Anyone have any suggestions as to why after a thorough cleaning, the GF won't cut through matierial that it had just a day before?

After a one minute cut, the the laser no longer cuts through an 1/8 inch piece of acrylic. I can gently take the laser head off of the tray and with a lens wipe I can push the lens back up into the laser head unit so it re-seats where the magnet use to hold it in place. The lens drops over a 1/4" while cutting.

This is on a Pro series and the unit is not even a year old. I do thorough cleanings on the printer every 30 to 35 hrs of cutting time.

Ridiculous for a $6,000.00 piece of equipment. And now lost time and materials to get orders out to my customers. Unacceptable!

And the Support line just has you leave a message and they will get to you when they can.

No, not in many years of ownership.

I believe you just have a mistaken mental model of what’s going on.

The lens magnetically attaches to a platform that floats – it moves up and down up to half of an inch. That’s how the laser beam is focused on material between 0" and 0.5" above the crumb tray – by moving the lens up and down that amount.

A small motor in the print head controls this movement when the machine is turned on, but when it’s off, you can freely move the platform up and down and you can feel that when inserting the lens. The first thing the Glowforge does after turning on is calibrate this mechanism by moving the platform up and down through its full range of motion several times. You can hear a clicking noise coming from the print head when it does that. You’ll hear it again after every print job, as it calibrates again between jobs.

You would not expect the lens to be “all the way in” after you use the machine, because that would be the position needed to focus on 1/2" thick material. To focus on 1/8" thick material, it’ll be dropped about 3/8" of an inch from its topmost range of motion. It is completely normal for the lens to have “dropped” compared to where you pushed it in when inserting.

There’s also no need to push it in that far, it’s not going to stay where you put it, since it’ll be moved as soon as the machine is turned on.


Stop pushing your lens around. It’s supposed to move up and down, that’s how it focuses.


Thank you Dan84, that makes sense. You are correct, I thought that since the lens pulls itself in to the head after cleaning the lens, it was meant to stay in place there. My mistake, now I can try to figure out why after a thorough cleaning I can’t cut 1/8" acrylic for a cut time of more than a minute.

It makes no sense how it cut fine one day, and then the next the same material with the same settings won’t cut clean.

Thank you for the information.

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I have that problem every few hours, and it’s just because I cut lots of 1/4" MDF and the optics get dirty that fast. As soon as the mirror in particular gets cloudy, my cuts don’t go through all the way any more. Cleaning the 7 optical bits and the air assist fan brings it back to normal.


As you now know, you are not getting poor results because of a sub par magnet.
If material does not cut as expected there are several things to consider. Perhaps your side windows are not clean. Perhaps you have a blemish on the mirror. Perhaps your material is not held flat. Perhaps your settings are incorrect. Perhaps it is the material.


Thank you Dan! I clean the entire inside when I do the maintenance on the GF. I clean the camera lens, the lens on the inside left of the unit, the side lens on the laser head, and the mirror.

I do need to get some compressed air I guess, to clean out the smaller fans in the unit from what you are recommending. Thank you again!

Yes, the magnet issue has been clarified. But I do a very thorough cleaning of the unit. I inspect the mirror and the lenses every time I clean the unit.

I have also been cutting the same acrylic material for months without issue. The settings are for proof grade materials. Nothing has changed for the settings or the material in months.

I am going to try blowing out the fans to make sure the airflow is what it needs to be.

Cleaning optics is generally helpful more often than “thorough cleaning”. There’s very little reason to “thorough clean” on a regular basis, it’s not recommended in the manual and dirty looking inside GF doesn’t affect it’s operation. Optics on the other hand are critical - many people clean the optics every day or multiple times a day if they’re heavy users. It’s the first and usually best solution to cuts not going through.


If you have never properly cleaned the air assist fan, you definitely are not doing a thorough job of maintaining the machine. Have you cleaned the exhaust fan? Simply blowing compressed air into your air assist fan is not going to help if you have residue built up. You will need to remove the fan hood and clean the fan blades.


Sometimes people accidentally put the lens in upside down after cleaning. Worth double checking.


That was my first thought from the description. You want to make sure it is “cup side up”. :slightly_smiling_face:

after a thorough cleaning, the GF won’t…

Wow. If I had a dollar for every time a post started with this.


In my case you would have a dollar

Thank you Chris, I did confirm and reconfirm the lens is in with the arrow pointing up. Cup side up.

I clean the fans roughly every third time I clean the optics. The fans have been cleaned prior.

Yeah and many more from the numerous times someone starts a post with those words. Unfortunately the machine is quite fragile and over zealous cleaning can sometimes do more damage than good. I hope you find a simple solution to your problem.


The mechanism that moves the lens is quite delicate and can be easily broken when re-installing the lens.

I have no idea if that’s what happened here.

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