I printed this bin out of PETG so it would be able to hold up to the elements and the composting process. The bin is completely modular, and you can print whichever bins you feel like would be best for your application. I have included a bin with large openings, one with medium openings, one with fine openings, and a bin with an enclosed bottom for catching liquid from the compost. The lid has small holes for ventilation. My setup is configured as follows (from top to bottom):

1. Bin with large openings- For fresh scraps.
2. Bin with medium opening- For scraps that have been decomposing/composting, some dirt/worm bedding, and worms.
3. Bin with fine openings- For compost, worm bedding, and worms.
4. Closed bottom bin- To catch liquid

When printing the bin with fine openings, if you're having trouble with adhesion during the first layer slow your initial layer speed down.