Thanks for taking the time to run these tests and provide the photos. I’ve let the team know and we’re looking into it now.
Your Glowforge unit’s laser is powerful, yet it can be stopped by a tiny amount of dirt or damage to the lens or windows. If something gets between the laser light and your materials, they won’t cut through. Here’s how to check for damage and clean your lens and windows at the same time.
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Remove printer head
Turn off your Glowforge. Grasp the printer head as shown, and pull gently up and back to disengage the magnets and remove it.
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Remove lens and check for scratches or dirt.
Gently insert the lens tool into bottom of the head with the “Remove” arrow pointing in. When you hear the magnet click, withdraw the tool and the lens.
Look at the lens on the tool. It should be resting on top of the tool like a bowl, with the top open and with the orange-colored optics on the bottom. If it’s upside down, it won’t work properly.
Gently slide the lens off the lens tool. Be careful to touch only the metal ring to avoid fingerprints on the lens.

Check the lens for fingerprints, dirt or scratches. If you see a scratch, you can order a new one at shop.glowforge.com.
Wipe both sides with a Zeiss lens wipe.
- Put the Lens Back In
If the lens appears clean, you can put it back.
Flip the lens tool until the “Install” arrow points up.
Set the lens down on the lens tool. The open side goes away from the blue plastic, so it looks like a bowl on top of the tool.
Slide the lens tool up into the printer head until the magnet clicks, then remove the tool.

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Replace Printer Head
Review instructions for snapping in your printer head, then put the head back on.
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Inspect the Head Window and the Laser Window
Check the windows for damage. You can find one window on the left side of the printer head, and another just over the left rail. Shining a bright flashlight at an angle onto the window may help you to see more clearly.
If you see damage, let us know.
Otherwise, wipe the window clean with a Zeiss wipe.
Once you’ve inspected and cleaned, could you please run a print? Also, could you try printing on another material, such as Hardwood, and let me know if the same problem occurs?