It has been said that 3D printing will change the world. Described as ‘the second industrial revolution’ by experts, academics and the media, 3D printing has the potential to impact all industry sectors. MOD DCB takes a look at how 3D printing is being used in the defence industry.

3D printing is a revolutionary technology. It is the layer-by-layer building of a three-dimensional solid object of virtually any shape on a 3D printer. 3D printers work like inkjet printers, but instead of ink they deposit desired materials in successive layers to create a physical object from a digital file, such as a Computer Aided Design (CAD) drawing. The successive layers of material are laid down in different shapes and are bound or fused until the object is produced.

The first working 3D printer was created in 1984 by Chuck Hull of 3D Systems Corp and the process has been used widely in prototyping. Over the years, however, the idea and technology has been advanced and used in a variety of different industries. The last decade has seen 3D printing used in almost everything from the creation of aerospace components to toys, prosthetic legs, functioning kidneys and blood vessels.

In the defence industry, the developing interest in 3D printing technology is global. There have been reports that China is printing aircraft parts and putting them directly into J-15 fighters on the runway. The US Department of Defense has been spending on 3D printers, supplies and upkeep since the 1990s, while Singapore has reportedly recently invested $500 million in its own 3D printing programme.

3D printing could be ideal for meeting the urgent operational needs of warfare. One obvious advantage would be to 3D print damaged components in hostile environments rather than wait for replacement parts to arrive. In extreme cases, vehicles fitted with 3D printers could produce components in the field. Perhaps it would be safer to 3D print sensitive objects on-site rather than risk them falling into the wrong hands while in transit. Providing you have the desired digital designs and materials, 3D printing enables you to develop desired objects on the spot when needed rather than placing an order and waiting on the supply chain to deliver.

3D printing processes are becoming prominent in the creation of Unmanned Air Vehicles (UAVs). In 2011 engineers at the University of Southampton designed and flew the world’s first 3D printed aircraft. The UAV was built in seven days for a budget of £5000 – a tiny sum considering 3D printing allowed the plane to be built with normally expensive elliptical wings. No fasteners were used and all equipment was attached using ‘snap fit’ techniques so that the entire plane could be put together without tools in minutes. The electric-powered aircraft, with a two-metre wingspan, has a top speed of nearly 100 miles per hour, and when in cruise mode it is almost silent.

A direct descendant of this is 2Seas; a UAV designed to fly lengthy surveillance missions for coastguards in the UK, the Netherlands, Belgium and France. The wings and the tail are made out of carbon fibre, but the central wing box, fuel tank and engine mounting are all manufactured by 3D printing. 2Seas has a flight time of six hours, cruises at 55mph and could soon be monitoring the English Channel and the North Sea for risks to shipping, illegal fishing operations and even drug-running boats.

2Seas’ wings were made from carbon fibre because although 3D printing has been highly successful in producing small objects, there have been problems when making reliable larger components such as wings – until now. Reports have emerged that BAE Systems recently developed a ground-breaking technique that reduces the distortion in 3D printed metal parts, ensuring there are no defects in the metal. It could potentially lead to the production of quality large components with enough strength to use in aircraft.

The potential for 3D printing doesn’t end there. The process has also been used to create complex objects than can include both chemical and biological elements. For example, there has been progress in research into 3D printed medicine. In 2012, the University of Glasgow demonstrated that it is possible to use 3D printing techniques to create chemical compounds, including new ones. Professor Lee Cronin, Gardiner Chair of Chemistry at the University, believes his research could lead to the development of home chemical fabricators which could be used to design and create medicine on location.

Using a commercially-available 3D printer, Professor Cronin and his team built what they call ‘reactionware’, special vessels for chemical reactions which are made from a polymer gel which sets at room temperature. By adding other chemicals to the gel deposited by the printer, the team have been able to make the vessel itself part of the reaction process. While this is common in large-scale chemical engineering, the development of reactionware makes it possible for the first time for custom vessels to be fabricated on a laboratory scale.

Professor Cronin said at the time: “3D printers are becoming increasingly common and affordable. It’s entirely possible that, in the future, we could see chemical engineering technology which is prohibitively expensive today filter down to laboratories and small commercial enterprises.

“Even more importantly, we could use 3D printers to revolutionise access to health care in the developing world, allowing diagnosis and treatment to happen in a much more efficient and economical way than is possible now.

“We could even see 3D printers reach into homes and become fabricators of domestic items, including medications. Perhaps with the introduction of carefully controlled software apps we could see consumers have access to a personal drug designer they could use at home to create the medication they need.”

Access to medicine in a manner such as this could be very effective for the military in the field. The urgent access to medicine in remote parts of the world could be aided by 3D printing techniques. The possibilities and potential benefits appear endless.

3D printing technology is also being studied by biotechnology firms and academia for possible use in tissue engineering in which organs and body parts are built. For some time now 3D printers have been used to build joints, titanium cranial plates and prosthetic limbs but the printers are also being used to build layers of living cells. The cells are deposited onto a gel medium or sugar matrix and form three-dimensional structures including vascular systems.

Research at Princeton University has taken this further by 3D printing a bionic ear. 3D printing enabled the team to achieve a seamless integration of electronics, in this case a coiled antenna, with biological tissue and the human body. The bionic ear can receive and transmit sound, pick up radio signals and also hear signals a million times higher than a human ear can.

Manu Sebastian Mannoor, part of the team at Princeton’s Department of Mechanical and Aerospace Engineering, believes this kind of technology can benefit the defence industry in areas such as surveillance and communication.

Mr Mannoor said: “We were able to demonstrate the creation of a bionic ear that possesses both biological and electronic functionalities. The ear is able to listen to radio signals via an embedded coil antenna also created using 3D printing. One could envision the use of such a technology for eavesdropping on covert sounds or even as a means of military communication.

“The traditional uses of 3D printing have been to make passive and mechanical parts and also to make figurines, guns etc. Our idea is to utilise the potential of this technology to enable multimaterial assembly to create multifunctional devices. This could have a variety of applications in various fields from biomedicine to defence.”

One question would be: Are 3D printed products top quality? Mr Mannoor thinks so. He said: “Quality wise, 3D printed products can be even better than the counter parts that are created with any other means. In the case of our research outcomes, 3D printing serves as a unique and only way to create such an integration between electronics and biology.”

It’s hard to predict just how big an impact 3D printing will have in the long run. In simple terms this is a technology that has the potential to change the way we look at making a product or object. Basically, by having CAD drawings, it’s possible to print out any desired object on a bench top. It’s clear the potential is there for it to revolutionise not just the defence industry, but all industries. As 3D printing techniques and the quality of 3D printed objects improve it probably shouldn’t be surprising if we see more exceptional 3D printing innovation in the future.

For further Information, visit: www.gla.ac.uk, www.princeton.edu/~mcm/