My $.02 contribution: .025" white PETG shim stock from McMaster Carr … cut at 200/50/1 pass (GF Pro) gets the features done, but takes a final manual tug/tear to set the part free from the sheet. It also ends up with yellow edges and streaks of black smoke on the top side, downwind of any concentrated features. So not perfect, but it gets the prototype done.
I, too, have had clear .020" PETG cut by Big Blue Saw, and it was totally clean. A nice thing about PETG in thin sheets is it can be bent on a sheet metal brake, so it works well for prototyping or for applications that want bent forms.
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I used the updated settings and it worked perfectly the first time. We are donating face shields to the Coronavirus cause to get enough for Medical and Dental professionals.
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I wonder if you could get better results if you put the PETG in the freezer before? Kinda silly but it could possibly reduce heat buildup a bit and help with some defects? I doubt it but could be neat to try.
I am cutting 0.030 inch sheet PETG, to make the Prusa Face Masks https://www.prusaprinters.org/prints/25857 and speed 250 power 100 1 pass is working perfectly.
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That is good to hear. Would you be willing to do a small test on scrap?
One of the things I want to do with this material is make shaker tops for Mason jars-- that means lots of little holes. When I tested this on 0.060" material it was a melted mess.
If you could cut a small part of the of that pattern, it would be very illuminating. This piece is about 1.3" x 1.3".
If you are game, here’s a vector file.
jar_shaker_top_test holes.pdf (285.8 KB)
Any chance you have a svg template for prusa masks that you could share?
I got good results cutting PETG sheets with 1.0 mm with this settings:
Speed: 300;
Power: 90;
Pass: 2;
Focus: 0.5 mm
The file they provide is a DXF, which took some effort to convert correctly to SVG (Illustrator and online converter failed, had to use Fusion360) 
This cuts on the GF fine.
I didn’t try your file, but the Prusa face shield has quite a few holes less than a quarter inch across and they all cut just fine with the settings I posted, so I wouldn’t expect your slightly smaller holes to have trouble.
hi, i’m also trying to make face shields to donate - i tried the .06 and it seems a bit too thick - is that what you are using?
I’ve used 0.030. The Prusa design can work up to 0.040, or as thin as 0.020.
Thank you! Any idea where I can find it - everywhere I’ve looked online is sold out.
Would it be possible for you to provide the SVG file you were able to convert? I have been asked to participate in manufacturing these masks for my local hospital. I have teamed up with a company that is doing the 3D printing, but I can’t seem to get the file to convert properly. Thanks in advance!
It’s in their post:
Whoops! I totally missed that. Thanks for looking out!
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I used the .06" on the first few. It cut just fine and fit the headband part of the shield but the little piece you grip on the bottom wouldn’t go on. I did change to the .03" thickness and that works great.
Here is the Prusa Face Shield RC3 in a glowforge-friendly format:
I had luck cutting 0.02" PETG on my Pro machine with 375 speed at full power.
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I’m laser cutting some PETG from a local hackerspace to help with the face shields as well and I’d love to know more about your setup. Are you placing the sheets directly on the crumb tray or on a piece of draftboard? Are you cutting one at a time or multiple? Would love some advice so I can help contribute to the cause!
I tried printing my 0.020" PETG sheet from ProfessionalPlastics with the 250 speed, 100 power, and 1 pass and this is what I got:
Any suggestions on how to get rid of the color striations? I’ve tried it with the plastic attached (didn’t work, just created a ton of fumes and fused the plastic covering to the PETG) and without the plastic attached, and neither has worked.
Like everyone here, I hope that I can get my issue resolved as I’ve got hundreds of these face shields waiting to be shipped to some hospitals in need here in NY. Thank you all!