Here are coin return modules for R2-D2 and similar astromech droids. These are for use with 0.040 inch skins. I have aluminum skins, but they'd work fine on styrene or anything else. Use organic / tree supports as needed. They should print upside down (larger cutout area downward) to use the least amount of supports.

I found that there existed no publicly available, 3d-printable coin returns that fit in my aluminum skins. The 3D models on astromech.net are for attaching from the inside, and are pretty bulky. I need to be able to attach them to the inner skin from the outside with VHB tape or silicone sealant or some other adhesive. So I finally modeled some for myself. I've done my best to design these to CS:L aka CSL Legacy specs from astromech.net. The rear ones may not be the most spec-accurate, but I defy anyone to tell the difference from afar, especially when both rear coin returns are from this model. I added some thickness to the main structure so it will hopefully endure for a while, but I allowed space on all edges to allow for close mounting. I also have alternate versions with tabs and clips for snap-fit installation. You can and probably should still use some adhesive, but this should make things better. If nothing else, it was fun to do. Some extra manipulation and fine-tuning may be necessary to make them fit in your droid.

Feedback from actual prints and test fits are appreciated! If this works well, I may be persuaded to do CS:R as well--or of course feel free to remix, but don't sell any models based on these.

The rear models here are for the right side. For the left, simply mirror the rear model on the x axis and print that.

Creality

Doesn't Matter

20%

Tinkercad and a lot of math