Case History

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Case History

An increasing number of things, from mock-ups of new consumer products to jewellery and aerospace components, are being produced by machines that build objects layer by layer, just like printing in three dimensions. The general term the industry uses for this is "additive manufacturing", but the most widely used devices are called 3-D printers. They are making their way not just into workshops and factories, but also into the offices of designers, architects and researchers, and are being embraced by entrepreneurs who are using them to invent entirely new businesses.

The 3-D printers currently available use a variety of technologies, each of which is suited to different applications. They range in price from under $10,000 to more than $1m for a high-end device capable of making sophisticated production parts. Depending on the size of the object, the material it is made from and the level of detail required, the printing process takes around an hour for a relatively small, simple object that would fit into the palm of your hand, and up to a day for a bigger, more sophisticated part. The latest machines can produce objects to an accuracy of slightly less than 0.1mm.

The ability of 3-D printers to speed up the design process will have a big impact on industry. Machines can produce not only solid things out of plastic-type materials, but complex ones with moving parts too, such as a working model of a bicycle chain or a small gearbox. And they can print objects in multiple materials, such as a plastic remote-control unit with rubbery buttons.

The first step in all 3-D printing processes is for software to take cross-sections through the part to be created and calculate how each layer needs to be constructed.

Such machines build up objects, a layer at a time, by dispensing a thin layer of liquid resin and using an ultraviolet laser, under computer control, to make it harden in the required pattern of the cross-section. The build tray then descends, a new liquid surface is applied and the process is repeated. At the end, the excess soft resin is cleaned away using a chemical bath.

It is anticipated that the market will be developing in two directions. On one hand, there will be more demand for cheaper and simpler 3-D printers capable of quickly turning out concept models, which are likely to sit on the desks of engineers and designers. On the other hand, there will also be demand for more elaborate machines with added features and higher performance, the most elaborate of which will provide a cost-effective way to manufacture thousands, and perhaps even tens of thousands, of components. Today's rapid prototyping, in other words, will shade into tomorrow's rapid manufacturing. There is a close analogy with the development of document printers, which range from small, cheap devices for home use to industrial printing presses capable of producing high-quality glossy magazines.

Today's largest and most expensive 3-D printing machines, capable of directly producing complex plastic, and metal and alloy components, are becoming increasingly popular in the consumer-electronics, aerospace and carmaking industries. It is not just their ability to make a small number of parts, without having to spread the massive toolup costs of traditional manufacturing across thousands of items, that makes these machines useful. They can also be used to build things in different ways, such as producing the aerodynamic ducting on a jet-fighter as a single component, rather than assembling it from dozens of different components, each of which has to be machined and tested.

Many in the industry believe that low-cost 3-D printers for the consumer market will eventually appear. A new model was launched costing less than $10,000 . That may sound a lot, but it is what laser printers cost in the early 1980s, and they can now be had for less than $100.

Medical applications of 3-D printing also have a lot of potential. It is already possible to print 3-D models from the digital slices produced by computed-tomography scans. These can be used for training, to explain procedures to patients and to help surgeons plan complex operations. Some hospitals have started using 3-D printing to produce custom-made metallic and plastic parts to be used as artificial implants and in reconstructive surgery.