3D printing has a new technology ~ under the irradiation of the beam, we will see a printed part "emerge out of thin air", the whole process only takes a few minutes.

(video source: original paper)

the outstanding feature of this new technology is that it breaks away from the traditional layer-by-layer printing method of 3D printing, and each part of the printed object can be said to be molded at one time. In this way, not only the printing speed is fast, but also the printing element with a smoother surface can be obtained.

Let's compare in detail how it differs from previous 3D printing. There are two common types of 3D printing before, the first one should be the easiest to see: heat and melt the raw materials and pile them up layer by layer like cream.

(photo source: prostheticknowledge)

the other is to use light to solidify liquid resin materials. This is also cured layer by layer.

(photo source: Gigaom)

the layer-by-layer printing method has some disadvantages, such as printing things that may still show traces of layering on the outside, and the printing speed is usually slow.

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and in the opening video, we don't see this layering at all. This new technology also uses a curing principle similar to the second mentioned above, in which the rotating cylinder is filled with light-cured resin material, and then irradiates it with a beam of constantly changing shape at the same time. Each beam corresponds to the projection of the 3D model at an angle (pictured below).

(picture source: original paper)

for the resin at a certain position in the cylinder, after the superposition of multi-angle light dose reaches a certain amount, the energy is enough to initiate the curing of the resin, and if the amount of light is not accumulated enough, the resin will remain in a flowing state. As a result, after rotating irradiation, the superposition of light causes the resin to solidify into the desired shape, and the rest of the uncured resin can be washed away.

(print the finished product. Screenshot Source: UC Berkeley)

the researchers took inspiration from CT scans in the hospital. They say that this kind of 3D printing can be seen as the exact opposite of doing CT: to do CT, the machine rotates to take a series of 2D projections at different angles, and then rebuilds it into a 3D image; here, 3D printing first has a 3D model, and then turns it into a projection of different angles, and then uses a light source to transmit these 2D projections to the rotating resin.

this method can quickly print small transparent resin parts with a smooth surface, and it can also print directly around other objects, such as adding a resin handle to a metal screwdriver.

(screenshot: Science Magazine)

original paper: http://science.sciencemag.org/content/early/2019/01/30/science.aau7114

related report: https://www.nature.com/articles/d41586-018-07798-9

https://www.sciencemag.org/news/2019/01/star-trek-replicator-creates-entire-objects-minutes