You'll also need a way to suspend the assembly in the casting chamber - an easy way to achieve this is just to glue or screw some lolly sticks to the casting holder. If you forget to make the channels like I did, you could always cut them in the mould with a knife once the silicone has set. Also, you'll want to make some channels with the blu-tack or plasticine so that excess resin can escape, just make sure your channels go all the way to the end of the casting holder. You'll notice a small gap where the bottom of the eye meets the holder - this can be filled with plasticine or blu-tack to make the assembly water-tight. Then, the casting blank should fit on to the casting chamber holder without too much trouble. The two types of holders should go together easily with some 10mm or 20mm M2 screws, as can be seen above. I don't think you'll need a particularly expensive or well-tuned 3D printer to do this project (mine is a Geeetech i3), but it would help to be able to reliably print small bridges, use a layer height of around 0.2mm and ideally print in ABS. I made just about every mistake I could have with this one, so I feel like I'm in a good position to prevent you from doing the same!

I wanted it to be easy to print and accessible to anyone with a 3D printer, yet as realistic as possible within those requirements. The idea behind this design was to have a component that could easily clip into a holder for painting, then into a a casting chamber and finally into the eye mechanism using the same standardised fitting. In this instructable I'll show you the process of making these eyes and provide you with the STLs so that you can make your own. In my pursuit to design an effective and reproducible 3D-printed eye mechanism, It became apparent that I would need a reliable system to make realistic eyes.

Printable pictures of eyeballs