Current projects like RepRap tend to concentrate on reproducing simple plastic parts, but there are interesting developments not that far away. For example, some experiments have already been done on ways that the technology can make circuit boards – or at least lay down the tracks. By using an etch-resistant material instead of the usual plastic polymer, all the user needs to do is take the board and place it in an acid bath, in the usual way – a process that can itself be automated. Longer term, it may be possible to use different heads to lay down layers of circuitry.
Another useful avenue of exploration is enabling RepRap type machines to recycle, so that instead of relying on a fresh supply of polymer to create things, existing objects can be shredded to a granules, and then re-extruded as something else. So, the example children’s shoe that the machine can make could be recycled, with a little extra material, and turned into a larger size.
It’s even possible to grow crops that will provide the raw material to feed a machine. Starchy crops, such as maize, can be fermented to produce the polymer polylactic acid (PLA), which can then be used to create products like cups and containers in a RepRap, which can be recycled or simply composted when they’re no longer needed. On a much larger scale, similar techniques to prototyping are being explored in the construction industry, where machines may be able to create buildings by laying down thin layers of concrete, potentially enabling fast automated construction of any self-supporting structure. Ideal, perhaps, for building on other planets.