3D printing takes to the skies

Materials World magazine
,
1 May 2015

The aerospace industry is gravitating towards 3D printing, as waste-, weight- and money-saving additive manufacturing techniques continue to improve. Simon Frost and Natalie Daniels look at some new applications of this technology. 

Airbus Defence and Space announced in March 2015 that it had produced its first space-ready 3D printed aluminium component, thanks to a two-year R&D programme assisted by Innovate UK and the UK Space Agency.

The company used aluminium additive layer manufacturing to make a structural bracket for its Eurostar E3000 telecommunications satellite that is 35% lighter and 40% stiffer than its traditionally machined counterpart, and also boasts minimal waste in production. While its predecessor comprises four parts joined by 44 rivets, the new bracket is produced from a single laser-melted piece of aluminium alloy. 

The bracket is used to mount telemetry and telecommand antennas, which enable the satellite to communicate with the ground station. It was manufactured for Airbus by 3T RPD Ltd, a production additive manufacturing company based in Newbury, UK, and has completed flight qualification testing, ready to be installed on a forthcoming satellite. 

Meanwhile, GKN Aerospace and Arcam AB are partnering to develop the next generation of electron beam melting (EBM) technology, which Arcam AB first patented in 2001. The plan is to create titanium components superior to those that are cast, and with comparable properties to wrought metal at a high volume and low cost.  

EBM works by using an electromagnetically powered electron beam to melt metal powders layer by layer in a high vacuum, resulting in stress-relieved parts that require very little finishing.   

When contacted by Materials World, GKN was guarded about the next generation of EBM, but the overall objective is to make machines capable of building complex titanium structures at very high production volumes. 

Rob Sharman, Head of Additive Manufacture at GKN, says, ‘You can not only stabilise the production to meet existing bulk material property requirements, but begin to tailor the microstructure and thus material properties as desired.’ 

Arcam and GKN will combine their expertise and facilities at GKN’s Centre of Excellence in powder bed additive manufacture in Bristol, UK and Arcam’s headquarters in Gothenburg, Sweden. 

This year, Rolls-Royce will flight test a version of its Trent XWB-97 engine – under development for the upcoming Airbus A350-1000 – fitted with the largest aerospace component built using 3D printing yet. 

The 1.5m-diameter titanium front bearing housing (FBH), which would normally be produced by casting or forging, is the first load-bearing jet engine component ever to be produced by 3D printing. 

The FBH was developed with the University of Sheffield’s Faculty of Engineering. Iain Todd, Professor of Metallurgy and Materials Processing, says, ‘For those of us that work in additive manufacturing, the barriers have not been the maturity of the technology itself, but the huge programme of testing, research and quality assurance that is needed for a new manufacturing process to gain approval.’ 

While the first XWB-97s in production will not contain the 3D-printed component, the project is a step towards proving the process, which Rolls-Royce claims could trim 30% from like-for-like manufacturing lead time.

And finally, GE Aviation made history in April 2015 when its new housing for a compressor inlet temperature sensor became the first 3D printed part to be certified for use in a commercial jet engine by the US Federal Aviation Administration. 

From our blog ...

In March, we shared the story of Cleopatra, the leopard tortoise with a brand new shell thanks to the wonders of additive manufacturing. A resident of the Canyon Critters reptile rescue centre in Colorado, USA, Cleopatra suffers from fibrous osteodystrophy, a metabolic bone disease that causes ‘pyramiding’, where parts of the shell stand out prominently. Roger Henry, a student at Colorado Technical University, created a 3D-printed protective shell over more than 600 hours of design. The new shell, printed with corn-based plastic polylactic acid, drapes like a piece of cloth over Cleopatra’s own ridges and is attached using Velcro. She’ll need new shells printed as she outgrows them, but her own shell could recover well enough in the next two years. Visit materialsworld.tumblr.com for more.

Printing for protection 

Researchers at MIT have 3D printed a flexible armour prototype inspired by elasmoid fish scales. A paper that details the work, published in Soft Matter in February 2015, describes how indentation and bending tests on the composite material, made of acrylic and elastomeric polymers, revealed good plate inclination angles and volume fractions. The lead researcher, mechanical engineer Stephan Rudykh, said, ‘This work is part of a revolution in materials properties. Once we can gain control over a material’s micro-properties, using 3D printing we can create materials of an entirely different type, each with the ability to be adjusted to fit the person, the need, and the environment.’ Researchers are still in early test stages and the next step will be to study the armour’s strength against bullets and shrapnel. 

A robot ant army

Goal-driven, indefatigable and revolutionary are three words that describe the 3D-printed bionicANTS designed by German engineering company Festo. Each of the plastic-bodied ants is 3D printed with electronic circuits placed on top. The ants’ six legs are made from ceramic actuators that bend easily. These artificial insects mimic the behaviour of the real thing – making autonomous decisions but communicating with one another to coordinate their actions. The ants were designed with the ‘smart’ future of factory production in mind.