3D Printing

EPFL's super-fast 3D-printing technique makes resin objects in seconds

EPFL's super-fast 3D-printing ...
EPFL's light-based volumetric 3D printing is super-quick, and now possible in opaque resins
EPFL's light-based volumetric 3D printing is super-quick, and now possible in opaque resins
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EPFL's light-based volumetric 3D printing is super-quick, and now possible in opaque resins
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EPFL's light-based volumetric 3D printing is super-quick, and now possible in opaque resins
The team analyzed how light passed through opaque resins and used the results to create correction algorithms
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The team analyzed how light passed through opaque resins and used the results to create correction algorithms
The team managed to bring light printing in opaque materials up to a similar resolution as it's achieved in transparent resins
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The team managed to bring light printing in opaque materials up to a similar resolution as it's achieved in transparent resins
The team printed this little Yoda figure in about 20 seconds
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The team printed this little Yoda figure in about 20 seconds
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Researchers at EPFL have demonstrated a light-based 3D-printing method that's about 30 times faster than conventional additive manufacturing, creating objects in 20 seconds that would normally take more like 10 minutes thanks to photocurable resins.

Where regular 3D printing is all about sticking blobs of material on a substrate and allowing (or causing) it to solidify, EPFL's light-based process, pioneered back in 2017, takes a totally different approach that's much, much faster.

“We pour the resin into a container and spin it,” says Christophe Moser, a professor at the EPFL's Laboratory of Applied Photonic Devices. “Then we shine light on the container at different angles, causing the resin to solidify wherever the accumulated energy in the resin exceeds a given level. It’s a very precise method and can produce objects at the same resolution as existing 3D-printing techniques.”

The team printed this little Yoda figure in about 20 seconds
The team printed this little Yoda figure in about 20 seconds

Building things this way is extremely quick – tens of seconds as opposed to minutes. Another advantage is that you can print shapes with complex hollow sections without needing the kind of support structures you do with a flat-bed printer.

The problem with this technique, up until now, has been that it's only been possible using transparent resins – since anything with a bit of color in it, such as the opaque resins used to make artificial arteries in the biomedical industry, would bend and distort the light as it came through, causing a drastic loss in resolution and some pretty sad-looking printed objects.

The team managed to bring light printing in opaque materials up to a similar resolution as it's achieved in transparent resins
The team managed to bring light printing in opaque materials up to a similar resolution as it's achieved in transparent resins

But in new research released this week, Moser and his team demonstrate a technique that allows the use of opaque resins, by using a video camera behind the resin to calculate the path of the light through the resin. After analyzing the light that made it through, the team was able to create a distortion correction algorithm, and apply it to the print instructions as the machine operates so that the correct amount of energy arrives at each spot.

The resulting printed pieces in opaque resin, says the team, are still very quick to make – the team produced a small printed Yoda in about 20 seconds. They're also almost the same resolution as for transparent resin at about one-tenth of a millimeter. The team is now working to increase that resolution a hundred-fold, aiming for micrometer level precision.

The research is open access in the journal Advanced Science.

Source: EPFL

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3 comments
3 comments
paul314
A tenth of a millimeter is about the nominal (not necessarily actual) resolution of an old-style melted-plastic deposition 3D printer.
Ralf Biernacki
So this is essentially the same as stereolithography; except that instead of exposing the material layer by layer, then moving the table up, there is no table and the material is exposed in bulk, in 3D. And the intensity of laser beams is such that the resin only solidifies where they cross within the vat. Neat.

IMHO, there is little point trying to adapt the process to what they call "opaque" but are actually milky translucent materials. It is necessarily less precise, and requires oodles of processing power to even try to correct for scattering. Why not make a transparent, disposable form for casting or polymerizing an opaque object? You can then melt away the form, and extract the object.
Martin Hone
I fail to see the connection between spinning the resin in a container and hitting it with light, and printing the object in 3D. Does the spinning container contain the mould, in which case how is the 'printing' made ?