Now the Ministry of Defence (MoD) has taken an interest, and is experimenting with 3D printed bombs that could be produced on military front lines.
The Defence Science and Technology Laboratory (Dstl) — the MoD’s R&D lab – said today that it has created new explosive formulations that allow bespoke bombs to be printed at the push of a button, in a world-first for the industry.
This could be crucial amid what the Dstl admits is a bomb-making skills shortage. (It describes this, politely, as a “national decline in the energetics sector”).
3D printing, it said today, could allow the creation of new new shapes and complex explosives designs that were previously unattainable.
This is important because shaped explosive charges focus the energy from the blast more efficiently in a chosen direction, something that has applications not just in the defence realm but also in industries like mining and demolition.
(In the late 1880s it was discovered – in what is known as the Munroe or Neumann effect – that explosives with an indented stamp on them would cut this lettering into a steel plate when detonated. In the early 1900s conical indentations were added to explosives, greatly increasing their ability to punch a hole in armour plating.)
Printing explosive can help further our understanding of explosive effects on amour and defence installations, highlighting vulnerabilities. Manufacturing explosive charges in this manner also helps to reduce transport and storage costs.
A DSTL spokesperson said: “Energetics knowledge and experience is vital for the UK to develop the best equipment, platforms and operational assets.
“We need to know how energetic systems damage or defeat our platforms and how we can counter threats, so we can advise on things like countermeasures, detection, safety, transportation and disposal.”
Using 3D printers to manufacture energetic materials is not a new concept; industry and academics are actively doing trials of the process.
Many everyday items have explosive materials incorporated into their design such as vehicle airbags, which use a small chemical explosion to propel the bag.
Researchers at Purdue University, for example, have created a customised ink jet printer that deposits materials in overlapping patterns to print thermite charges.
Thermite is a mix of iron oxide and metallic aluminium, when ignited the material burns at 2204 degrees Celsius.
A spokesperson from Dstl said: “Without investment, the UK capability would die,”
“It’s up to MOD to make sure that doesn’t happen, as industry has limited or no capability in many critical areas.”
The formulations for 3D printing are manufactured in a LabRAM resonant acoustic mixer, it added, which uses acoustic energy rather than physical blades to mix materials, making it safer and more efficient to use.
Such mixers process powders, pastes, liquids, using specific resonant frequencies. These, nominally between 58 and 62 Hz, continually monitor and adjust mixing when operation, typically several times per second to balance kinetic energy.