Cleaning the Mirror in the Head


This is more of a support question then having a problem.

I have been purchased the lens wipes that were recommended and included with the machine. I clean off the windows for the beam from the head and left side of the machine somewhat regularly. With all the stuff that seems to coat the beam tube cover and lid I’m sure those windows get it bad also with the fan pulling everything by them as it cuts.

My question is how often do we need to clean the mirror in the head? The lid is held on with magnets and it pulls right out so it seems like a user serviceable task. Also would the lens wipes be the way to go for cleaning that mirror?


The “official” cleaning page answers everything except for how often. I recall that the recommended time between cleaning was every 40 hours of use.


I have been going by that manual for the cleaning. It does not state anything about the mirror under the top cover of the head. Since it’s so easy to get to I was wondering if that is something we should be giving attention to as well if it was missed in the cleaning section. Seems like all the optics would need a cleaning at some point.


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I think the whole point of the windows is that the inside of the head is sealed against dust/particulate infiltration. I’ve never seen any mention of a need to pull out the mirror. If you’re not seeing any impact to performance / cutting power, it’ s probably fine.


I know nothing, but I strongly advise not thinking about touching the mirror, nor even opening up the head, until @dan posts definite instructions to do so.
Just my 2d worth, and short experience of coated optics, ie mirrors.


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If the mirror has any fog or residue on it, looking closely you will be able to see it. If you can’t see anything, I wouldn’t touch it.

When I was having the occluded fan grill issue the machine got really dirty inside. Once I discovered and corrected that, I cleaned it well. During the course of that task, I noticed a slight ‘fog’ on the head window. Turned out it was on the inside.
The head uses a tiny fan mounted on the bottom to induce airflow out of the lens bore to help keep the lens clean. Since the atmosphere in the machine was filthy because of the blocked exhaust fan grill, the air pushed through the lens bore carried smoke with it, so the lens, the mirror, the inside of the window and the entire air path through the head needed cleaning.

I removed the mirror, the lens, and unscrewed the window. Using compressed air I blew out the fan (holding the fan blade still with my thumb so as not to over speed it) and using a Q-TIP and alcohol, I swabbed out the lens bore, window hole and mirror seat.

The lens, mirror and window are precision optics, so great care should be used in handling and cleaning them.
Any film or fog you see is an accumulation of very fine particulate and is abrasive, if only mildly. I recommend using an alcohol in a spray bottle to blast off as much as possible before ever touching the surfaces with a lens wipe.

The other window and mirrors on the gantry are sealed and shouldn’t ever need cleaning, only the outside of the window.
That is a maintenance saving innovation of the glowforge, never having to clean or adjust those mirrors. Sealing that section of the beam path is enabled by the tube riding in the gantry. :+1:

So, yes the optics inside the head, the lens bore and the tiny fan may need cleaning at long intervals.
Bear in mind this is from my limited experience as a laser idiot, and in no way an official practice or method condoned by the company.


Not just abrasive but flammable and so can scorch under application of the unfocused laser beam. That will bake on and then burn off the coating on a mirror or lens if left on for too long.


Interesting. Thank you! :+1:

I’m investigating - I will get back to you when I have an answer.

Thank you.

Just wondering if you found out anything about this mirror?

Thanks again.

I’m sorry I took so long – cleaning guidance is now available here: