A team at the Vienna University of Technology has used the world's fastest 3D printer to create model Formula 1 car that is just 0.285mm long. That’s about four times the width of a human hair, or the same size as a grain of sand. The team has also created microscopic models of Tower Bridge and Vienna's St. Stephen's Cathedral using a technique called two-photon polymerisation.
The process, developed by Jan Torgersen and a team at the University, builds on existing technology, adapted to produce much greater speeds than ever before. To create the 3D model car, the printer built up 100 layers consisting 200 printed lines each. The model is made from a liquid resin which is hardened using a laser beam to create a solid polymer. Whilst this technique is well established, the team's breakthrough came from using a series of constantly moving mirrors to speed up the process significantly.
3D printers work by building up multiple layers to create a solid object and the speed at which they work is limited by the time it takes the material to harden. Traditional methods only allow the top layer of material to be worked on and are therefore too slow for many practical applications.
The team used a customised resin incorporating light-sensitive molecules, which allow any part of the structure to be hardened by the laser. A system of mirrors continuously guides the lasers around the material and the super-fast steering mechanism means that the printer can create nano-objects at an incredible 5 metres per second – hundreds of times faster than previous techniques.
Although the creation of miniature 3D models may seem frivolous, the speed and accuracy of the process mean that it has far more serious and beneficial applications. For instance, it has already been used to create scaffolds designed to be seeded with living cells for the creation of biological tissue. No doubt, there will be many more applications in the field of biomedicine and beyond and the next challenge is to create larger 3D objects to the same level of detail.
by Anthony Morgan