I designed this key cap when I was working on my custom 15-Key Macro Keyboard project. The file has support included in the form of a brim on the center post as well as around the edge of the key cap. I've printed 50 of these at at time without a failure. Turn off automatic supports when printing this key cap.

These key caps come off the build plate pretty clean. I use glue stick and a sheet of glass, though any print surface that is working for you should be fine. The brims should pull off easily, then the key caps also benefit from light sanding on the top edges. The key caps in the pictures had not been fully sanded yet.

I print these at a 0.1mm layer height 3 perimeters and 90% infill.

Adjust how large the model is in slight increments in your slicer to tailor how tightly the key caps hold onto the stem of your switches.

Enjoy!