3D printing micrometre-sized parts in the blink of an eye

A research team from the Queensland University of Technology (QUT), the Karlsruhe Institute of Technology (KIT), and Heidelberg University have developed a laser printing process that can print micrometre-sized parts precisely and quickly. The international team published its research findings in Nature Photonics. Stereolithography 3D printing is a popular additive manufacturing process for plastics, both for private and industrial applications. In stereolithography, the layers of a 3D object are projected one by one into a container filled with resin. The resin is cured by UV light. However, previous stereolithography methods are slow and have too low a resolution. Light-sheet 3D printing, which is used by the QUT researchers, is a fast and high-resolution alternative.

In light-sheet 3D printing, blue light is projected into a container filled with a liquid resin. The blue light pre-activates the resin. In a second stage, a red laser beam provides the additional energy needed to cure the resin. However, 3D printing can only print resins that quickly return from their pre-activated state to their original state. Only then can the next layer be printed. Consequently, the return time dictates the waiting time between two successive layers and thus the printing speed. First author Vincent Hahn from KIT’s Institute of Applied Physics (APH) said that for the resin used by the researchers, the return time was less than 100 microseconds, which allowed for high printing speeds.

To take advantage of this new resin, the researchers built a special 3D printer, in which blue laser diodes were used to project images into the liquid resin using a high-resolution display with a high frame rate. The red laser was formed into a thin “light sheet” beam and crossed the blue beam vertically in the resin. With this arrangement, the researchers were able to 3D print micrometre-sized parts in a few hundred milliseconds. However, Professor Martin Wegener of APH said that with more sensitive resins, the researchers could even use LEDs instead of lasers in their 3D printer. “Ultimately, we want to print 3D structures that are centimetres in size, while maintaining micrometre resolution and high printing speeds,” Wegener said.

The publication was produced within the framework of the joint “3D Matter Made to Order” Cluster of Excellence of the KIT and Heidelberg University.

Image credit: Vincent Hahn, KIT