my magnet/badge/button. 50mm diameter with hole for magnet on the back, 8x2 mm.

There are two badges in this file, one is empty for your content and one is mine as an example with my logo for the observatory…

I don't have AMS so:

after slicing, move the slider to layer 26, add a pause (by right click), so you can change the filament and print your content on top.

Insert magnet on the backside and fix it with a little drop of glue.

I used these

MAGXCENE 50 Stück Magnete Stark 8x2mm Neodym Magnete Extra Stark, Mini Magnete Flach Runde Kleine Magnete, Starke Magnete für Kühlschrank, Magnettafel, Whiteboard, Büro, Fotos, Basteln : Amazon.de: Bürobedarf & Schreibwaren