Corner mounts for posters that hold the poster in place via friction. That way the poster can later be removed from it's mount without having any cosmetic defects, or be swapped for another same sized poster with ease. The holders use magnets to hold the poster in place and command strips (small) to mount to the wall (other tape can be used provided it has similar dimensions).

Originally I loosely based this on the “Frameless Poster Frame” by @SirSeph on Printables. After some iterations only the original dimension remain. I've swapped the screw mounts for magnets hidden on the inside of the frame, added a lip to make it easier to fit the poster correctly and added cutouts for command strips on the back.

Materials needed (per poster)

32 6x2mm magnets (Aliexpress, or you may already have them from Gridfinity etc.)

8 command strips (small picture hanger)

optional - some cyanoacrylate glue to ensure the magnets stay in place for good

Assembly

Pressure fit the magnets into the top and bottom of the poster hangers, make sure to reverse polarity so they stick together. (I recommend using a pressure fitting jig such as this one to seat the magnets). Optionally add a tiny drop of cyanoacrylate based glue before fitting the magnet depending on the tolerances of both your printer and the magnets you have.

Add the command strips to the cutout in the back of the hangers with the pull tab oriented so it remains hidden behind the plastic.

Insert the poster into the bottom (big part) of the holder, make sure the corner of the poster touches the lip, place the top part onto it to have the poster fixed in place. Repeat for all 4 corners and mount to the wall using the command strips.

Thanks for reading and enjoy one of my first CAD designs - with love from the Netherlands, Matt.