3D PRINTING: MAKING THE DIGITAL REAL

Imagine a future in which a device connected to a computer can print a solid object. A future in which we can have tangible goods as well as intangible services delivered to our desktops or highstreet shops over the Internet. And a future in which the everyday "atomization" of virtual objects into hard reality has turned the mass pre-production and stock-holding of a wide range of goods and spare parts into no more than an historical legacy.

Such a future may sound like it is being plucked from the worlds of Star Trek. However, whilst transporter devices that can instantaneously deliver us to remote locations may remain a fantasy, 3D printers capable of outputting physical objects have been in development for over two decades. What's more, several 3D printers are already on the market. Available from companies including Fortus, 3D Systems, Solid Scape, ZCorp, and Desktop Factory, these amazing devices produce solid, 3D objects from computer data in roughly the same way that 2D printers take our digital images and output hardcopy photos.

The Desktop Factory currently sells a 3D printer for $4995. This can print models up to a five-inch cube in size with consumables costing around $1 per cubic inch. However, prices for most 3D printers tend to start in the ten-to-twenty thousand pound bracket and spiral upwards. Although some desktop models are on the market, most 3D printers are usually fairly bulky and often floor-standing.

Current Technologies

3D printing is an additive technology in which objects are built up in layers and usually over several hours. The first commercial 3D printer was based on a technique called stereolithography. This was invented by Charles Hull in 1984. Stereolithographic 3D printers (known as SLAs or stereolithography apparatus) position a perforated platform just below the surface of a vat of liquid photocurable polymer. A UV laser beam then traces the first slice of an object on the surface of this liquid, causing a very thin layer of photopolymer to harden. The perforated platform is then lowered very slightly and another slice is traced out and hardened by the laser. Another slice is then created, and then another, until a complete object has been printed and can be removed from the vat of photopolymer, drained of excess liquid, and cured. Stereolithographic printers remain one of the most accurate types of hardware for fabricating 3D output, with a minimum build layer thickness of only 0.06mm (0.0025 of an inch).

Another common commercial 3D printing technology is multi-jet modelling (MJM). This uses a print head with a large number of nozzles that spray droplets of hot thermoplastic to build up the slices of a final object. Other current technologies include selective laser sintering -- which builds objects by compacting and fusing solid with a laser successive layers of a cocktail of powdered wax, ceramic, metal, nylon or one of a range of other materials -- and fused deposition modelling (FDM), which extrudes hot thermoplastics from a temperature-controlled print head to produce fairly robust objects to a high degree of accuracy. There are also powder-based systems that spray a binder solution to solidify object layers. These include printers such as the ZPrinter 450 from ZCorp which can produce full-colour 3D objects at over 300dpi.

Current Applications

Most current 3D printers are not used to create final consumer products. Rather, they are generally employed for rapid product prototyping, or to produce moulds or mould masters that will in turn allow the production of final items. Such printing of 3D objects already enables engineers to check the fit of different parts long before they commit to costly production, architects to show detailed and relatively low-cost scale models to their clients, and medical professionals or archaeologists to handle full-size, 3D copies of bones printed from 3D scan data. There are also a wide range of educational uses.

The range of products that have employed 3D printers in their design process or to produce final moulds or mould masters is constantly growing. To date such products include automobiles, trainers, jewellery, plastic toys, coffee makers, and all sorts of plastic bottles, packaging and containers. Dentists are now also starting to use 3D printers to produce dental appliances.

Whilst most 3D printers are currently used for prototyping and in pre-production mould making processes, the use of 3D printing to manufacture end-use parts is also now occuring. Fortus, for example, sell 3D printers that use an FDM process that allows the direct digital manufacturing (DDM) of final thermoplastic components. As they explain, for low-volume manufacturing DDM is more cost-effective and simpler than having to pay and wait for machining or tooling, with on-the-fly design changes and just-in-time inventory being possible. For example their customer Klock Werks Kustom Cycles builds one-of-a-kind motorcycles using a Fortus 3D printer to directly digitally manufacture some of the required custom parts. Another company using 3D printing to create final products is Freedom of Creation. Their range of incredible, designer 3D printed products includes lighting, furniture, trays, bags and jewelry.

Future Applications

Whether or not they arrive in the home, 3D printers have many promising areas of potential future application. They may, for example, in future be used to output spare parts for all manner of products, and which could not possibly be stocked as part of the inventory of even the best physical store. Hence, rather than throwing away a broken item (something unlikely to be justified a decade or two hence due to resource depletion and enforced recycling), faulty goods will be able to be taken to a local facility that will call up the appropriate spare parts online and simply print them out. NASA has already tested a 3D printer on the International Space Station, and recently announced its requirement for a high resolution 3D printer to produce spacecraft parts during deep space missions. The US Army has also experimented with a truck-mounted 3D printer capable of outputting spare tank and other vehicle components in the battlefield.

Another possible future application is in organ printing (also known as bioprinting or tissue printing). This is where replacement parts for the human body may be printed via an inkjet style process with the nozzles outputting layers of living cells. This is also an area of rapid development, with the US National Science Foundation currently funding a multidisciplinary project (see organprint.missouri.edu). As reported here, Organovo recently took delivery of the first production model 3D bio-printer manufactured for it by Invetech.

Another pioneer of 3D organ printing is Japanese scientist Makoto Nakamura. As reported in this fascinating article, he is working on modified inkjet printers that can output different types of cells. He has also already successfully bioprinted tubes similar to human blood vessels. Epson, apparently, are even providing him with technical support!

As reported by Nature in March 2008, a company called Organovo has already managed to output blood vessels and cardiac tissue via a printer that dispenses cells instead of ink. The material so created actually fused into living tissue just 70 hours after being printed, and started beating 20 hours after that. Replacement bones or parts thereof are another obvious application for 3D printers in the future, with 3D patient scan data used to enable doctors to print precise replacement parts before any flesh is cut.

Another potential 3D printing application is in the culture industries. Sculptor Bathsheba Grossman already uses 3D printers to create her works. In the future, museums could also print out exhibits as required from their own digital collection, or indeed from a global archive of artworks scanned from long-lost or too-delicate-to-display originals. You can find out more about 3D artworks, including a great video, on the Singularity Hub.

A Solid Tomorrow

In an age in which the news, books, music, video and even our communities are all the subjects of digital dematerialization, the development and application of 3D printing reminds us that human beings have both a physical and a psychological need to keep at least one foot in the real world. 3D printing has a bright future, not least in rapid prototyping (where its impact is already highly significant), but also in medicine, the arts, and outer space. Desktop 3D printers for the home are already a reality if you are prepared to pay for one and can find an application. 3D printers capable of outputting in colour and multiple materials also exist and will continue to improve to a point where functional products will be able to be output. As devices that will provide a solid bridge between cyberspace and the physical world, and as an important manifestation of the Second Digital Revolution, 3D printing is therefore likely to play some part in all of our futures.

For a fasciating glimpse at a wide range of amazing and unusual printers -- including concrete printers, glass printers, bioprinters, and printers that print on toast! -- click here. You may also find interesting the website Fabbaloo.com, which is dedicated to personal manufacturing and 3D printing. Hurrah!