A team from Kiel has developed a new 3D printing process for glass. According to the researchers, it significantly simplifies the processing of glass, as a built workpiece no longer needs to be hardened.

Laser-Assisted Melt Printing (LAMP) is what the material scientists from Kiel’s Christian-Albrechts-Universität call the process. It uses a special silica-based particle ink. A high-energy laser fuses the particles into a glass workpiece.

Some parameters can be adjusted during printing: “LAMP allows the physical properties such as density, smoothness, color, and transparency to be controlled during printing,” says project leader Leonard Siebert.

Viscous ink with silicate particles

The ink contains about ten percent silicate particles with a diameter of 40 nanometers and 43 percent borosilicate particles with a diameter of 40 micrometers. The particles are stirred into a solution of water, the binder polyethylene glycol, and a small amount of acetic acid. This creates a viscous liquid that can then be processed with the 3D printer.

The ink is applied layer by layer to a printing plate. A laser fuses the ink with the layer below. This creates “smooth, dense structures without air inclusions,” the researchers announced. Measurements with the electron microscope and spectroscope showed that the material was completely densified. Color and transparency of the glass can be modified via laser power and writing speed.

In addition, the researchers can change the optical properties by adding gold and silver ions to the ink, which turn into metal nanoparticles during printing. “These nanoparticles act like tiny filters: they only let certain wavelengths through and block others,” said team member Kolja Krohne.

Particle size determines color

The size of the particles determines which light colors are absorbed or scattered: small particles shift the color towards blue, larger ones towards red. For example, filters can be printed that only allow light of a certain color to pass through.

This is not the first 3D printing process for glass. However, with previous methods, the workpiece usually has to be hardened in a kiln after printing, which takes several hours and requires a high energy input.

For the study, which was published in the journal Materials & Design, in the journal Materials & Design, the team led by Siebert printed with glass. However, other materials could also be processed in this way, they say. They are primarily thinking of ceramics.

“With conventional methods, ceramics usually have to be fired in kilns at well over 1000 degrees Celsius. This consumes a lot of energy, takes a long time, subjects the components to strong stresses, and makes it difficult to produce filigree or patient-specific implants,” says Siebert. This is not the case with LAMP. In the future, this process could be used to produce dental or bone implants, for example.

(wpl)

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This article was originally published in German. It was translated with technical assistance and editorially reviewed before publication.