Super fast 3D printer offers nanoscale precision

A high precision 3D printer capable of producing nanometer sized objects at record breaking speeds has been touted by researchers at the Vienna University of Technology.

The 3D printer utilises a liquid resin, which is hardened at precisely the correct spots by a focused laser beam. The focal point of the laser beam is guided through the resin by movable mirrors and leaves behind a hardened line of solid polymer, just a few hundred nanometers wide. This fine resolution is said to enable the creation of intricately structured sculptures as tiny as a grain of salt. "Until now, this technique used to be quite slow," explained Professor Jürgen Stampfl, from the Institute of Materials Science and Technology at the TU Vienna. "The printing speed used to be measured in millimeters per second – our device can do 5m in one second. In two-photon lithography, this is a world record." According to Prof Stampfl, the progress was made possible by combining several new ideas. "It was crucial to improve the steering mechanism of the mirrors," he said. "The mirrors are continuously in motion during the printing process. The acceleration and deceleration periods have to be tuned very precisely to achieve high resolution results at a record breaking speed." As well as mechanics, Stampfl says chemistry also played a crucial role in the printer's development: "The resin contains molecules, which are activated by the laser light. They induce a chain reaction in other components of the resin, so-called monomers, and turn them into a solid. These initiator molecules are only activated if they absorb two photons of the laser beam at once – and this only happens in the very center of the laser beam, where the intensity is highest." In contrast to current techniques, the new printer enables solid material to be created anywhere within the liquid resin, rather than just on top of the previously created layer. This means that the working surface does not have to be specially prepared before the next layer can be produced, saving a considerable amount of time. Because of the dramatically increased speed, the researchers believe much larger objects can now be created in a given period of time. The team is now developing bio-compatible resins for medical applications and believes it could yield tailor-made parts for biomedical technology or nanotechnology.