Some days ago, my very old cap broke into pieces, so I started designing a replacement one.

Differently from what I found online, this model can be printed without support directly in the direction you import it in the slicer. In this way you are able to get a very smooth top part, reducing the layer thickness as much as you want.

The first layer is composed by at least 2 walls, which will ensure a great adhesion.

I would suggest to use as many walls as possible in order to avoid infill. The print itself is so small it wouldn’t waste much more material.

The only printing tip is to use a minimum layer time of around 10 seconds, because any higher speed could result in distortion due insufficient cooling.

This model is designed so that it directly fits onto the pen with a pretty good grip, but loosing the magnetic mating of the original one. If the tolerance are too loose or too tight for your printer, you can play with the “hole horizontal expansion”  (in Cura) or equivalent in other slicers in order to correct for this.

UPDATE: Even if the original model matches the dimensions of the actual cap, I added 2 new models, which are identical, but shorter (respectively of 0.5mm and 1mm) in order to have a better fit into some covers without risking to damage the tip.