didn’t mention the smoke issue earlier – definitely not good. Something is not right if the GF isn’t under negative pressure during a job. Just to cover all bases, you’re certain the exhaust hose is clear and unobstructed? How about the intake on the bottom right?

Best of luck!


The exhaust hose is definitely clear. The intake appears clear as best as I can tell.

Can’t think of anything else to try… I’d wait to hear back from support. You can probably save at least one round of interaction by providing the date, time, and time zone of your last attempt-- this will help them check the logs for diagnostics. Good luck!


I have added links to two videos. Does this amount of smoke seem excessive? Also, because it doesn’t cut all the way through, I have to do multiple cuts, which freaks me out because 2 inch flames shoot out of the wood. The second video is my second cut and it still didn’t cut all the way through.

It looks to me like the air assist fan isn’t running which might explain why it also doesn’t cut as deep as it should. However the air assist fan connection is four pins, so it should include a tacho signal. I would expect the GF to detect a fault if it wasn’t running but if might be something they haven’t implemented yet.

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One should be able to look over the back of the machine (back of the gantry) and see if the fan is spinning while in operation. I know that at this point, it does not throw any errors if the fan is not spinning.


The logging information that is sent while the unit is connected to the cloud includes details about the operation of the fans.

While not a proactive warning, I would imagine Support should be able to see from the logging data if the fans have been operating correctly.

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I agree with palmercr – looking at the direction of charring and the pattern of smoke distribution, it would appear that the air assist isn’t working. Were it on, the smoke (and flames) would be flowing straight at the front door, then deflecting around and getting pulled to the back left.

Were it me, I would remove the head and detach the ribbon connector, checking to make sure all the pins are straight, and then reconnect, making sure that both the connector and the head itself is fully and correctly seated. Others may disagree, but it’s easy to check, so why not?


I don’t think that the ribbon cable along the X axis drives the fan, other than providing power to the head. I think it is controlled by the ARM MCU in the head in response to serial commands down the ribbon cable. I would hope the GF errors if it can’t talk to its head.

I would check the head is seated correctly as there are four contacts on the bottom which connect to the fan.

These are worth wiping down anytime you take the head off, in my opinion. Minute amounts of “dirt” can accumulate in there.


Good point – I updated my reply above to include mention of the head itself.

Good point. Figured the process of removing and re-seating the head would cover that, but I’ve edited my reply above to explicitly mention this.

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Here is a video of a fan test that support had me do. It is a little hard to hear, but if you have headphones, you can hear it better. Right around 4 seconds, you will hear a pretty distinct kind of grinding noise coming from the fan.

Is it possible to put your phone to the back left of the GF :glowforge: and run the test again.

It would be helpful to hear if it is more distinct/louder in that position.

That is a very odd sound. It reminds me of something being sucked up against an opening where air is being drawn through.