Volumetric 3D printing enables fast and precise printing
A new, volumetric 3D printing process builds objects completely, and very quickly: a millimeter-sized object is created in less than a second.
3D-printed object made of resin
(Image: MarinaGrigorivna / Shutterstock.com)
3D printing can be a lengthy business: a workpiece is built up layer by layer. A team from China has now developed a 3D printing process in which, according to the developers, a workpiece can be completely built up in seconds.
The team around Xukang Wang, Yuanzhu Ma and Yihan Niu from the renowned Tsinghua University in Beijing calls the process Digital Incoherent Synthesis of Holographic Light Fields (DISH). According to the team in the journal Nature, it allows objects in the millimeter range to be printed with a resolution of about 19 micrometers in just 0.6 seconds.
The process is similar to stereolithography, in which a resin is cured by light. However, it is a volumetric process. Here, a workpiece is not built up layer by layer. Instead, light is projected into the resin from different angles, so that the workpiece is created as a whole.
The laser rotates around the resin
The Tsinghua team uses a coherent laser with a wavelength of 405 nanometers for exposure, which is modulated by a digital micromirror system at a frequency of 17 kilohertz. A periscope system that rotates up to ten times per second around the resin container directs the laser beams into the resin. This projects a pattern into the resin so that the light energy needed to cure the resin reaches the correct depth.
DISH is not the first volumetric 3D printing process. However, previous approaches such as Computed Axial Lithography require compromises in precision or printing speed.
The resin container is rotated
Volumetric processes require the container with the resin to be rotated. If the container is rotated too quickly, it can lead to vibrations or movements in the resin, and thus to inaccuracies in printing. For slow rotations, a very viscous resin is necessary to maintain positional stability during slower exposures.
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The team has also shown that objects made of different materials can be built with the DISH process: In addition to resins with different viscosities, the researchers also printed with bio-based hydrogels such as gelatin methacrylate (GelMA) and silk fibroin methacrylate (SilMA).
The researchers see applications for their process in medicine or robotics, for example. In the long term, it is also intended to be suitable for use in industry.
(wpl)
