Lightning fast 3D micro-printing with two lasers – ScienceDaily

Printing plastic objects accurately, quickly and economically is the goal of many 3D printing processes. However, speed and high resolution remain a technological challenge. A research team from the Karlsruhe Institute of Technology (KIT), the University of Heidelberg and the Queensland University of Technology (QUT) has come a long way to achieve this goal. He has developed a laser printing process that can print micrometer-sized parts in the blink of an eye. The international team published the work in Photonics of nature.

Stereolithography 3D printing is currently one of the most popular additive manufacturing processes for plastics, for both 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 UV cured. However, previous stereolithography methods are slow and have too low resolution. Light foil 3D printing, used by KIT researchers, is a fast, high-resolution alternative.

Two-step 3D printing with two colors

In light foil 3D printing, blue light is projected into a container filled with a liquid resin. The blue light pre-activates the resin. In a second step, a red laser beam provides the additional energy needed to harden the resin. However, 3D printing can only quickly print resins that quickly return from their pre-activated state to their original state. Only then can the next level be printed. Consequently, the turnaround time determines the waiting time between two successive layers and thus the printing speed. “For the resin we used, the turnaround time was less than 100 microseconds, which allows for fast print speeds,” says first author Vincent Hahn of KIT’s Institute of Applied Physics (APH).

Micrometer-sized structures in the blink of an eye

To take advantage of this new resin, the researchers built a special 3D printer. In this printer, blue laser diodes are used to project images in liquid resin using a high resolution display with a high frame rate. The red laser is formed into a thin beam of “sheet of light” and traverses the blue beam vertically into the resin. With this arrangement, the team was able to 3D print micrometer-sized parts in a few hundred milliseconds, or in the blink of an eye. However, it shouldn’t stop there: “With more sensitive resins, we could even use LEDs instead of lasers in our 3D printer,” says APH Professor Martin Wegener. “Ultimately, we want to print centimeter-sized 3D structures while maintaining micrometric resolution and fast print speeds.”

The publication was produced under the joint “3D Matter Made to Order” Cluster of Excellence of the KIT and the University of Heidelberg. Junior professor, Dr. Eva Blasco, group leader of the Institute of Organic Chemistry and the Institute of Molecular Systems Engineering and Advanced Materials, was involved by the University of Heidelberg.

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Materials provided by Karlsruher Institut für Technologie (KIT). Note: The content can be changed by style and length.

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