Long-time readers of my site no doubt know of my fascination with the field of 3D printing and tracking the advances that are made almost weekly to this technology. From simple plastic tchotchkes to replacement parts to materials that few ever dreamed would be used, 3D fabbers are fast becoming an integral part of manufacturing at all levels of complexity. A few months ago researchers at Lawrence Livermore National Laboratory published the results for a revolutionary 3D printer called the Optomec Aerosol Jet 500, a fabber which uses a range of nanomaterials as its feedstock. To cut to the chase they've been using it to construct electronic components and integrated circuits at the molecular level, laying down conductive pathways in three dimensions, constructing semiconductor units material by material, and linking everything together into working circuitry in situ. Current semiconductor prototyping fabs are huge, on the order of thousands of square feet in size but the Optomec is just slightly over 250 square feet in size, well within the working space of your average science lab (and doesn't use any of the incredibly dangerous chemicals ordinarily involved in semiconductor manufacture). The new generation fabber prints at a resolution of 10 microns, which is about the size of a large grain of pollen or silt but far to small for the human eye to discern unaided. I don't know when this technology will leave the lab but you can bet that the semiconductor giants are going to be keeping a close eye indeed on them, if only because eliminating many of the chemicals they use would raise their bottom line significantly (by not needing to worry about licensing and disposal costs).