The tiny bicycle in this picture is made of glass, but it’s not the delicate work of a glass blower. Instead, behind this work of art is a new 3D printing process for glass
Most 3D printing processes build an object layer by layer from a raw material. Each layer is firmly connected to the one below so that the result remains stable later. A prerequisite for the material is therefore that it can be hardened, melted or glued with an adhesive.
While objects made of plastic, ceramic or plaster can now be printed without any problems, it has been more difficult to produce filigree glass objects using 3D printing. Researchers led by Thomas Doualle from the University of Marseille have now researched a new laser-based process for printing complex glass parts.
For their new 3D printing approach, they did not choose the typical additive layering process, but so-called multiphoton polymerization. In this process, the liquid basic building blocks are precisely heated at the focal point by laser pulses. As a result, they bond together and harden to form glass.
The approach required a material that would remain transparent at the wavelength of the laser both during the initial liquid phase and after polymerization, and that would polymerize and cure without undesirable deformation. To do this, Doualle and his colleagues tested a starting mixture that contained a photochemical initiator for absorbing the laser light, a resin and a high concentration of silicon dioxide nanoparticles.
And indeed: this mixture, in combination with the ultra-short laser pulses, proved to be suitable for producing even the finest glass structures with high precision. With the new process, three-dimensional glass objects with a size of a few micrometers up to ten centimeters can be produced. In initial tests, the researchers created both the miniature glass bicycle in our picture and a miniature model of the Eiffel Tower.
The researchers are now working on further optimizing the process in order to also manufacture glass parts for luxury watches, perfume bottles and optical components in the future. “Glass is one of the most important materials for optical applications,” say the scientists. “Our work represents a first step in the development of a process with which one day scientists can simply print the required optical components themselves.”