Enter the third dimension

Have you got a screw loose? When you need some DIY essentials in the future, there will be no need to drive to the hardware store. Just download the exact size of the component you need and print it off in 3-D.

It might sound futuristic, but the era of 3-D printers in our homes is almost upon us. It promises to be the ultimate bespoke home shopping experience, where everything from a piece of furniture or a picture frame to a pair of shoes can be customised, designed and produced entirely at home.

'Down-fabbing' - fabricating an object at home using a downloaded digital design and a 3-D printer - is becoming more and more popular in industry. Some analysts predict that in 20 years, 3-D printers will be as common in homes as laser printers are today. For now, 3-D printers, also known as personal fabricators, are too expensive for consumers but are increasingly being used in engineering to manufacture prototypes cheaply.

Traditionally, dedicated tooling machines had to be created to produce each separate component of a product. But this new generation of mechanised modellers makes developing one-off prototypes much quicker.

Taking three-dimensional data from a computer, the printer slices the virtual object into cross sections before depositing layer after layer of wafer-thin material to create an actual object.

The resolution of both the printer and the image determine how many cross-sectional layers are produced and therefore how detailed the finished product is. More than one material may be used. With reservoirs for several different materials, a 3-D printer can produce simple toys and tools.

Since the technology is so expensive, it's better used for one-offs and bespoke household items such as special plates and cups. Customised, unique products are a 3-D printer's raison d'?tre. A designer can create something on a computer and have a plastic model printed out overnight. But there is a catch, aside from the high price: it can take days for a 3-D model to be produced.

Despite that, the race is on to develop the technology for homes.

'Companies such as Shapeways, MakerBot Industries and Ultimaking are paving the way for the use of 3-D printing for consumers,' says Pieter Hermans, who heads Jakajima, a company that hosted a 3-D printing conference in the Netherlands. 'As 3-D printer prices are getting more affordable by the day, eventually they will become normal home gadgets.'

MakerBot Industries recently received US$10 million in financing to drive its development. The Brooklyn, New York-based company sells an open source 3-D printer called the MakerBot Replicator, which is small enough to sit on a desktop and can produce two-tone objects as big as a loaf of bread. It costs HK$15,500. A commercial 3-D printer will currently set you back as much as HK$1 million.

Another problem is ink. Ink for standard printers is already among the most expensive commodities in the world. Although most use some kind of plastic or nylon material, 3-D printers can just as easily output 'inks' made from silicone, cement, stainless steel, copper, nylon or glass. So you might just find yourself waiting for a shipment of liquid titanium to arrive in the post before you can finish printing.

It could mean a run on the world's raw materials, though 3-D printers could just as easily be about consumption of a completely different kind. 'Digital gastronomy' - 3-D food printing - using gently heated reservoirs of chocolate, for instance, is more about industrial mechanisation than a technology for the home, but it shows what 3-D printers can achieve.

For bespoke food to catch on, it would need to promise something new - texture, gravity-defying shapes or a presentation so precise as to be beyond the wit of the human hand.

We may also be one step closer to piecing together the past, with robot dinosaurs.

'Technology in palaeontology hasn't changed in about 150 years,' says associate professor Kenneth Lacovara of Drexel University in Philadelphia in the United States. 'We use shovels and pickaxes and burlap and plaster - until now.'

As well as producing synthetic copies of fossils and dinosaur bones for display, Lacovara is using 3-D printers to reproduce small-scale models of the biggest creatures. By scanning in bones from the 60-80 tonne paralititan stromeri dinosaur, a 3-D model of the creature can be constructed on a much smaller scale. Ultimately, a moving robot version can then reveal exactly how the beast moved, something that would otherwise be impossible.

'It's kind of like Star Trek technology, where you can press a button and the object pops out,' says Lacovara.

Often thought of as a novelty technology, 3-D printing is more than skin-deep. Using a 3-D printer with silicone gel or plastics as its 'ink', it's possible to repair or produce body parts such as bones, ears, cartilage or skin. Such 'bio-printing' could make skin for use in burns units. Hip replacements and organ transplants also on the horizon for 3-D printers.

The only limit to the innovations and inventions 3-D printing can bring forward, it seems, is the creativity of the human mind - and who knows how long it will be until we can print that out?