Defence industry set to propel additive manufacturing into the mainstream

The defence industry has traditionally been at the cutting edge of technology – and for good reason. The need to stay one step ahead of the enemy has meant that defence industries are not only able to be, but are actively required to be somewhat less risk-averse than some of their civil counterparts.

This need to be flexible and quick to respond has long meant that the defence sector has been an early adopter of certain technologies, being able to circumvent many of the assessment and evaluation processes that necessarily delay other sectors. This peculiar set of circumstances has made defence a fertile breeding ground for innovation in the use of additive manufacturing (AM) technologies. In some senses, of course, there is a near-perfect fit between AM and defence. Defence often requires parts quickly, in low volumes (often singly, in fact) and to allow for rapid reconfiguration, modularity and even 'on the fly' redesigns. These and other factors mean that additive manufacturing is moving further and faster in the defence sector than elsewhere. Jeff DeGrange, Stratasys' vice president, new business development in direct digital manufacturing, says: "The necessity for the design process to move quickly is a huge pull for AM. You can reconfigure vehicles very quickly based on additive manufacturing and in the CAD process." One area where AM has seen rapid and extensive adoption is in Unmanned Aerial Vehicles (UAVs). Their unmanned nature means that safety concerns are somewhat lessened, of course, while the constant and pressing need to adapt them makes them ideally suited to the application of AM. "Adoption of additive manufactured parts in unmanned vehicles is much, much easier," says DeGrange. "But also, the designers are always trying to push five pounds of stuff into a three-pound area. So how can you do that from a product design point of view? Well now you can actually optimise design and have freedom of design. You can do that in such a way that you can get as much electronics or hardware as you need to get into a structure. It gives you the ability to design what you need to do with the additive processes. In the UAV and drone community there has been a huge pull for the technology and one of the main reasons is in order to put that five pounds of stuff into a three-pound area." One example of a company doing precisely this is France-based Survey Copter. A subsidiary of the European Aeronautic Defence and Space Company NV (EADS), specialises in the design, production and integration of complete remote systems for surveillance photography and video service applications for UAVs and other airborne craft, as well as for sea and overland vehicles. Having previously outsourced its prototyping requirements, Survey Copter turned to Stratasys for an in-house solution that could reduce costs and ensure greater efficiency and autonomy, granting the company the means to rapidly produce very small quantities within 24 hours. Via Stratasys' French distributor CADvision, Survey Copter subsequently installed two 3D printing solutions – a Stratasys Dimension Elite 3D Printer and Stratasys Fortus 400mc 3D Production System, which offers nine production-grade engineering thermoplastics using Stratasys' patented Fused Deposition Modelling (FDM) technology. "Effectively meeting our 3D printing needs can only be achieved via machines that are capable of producing quality parts with high reliability," explains Jean Marc Masenelli, managing director of Survey Copter. "Stratasys' reputation for delivering 3D printers that meet these criteria head on made them the logical company with which to partner." Spearheading Survey Copter's prototyping and short-run manufacturing activities, the Stratasys Fortus 400mc and Dimension Elite 3D Printers are deployed in the production of component parts for the company's mini-UAV systems, including both helicopter and fixed-wing variants weighing up to 30kg and 10kg respectively. Ranging from a few millimetres up to parts measuring 40cm x 10cm, these components comprise mechanical structures for optical turrets, structural elements of aircraft, battery compartment housing, supporting structure, as well as scale models. For Masenelli, the ability to utilise different materials according to specific application needs offers key advantages for producing durable 3D printed parts. Such materials include FDM thermoplastics polycarbonate, ABS and high-performance ULTEM 9085 which boasts superior strength and lightweight properties, as well as other desirable characteristics including FST (flame, smoke and toxicity) rating. This safety standard, particularly valued within the aerospace and transportation industries, ensures a material won't promote a fire, release harmful smoke, or emit toxic fumes. "That we are able to print production-grade materials such as high-performance FDM thermoplastics like ULTEM, which is qualified for aerospace applications, is a definite plus for our operations," he explains. "The Stratasys 3D Printer can produce parts with complex shapes – for us a highly sought after requirement and a principle differentiator that sets Stratasys' proposition apart from that of other providers," he adds. "This specific capability enables us to produce parts of wide-ranging dimensions and hollow forms, as well as full honeycomb structures." Featuring two material bays for maximum uninterrupted production, the Stratasys Fortus 400mc 3D Production System produces accurate, durable, repeatable 3D parts with superior throughput. It is available in two configurations: the basic system which builds parts as large as 355mm x 254mm x 254mm, and an optionally upgraded system which builds parts as large as 406mm x 355mm x 406 mm. With four layer thicknesses to choose from, users can fine-tune their desired balance between FDM's finest possible feature detail and the fastest build. The Stratasys Dimension Elite 3D Printer features the finest resolution of any Stratasys Design Series Performance 3D Printers and produces nine colours of real ABSplus thermoplastic. When the finest dimension resolution of 0.178 mm is not required, the Dimension Elite allows users to accelerate printing with a layer thickness of 0.33 mm. According to Jeff DeGrange, the impact of AM in the defence sector is only just beginning to be felt. He believes, in fact, that it will fundamentally alter the way in which products are made completely. He says: "I think in the defence industry that you're not going to see tens of thousands of military products being produced anymore. I think you're going to see maybe a thousand of the objects being produced and then maybe a faster evolution of those original products." He continues: "The enemies are finding a way to counter defence innovations, so that evolution has to be matched and bettered. So, for instance, if you're using small UAVs in the Middle East and you're using a lot of those and they're being shot down, you may need a redesign to allow you to fly at a greater altitude or a greater airspeed. So you're going from model one to models two and three very quickly. Alternatively, what if you need to have a base system that you can reconfigure to do multiple missions – ie putting on different wings to allow you to have extended ranges or to carry a greater payload? So the idea is to be able to do that easily. AM can achieve that."