Increasing speed of 3D printers with nano-precision

Researchers at the Vienna University of Technology (TU Vienna) made a major breakthrough in speeding up the “two-photon lithography” 3D printing technique that enables their high-precision-3D-printer to print object in orders of magnitude faster compared to similar devices. Since dramatically increased speed of printing enables creation of much larger objects, the technique could find its application in industry.

“Until now, this technique used to be quite slow”, says 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 five meters in one second.”

Although its printing capability might seem rough due to speed, printing 3D objects with two-photon lithography technique actually enables 3D printing with incredibly fine details on a nanometer scale. The printer uses a laser beam which is guided by movable mirrors. The beam – which is a few hundred nanometers wide – travels through liquid resin and induces a chain reaction within the components of the raisin between molecules which turns it into a polymerized line of solid polymer.

Since the mirrors continuously move during the printing process, the researched had to make improvements in control of their acceleration and deceleration-periods in a way that enables high-resolution results at a record-breaking speed. Led by Professor Robert Liska, a team of chemists from TU Vienna contributed to increased speed with development of suitable initiators for previously mentioned resin.

The initiator molecules they developed are activated only when they absorb two photons of the laser beam at once – and this only happens in the very center of the laser beam. Unlike other 3D printing techniques, where material gets stacked or etched in layers, the liquid resin enables the contours to be created anywhere within it. Therefore, it saves time because the working surface does not have to be specially prepared before the next layer can be produced.

TU Vienna researchers are now developing bio-compatible resins that could employ this fast and precise 3D printing technique to be employed in medical applications. Aside creating custom made parts for biomedical technology or nanotechnology, this 3D printing technique could be used to create scaffolds or molds in which living cells could be directed during the biological tissue formation.