We were all quite impressed when the RepRap printer managed to reproduce itself some months ago
. But in fact the reproduction was only of its structural members, whereas the metal bits and electronics were not actually reproduced. No worries, it will eventually happen. Metal printing has emerged in several 3D print services, but what about the electronics? It's hard to do because conductive material typically has very high melting points - so high that it would burn or melt surrounding 3D printed material if you tried to print the wiring.
Recently a big step towards electronics printing occurred. Xerox has invented a new type of "Silver Ink", purportedly for 2D inkjet-style printing. However, we suspect this might also be ideal for 3D printers. Imagine an Objet printer (capable of handling two different print materials simultaneously) loaded with plastic and "silver ink". You could theoretically print objects with embedded (albeit simple) electronics. Well, wiring at least.
Via PhysOrg (Hat tip to Micah)