Scientists 3D Print Gunpowder Substitute, Achieve 420m/s Bullet Velocity
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Scientists 3D print gunpowder substitute, achieve 420m/s bullet velocity - 3D Printing Industry:
Researchers from the Xi'an Modern Chemistry Research Institute in China have 3D printed a functional gun propellant using SLA technology. The gunpowder-esque substance is a carefully constructed blend of photopolymer resin, RDX (a high explosive), and other reactive additives. Initial gun testing of the 3D printed propellant has garnered some promising results, as the scientists managed to achieve a more-than-lethal muzzle velocity of 420m/s. This, of course, depends on your definition of 'promising'.
[...] Currently, the main ways to improve the ballistic efficiency and damage potential of propellants are to increase the burning surface or the burning rate. This is commonly done by foaming the propellants, coating them, or packing them in their casings in selective layers. According to the researchers, simply filling the cylindrical casing with a granular propellant works but is quite limited in its energy release efficiency. So, the team looked to 3D printing to see if it could pack a greater punch.
[...] Once the UV safety of the newly formulated explosive was confirmed, the team 3D printed a set of thin disks, each about 40mm in diameter. These disks could be stacked on top of each other to form a longer cylinder, resembling the body of a bullet casing. Each layer featured a honeycomb-like structure with holes and was about 5mm thick.
Then came time for the grand finale - the gun test. The cylindrical stack was loaded into a 30mm barrel with a 200g mass acting as the bullet, although at 200g it's probably closer to a mini cannonball. The team set up a high speed camera and an internal pressure gauge in the barrel before pulling the trigger. Once the smoke cleared, the researchers calculated a rather high pressure exponent value of 1.46 and a muzzle velocity of 420m/s, with plans to increase the chamber pressure in future tests.
Journal Reference:
Weitao Yang, Rui Hu, Lin Zheng, Guanghu Yan, Wenrong Yan. Fabrication and investigation of 3D-printed gun propellants [open], Materials & Design (DOI: 10.1016/j.matdes.2020.108761)
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