Material thickness error issue

I’ve been cutting face shields for ICU nurses in our local hospital and hit a snag yesterday. Suddenly my GF Pro started giving me a Materials Thickness Error every time I start a print. I’m cutting .020 acrylic and have been using uncertified materials settings for the past week without issue.
I have logged out, cleaned and rebooted everything but still getting the error message this morning.
I can use auto focus and it works but the cut only takes 28 seconds however with all the scanning it takes 3-5 minutes using auto focus.
Help please! I’ve 210 more to cut and get to our nurses!


I’m sorry you ran into trouble when trying to set up and run your print. I extracted the logs from your failed prints today, and it looks like the red dot your print head uses to measure the material height may have gone through a transparent material or missed the material.

Is the material you’re printing on unmasked, or have a fairly transparent masking material? If so, something you could try would be to place a small piece of masking tape on your material in an area you aren’t printing on, and then use Set Focus to target the masking tape so your unit can get an accurate measurement of the material height.

Use Set Focus and place the focus area on the masked area, so it’s not near an edge. Then watch to make sure the red dot hits the material. Will you please let us know if this helps get you back up and running?

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I wasn’t using or wanting to use Set Focus. I told it material thickness .020 and it was working fine but now Set Material thickness is greyed out and not editable.
For speed I’d rather just tell GF the thickness but that doesn’t seem to be doable now?

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Is there some way to turn off autofocus? It is not needed and is adding a lot of time to this project?

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A bit of masking tape even where you are not cutting makes a better landing place than the clear material and thus a lot faster.

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I’m sorry for the ongoing trouble. In order to look into this further for you, will you please share a screenshot showing what you see in the Glowforge App when you’re unable to input the material thickness?

Please make sure to include the rulers in your screenshot and show as much of the bed as possible.

To take a screenshot:

  • Mac: Press Shift-Command-4 and click and drag a box around your image. You’ll find the screenshot file saved on your desktop.
  • Windows: Click on the Start Menu and type “snipping tool”. Open the Snipping Tool > New then click and drag a box around your image. Click the Save icon and name and save your file.

Thanks for your ongoing concern for my issue. I think it’s mainly my internet connection. I’m in a rural area with really poor service. It is working better today.
Thanks again.

Thank you for the update. I’m sorry to hear that you’re running into challenges with your internet connection. It’s good to hear that you’ve been able to get back up and printing as expected! I’m going to close this thread. If you run into trouble again, or have any questions, please post a new topic here on the forum or email us at and we’ll be happy to help.