Lens Material & Cleaning Materials

I was wondering if anyone knows that the lens (the removable cleanable one) on the GF is made from. Is it actually glass, or a high grade plastic.

Does the lens have an optical coating?

I’m asking because when I ran a 4.4kw CO2 CNC metal laser and we cleaned the lenses, we used the similar lens cleaning wipes, however we also used a solution of weak acetic acid (the equivalent to lab grade/filtered vinegar). We would lay the lens cleaning wipe on the lens, dropper 2 to 3 drops of the vinegar and using no down pressure, simply pull the cleaning wipe to the side. Discard each wipe after each use, always using a new wipe.


There’s a very high chance that the lens is made from ZnSe.


It can’t be glass or plastic because both are opaque to CO2 laser light. It won’t have an optical coating because it isn’t an optical lens. The wavelength is about 10 times greater than visible light and it behaves quite differently with regard to what materials are transparent and reflective.


Well I was meaning glass, in so far as non-plastic. I’m not sure what I’d consider the lenses that I ran in the 4.4kw CO2 laser, but they would chip just like glass…

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They might be glass as in the state of matter but not the common material known as glass.

Removed link to a version of the manual that’s not yet public - we need to make sure people have the correct information for their machine.

It’s ZnSe.


A quick search says that cleaning ZnSe carefully is finicky but not evil. So no great anticipatory fears.

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But we don’t tend to need to clean the lens (or mirrors) of the GF. We’re cleaning the windows. There’s a special lens removal tool (@marmak3261 is the only PRU to have it). The lens is housed and the air assist keeps it clean. We shouldn’t fret about lens cleaning.


The V2.0 manual that appeared in these forums briefly before Dan removed it says “After every 40 hours of printing, use ZEISS lens cleaning wipes to clean the laser lens and windows.”

A normal air assist would keep it clean but it seems the GF one doesn’t. Perhaps because it is blowing air from the chamber rather than an external clean supply.


I’ve always worried about that since I heard how it worked.

Is that measured now in the GFUI so we know when that is?


Haven’t had to clean the lens yet - after two and a half months of normal usage. I do wipe the windows over the lens every other week or so, and the camera in the lid. (ALWAYS with the unit turned off.)

I ran out of lens wipes after the first cleaning. I use a special non-scratching lens cleaning cloth spritzed lightly with a 50/50 vinegar/water cleaning solution to remove the smut. What you are dealing with is a thin film similar to what you find on the bottom of an ash tray. The same slightly oily film can be found on glass shelves if you happen to have them…it just smears if you don’t cut the oil with something. A quick gentle wipe with the vinegar solution removes it.

I also clean the grime/soot/ ashes off of the tube when needed…again, always with the unit turned off.

Some operations (like deep engraving) create a much messier environment in the closed case than others, and some materials are worse than others. (Some plywoods are bad depending on the glues, acrylic is worse, extruded acrylic is horrible from a smell standpoint, eggshells are the worst for throwing up powder fine particles…you will have to dust the tube between eggshells and anything else. Haven’t tried stone but it might be the same for those…working with minerals in both cases…it seems to pulverize the material instead of actually burning it. Don’t know yet…still have a lot of learning to do.)

Point is…there are probably going to be different cleaning requirements for different usage, and that’s going to vary based on the user, and what they are trying to do with it. Until you actually start using the machine, you won’t really know what your cleaning schedule is going to look like.

But in any case, it’s not particularly difficult or often.


Sorry about posting that - I should*'ve* PM’d someone at GF first.


Is there any reason to keep the tube clean other than aesthetics. I thought the business end is enclosed.

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I thought it was made from the solidified tears of FS laser owners? Oops sorry… that was not nice or very politically correct. (Glowforge™ owners are better than that, but it slipped out…):mask:

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Not that I know of, but it looks much nicer. (Of course the rest of the office looks like a bomb went off in it, but I’m weird with tools.)


There are just two windows, right? Both between the second and third mirrors, one on the gantry and one on the head?

That I know of…I thought they had the lens itself enclosed, but I haven’t taken the head off and checked by turning it over.

(Haven’t cleaned that part. Actually hoping to get one of the lens removal tools before I try it.)

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As far as I know - only one of the PRU users received that tool. I wonder if the PU recipients will get one (or have an option to get one?)

Might be later…:relaxed:
(Supplies will go out to the actual Production people first, i imagine. These are not technically our machines, and they might want to see how long they can go before they crud up.)

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