Thickness Error

Hi, I seem to have a problem printing. The error screenshot is attached.
The laser cant focus on the material. It is cardstock lying flat on the tray. Nothing is propping it up or changing the height. In fact right before this error, I cut another layer with the same dimensions without any problems. I put the cardstock for the next layer and this error shows up.

I have cleaned the printer head with alcohol wipe.
I have restarted the machine.

Not sure what else I can do at this point. Any help is much appreciated. Thanks.

I need to get this fixed ASAP as i have a deadline for a project. Thanks.

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I think I’ve read on the forum that very thin material, like card stock, can cause focusing problems. Could you place something beneath the card stock, like a piece of 1/8" cardboard to increase the height a bit?


OK, thanks, I can try that but I have been cutting card stock of different weights for so many of my projects with out any issues so far. But I will try your suggestion, may help. Thanks.

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You can try using the set focus tool on another section of the material, or you can enter the actual thickness of your cardstock - assuming that you have accurate calipers.


I cleaned the printer head/Left laser window and calibrated the machine. My calibration seems to be a but off but I am not sure how it compares with others (Attached screenshot).

When I use 1/8 material there is no thickness error. However, with the cardstock I still see the error. I tried to manually input the measurement using a caliper but still it is giving me the same error. My understanding of the 0.5 inch thickness limit it that it is the maximum thickness not the minimum. I read on the form that people have cut toilet paper/fabric with it.

Not sure what is happening here. But another user seems to be having a thickness error in the past hour. Could it be due to a software issue/update?

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Cardstock is pretty close to the limit for focusing…it’s super thin. I’d second the recommendation to tape or affix the cardstock to something to anchor it and raise it a bit higher. But I wouldn’t use cardboard, that’s too flammable. A very flat sheet of scrap plywood would work fine, or you could buy one of the Seklema mats that are created for exactly this purpose in lasers. They hold the cardstock, and raise them slightly. They also keep flashback from hitting the back of the card. (If you are doing a lot of them, it’s worth the purchase price just from an ease of use standpoint.)

For now though, just taping it to a sheet of plywood should solve the problem.


Thank you, can I raise the whole honeycomb bed using 1/8 draft board below the tray? Flashback being the main reason.

How is it that this has never happened to me before. I have been cutting/engraving cardstock, from 60 lb to 110lb, more than 40 times now and only today it becomes an issue?

Flashback will be lessened if you cut off the source of air underneath the paper…so putting the plywood on the tray to block it would be the way to go. (Also, I’m not sure it’s a good idea to raise the tray any higher, it’s wider than the material on top and the sides of the tray might hit the laser arm, bouncing it out of alignment. Better not try that.)

As to why it’s having trouble focusing now? You might need to clean the two tiny round windows on the bottom of the head. (Either side of the lens opening.) That’s also something to check. When they get dirty, it diffuses the beam.

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I cleaned them before calibration but may be they are not clean enough. Thank you.

How transmissive the paper is might make a difference, that might explain why one sheet works while another does not. I don’t expect the rangefinder needs a lot of light to be reflected, so I’d kind of expect anything that isn’t completely transparent to work. But I don’t know, maybe some paper is more translucent at low frequencies like the red laser used for focus… Try stacking a second sheet under the first, not to cut, but to confirm if that makes a difference.


The paper is thick cardstock, cream or dark blue, 0.01 inches thick. I assume there would be minimal transmission of the laser beam thru the card stocks. I could cut Chipboard, 0.02 inches in thickness and it works well, no issues in focusing.

Just for my understanding, aren’t the use of the Seklema mat/vacuum hold-downs, more for flyaways rather than increasing the thickness of the cut material per se? The rangefinder should be able to autofocus between 0.5 - 2 inches (without the tray), correct? Am I missing something here, may be all dumb questions :slight_smile:?

I was engrave a slate tray, could the laser bouncing back have damaged the range finder in some way? 50 min run time with 950 speed and 40 power.

No, that should be fine. Lots of people engrave on slate. (Just don’t look at it…hurts.) :grinning_face_with_smiling_eyes:

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Hi @Yogi_Bear. I’m sorry to hear that you ran in to some trouble with your the focuser during recent prints. i see that fellow users have given some great advice in terms of trying to check the bottom of the printer head to ensure no debris is covering the focus windows, as well as trying to raise the material slight in order to help the focuser gauge the material thickness. Since this is not a supported Proofgrade material being used for prints, I’d like to go ahead and move this to the Beyond the Manual section of our Community to allow the discussion to continue. If you run into any trouble with the focuser or results of prints on any Proofgrade material, feel free to create a new thread, or write us at, and we’ll be happy to help. Thank you!

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