Making 3D Printing Truly 3D (phys.org) 14
An anonymous reader quotes a report from Phys.Org: Don't be fooled by the name. While 3D printers do print tangible objects (and quite well), how they do the job doesn't actually happen in 3D, but rather in regular old 2D. Working to change that is a group of former and current researchers from the Rowland Institute at Harvard. [...] The researchers present a method to help the printers live up to their names and deliver a "true" 3D form of printing. In a new paper in Nature, they describe a technique of volumetric 3D printing that goes beyond the bottom-up, layered approach. The process eliminates the need for support structures because the resin it creates is self-supporting.
The key component in their novel design is turning red light into blue light by adding what's known as an upconversion process to the resin, the light reactive liquid used in 3D printers that hardens into plastic. In 3D printing, resin hardens in a flat and straight line along the path of the light. Here, the researchers use nano capsules to add chemicals so that it only reacts to a certain kind of light -- a blue light at the focal point of the laser that's created by the upconversion process. This beam is scanned in three dimensions, so it prints that way without needing to be layered onto something. The resulting resin has a greater viscosity than in the traditional method, so it can stand support-free once it's printed.
"We designed the resin, we designed the system so that the red light does nothing," Congreve said. "But that little dot of blue light triggers a chemical reaction that makes the resin harden and turn into plastic. Basically, what that means is you have this laser passing all the way through the system and only at that little blue do you get the polymerization, [only there] do you get the printing happening. We just scan that blue dot around in three dimensions and anywhere that blue dot hits it polymerizes and you get your 3D printing." The researchers used their printer to produce a 3D Harvard logo, Stanford logo, and a small boat, a standard yet difficult test for 3D printers because of the boat's small size and fine details like overhanging portholes and open cabin spaces.
The key component in their novel design is turning red light into blue light by adding what's known as an upconversion process to the resin, the light reactive liquid used in 3D printers that hardens into plastic. In 3D printing, resin hardens in a flat and straight line along the path of the light. Here, the researchers use nano capsules to add chemicals so that it only reacts to a certain kind of light -- a blue light at the focal point of the laser that's created by the upconversion process. This beam is scanned in three dimensions, so it prints that way without needing to be layered onto something. The resulting resin has a greater viscosity than in the traditional method, so it can stand support-free once it's printed.
"We designed the resin, we designed the system so that the red light does nothing," Congreve said. "But that little dot of blue light triggers a chemical reaction that makes the resin harden and turn into plastic. Basically, what that means is you have this laser passing all the way through the system and only at that little blue do you get the polymerization, [only there] do you get the printing happening. We just scan that blue dot around in three dimensions and anywhere that blue dot hits it polymerizes and you get your 3D printing." The researchers used their printer to produce a 3D Harvard logo, Stanford logo, and a small boat, a standard yet difficult test for 3D printers because of the boat's small size and fine details like overhanging portholes and open cabin spaces.
Where to see what they printed (Score:2)
Although the main paper is behind a paywall, if you visit the site [nature.com] and click on "figures" on the bar on the upper-right hand side, you can get a view of the small prints they produced (all smaller than a coin it appears). The images themselves are not very large, but large enough to get a better sense of what is going on.
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The old math prof and the sculpture ... (Score:2)
The old prof replied, It is actually quite simple. Take a large block of marble, and chip away everything that does not look like the sculpture you want. By definition what remains must be the sculpture you seek.
This method takes a large block of resin, and focuses light and harden what looks like the sculpture. The rest of the resin is washed away or peeled away? The sculpture remains.
Methinks, the real 3D
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This method takes a large block of resin, and focuses light and harden what looks like the sculpture. The rest of the resin is washed away or peeled away? The sculpture remains.
So, they've re-invented CNC milling?
Expensive resin (Score:4, Informative)
This micro-engineered resin has got to be a lot more expensive than the plastics used by typical 3-D printers today. For most applications, there are ways to overcome the limitations of 3-D printing, layer by layer. In the boat example, multiple parts can be printed and assembled after the fact. Maybe not as cool as in0-place 3-D rendering, but practical and cheap.
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How is this different from the resin printers that already exist? The description sounds to me exactly the way current resin printers already work. Are these researchers coming late to the game? If not, what's different about _their_ resin printing process?
My fuzzy memory says the resin is cheaper than PLA, et al. The overall process may be more expensive up front, because you need two additional devices to clean and cure the printed object. One-time cost, though.
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The article actually does a good job of explaining how this new process is different from today's resin printers, and how the resin itself differs from today's resins.
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Intersection (Score:2)
I had an idea twenty years ago to do something similar, except using two lasers whose point of intersection resulted in heat high enough to cause polymerization. Of course, not knowing anything about physics, lasers, or polymerization, I wasn't able to determine whether that idea was good or bad.
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In other news: 3D printing hype... (Score:2)
3D "slicing" software must be wild (Score:2)
I get the part about focussing anywhere in the volume to convert the resin at that spot. I'm really interested in the equivalent of the 2D slicing software, which is pretty fancy these days. To avoid the need for supports, the 3D sequencer has to start on the bottom, then work its way along the object sort of "from the center to the edges" . There's going to be a bunch of path calculations probably based on tangent faces in the model.