Smart move

Research is underway to convince automotive manufacturers that components produced using rapid prototyping are functional and not as fragile as is widely thought.

A project to rebuild smart car parts using rapid prototyping aims to show how the technology can be used to manufacture functional components.

The project, which will be based at the Newbury headquarters of RP expert 3T RPD, will attempt to replicate or redesign the car’s components, and rebuild them using selective laser sintering (SLS).

This is a process by which plastic or metal components are built up layer by layer from a powder selectively bound together by a laser beam.

The vehicle will then be driven in normal, everyday conditions to demonstrate the behaviour of the components in true working environments, thereby increasing the database of knowledge surrounding the technology.

Tim Plunkett, 3T RPD’s chief executive, believes the experiment will change the perception that components made on RP machines are fragile. ‘We’re trying to prove that this is not just a prototyping concept but a production concept as well. We know from experience that the capability of these laser sintered parts is way beyond peoples’ normal expectations,’ he said.

It is likely that one of the first parts to be replicated will be the radiator grille. Plunkett said that as it is open to the elements, a laser sintered grille would demonstrate perfectly the hardiness of today’s RP materials.

Plunkett said that his team will also be looking into using the technique to customise car parts. For instance, the Smart car’s engine is in the boot, and is fed air by an intake that is flush with the side of the car. Computational Fluid Dynamics (CFD) work carried out by Plunkett’s team has indicated that by putting an air scoop over the intake it will be possible to boost the air inlet pressure on the engine and up the power input.

To manufacture this air-scoop as a custom-component would be prohibitively expensive using traditional production methods such as injection moulding. RP, however, is able to deal with complex geometries which means that mass-customisation becomes cost-effective. This, said Plunkett, is where RP’s immediate future lies.

‘Sintering is a way to make custom components without tooling that is not complex, and we’re trying to prove that the materials can cope with it which would make it a very neat production technique.’

Plunkett cited Phonac and Siemens who both use laser sintering to make digital hearing aid enclosures. ‘They make thousands in a 12-hour build and each one is customised to a particular client’s ear,’ he said. Since introducing the system, rejects due to customer discomfort have plummeted.

In the longer term, Plunkett said that one of the technology’s great potential advantages will be the ability to build graded parts – where a varying grade of powder throughout the part could be used to create flexible areas and stronger areas.

‘For instance,’ he said, ‘you may require a part under the bonnet where a hard duct isfollowed by a flexible joint, followed by a hard duct.’ While a part like this is now produced using something like a two-shot moulding process, RP could be used to produce it in one go.

But will the technology ever be capable of reproducing active mechanical components? ‘It’s not going to happen next week, but as materials and processes develop it’s certainly going to happen,’ said Plunkett.

Graham Lindsay, UK manager of RP giant 3D Systems, agreed: ‘In 20 years’ time, I think there will be RP machines in the home, and if someone comes round to repair your washing machine, they’ll be able to download the part off the web and produce it there and then,’ he said.

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