Numerous 3D printing technologies aim to produce objects from plastic precisely, fast, and affordably. However, speed and high resolution continue to present technological obstacles. A team of researchers from the Karlsruhe Institute of Technology (KIT), Heidelberg University, and the Queensland University of Technology (QUT) has made significant progress toward this objective. It created a laser printing technique that can print micrometer-sized components in the blink of an eye. The international team’s findings were reported in Nature Photonics.
Stereolithography Currently, 3D printing is one of the most popular additive manufacturing technologies for plastics, both in private and industrial settings. In stereolithography, successive layers of a three-dimensional object are projected into a resin-filled container. The UV light cures the resin. However, prior stereolithography techniques were excessively sluggish and lacked sufficient resolution. Utilized by KIT researchers, light-sheet 3D printing offers a quick and high-resolution alternative.
Two-Color 3D Printing in Two Stages
In light-sheet 3D printing, blue light is projected into a liquid resin-filled container. The resin is preactivated by the blue light. In a second stage, a red laser beam gives the resin the additional energy required for curing. However, 3D printing can only print swiftly with pre-activated resins that quickly revert to their former state. Then, the subsequent layer can be printed. As a result, the return time defines the interval between succeeding layers and, consequently, the printing speed. “The resin we used had a return time of less than 100 microseconds, which made it possible to print quickly,” says Vincent Hahn, the lead author from KIT’s Institute of Applied Physics (APH).
In the Blink of an Eye, Micrometer-Sized Structures
To utilize this novel material, the researchers developed a specialized 3D printer. This printer uses blue laser diodes to project images onto liquid resin using a high-resolution, high-frame-rate monitor. The red laser beam is produced into a thin “light sheet” and crosses the blue laser beam in the resin in a vertical direction. The team was able to 3D print micrometer-sized components in a few hundred milliseconds, or in the blink of an eye, thanks to this arrangement. With more sensitive resins, we could even use LEDs instead of lasers in our 3D printer, says APH Professor Martin Wegener. “Our ultimate goal is to print centimeter-scale 3D structures while keeping micrometer resolution and fast printing speeds.”
The paper was prepared under the framework of the KIT and Heidelberg University’s “3D Matter Made to Order” Cluster of Excellence. On behalf of Heidelberg University, Dr. Eva Blasco, a group leader at the Institute of Organic Chemistry and the Institute of Molecular Systems Engineering and Advanced Materials, was involved.
