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3D Printing Certification

Experts 3D print gunpowder substitute, realize 420m/s bullet velocity


Researchers from the Xi’an Modern Chemistry Research Institute in China have 3D printed a practical gun propellant using SLA know-how. The gunpowder-esque compound is a cautiously created mix of photopolymer resin, RDX (a superior explosive), and other reactive additives. Initial gun testing of the 3D printed propellant has garnered some promising success, as the researchers managed to achieve a a lot more-than-lethal muzzle velocity of 420m/s. This, of course, depends on your definition of ‘promising’.

Printing and testing the gun propellant. Image via XMCRI.
Printing and screening the gun propellant. Image via XMCRI.

Large-velocity projectiles

Gun propellants are the chief electrical power supply in barrel weapons, and are the driving power driving the significant-velocity projectiles generally recognized as bullets. In the black powder muskets of aged, bullets normally exited the barrel with a muzzle velocity of up to 370m/s. In modern day rifles, this quantity can exceed 1200m/s, but anything at all above around 70m/s can penetrate human pores and skin.

At this time, the most important approaches to make improvements to the ballistic efficiency and hurt possible of propellants are to improve the burning surface or the burning charge. This is typically performed by foaming the propellants, coating them, or packing them in their casings in selective levels. According to the researchers, simply just filling the cylindrical casing with a granular propellant functions but is rather limited in its electrical power release effectiveness. So, the team looked to 3D printing certification to see if it could pack a bigger punch.

3D printing certification gun propellant

The very first phase of the experiment concerned formulating the propellant, which consisted of 3 major ingredients. Photosensitive epoxy acrylate was picked as the main substance matrix, as this demonstrated an great stability amongst curability and viscosity. Next up was the explosive filler, and the researchers opted for great RDX powder with a indicate grain diameter of 25 microns. Finally, Bu-NENA was utilized as the energetic plasticizer, which amplified the entire vitality content material of the propellant without rising its viscosity.

Preliminary compressive loading test with the propellant. Photos via XMCRI.
Preliminary compressive loading test with the propellant. Photographs via XMCRI.

As soon as the UV protection of the freshly formulated explosive was verified, the group 3D printed a set of skinny disks, each individual about 40mm in diameter. These disks could be stacked on leading of each individual other to kind a for a longer period cylinder, resembling the body of a bullet casing. Every layer featured a honeycomb-like framework with holes and was about 5mm thick.

Then came time for the grand finale – the gun examination. The cylindrical stack was loaded into a 30mm barrel with a 200g mass performing as the bullet, while at 200g it is most likely nearer to a mini cannonball. The workforce established up a superior velocity camera and an internal strain gauge in the barrel prior to pulling the set off. As soon as the smoke cleared, the researchers calculated a rather substantial strain exponent worth of 1.46 and a muzzle velocity of 420m/s, with strategies to raise the chamber stress in upcoming assessments.