Leonardo UK, a subsidiary of global defense manufacturer Leonardo Group, is increasingly integrating additive manufacturing across its operations. With 8,500 employees nationwide, the business is expanding its 3D printing operations to boost production capabilities and reshape Britain’s defense supply chain.
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Speaking at TCT 3Sixty 2025, Additive Manufacturing Technical Specialist Ross Herbert discussed how the technology is building resilience, accelerating production, and unlocking complex design.
Herbert works at Leonardo’s Edinburgh-based radar and advanced targeting systems facility, where the company operates in-house polymer 3D printers. It outsources all metal 3D printing to its 2,100 suppliers, two-thirds of whom are SMEs.
Leonardo’s additive manufacturing advantage extends well beyond rapid prototyping, spanning all stages of the product lifecycle, from jigs and fixtures to end-use parts. Herbert called AM a “need-to-have technology,” showcasing several mission-critical parts that conventional manufacturing can’t produce. Notably, 3D printing enabled the company to consolidate 3–4 parts into single components, unlock complex new cooling channels, and reduce the weight of its Fast Moving Mirrors by 80%.
Over the past year, Leonardo spent £1 billion with its UK supply base and invested £500 million in research and development (R&D). Herbert, a Chartered Mechanical Engineer who joined the company in 2011, emphasized the importance of building strong partnerships with its additive manufacturing suppliers.
“Without them, Leonardo doesn’t exist,” Herbert said. “There’s a lot of work that we’re looking to do to make sure the suppliers all have the confidence to adopt new technologies.” The effort spans multiple sectors, from aerospace and defence to automotive and energy, with the view that “a rising tide raises all ships.”
3D printing at Leonardo: climbing the “Slope of Enlightenment”
Leonardo’s additive manufacturing journey has not been without its pitfalls. Herbert described an early phase of over-enthusiasm after the company adopted the technology for production in 2014, likening it to climbing “Mount Stupid” on the Dunning-Kruger curve.
“We massively jumped on that bandwagon and then realised that certification and qualification get in the way,” he admitted. The result? “Some parts now sit as the most impressive paperweights you’ve ever seen.” Moving along the curve, by 2020 Leonardo had fallen into the “Valley of Despair,” before starting to climb the “Slope of Enlightenment.”
Now, the defense manufacturer pursues a more measured approach to 3D printing. “We’ve started to realise additive manufacturing is not a replacement technology for conventional manufacturing,” Herbert said. “It is there to augment the existing supply chain. It’s there as an additional tool in the toolbox.”
While most parts that are already CNC machined will not be replaced by 3D printing, the company is actively identifying where additive manufacturing can offer the most value. This will help to diversify “single source” supply chains and build greater resilience for defense applications. For Herbert, 3D printing needs to move away from its image as a niche, cool technology to become a “boring” and commonplace engineering tool. He hopes to reach this “Plateau of Sustainability” by the end of the decade.
At Leonardo UK, additive manufacturing is split between in-house polymer systems and its third-party metal 3D printing supply chain. On the metals side, around 80% of its AM activity involves laser powder bed fusion, with some parts also made with direct energy deposition. While metal parts are fabricated externally, Leonardo UK owns the design IP and assembles the final parts in-house. For polymers, the company possesses SLA, SLS, FDM, and PolyJet capabilities, primarily used for rapid prototyping and R&D operations.
Ross Herbert also revealed that Bambu Lab FDM 3D printers are used at Leonardo’s Edinburgh radar and advanced targeting systems site. The Chinese-made printers deliver impressive performance at an affordable price. However, Bambu Lab, based in Shenzhen, has been the subject of online discussions concerning data security. In response, the desktop 3D printer manufacturer has strongly denied allegations of malicious software, rejecting claims that the company monitors or steals 3D files.
Herbert told me that Leonardo takes digital security seriously. He explained that Leonardo’s Bambu Lab 3D printers are operated offline without an internet connection. He also revealed that these systems are used purely for non-sensitive rapid innovation projects, providing access to graduates, apprentices, innovation hubs, and engineering teams. Bambu Lab technology will “never be used with a production part, unless there are robust security measures in place,” Herbert added.
Leonardo’s additive manufacturing advantage
Herbert argued that additive manufacturing is increasingly necessary in aerospace and defence. He noted that traditional mechanical engineering techniques, many of which still rely on methods dating back to the 20th century, are struggling to keep pace with modern demands. “We are now reaching the limits of what’s physically possible with conventional manufacturing,” he said.
Leonardo’s electronics division offers some of the most compelling use cases for additive manufacturing. “One of the biggest challenges we’ve got is electronics cooling,” he explained. With Moore’s Law driving an exponential rise in processing power, and therefore heat, every year, conventional methods such as brazing, casting, machining, and forging are falling behind.
To overcome this challenge, Leonardo is leveraging multiphysics computational fluid dynamics design software from companies like ToffeeX, Morpheus Designs, and Diabatix. These tools lend themselves to the design freedom offered by additive manufacturing, creating organic structures that unlock more efficient cooling architectures that simply cannot be machined or cast.
These novel geometries can include inherent cooling, offering “incredible” benefits for low-volume, high-cost radar and advanced targeting applications. Leonardo is also exploring novel 3D printable powders and resins with improved structural and thermal properties.
Lightweighting is another valuable advantage of additive manufacturing in aerospace. Herbert pointed to Leonardo’s Fast Moving Mirrors (known as Fast Steering Mirrors in the US). These components are key to ensuring the operational effectiveness of the company’s DragonFire Laser Directed Energy Weapon (LDEW) systems, powerful weapons that destroy targets using high-power lasers.
Leonardo’s Fast Steering Mirrors stabilize the laser beam, keeping it precisely on target despite atmospheric turbulence or movement of both the platform and the target. This stability is crucial because LDEWs are typically mounted on vehicles and ships to counter fast-moving aerial threats such as drones.
The stabilization requirements for these devices are typically less than a microradian (µrad), meaning they must maintain precise alignment within a tiny fraction of a degree. This precision must be sustained at a response speed, or bandwidth, of around 100 Hz, meaning the system can correct disturbances up to 100 times per second. Therefore, minimizing the mass of the components is crucial, as lighter parts allow faster and more accurate stabilization.
Leonardo leveraged additive manufacturing to produce lightweight lattice structures that replaced the existing solid block architecture. This reduced the Fast Moving Mirrors’ mass from 1.48 kg to just 332 grams, while matching the manufacturing costs of traditional methods.
According to Herbert, the 3D printed assemblies “outperformed conventionally manufactured parts.” Beyond being lighter, 3D printing allowed Leonardo’s engineers to increase stiffness and fine-tune the material properties more precisely.
Elsewhere, he revealed efforts to develop novel 3D printable alloys that can expand and contract. These can be used to create optical systems that maintain perfect alignment through temperature cycles, a critical capability for defense applications.
For Herbert, 3D printing allows users to break away from using restraints set by conventional titaniums and high-silicon-content aluminums. Instead, manufacturers can prioritize design for additive manufacturing (DfAM) from the start to create devices that “work in perfect harmony” with operational requirements.
Targeting the future of defense manufacturing
Amid the growing presence of additive manufacturing in the defense supply chain, Herbert identified that customer attitudes are evolving.
“We are now seeing that Customers are saying, ‘Why are you not using additive?’” He noted. “We’ve seen other systems on our products using additive, why are you not using it?” This pull from end customers marks a significant shift from earlier years, when additive was largely a technology push from engineering teams.
The key challenge now is to apply AM where it makes both technical and commercial sense. “There’s nothing worse than the customer saying ‘I want an additive part,’ and you give them something that costs 10 times the amount and doesn’t do the job,” Herbert cautioned.
Leonardo is therefore working closely with its clients to identify suitable applications, balancing performance, cost, and manufacturability. This collaborative, data-driven approach will be critical to ensuring AM is deployed where it can truly add value.
Looking ahead, although most of Leonardo’s current 3D printed parts are limited to a “shoebox-sized” envelope, Herbert outlined plans to expand into large-format 3D printing. This move is driven by specific engineering demands, as the company aims to address low-volume, high-cost components that are currently produced through traditional machining or forging. 3D printing these larger parts could unlock cost and lead-time savings for more of the UK’s critical defense applications.
Ultimately, Herbert hopes the not-so-distant future will see additive manufacturing ingrained as a “commonplace manufacturing process.” That cultural shift is central to Herbert’s ambition for the next 18 months: embedding 3D printing as a standard option in Leonardo’s engineering toolbox. “It’s ambitious,” he admitted. However, Leonardo has a team of 180 mechanical engineers working to demystify the technology and promote broader adoption across the UK defense supply chain.
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Featured image shows Leonardo’s Edinburgh-based radar and advanced targeting systems facility. Photo via Leonardo.
