Metal 3D printing is not the most mobile of technologies. However, the Australian Army and additive manufacturing (AM) company SPEE3D have found a way to manufacture metal armored vehicle parts in the field in just this way.

In 2021, the Australian Army conducted a series of tests to see if there was a viable way to replace armored vehicle parts in the field using metal 3D printing.

The technology was tested during Exercise Koolendong, an annual field training military exercise between the Australian Defence Force (ADF) and the Marine Rotational Force Darwin, a United States air-ground task force. The trial aimed to prove metal 3D printing can produce parts that are high quality and at military grade level, so that they could that can be validated, certified for use in the field, and then installed.

To make it more difficult, the exercise took place in the remote Bushland of Bradshaw Training Area in the Northern Territory of the country. The 3D printer would have to be transported in a round trip over 1200km, over rough terrain, to operate in hot and dusty conditions for three weeks.

The parts in question were for the M113 Armored Personnel Carrier. The M113, first used by the US in 1961, has been used by the Australian Army for over 40 years. It has an aluminum hull, making it much lighter than earlier similar vehicles.

The Army decided to use a WarpSPEE3D Tactical Printer developed by Australian company SPEE3D to make the replacement aluminum components. According to the company, WarpSPEE3D uses patented cold-spray technology that uses the power of kinetic energy, rather than relying on lasers and gases, to form metal parts. According to SPEE3D, WarpSPEE3D can print parts up to 1000mm x 700mm up to 40 kilograms at a rate of 100g per minute. It has a deposition rate of 100g/min and can build parts up to a maximum part weight of 45kg.

SPEE3D says that WarpSPEE3D can produce parts with have a lower embedded energy component than other technologies can. “Research has shown that the embedded energy for aluminium casting is in the range of 30-38MJ/kg,” the company website said. “In comparison WarpSPEE3D produces parts with an embedded energy in the order of 18MJ/kg.”

The 3D printer also has an option to have solar panels installed, allowing it to run off solar energy.

Replacement parts

During the Exercise Koolendong trial the 3D printer produced more than a dozen differentreplacement parts for the M113. One of the parts produced was an 2kg wheel bearing cover, a part which is often damaged by trees when driven through bushland, which was printed in 29 minutes at a print cost of US$100, the company said. The team were also able to redesign and fortify other existing parts, reducing the risk of future damage. Before this Army trial, SPEE3D had already worked with the Australian Army and Royal Australian Navy, carrying out field trials designed to test the feasibility of deploying metal 3D printing both in barracks and in the field. According to SPEE3D, field trials carried out in 2020 resulted in over 50 case studies of printable parts.

The project also involved training the Australian Army’s first military additive manufacturing cell (AMC) technicians to carry out design, printing, machining, heat-treatment, and certification of parts. “This is a great example of how expeditionary metal 3D printing can improve defence readiness,” said SPEE3D’s CEO, Byron Kennedy. “Field trials conducted in 2020 proved SPEE3D technology was deployable. This year’s trial extension was bigger, longer, and more remote, making it the worlds’ toughest and longest metal 3D printing trial so far.” Plans are for the AMC to explore more components that can be repaired using metal 3D printing as an alternate solution, having parts at the ready in the field.

Reinforced Plastics spoke to Steven Camillieri, SPEE3D's chief technical officer (CTO) about SPEE3D’s technology.

What enables the 3D printers to work so quickly?

We designed the printers so that rather than using heat to melt metal powders like in traditional additive manufacturing (AM), we developed ‘supersonic 3D deposition’ (CSAM). It’s a patented, solid-state process where a rocket nozzle is fixed at the base of the printer and accelerates air up to three times the speed of sound, or up to MACH 3. Metal powder is injected, then deposited onto a substrate maneuvered by a six-axis robotic arm controlled by pre-programmed software algorithms developed by SPEE3D. The sheer kinetic energy of the particles hit each other, causing the powders to bind together to form a high-density part with metallurgical properties superior to casting. This means our technology can produce parts in a few minutes for small parts, to about a few hours for larger parts.

What else makes them suitable for use in the field?

Our printers do not contain fragile components and have been designed with more robust hardware when compared to other more traditional metal 3D printing technologies. While they were built for a manufacturing environment, our work with the Australian Army has proven that they also work perfectly well out in the Bush as well. Another reason why they work so well out in the field – in the hot, dusty outback – is that our printers do not need any special gasses to run. Instead, they use compressed air to build up the parts. In fact, the only things needed to run our technology anywhere is to have an electricity supply – supplied through a generator or even solar panels – and a sustainable supply of metal powder. As we have proven so far, our 3D printing technology does not need a carefully controlled environment to operate in.

Why is metal 3D printing outside a manufacturing facility difficult?

For other metal 3D printers the environment can affect how well the machine works and the quality of the printed part. However, our printers are not affected in the same way. The Australian Army have been able to print dozens of parts outfield in 40⁰C weather, and in the trials that they have done, the Army have been transporting the printer back to base and out to the field with no real issues. A controlled environment is not required. Our printers can also be moved with normal transport infrastructure the army already has and don’t require any special training to move.

Are there any downsides to metal parts printed in the field?

Of course, engineers should use the original manufacturer’s part where they can. Where you can’t, our technology is the answer. With regards to finishing, when the Australian Army was using our technology in the field, they were also able to heat treat and machine print parts in the field because they brought furnaces and CNCs with them. Of course, no matter the metal 3D printing technology, if you just print the part it will require finishing. Every part needs a post-process. The Army engineers were also able to test the hardness and strength of the material in the field because they also brought testing equipment. So, after 3D printing and heat treatment, we could be sure that the parts were of a working, quality standard for the vehicles they used during the exercise.

What other field applications could the 3D printers be used for?

Our printers can manufacture parts such as brackets, spanners, flywheels, bulk fuel support modules, engines, and so on. They are useful for anyone who needs a metal part and can’t easily get one at any time. So potential markets for our technology are wide and varied – including defence, space, maritime, energy, mining, and agriculture.