3D printed reindeer
3D printed reindeer

Christmas has come early for Professor Moataz Attallah: the first multi-laser metal 3D printer to be installed at a university anywhere in the world – and the largest on a European campus – recently arrived at Birmingham.

Just in time to start making festive gifts, in fact! For Moataz, Professor of Advanced Materials Processing, believes it won’t be long before we are printing our own Christmas presents.

To demonstrate this, two years ago three of his post-doc researchers created an aluminium 3D laser-printed reindeer. In a process properly known as selective laser melting or additive manufacturing, they used lasers to fuse thin layers of metal powders sequentially spread on a substrate to build the reindeer bottom upwards based on a computer geometrical model of the animal. The complex features in the body were a special mesh-like structure with unique mechanical properties that can be applied in a wide range of applications such as medical implants and structural parts in aeroplanes.

‘The joy of Christmas brought to you by 3D printing, where in the future Santa could be printing your Christmas presents,’ Moataz commented at the time. Today, the world-leading scientist explains that what makes the reindeer a standout additive engineering feat is its porous structure.

‘It’s designed to have a certain amount of space and a certain amount of material, so essentially you’re designing the volume, which means you can design the properties. One application is shock absorption. When you hit a lattice (or a mesh) structure of this kind, instead of a “bang” impact, the struts start to break one at a time, and it slows down the shock.’

Military armour could be modelled in a similar way, so that a bullet is trapped between the breaking struts, preventing it from passing through the material and into the body.

Another equally innovative and exciting application is customised medical implants. Moataz is working with Liam Grover, Professor of Biomaterials Science, to design porous structures or orthopaedic implant structures with cavities for drug-delivery, to administer drugs such as antibiotics or anti-inflammatory medicines following implantation. Instead of using an off-the-shelf implant that may work for some patients but not others, implants can be made that are specifically tailored to patients, or specifically tailored to address very complex injuries such as those sustained in war zones or on the sports field.

‘So, for example, instead of a hip replacement implant being solid, as it is now, it can be made using this technology so that it is hollow inside,’ explains Moataz. ‘This hollow area can be filled with drugs and then, when the implant is inserted into the patient, the drugs will leak out locally – rather than having to travel around the body first, if taken orally or through the blood – reducing the risk of infection and extending the implant’s life.’

The pioneering research Moataz has carried out over more than a decade at Birmingham has put the University at the heart of the ‘third industrial revolution’ – developing new materials and manufacturing processes for applications in the aerospace, nuclear and defence industries, in partnership with major firms. Cleaner, cheaper and more environmentally friendly than traditional casting or forging methods, theses novel processes are referred to as high-value or resource-efficient manufacturing.

Birmingham is the only UK university using a variety of metals, including nickel-base superalloys, titanium, ferrous alloys and aluminium, to make a range of complex components such as turbine blades for planes and pump housings for nuclear reactors.

Egyptian-born Moataz, who received his PhD in Metallurgy and Materials Science from Birmingham in 2007, has built up an internationally renowned research portfolio spanning nearly 15 years. As well as 3D printing, this has been focused on studying the changes the happen in the material during advanced manufacturing operations , including friction welding technologies and netshape powder hot isostatic pressing, and how these ‘microstructural’ changes impact the material performance. He has been involved in research partnerships with industry giants including Rolls-Royce, BAE Systems, Safran Group, and the European Space Agency in projects worth more than £10m.

It was with Rolls-Royce that Moataz used friction welding to develop a ‘blisk’, an aeroplane engine component comprising a rotor disk and blades where the titanium blades are joined to the disk or cylinder by rubbing the two parts together at very high speed. This replaces the mechanical joining method using a ‘fir tree’ blade, which makes the engine significantly heavier because of the weight of the ‘fir tree’ end of the blade. As a result, there are now planes with turbine engines 30 per cent lighter than a few years ago – thus maximising passenger, freight and fuel capacity.

Moataz is also involved in collaborative work with Kai Bongs, Professor of Cold Atoms Physics, to use metal additive manufacturing to create packages for quantum sensors. These sensors will make it possible to look accurately and non-destructively in many scenarios, from mapping pipework and cabling under the road surface before digging takes place to providing a non-invasive way of measuring brain activity to further research into dementia.

‘Our understanding of materials has improved, and so has our understanding of how to design them,’ he says. ‘Materials can be designed on different levels – chemical and microstructural. The materials we use are extremely flexible: there’s one type of steel for a sink and another for a medical implant, or a jet engine. There’s one type of titanium for an oil and gas application and another for an aero engine.’

Moataz believes 3D printing will develop significantly over the next decade, in the same way mobile phones have progressed in the past ten years. As well as Christmas presents, he says we could soon be seeing wholly printed houses, cars and planes.

‘My specific interest will continue to be the use of additive manufacturing to produce components for aeroplanes or for cars, and there is now a lot of emphasis on multi-disciplinary research,’ he observes. ‘Additive manufacturing is a solution provider and there are lots of new solutions that are needed. I envisage myself working more and more with researchers from a range of fields, from physics to biosciences. This is the way the impact of these technologies can be further magnified. All the time I’m talking to people about what we can do – and there is lots still to be done.’