This 3D-printed model of the Tower Bridge is only 200 micrometers long. To put that into perspective, the distance between the towers is the width of a human hair. This model is the product of research at the additive manufacturing department of the Vienna University of Technology
The models were fabricated much like normal stereolithography – a laser shines onto a vat of light-sensitive resin. The resin hardens when exposed to light, and the model is built up layer by layer. These nanoscale models were made using a process called “two-photon lithography,” something we’re not going to pretend we understand completely but here’s a nice paper that provides a good overview. Needless to say, the precision these prints exhibit are nearly ludicrous. The researchers claim a precision of ±1µm, a respectable amount of precision for very high-tech machining applications.
The researches posted a video of the fabrication of a nanoscale F1 race car filmed in real-time. Check that out after the break.