Within weeks of Russia’s invasion of Ukraine, according to reports, 3D printing tech companies in Eastern Europe were supplying Ukraine with hundreds of plastic and polymer 3D printers, since used on the battlefield to make anything from observation drone airframes, to tourniquets and prosthetic limbs.
Having the ability to manufacture components or complete items in or close to the battlespace overcomes a multitude of logistical challenges, especially considering the pressure on an army’s supply chain to keep its fighting units supplied with weapons, water, food, fuel and ammunition.
But within the home base, serious issues have developed over time within the military supply chains responsible for keeping military hardware maintained and operational. The majority of today’s military aircraft, ships, weapon systems and armoured fighting vehicles have been in service for decades. Given the age of the equipment many of their component parts are obsolete and new ones take months to manufacture and are very expensive. Lt Gen Richard Wardlaw, chief of the British Army’s Defence Logistics and Support organisation, summed the issues up by saying: “The biggest single threat to defence supply is obsolescence.” He was speaking at the Defence Security and Equipment International event.
The use of additive manufacturing (AM) to make replacement legacy parts has been seen as the solution by the US, Dutch and French militaries for some time, and now the UK’s Ministry of Defence (MOD) is now developing the technology here.
Its programme centres around Alex Champion, who has a degree in motorsport engineering and spent his early career manufacturing parts for Formula 1. He is also an Army Reservist. In October 2019, he was introduced to the Royal Electrical and Mechanical Engineers’ (REME) staff officer responsible for the Army’s project to expand its manufacturing and engineering capabilities – Lt Col Dan Anders-Brown. Anders-Brown subsequently asked Champion to give a talk on AM to several senior army officers. After delivering a successful briefing, he was offered 44 days a year working as a reservist at Army HQ. He was tasked with designing four small deployable factories containing laser scanners and 3D printers, which could be transported on the back of an Army Support Vehicle. These would be trialled in remote locations, helping to inform the Army’s future engineering, manufacturing and logistics policy.
Champion says: “The Army had been looking to adopt technologies such as 3D printing in order to manufacture urgent parts. This will help to reduce the logistics burden and save money in developing or updating equipment. We initially focused on using the technology to produce temporary and non-safety critical ‘get me home’ repairs. At the other end of the spectrum, the American Department of Defence has invested heavily in this technology and is now benefiting from being able to 3D print metal components for main battle tanks and this one capability alone has saved months of repair time and millions of dollars. UK Defence is now developing the capability to manufacture the full range of safety and non-safety critical components for its assets.”
The MOD’s programme to invest in the strategic use of AM goes by the name of Project TAMPA. One of the project’s aims is to incentivise the defence manufacturing industrial base to accelerate and drive up the levels of innovation that it applies to strategic supply chain management.
EXPANSION
In September 2022, DE&S’s Commercial Future Capabilities Group published a notice to existing defence contractors that supply NATO Stock Number (NSN) parts to the MOD inviting expressions of interest for the three-year, £5 million project which would use AdM technology to supply obsolete components for weapons systems and maritime, air and land assets.
In April 2023 DE&S announced it had set up the first framework under Project TAMPA by awarding industry contracts to AMFG, Babcock International, NP Aerospace, RBSL and Thales. Project TAMPA is initially looking into what limitations of AM will prevent DE&S and its industry partners from using the technology to best effect.
The first phase of the project is to produce and fit 11 non-safety critical 3D printed metallic NSN parts onto in-service platforms. This will be followed by safety-critical metallic NSN parts produced in an industrial base, certified by the producer (OEM or under licence). The next phase is to manufacture non-safety critical metallic (or polymer) NSN parts, produced in a location remote from the industrial base, certified by the producer; then a safety-critical metallic (or polymer) NSN part, produced in a location remote from the industrial base. The final phase will be to produce non-safety critical metallic (or polymer) NSN parts, produced in a location remote from the industrial base, certified by the producer and where access to design rights are required.
While several of the MOD industry partners involved in Project TAMPA are OEMs, Babcock International is in a unique position as also providing third party through-life technical and engineering support to the MOD. Its manufacturing and MRO lead (technology) Jonathan Morley says: “There are a lot of legacy assets within the defence equipment portfolio and the severe challenges of obsolescence is something we face every day. These legacy platforms are low-volume, which makes supply chain provision even more difficult. In some cases, platforms, especially submarines, are unique and there have been cases where there are no drawings for a part, so they have to be re-engineered. AM provides the solution. These new technologies not only have the potential to address these issues, they also help us improve our productivity and ability to support our customer and reduce downtime.”
Separate to Project TAMPA, Champion says frontline commands in the Army, Navy and Royal Air Force have now procured their own AM machines to support their own programmes to enhance manufacturing capability to support operations. The equipment is deployable and suitable to make expedient in-situ repairs and the MOD is looking to establish regional hubs with this capability.
In November 2022 Renishaw supplied a RenAM 500Q Flex metal AdM machine to RAF Wittering help improve its component manufacturing capabilities. The station is using the system, along with other 3D printing and scanning equipment, to produce custom-built structural aircraft components for rapid repairs. Its arrival marks the RAF’s first steps into advanced component manufacturing. In March 2023 DE&S purchased a SPEE3D Coldspray printer and signed a two-year contract to work with the Australian company.
TECHNOLOGIES
The 3D print technologies being utilised include powder bed fusion (PBF), wire arc additive manufacturing (WAAM) and SPEE3D Coldspray additive manufacturing which uses supersonic deposition. A rocket nozzle accelerates air up to four times the speed of sound. Injected powders are deposited onto a substrate that is attached to a six-axis robotic arm. In this process, the sheer kinetic energy of the particles causes the powders to bind together to form a high-density part with dimensions up to 1000 x 700mm. Materials currently available are aluminium, aluminium bronze, stainless steel and copper, with others in development. The printer and associated equipment will fit inside a 20-foot ISO container so can be transported and deployed using a military load carrier.
PBF methods use either a laser or electron beam to melt or sinter material powder together. The process can create highly complicated geometric shapes from a range of metals and polymer powders, although polymers cannot be melted so use the sintering process.
The technology lends itself to small complex components and, due to the accuracy of the manufacturing process, they only require basic finishing such as threading fixing holes; Champion says PBF is most suitable for making small, complicated aerospace parts.
WAAM is the oldest 3D printing technology, and is basically a MIG welder mounted on a robotic arm. The workpiece is formed on a rotary table and the machine builds up the part from weld, controlled by CAD/CAM software. WAAM has a resolution of approximately 1mm and a deposition rate of between 1-10kg per hour. This is a technology that Babcock uses, and Morley says it has the capability to make a four-metre diameter ship propeller or other large, high-strength components.
Coldspray and WAAM effectively make castings that require machining and finishing. For decades, the Army’s REME and Royal Engineers have deployable field workshops equipped with machine tools which can be used for this purpose. These AdM technologies have already been used to make armoured fighting vehicle access hatches and drive sprockets for tracks.
Babcock says it proudly supports the UK MOD Defence Support Strategy. The company also sees opportunities to deliver the benefits of AM to other military and civil customers, and is currently working to realise the value from its development programme.
BOX: WHAT ABOUT QUALITY?
Responds Babcock’s Jonathan Morley: “Porosity is a risk, as it is in many manufacturing processes, and during research into AM, Babcock has identified factors affecting porosity. It is primarily mitigated by robust process controls, and careful selection and governance of print parameters. A good example is [when] we were asked to replace a shoe box sized metallic part on a 4.5-inch naval gun, made in the 1960s, fitted to a Type-22 Frigate. There were no drawings available for the part, so we had to re-engineer it and then made it using powder process AM. X-rays of the original part revealed several flaws in the steel casting. When x-rayed, the one we produced was flawless and much stronger than the original.”
BOX: WHAT ABOUT IP?
Objections about the ownership of parts’ intellectual property (IP) have been raised about 3D printing. Babcock’s Jonathon Morley replies: “With IP, where we are starting from is a large proportion of the bill of materiel is obsolete or obsolescent, so there is a problem sourcing it. This obsolescence can be driven by a coating that is no longer produced due to a withdrawal under COSHH. Or it could be that a raw material is no longer used, or the OEM is no longer trading or has been bought out. Irrespective of the cause, it boils down to no-one being available to make the part. In these cases, we don’t see there is an issue with IP. Those defence prime manufacturers still in business aren’t interested in producing low volume legacy parts, but at Babcock supporting legacy equipment is what we specialise in, so we are already working with a number of the big primes and they are all very supportive.”