What is 3D printing?

3D printing is a method of manufacturing everything from tools to shoes to jewelery, or even car and aerospace parts using a computer-controlled printer. The fundamental rule of 3D printing is that it’s an additive manufacturing technique, unlike machining, turning, milling, and sawing which are subtractive.

While there are different kinds of 3D printing, all 3D objects are generally built out of layers. A 3D printer starts with the bottom layer, waits for it to dry or solidify, and then works its way up. This layering process differs depending on the printer and the material it works with — metal, plaster, polymer, resin — but it also depends on whether it’s an industrial or commercial 3D printer.
Industrial vs. commercial

While consumer- and small business-oriented 3D printing is only just taking off, mostly thanks to the MakerBot and RepRaps, 3D printing has been used in an industrial setting for 30 years. Industrial 3D printers tend to be very large and very expensive, but at the same time they are a lot faster than commercial printers. Some industrial printers can print with multiple nozzles at the same time, or even use metal (more on that later). For the most part, industrial printers are nearly always used for rapid prototyping (usually by architects, automakers), but sometimes 3D printed objects — especially in the case of metal objects — are used in final products.

Consumer-oriented 3D printers are cheaper, smaller, slower, and are usually lower resolution than their industrial counterparts. Consumer printers are still used for rapid prototyping, but they’re also used by people who just like the idea of printing stuff out. Generally, consumer printers use thermoplastic extrusion — i.e. it dribbles out tiny dots of melted plastic.
Different printing techniques

3D printing -- the original is on the left hand sideDepending on the material used, how many colors you want, the resolution you require, and how much money you’re willing to fork out, there are at least five popular 3D printing methods to choose from. Some are very similar, but some are really rather crazy (or brilliant).

Fused deposition modeling – The most common 3D printing method is fused deposition modeling (FDM). The raw material with this process is a spool of plastic or metal wire, which is melted and placed by the printer’s nozzle. It quickly hardens, and then the next layer can be added. As far as commercial printers are concerned (like the MakerBot), FDM always uses plastic wire (filament) and is usually called “thermoplastic deposition” in layman’s terms
Inkjet printing — Using special inks (resins and binders) it’s possible to build up a 3D model using a device that’s very similar to a home or office inkjet printer. Layer upon layer of resin and binder are added until an object is created. This is the only 3D printing process that allows for custom colors.
Selective laser sintering – Sintering is the process of creating solid objects from powders, and in the case of selective laser sintering (SLS) the powder can be metal, plastic, ceramic, or glass. Basically, SLS uses a pulsed laser to “draw” the desired cross-section. The powder fuses, and then then the laser forms the next layer on top. This is very much an industrial method, as it requires a rather strong laser.
Digital light processing – With DLP (yes, the same technology behind DLP projectors), a vat of liquid polymer is turned into a very strong solid by exposing it to light. Very high accuracy/resolution can be achieved with this technique — and again, this is an industrial method. Stereolithography is similar to DLP manufacturing, but a lot more expensive.
The others – Finally, there are a few 3D printing techniques that aren’t used extensively, but could be in the future. Resin can be cured using LEDs (similar to the DLP approach); 2-photon photopolymerization can be used to create ultra-small 3D-printed features; laminated object manufacturing uses bits of paper or card stuck together that are then cut out using a laser.

The future of 3D printing

Star Trek teleporterWe’ve already alluded to a few uses for 3D printing — prototyping, making stuff at home — but it’s worth diving into some of the crazier things that 3D printing is capable of now, and what it will be capable of in the future.

3D printers can be used to create titanium aircraft parts, human bones, complex, nano-scale machines, and more. In the future, it’s fairly safe to assume that we’ll be able to manufacture almost anything with a 3D printer — and everything we can’t make with a printer (clothes, textiles), automated CNC machines, or something like them, will take care of. Ultimately, 3D printers might also be the key to matter replicators, just like in Star Trek. It’s important to note that we already have very accurate tools for creating 3D models of existing objects; we have the ability to scan a cup, and then create an exact copy using a 3D printer.

Eventually, one day, you will walk up to a 3D printer and say “make me an iPad,” and it will make you an iPad. If we can create 3D printers with atomic-level resolution, they might also usher in another Star Trek gadget: teleporters. There’s also the (rather worrying?) fact that many commercial printers are labeled as “self-replicating,” in that they’re capable of printing their own replacement parts. In other words, if we gave a 3D printer some kind of artificial intelligence, who knows what it would into.

3D TV: Will 2012 be the year to trash the glasses?

After the rush to upgrade to HDTV, 3D was supposed to be the next big thing. Propelled by the enthusiasm for a few well-crafted media properties like the blockbuster movie Avatar, initial expectations were set very high. But cost, a lack of compelling content, potential health issues, and the need for annoying and expensive glasses have kept 3D TV from getting very far. Now, several firms are trying to break through by getting rid of those pesky glasses, offering glasses-free 3D experiences, while others are upping the ante by providing a premium experience with inexpensive polarized glasses or even new version of expensive, but now wireless, active glasses.

CES 2011 was billed as the year of 3D, but this year’s show also had dozens of offerings, many of which sound quite similar on paper. Here, ExtremeTech checks out the most exciting prospects for no-glasses 3D in 2012 and beyond.
StreamTV’s Ultra-D: Wide-viewing-angle 3D without glasses

Until now, the most common way to achieve 3D viewing without glasses has been with specially designed displays using what is called a “parallax barrier” — where any viewer to the left of the display’s center sees the image recorded by the left camera (and meant for the left eye) and any viewer to the right sees the right-side image (meant for the right eye). As you can imagine, this only works if the person viewing the screen sits exactly where the parallax barrier is set up to divide the image. As a result, it works well for personal display screens like the one on the Fujifilm and Panasonic 3D cameras, and the LG Thrill and HTC Evo 3D smartphones, which allow capturing and viewing 3D. But a parallax barrier doesn’t work well when you have more than one person in the audience, or if you want to move around at all while watching the media — since it only performs properly if the viewer is directly in front of the direction for which the barrier is tuned.

StreamTV prototype display showing multi-viewer 3D without glasses or face tracking. CES 2012 Images by David CardinalSeveral companies are using this year’s CES to launch new solutions for multi-viewer 3D without glasses. StreamTV, best known for the Elocity tablet, rolled out an impressive platform called Ultra-D, which allows not just autostereoscopic (without glasses) viewing of existing 3D content, but realtime conversion of conventional 2D images and video into its 3D format. On paper Ultra-D slices through the two major bottlenecks hampering 3D very nicely. By having displays that are autostereoscopic no glasses are required, and by allowing realtime conversion to 3D, suddenly a near infinite amount of content is available.

The Ultra-D system requires quite a bit of heavy lifting on the hardware and software side. Existing LCD, LED and OLED panels can be used, but an additional microlens layer is required for the displays, as well as new firmware and software. StreamTV is aggressively licensing its platform to makers of TVs, tablets, and smartphones, with the promise of 42-inch and 55-inch LED TVs available in retail by this summer. The Ultra-D TVs will be bundled with StreamTV’s SeeCube, which enables the realtime conversion of 2D to 3D and of traditional 3D content — designed for use with glasses — into autostereoscopic content for display on an Ultra-D device. Tablets and digital picture frames are also on tap, although details haven’t been disclosed.

StreamTV is fairly tight-lipped about how the system actually works, but from watching a variety of their prototypes and talking to some of their researchers, it turns out that instead of the traditional glasses-free solution of having two images — one for the left eye and one for the right — then showing one to each eye — Ultra-D creates 9 different images, each with a unique angle on the scene. The specially built display has an array of microlenses in front of the conventional LCD that project each image out in a series of overlapping cones. As a result each eye sees a combination of as many as 4 different images — all with a slightly different perspective — and is responsible for integrating the total into a coherent picture. Since your eyes are a few inches apart, at most viewing positions your left eye sees a different set of 4 images than your right eye (in essence your right eye is moved over by one, so if your left eye sees image 2, 3, 4, 5, for example, your right eye might see images 3, 4, 5, and 6). This clever approach means that as you move around the viewing area, the image you see actually changes.

The StreamTV Ultra-D prototype looked great on original 3D source material like the 3D Superbowl, but not as good on traditionally filmed football games automatically converted to 3D.The downside of this technique is an apparently less-sharp image, and a tendency for ghosting to occur. While StreamTV downplayed both issues, refusing to discuss resolution by saying there wasn’t a 3D standard for it, and blaming any ghosting on the prototype nature of the monitors, both issues are likely to dog them through its launch later this year, at least until it can show it has solved them adequately for the marketplace. In our testing, some source material, like the Superbowl filmed in 3D, was stunning, with the experience rivaling that of a 3D TV with glasses. Other material, like conventional 2D football coverage converted to 3D, was a little disorienting and the 3D effect detracted from the viewing experience. StreamTV provides two controls, found on the TV remote, to allow for tuning or turning off the effect. One changes the apparent depth of the action in the scene, and the other controls the apparent distance of the scene from the viewer. So you can have action “pop” right in your face, or have scenes with plenty of apparent depth, off in the distance.