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3D print your own Aston Martin


LIKE most people, Ivan Sentch realises that unless he wins the lottery, buying an Aston Martin DB4, his dream car, will always be out of reach. Just last month a 1960 series II model sold at auction for $US550,000 ($607,000). But the computer programmer has a backup plan. He is printing the car, piece by piece, in his garage, until he has a working replica.

For the past year the car's raked back, windscreen pillars, swooping roofline and distinctive side "gills'' have been slowly emerging from a 300 3-D printer at Sentch's home in Auckland, New Zealand. Working from a digital model downloaded from the internet, Sentch, 32, has split the car's panels into hundreds of 10cm x 10cm pieces so they can be replicated by his small Solidoodle 2 printer, which slowly builds up the shape, layer by layer, with molten plastic that is directed through a nozzle, taking about eight hours for each part.

The printed shapes are glued together to make moulds for fibreglass panels. These are mounted on a metal frame, containing the engine, gearbox and suspension from a Nissan Skyline coupe, to make a working car looking identical to a DB4. It has taken a year to print the bodywork in full. Now Sentch plans to start on the interior.

"If it was not for 3-D printing, I would not have been able to do this project,'' he says. "The normal way of doing it is to mill the shape out of foam, which is too expensive, or to shape it by hand, which was too big an undertaking.

"By doing it this way, the final cost, including the printer, plastics and the donor car, will be around $NZ40,000 ($37,700). I hadn't thought about using a 3-D printer before this: it was just a solution to a problem.''
He is not the only car enthusiast to find that the rapidly developing technology will allow him to build a dream car.

In 2008 Citroen unveiled its GT concept car, which was designed for a computer screen. It was featured in the Gran Turismo 5 PlayStation game, but in real life its sharp lines, gaping air intakes and wraparound windscreen were a step too far for the French company. Apart from a prototype driven by a few journalists, the GT remained firmly on the drawing board.

Now, slowly emerging in a Toronto garage is a replica of the car, formed on a MakerBot 3-D printer. "I fell in love with the car when I saw it for the first time and I thought that I'd have a go at making it,'' says the owner, who gives his name only as Arthur K, fearing that Citroen will take a dim view of his project. Like Sentch, Arthur will make the panels out of fibreglass and needs plastic moulds.

"I have got no modelling skills at all, so I can't translate what I see into a clay or foam model,'' he says. "I've downloaded a 3-D model and I'm printing the doors, the interior, the skirts on the front, rear and side, as well as the mirrors.''

There are limits on what the MakerBot can do, though: the engine will come from a Chevrolet Corvette and the gearbox from a Porsche Cayman. The oldest 3-D printers were built in the mid-1980s, but consumer versions have emerged only in the past five years, and at first there were few obvious things to make with them. Now it's the car industry that is planning to make greatest use of the technology.

Dealerships may no longer have to keep your car for days until a part is delivered: they could print it on the spot. Classic car owners won't have to track down a rare panel: as long as they can get a copy of the blueprints, they will be able to create a replica at home. American chat show host Jay Leno is using the technology to maintain his garage of almost 200 cars.

"My 1907 White Steamer has a feedwater heater and over the 100-plus years it's been in use, the metal has become so porous you can see steam and oil seeping through,'' he wrote in Popular Mechanics magazine.

"Rather than have a machinist try to copy the heater and then build it, we decided to redesign the original using our NextEngine 3-D scanner and Dimension 3-D printer, which makes an exact copy of a part in plastic, which we then send out to create a mould.

"It's like The Jetsons. George Jetson would say, I want a steak dinner. He'd press a button and the meal would come out of the machine, with the roasted potatoes and everything, all on one plate. We may not have the instant steak dinner yet but my NextEngine system is like the car-guy equivalent.''

Ford embraced 3-D printing after it printed an engine intake system in four days at a cost of $US3000. The company said a prototype component would have cost $US500,000 and taken four months to make. "We can go from art to part overnight,'' says Matt Zaluzec, Ford's global materials manager. "Three-D printing is all the rage now.''

TJ Giuli, leader of Ford's research lab in Silicon Valley, California, is looking at how owners may be able to adapt their cars. "What we really want to do is give people the same kind of acces-sibility they used to have for tinkering with their car, maybe when it was the 1950s, 1960s," he says. "We are interested in seeing how you can use techniques to personalise your car in interesting ways reminiscent of when cars were much more accessible.''

Audi has five 3-D printers producing prototype parts for models that run for 24 hours a day, seven days a week. Jaguar Land Rover used a 3-D printer from Stratasys to make the air vents in development versions of the Range Rover Sport.

Each winter BMW takes its cars to the Arctic for cold weather testing. In recent years the vehicles have been accompanied by a 3-D printer so replacement or redesigned parts can quickly be produced and fitted. Many Formula One teams also have machines in pit lane.

Some Lamborghini Gallardo customers had 3-D printed parts fitted after a production problem meant the flap covering the headlight washers was not fitting properly. Instead of holding up production, a new part was produced on a 3-D printer made by an Italian firm called CRP.

One hundred cars had left the production line before the tools for the redesigned part were finished, after which the part could be produced normally using injection moulding. Even Rolls-Royce is using the technology, producing life-size models of bespoke fittings.

"Buyers might want a drinks-carrying solution to hold a certain type of water bottle or champagne bottle,'' says James Warren, a Rolls-Royce spokesman. "We can present them with several options to ensure that the final version is right first time.''

For now, though, 3-D printers are unlikely to replace the stamping, pressing and moulding that take place on a production line because they simply take too long. Some of the most precise shapes are built up in layers only 127 microns thick. It takes 100 of these layers to make a part 13mm thick. But for enthusiasts who cannot afford today's stratospheric classic car prices, 3-D printing is a way to make their dreams come true.

SEVEN STEPS TO 3D HEAVEN

1. Buy a printer

The Solidoodle 4 ($1100, solidoodle.com) and MakerBot Replicator 2 ($2895, thinglab.com.au) are both popular consumer printers.

2. Download the 3D digital design

Websites include humster3d.com and turbosquid.com. Patterns cost from about $55.

3. Find a donor car

It should have similar dimensions to the car you're recreating and will provide the underbody components. Panels and trim will be replaced.

4. Adapt the design

Use 3D modelling software to adjust the digital design so it can be attached to the donor car. Divide it into small printable parts.

5. Fabricate

Form the fibreglass panels using the plastic as a template - a time-consuming process.

6. Fit

The moment of truth: find out if your calculations and processes were correct.

7. Paint

A good paint job can cost more than $10,000.