How to change material thicknerss

Did you try entering the equivalent mm value in inches? Inches is the default measurement unless you change it in the Settings area.

I am currently set to enter in ‘cm’. I often switch between ‘cm’ and ‘in’ in GF and then enter values using a ‘mm’ over ride. I never enter values in centimeters, actually do they really mean ‘cm’?

In any case, right now I can’t enter anything in the Material Thickness or Focus Height fields, they don’t accept any entries.


I am trying to design an element in a plexiglass model. I need to print 10 stacks of 20. Right now I am trying to get the element shape right with a paper model before I start to waste plexiglass. That’s why I am messing around with so much paper,


That might be your problem right there…set the focus on the material you plan to cut, not the paper. If they are not the same thickness when you set the focus, you will get an error. Every time. The thickness of the materials has to be the same.

Close the file by backing out to the Dashboard, then open it again. Open the lid and place in your material (not the paper) and then use Set Focus on the material to enter the correct thickness information.

Put a piece of white tape over the plexiglass if it is transparent and does not have a masking on it. Take the Focus measurement on that tape. The laser beam cannot focus on clear (transparent) materials.

I’m not doing plexi yet. but I had not thought if that. All of my plexi is looted from old LED computer monitors and doesnt have protective paper on it.

Right now, the material I am cutting on is paper, it’s supposed to be Cardstock, about 53lb and light brown.

It’s started working again. When I have problems again, I will try the procedures in the 2nd paragraph in the order listed and see if that helps. I will let you know.


What the laser does when it takes a height reading is shoot a tiny red dot onto the surface for a fraction of a second. The dot has to be visible, so darker or transparent materials can cause the dot to not be seen. It also happens if you are trying to take a reading on something that has a lot of cutouts in it or if it is very thin…the dot can miss the material.

So if you find yourself having issues, try a light colored masking or a sheet of white paper on top of the material when you take the reading. (Then remove it before cutting, or tape it down so it doesn’t shift.)

It’s why the Glowforge materials come pre-masked with a white masking tape.

I’ve had that issue a half dozen times in the past couple of weeks. The only way I can get it to resolve every time is to reboot the PC and then power cycle the GF then start the app. Sometimes just restarting the machine or shutting down the browser works but not every time.

I tried the procedures in the 2nd paragraph and they didn’t help. I also tried rebooting everything like @ jamesdhatch suggested and that didnt help either.

I did experience a problem with the focus pointer falling into a hole on the page so now I know what to look for.

Most of this evening has been spent cutting 3.5mm hard board and when everything came out OK, 20 of 200 pieces of 6mm plexiglass. I need to cut bright white 65lb card stock separators and that is what is causing the problem now.

No matter what I do, I can’t get past the material thickness error. The sheet I am cutting from is unblemished 8" by 11", so no holes, I am telling the GF UI to Set Focus in the middle of the page.

It’s 4:30am, good nite.

Sleep well.

P.S. @Jules I used painters tape when cutting the plexi as you suggested, it also protected the surface in most places. I noticed a few small areas and I don’t know if it was on the bottom or needed to be pressed down better.

I’m sorry about the ongoing trouble when trying to set up your prints and use Set Focus. As a next step, would you run a test print so that we can extract the logs from the test and take a closer look?

Here are the steps for the test:

  1. Turn your Glowforge on.
  2. We included an extra piece of Proofgrade Draftboard with your materials shipment for troubleshooting. Place the Proofgrade Draftboard in the center of the bed and print the Gift of Good Measure using the default settings.
  3. When the print finishes, leave the lid closed and wait until the fans stop and the picture updates. Without moving your artwork or your material, take a screenshot of the Workspace to show us the difference between the artwork placement and the actual print placement. Make sure to include the rulers in your screenshot and show as much of the bed as possible.
  • 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.
  1. Send us the screenshot along with the date and time of the print, and we’ll investigate.

Please let us know if you have any questions when setting up this test!

What happens if you put your cardstock on top of a sheet of something else? (Like 1/8” cheap plywood?)

It’s been a little while since I’ve seen any replies from the original poster 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