New Aluminium Processing Technique Allows Complex Prototypes to be Produced in Two Days

Producing one-off metal parts quickly for testing in cars or machinery has usually been the domain of plastics.

But two University of Queensland researchers have designed a new aluminium alloy and treatment process to turn aluminium powder into a specialised part in two days.

Polymers have traditionally been cheaper to make and easier to use for specialised test parts but have lacked metals’ strength and durability.

The alloy composition and process, created by UQ’s powder metallurgy unit head Professor Graham Schaffer and research fellow Dr Tim Sercombe, involves selective laser sintering (SLS) of a mix of aluminium and nylon powders.

SLS is one of about 20 methods of rapid prototyping, which produces the shape of the part.

“In all of these rapid prototyping technologies you build parts up, layer by layer,” Professor Schaffer said.

“Free form fabrication or rapid manufacturing . . . is the direct transformation of a computer drawing into a finished, functional part without using tools or a die.

“You take a 3D (three dimensional) computer model and slice it in to virtual layers.

“Each layer is about 75 micrometers thick [less than a human hair] and you put those layers down sequentially, one on top of the other, and build the part that way, from the bottom up.”

He said the shaped part was put in a furnace and reacted with nitrogen gas which created an aluminium nitride skeleton.

The part was then infiltrated with a second aluminium alloy to leave a strong, dense component.

The three-year UQ project was funded by Californian manufacturer 3D Systems and UK-based The Aluminium Powder Company and licenced to 3D Systems for commercialisation.

So far, parts up to 20 centimetres long have been made, including gears, pulleys, wheels and chess pieces.

Professor Schaffer said the system would probably be used to produce small, complicated shaped mechanical parts, but there was no size restraint.

“The key is that we can make very complicated shapes, very quickly.

“You send us a drawing of a part and we’ll put the part in a FedEx envelope and mail it back to you in two days.

“The market for aluminium parts is substantial because the automotive industry is one of the biggest users of rapid prototyping and they’re also one of the biggest users of aluminium.”

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