14 November 2011

New manufacturing process adds up

RMIT University academics are looking at the use of selective laser melting equipment to make small but expensive titanium-based components.

The SLM process is an aspect of additive manufacturing – a form of 3D printing technology.

Many see it as vital for the future competitiveness of the Australian manufacturing industry.

With additive manufacturing, parts can be built directly from computer models or from measurements of existing components to be re-engineered, bypassing traditional manufacturing processes such as cutting, milling and grinding.

SLM equipment at RMIT’s Advanced Manufacturing Precinct spreads a fine metallic powder in a thin layer typically 50 micrometres thick.

A laser beam scans along a path based on the shape of the part to be manufactured, melting the powder and fusing it to the layer below and producing a metallurgical bond between them.

The technique allows functional components to be built while minimising the material wastage associated with subtractive technologies such as turning and milling.

Professor Milan Brandt, Professor of Advanced Manufacturing in the School of Aerospace, Mechanical and Manufacturing Engineering at RMIT, is leading a new research project using SLM.

His team is working with the Defence Materials Technology Centre (DMTC), Lockheed Martin, 3D Systems, the University of Wollongong and the Defence Science and Technology Organisation (DSTO).

Their aim is to deliver new manufacturing technology for the production of small-scale, high-value titanium-based components for the Joint Strike Fighter (JSF), to increase local capability when bidding for defence and civil-related manufacturing projects.

The JSF program, run by the United States Department of Defence, aims to produce affordable next-generation strike aircraft weapon systems for the United States Navy, Airforce, Marines and its allies, including Australia.

An important aspect is reducing the cost of manufacturing titanium components, which are attractive because of their high strength to weight ratio, the ability to retain that strength at high temperatures and high corrosion resistance compared to other alloys.

Professor Brandt said a major problem of manufacturing components from titanium alloys was the high rate of wastage. Technologies which cut waste would significantly impact the cost of manufactured titanium components.

He said aerospace manufacturer Lockheed Martin was using additive technologies for large components and wanted to know if the same approach could be adopted for smaller parts.

“Initially we want to find out the effects of various parameters on the microstructure of the built titanium structures and the difference in mechanical properties between vertical and horizontal builds,” he said.

“This will then be used to redesign and manufacture the components based on bionic principles.

“At the end of the day it is all leading to manufacturing small-scale JSF titanium components more efficiently and effectively while maintaining their quality and integrity.

“On the fundamental scientific level our objective is to increase the understanding of the SLM process and translate that into practical information for the uptake by industry.”

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