U1 LID

I used Polymaker HT-PLA-GF (standard profile) with 6 walls and GYROID infill for the frame. Cut it to fit your plate. 4 equal corners will fit on the U1 plate. I was able to fit 3 large parts and a small rear pie shaped piece on my Prusa XL. The dome is 1/8" (3.18mm) Acrylic that is glued down in a 1/8" slot all around the frame. It can also be made using all flat parts glued together. Bending the Acrylic like shown takes a lot of heat and patience. Small hardware store hinges on the back lets it tilt up to let heat out. Or 3D print some. The lid cuts down on the fan noises by half at least.

I added a picture (.jpeg) showing the dimensions for using all flat parts. I would reccomend making them in cardboard first, test fit to frame and then just trace around each piece onto the clear 1/8" plastic. Use some thick glue to fill small gaps.