I have seen a few magic instances online where folks have 3D printed molds to put Sugru (silicon rubber putty) into and then bolt together (allowing to cure overnight) in order to cast custom silicon rubber parts.
Headphone Jack Example: [sugru.com]
Custom Coupling Example: [www.thingiverse.com]
(I like how this was bolted together)
I was wondering if any of you super geniuses out in TV Land might be able to write a script that given the input of an .stl (or .scad) generates a two new .stl files which are two halves of a mold that you can bolt together with Sugru in the middle to make said rubber parts.
This would be magic on Thingiverse A relatively simple script like this would open up all kind of casting opportunities; It would be helpful for materials other than Sugru as well. Sugru molds do not need a hole to pour in fluid; this makes them simpler. Just put Sugru in the middle and mash the halves together!
I don't think this would be TOO CRAZY to pull off, but it is beyond my relatively amateur scad/cad skills right now... But I don't think this would be to difficult for the kinds of folks who browse the RepRap General forum
Considerations might include the ability to choose what axis to cut the "input STL" on; and ensuring that the end result pieces are laying smooth side down, so they can actually be printed on a reprap!
I would love to use M3 nuts and bolts to hold the mold together; maybe this could be a variable for the user to change
Also, be sure to check out this blog post where Z-Corp 3D printers are being used to make molds for a bench-top plastic injection molding machine!
Kepp in mind, that casting like this, will indeed require air-holes and a pouring channel:
Neat video by them too!