Circular strainer that can be used for whatever a strainer is used for. In my case, this is used as a permeable, friction-fit lid to keep textiles submerged when soaking in a bucket, which is why the cutouts (which double as handles) go down all the way to the strainer part.

Printed in white PETG using a 0.4 mm nozzle and 0.2 mm layers. The outside part has 100% infill, while the strainer part is 5% gyroid infill, giving both good rigidity and water permeability.

When slicing, the top and bottom layers must be removed from the strainer part. One way of accomplishing this is to set the amount of wall loops as required to fill the outer walls, then add a cylindrical modifier for the strainer part only, removing the top- and bottom layers. If you do this incorrectly, you run the risk of the thick walls ending at the topmost part of the strainer, followed by only a single outside wall, or having no top- or bottom layers on the walls. For obvious reasons, neither of those are desirable in a strainer.

The model was made using Freecad v0.20.2 and is parametrized so it can easily be customized to whatever measurements you need. The wall cutouts can be moved higher up if you need to pour something into it, as opposed to pushing down on something.