Thank you all for the clarification.
As to what I’m trying to do - I have some larval peppermint shrimp, their food is newly hatched brine shrimp, which are a couple of hundred microns in size, and I need to be able to flow water out of their tank whilst retaining the food. To do this I need a (relatively) large surface area of many tiny holes, otherwise the food gets sucked against the holes. Twice a day, the sieves are removed and cleaned, and replaced temporarily with a sieve of larger holes, large enough for the old food to pass through whilst retaining the peppermint shrimp larvae, then new food is added. It is this constant removal, cleaning and replacement that means a mesh stuck to something doesn’t work, eventually if always gets a tiny hole, big enough for the brine shrimp or peppermints to go through.
So what I’m creating is this
but I need to cover the four sides and bottom with 150 micron holes.
From your responses, I think square holes are going to be more practical than round ones. As to the possibility of printing, the printer I’m looking at says it has a resolution of 80 microns, am I misunderstanding what they mean by this, will it not be able to produce such fine detail?
I’m currently creating the hollow square box by pulling up a rectangle into a solid, then creating an offset and pushing it back down, this won’t work with the hole creating methods described above, I guess I need to create each side individually then find a way of putting them together?