Black, Proofgrade acrylic, not cut through on default settings

Print today, about 11:38 am eastern time.

I was using proofgrade black acrylic. I made sure it was flat to start, and I used default settings from Glowforge. I believe it was near center-top of the bed. As you can see, it did not always cut through the masking, but also not always through the acrylic. When clearing out the cutouts. some of the pieces had more structural strength than actual structural parts, leading to the piece cracking.

Looks like Proofgrade settings may need some tweaking.

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Far as last time I used them, the settings are fine.

But I did have one time, just over a year ago, where my :proofgrade: Thick Black Acrylic didn’t cut through. Gosh that was disappointing. It was just a fluke though… The next run went fine. And Support was kind enough to credit me for the ruined sheet.


You probably already thought of it, but didn’t mention it so I feel compelled to ask…had you cleaned lenses, etc. recently? :wink:

FWIW, I cut a bunch of acrylic last night and it all cut fine. Sorry you’re having trouble though.

Cleaned it all last night to be sure. Tried some cutting today and got mixed results again.

Thank you so much for the details. I’m looking into it now. As soon as I have more information I’ll update this thread.

Are you still experiencing this issue with other pieces of Proofgrade?

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
  • 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.

Thank you!

I did a full cleaning, confirmed flat, and still have the same problem with both black and clear proofgrade acrylic not cutting completely through. Most recent is the clear, pretty much every print on 12/4/2018. Cut lines required more than one pass on proofgrade settings to cut.

For our troubleshooting purposes, it’s helpful to have the results of the Gift of Good Measure design. Now that you’ve cleaned your Glowforge, can you 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 and send photos of the front and back of the print.

Sorry about the delay:

Edit: Prints 12/7/2018, 2:45pm, 2:55pm, and around 3:30pm.

So I did the Gift of Good Measure on Proofgrade draftboard.

As you can see, it didn’t quite go through all the masking, but no wood was clinging. It popped out pretty easily. I followed this with the same burn on proofgrade black acrylic, where I was having trouble before. It cut so cleanly that it fell out of the acrylic sheet when I went to lift it from the bed.

Figuring “Go big or go home”, I finally tried to burn the Desktop Tool Carousel, which I’ve only been meaning to make since I first saw it. I placed the Proofgrade draftboard back in, and ran it with all default settings. The results, shown below, show how it isn’t being consistent in going through, some burned so poorly that a piece broke or peeled part of the board punching it out.

Before any of these burns, I made sure the honeycomb was properly seated, and that the board was completely flat to the honeycomb.

Thanks for following up with those results. Unfortunately, it looks like your unit is experiencing an issue that we can’t resolve remotely. I want you to have a reliable unit, so I’m recommending we replace this one. I’ll be in touch via email to sort out the details. I’m so sorry about the bad news.