A bit like the Starship Enterprise
Imagine if three-dimensional objects no longer had to be built up layer by layer in 3D printing, but instead slowly emerged as a whole from nothing. It’s a little reminiscent of beaming objects onto the Enterprise back in the day. Well, it’s not quite like that, of course, but it’s going a little in that direction. Allow me to make a comparison.
In conventional 3D printing, an object is printed layer by layer, and stereolithography is a particularly successful approach here. Due to the linear absorption of light, photopolymerization must always take place on the surface of the resulting object. However, this limits the choice of plastics and variety of shapes. Using so-called triplet fusion upconversion, it is now possible to print volumetrically with less than 4 mW of power.
Researchers at Stanford University together with colleagues at Harvard University in Cambridge, USA, have succeeded in printing 3D objects volumetrically in a stationary resin. This means that a support structure is no longer required; instead, the object is stabilized by the surrounding resin. If a blue laser is used for 3D printing in a gelatine-like resin, the resin hardens when exposed to blue light. But not just at the desired point, but over the entire length of the beam.
Instead, the researchers use a red laser that excites certain nanomaterials distributed in the resin to generate blue light precisely at the focal point of the laser and thus harden at this point. By continuously moving the laser around the resin container, very detailed and, above all, support-free objects can be created. This conversion of light of one wavelength into another is achieved by a method known as fusion upconversion. If the nanomolecules are directly adjacent to each other, this method makes it possible to convert low-energy red photons into high-energy blue photons.
This volumetric printing approach makes it possible to print very complex objects in a shorter time with less material, which has been almost impossible to achieve until now. The researchers are now trying to refine this technique and print several dots simultaneously. This would make it possible to print faster, smaller and with higher resolution.
We will certainly be hearing and reading a lot about this process in the future. We’ll stay tuned!
Dr Ronald Hinz, Market Intelligence Senior Expert
Sources:
- Sanders, S. N., Schloemer, T. H., Gangishetty, M. K. et al.; Triplet fusion upconversion nanocapsules for volumetric 3D printing; Nature 604, 474–478 (2022)
