I have not cleaned my lens yet. Is this hurting my unit?

I have the pro, I use in my classroom, and we just are really using this. I have yet to clean the lens. I thought that the only thing a dirt lens would do would be effecting the accuracy.

Anything wrong with letting this go? I am surprised its holding up so well, I use it a lot for the classroom. over 500 students a year!

I think it is always a good idea to follow the stated maintenance practices for a tool. Cleaning the lens is not a difficult process.

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There is a lot of things, from burning more than cutting, to burning the dirt on the lens and damaging the lens permenantly.

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Yes. You should always follow known recommendations for keeping machinery clean. In this case it’s every 40 hours of use. For some of us that’s once a year. For you it might be once every 2 weeks. You’ll have to track your own use-hours since Glowforge doesn’t tell you.

See below for details:

If the optics get dirty, it will no longer cut thru material, so if it’s still working fine, you’re good there.

The biggest concern would be how clogged up the fans are, especially the exhaust fan. A visual inspection is a good idea and, if it needs cleaning, take care of it as soon as you can.

The small air-assist fan on the head itself is also something to pay attention to, but not as frequently as the exhaust fan.

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Yes, you need to clean the lenses and camera & fans. The period between cleanings will vary by the material you use. Draft board is super messy and will clog up the fans really fast. Acrylics may not be as dusty, but sometimes you can get deposits of the acrylic back on the lens.

The first thing I notice is loss of effective power if the lens is not clean. And worse will happen if you don’t clean.

And if the camera is dirty, you won’t be able to see the bed clearly–it will look darker and blurry.

All elements of the laser system can be affected, and as others noted, can lead to damage to your machine and have expensive consquences.

If you’re not cleaning the inside of the unit, not only are the lenses affected, but the exhaust fan can also get clogged up, and this has a dramatic impact on the performance. Debris falling through the crumb tray needs to be cleaned up as it could impact the airflow and exhaust.

And since this is in a classroom, you have a great opportunity to teach your students that it’s important to take care of their tools to ensure they are always ready for use and maximize their life. And you can do a lesson on how a laser works and why it’s important the mirrors are clean!


First rule in lasers is keep your optics clean. The wavelength of infrared is just light until it touches something, then it’s heat. Dirt on the lens hinders transmission, and If the energy isn’t transmitted it’s deposited - it can burn the lens.

I sure wish my school had lasers! :sunglasses:


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I see that you’ve already received some good information from our other community members. Thanks folks!

Are you having any issue with print results or material not cutting through? Below is some general information about operation as well as steps for cleaning your unit’s optics.

To cut successfully, there are three important things to check. First, your material must lie flat. This requires a clean, properly installed crumb tray and flat materials. Second, there must be no obstructions, dirt, or damage preventing the laser light from reaching your material. Third, your design must be set up properly - for example, with lines that are fully on the material and that are set to cut. It’s hard to know which issue might be affecting your print, so please thoroughly inspect your unit and design according to the suggestions below.

Crumb Tray mispositioned or holding particles

If the Crumb tray is mispositioned or holding bits of material from packaging or printing, it could keep your material from lying flat. Even a millimeter difference in height could affect your laser’s ability to cut.

  1. To remove the crumb tray, lift the lid, then swing down the front door. Lift the crumb tray slightly and slide it towards you to remove it. Be careful not to tilt the crumb tray up, or it will knock into the printer head and rails.
  2. Remove all dust and debris from the bottom of your Glowforge.
  3. There are four dimples for the feet of the crumb tray to sit in. Wipe them with a damp tissue or cloth.
  4. There is a slot in front of the crumb tray, under the handle. Point it towards a garbage and shake the tray so that debris falls out. If debris is stuck in the honeycomb, gently push it out. Debris can force the honeycomb to be uneven, or prevent your material from resting flat against the honeycomb.
  5. Replace the tray. Make sure that it’s facing the right direction and that the tray’s four feet drop into the small dimples. When the four feet drop into place, the tray will no longer slide freely.

Material not lying flat

Even when the Crumb Tray is clean and flat, the material may not be lying flat on the surface. Some materials can develop a curve (called ‘warp’), and warped material may not cut through consistently. The problem is especially likely to occur if the print is large.

  • Soft materials, like Proofgrade leather may need to be smoothed into place. Any lumps or bumps will affect the print quality.
  • Read our troubleshooter on warped material for ideas on how to take care of your materials.

Lens or Windows are Dirty or Damaged

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.

1. 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.
2. 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.

3. 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.

4. Replace Printer Head
Review instructions for snapping in your printer head, then put the head back on.

5. 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, write support.
  • Otherwise, wipe the window clean with a Zeiss wipe.

Once you’ve inspected and cleaned, please try another print. We included an extra piece of Proofgrade Draftboard with your materials shipment for troubleshooting. Please print the Gift of Good Measure on Proofgrade Draftboard and let us know the result. If it doesn’t print well, please let us know the date and time of your print and send photos of the front and back of the print.

Please let us know if you’re having any issue with your print results. Thank you!


It’s been a little while since I’ve seen any replies on this thread so I’m going to close it. If you still need help with this please either start a new thread or email support@glowforge.com.