This is a modular mesh/ screen for sieving.

The modularity allows you to print the main body and the collecting bowl only once. The modular screen- inserts are very lightweight and easy to store so you can print alot of different sizes. I made it for vermicomposting to separate worm castings but it will work for all kinds of sieving-purposes.
Because of the honeycomb shape it will have appr. 30% more openings per area compared to a rectangular stainless steel mesh of the same grid.

Adjust the mesh size and geometry to your liking by changing the infill pattern or density in the modifier-object in the slicer. You can also test a custom mesh size by printing the infill tester file.

For vermicomposting its best to use 6mm (1/4') (12% infill) and 3mm (1/8') meshes (20%infill). 
For particles of ≤ 3mm I recommend the thin screen (1.5mm thick) to make clogging less likely. 
For particles > 3mm I recommend the thick screen (3mm thick). 

I already optimized everything in the project-files.
If you want to DIY with the Step-Files: Use the "screen" file together with the "modifier" file, deactivate top and bottom surfaces and maximize infill anchor in the modifier file.