Edit 17-07-23: Can Cap V3 (sleek and regular beer cans)
Just posted a new version that fits better on the can, this version does needs minimal supports.

For this new version, the cap fits all the way around the can.

Printing details:
Quality: 0.20mm 
Infill: 100%
Speed: theres small details so 30-40mm/s would be great, did work at 60mm/s.
Print flat side on the bed, with minimal support. The flap will print upwards and need to be flipped back on the right side of the cap after it finished printing.

NOTE: since every can can be slightly different I suggest to play with the scaling tool. changing it with +/- 1-2% so you can find the perfect fit for your kind of cans.

Edit 16-07-23:
while i design some better fitting caps for different cans. 
For sleek size can i find printing at 99-98% scale better fitting.

Edit 30-06-2023:
I made a second version with a hinge opening so you can keep the cap on and still drink. 
(Can cap V2.stl)

I used the same print settings with PLA and got good results! When finished printing wiggle it gently to break off the printed in place hinge.

Original post:
Made this simple can cap to protect your drinks when drinking outside.
I wanted to protect my drinks from bugs during summer while unatended.

Print details:
Material: PLA (didnt try in TPU or PETG, but would probably work well)
Quality: 0.20mm 
Infill: 100%
Speed: theres small details so 30-40mm/s would be great, did work at 60mm/s.
Print flat side on the bed, no support.