3D Printing

New 3D-printing tech gets smooth results using light and resin

New 3D-printing tech gets smoo...
A miniature version of the statue "The Thinker," created using the new 3D-printing system
A miniature version of the statue "The Thinker," created using the new 3D-printing system
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The resin-based 3D-printing setup
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The resin-based 3D-printing setup
A miniature version of the statue "The Thinker," created using the new 3D-printing system
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A miniature version of the statue "The Thinker," created using the new 3D-printing system
The technology makes it possible to add 3D-printed parts to existing solid objects, such as the handle on a screwdriver shaft
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The technology makes it possible to add 3D-printed parts to existing solid objects, such as the handle on a screwdriver shaft

Currently, most 3D printers work by either depositing or melting building material in successive layers. Unfortunately, this results in the finished objects looking kind of chunky, as the ridges between layers are visible. A new zero-waste process, however, uses light to create smooth-edged items out of resin.

Developed by a team at the University of California, Berkeley, the system has been nicknamed "the replicator" in homage to the fictional Star Trek device that can materialize just about any object.

Users start by creating a 3D computer model of an item, which is converted into a series of light patterns. Using a standard video projector hooked up to a laptop, those patterns are then projected into a rotating glass cylinder containing a light-sensitive resin. That resin is composed of a combination of liquid polymers, photosensitive molecules and dissolved oxygen.

The resin-based 3D-printing setup
The resin-based 3D-printing setup

Activated by the projected light, the molecules deplete the oxygen in specific three-dimensional areas of the resin. Once all of the oxygen has been depleted in those areas, the liquid polymer transforms into a solid by forming molecular cross-links. After the resulting completed object is removed from the cylinder, the remaining non-cured resin can be reused after being heated in an oxygen atmosphere.

So far, the system has been used to print objects measuring up to 4 inches in diameter (102 mm), with build times ranging from 30 to 120 seconds. Not only are those items smooth because they're printed "all at once" instead of layer-by-layer, but they're also more flexible than traditional 3D-printed objects.

The technology makes it possible to add 3D-printed parts to existing solid objects, such as the handle on a screwdriver shaft
The technology makes it possible to add 3D-printed parts to existing solid objects, such as the handle on a screwdriver shaft

Additionally, the technology makes it possible to add 3D-printed parts to existing solid objects – for example, the replicator was used to print a handle onto a steel screwdriver shaft (pictured above).

"I think this is a route to being able to mass-customize objects even more, whether they are prosthetics or running shoes," says Asst. Prof. Hayden Taylor, senior author of a paper on the research. "The fact that you could take a metallic component or something from another manufacturing process and add on customizable geometry, I think that may change the way products are designed."

The paper was published this Friday in the journal Science. To see the printing process, check out the video below.

Sources: University of California, Berkeley, American Association for the Advancement of Science via EurekAlert

3 comments
MD
using a single Projector to "back-project" the 3D image on a column, has some benefits and some drawbacks. (This is the same technique as is used to "reconstruct" 3D volumes in Sectional Medical Imaging...) Any Single-Point Back projection causes artefacts in a 3D volume... If the Net-shaps is the only desired onjective this seems to be a usable technique (not technology). However for engineering reproductions and biological/scientific objects with critical internal geometry, there will be defects (lookup: backprojection artefacts), unless multiple simultaneous "intersecting" projection sources are used (or variable depth of focus - light emitters -coherent or noncoherent), whereby the material only solidifies at the intersection points of the multiple "beams"... We are not "there yet" with a one size fits all, though many industries have been working at it for a long time.... With this "rotating cylinder" concept, building from the "inside out" like an onion makes a lot of sense... NB. with Current Stereolithography, the "slices" are (quite a bit) smoothed out anyhow doe to the voscosity of the resin
Mzungu_Mkubwa
Watched the TED talk on this (https://youtu.be/ihR9SX7dgRo) and the main advantage to this oxygenation of the resin "soup" appears to be speed over its other advantages. This tech has been around for a while, but this difference allows a continuous motion of the z-axis rather than constantly pausing it to allow curing and adhesion. Cuts down the time tremendously... the primary hurdle to wide deployment of 3D printing for manufacturing. A small model is actually printed during the presentation to demonstrate this. Interesting tech.
Douglas Bennett Rogers
I have been trying to make filament wound connectors for composite tubing. I would like to use an epoxy releasable mold material, like polyethylene. This does not 3-D print well. If this material releases from epoxy it would be a boon to mold making.