Complex forms of glass can now be made by 3D printing
24 April 2017
A method developed at the KIT for the first time allows glass to be used for additive manufacturing techniques, an innovation in materials processing.
Three-dimensional printing allows extremely small and complex structures to be made even in small series. As a consequence of the properties of glass, such as transparency, thermal stability and resistance to acids, the use of this material in 3D printing opens up manifold new applications in production and research, such as optics, data transmission, and biotechnology. The process is published in “Nature” and also presented at the Hannover Fair.
An interdisciplinary team at the KIT led by mechanical engineer Dr. Bastian E. Rapp developed a process using glass for additive manufacturing techniques. The scientists mix nanoparticles of high-purity quartz glass and a small quantity of liquid polymer and allow this mixture to be cured by light at specific points – by means of stereolithography. The material, which has remained liquid, is washed out in a solvent bath, leaving only the desired cured structure. The polymer still mixed in this glass structure is subsequently removed by heating. “The shape initially resembles that of a pound cake; it is still unstable, and therefore the glass is sintered in a final step, i.e. heated so that the glass particles are fused,” explains Rapp.
The variety of 3D printing techniques available so far have been used on polymers or metals, but never on glass. Where glass was processed into structures, for instance by melting and application by means of a nozzle, the surface turned out to be very rough, the material was porous and contained voids. “We present a new method, an innovation in materials processing, in which the material of the piece manufactured is high-purity quartz glass with the respective chemical and physical properties,” explains Rapp. The glass structures made by the KIT scientists show resolutions in the range of a few micrometres – one micrometre corresponding to one thousandth of a millimetre. However, the structures may have dimensions in the range of a few centimetres, emphasises Rapp.
3D formed glass can be used, for instance, in data technology. “The next plus one generation of computers will use light, which requires complicated processor structures; 3D technology could be used, for instance, to make small, complex structures out of a large number of very small optical components of different orientations,” explains the mechanical engineer. For biological and medical technologies, very small analytical systems could be made out of miniaturised glass tubes. In addition, 3D shaped microstructures of glass could be employed in a variety of optical areas, from eyeglasses meeting special requirements to lenses in laptop cameras.