With the colder weather here, I needed a way to attach some lexan to my makerbot to keep some of the heat in. Here are some simple little clips I made that slide onto the plywood and will hold a piece of plexi or lexan. You can probably get away with using 3 per side but I ended up using 6.

The scad file is easily modified to adjust the thickness of the wood or the plastic.

It's currently set up for a plastic panel that is about 2.5mm thick (3/32" maybe?) It's just what I had laying around in my basement.

Print out the clips, clip them onto the sides and bottom of the opening. Slide the panel in.