How do you know when the print head lens needs to be replaced

Consistent problems with cutting. How do you know when the lens on the print head needs to be replaced? How long do they last?

They should last forever presuming you haven’t set it on fire, or scratched it, or done other damage. Mine is on year 3+ and doing just fine.

More commonly issues with cutting means you’re missing one of the other lenses that need to be cleaned. There are 6 total lens/mirror/glass that need to be cleaned regularly - are you hitting all of them?

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OK. thanks! I built a 45D ramp and tested the kerf on the angle. Surface of the workpiece cut is thick and barely cuts through the 0.118MDF. I need settings at 130/full set the automatic focus and go. Burns the WOW on the surface of the material and barely makes it through the board. Happens on all boards, MDF, acrylic, BBirch. It’s repulsive.

GF so far, no response.

That looks like your lens is in upside down - but it’s hard to tell at the angle. When the head is in place the cup of the lens should be up.

Cut a Gift of Good Measure (in your dashboard) on the spare piece of draftboard they sent - are you having the same issues with known good art?

If this means you also sent them an email then you would have received an instantaneous auto-response. If you didn’t either your email didn’t make it to them, or theirs didn’t make it to you. Check your spam folder and add to your whitelist. If yours didn’t make it to them, then posting here will let them know there is an issue with email. They generally respond with something beyond the auto-response within one business day.

Posting a duplicate entry here slows down their response as they’ll have to close this one before they respond to your email. In the future just post here if you also want community input :slight_smile:


Nope. Pulled it, checked it. Not in upside down. Wish it was. I’d be done with this turd.

Just to be clear, you are cutting an angled piece of material without a flat surface for the laser to focus on, correct?

If so, the results you are getting are exactly what I would expect as the laser does not change focus dynamically. It looks like the narrow part of the cut is where the focus ended up and what you are seeing is the hourglass shape of the beam. The kerf is changing because the beam isn’t a straight beam, it has a focus point and the wider parts of the beam can’t concentrate the energy like the focus point does.

You are also cutting at an angle so you have approximately 30% more material to get through, so you will need more power or slower speed.


You’re not going to get an even cut if the material is angled. It needs to be flat. (horizontal)


Trying to cut on an angle is itself a major problem. As you can easily see on your material an hourglass shape reflects the shape of the laser beam as it focuses to a point and is unfocused above and below. There are a number of issues having nothing to do with the lens that can also occur.


This is a fairly common tactic for figuring out the sweet spot on other lasers with manual focus, so you can either calibrate the bed, and/or calibrate the focus tool, but going to have a tough time utilizing the test on a Glowforge since there isn’t really anything to calibrate and the exact spot it took focus measurement at is going to be a tough guess at best.


The purpose of cutting at this angle helps me confirm that when the Set Focus is selected on a platform of specific height, I can confirm the sweet spot of laser focus is correct. The example from above shows the narrowing of the beam from the Cone above and below the focal point. My sweet spot though, it too fat and looks lopsided when magnified.

That test is exaggerated by the power and speed. It’s really meant to be ran at a lower power. At 130 speed you are cutting at 15.5 inches per minute/just over a quarter inch per second — even at a perfect focal distance it’s not going to be pretty just because of the speed and power creating a large heat affected zone.

As for the set focus, that box is a general area - that’s what, a square inch or so or maybe more? It doesn’t decrease the area by zooming in even if it looks like it. Mine was always down and left in the box.


HI @jbmanning5. I just sent a response to your original Community thread opened, and email ticket regarding this issue in the thread below:

To avoid any potential confusion or miscommunications that can result in delays, I am going to close this thread, and continue any troubleshooting through there. Thank you!