There are certain topics that cause people to have knee-jerk reactions: Try asking a crowd which Star Trek was best or–around here–take a stance for or against the Arduino and you’ll see what we mean. Certainly people polarize quickly when you talk about a 3D printed gun. However, if anyone can sneak [xtamared’s] 3D printed rail gun through airport security, then some guards will have to be fired. It looks like a cool prop from a bad movie, but (as you can see in the videos below) it can project a conductive slug into a decidedly low-tech target.
There aren’t many build details, although you can deduce a few things from the pictures and the captions. At the rear of the gun is a paintball tank that gets the slug moving before it hits the rails which further accelerate the projectile. The electric part is Arduino-based and the very prominent capacitors at the front end can deliver 1800 joules of energy (and add 20 pounds of weight to the gun).
It looks like a lot of the gun is printed in PLA, but the electronics case is ABS (doubtlessly to avoid exposing PLA to the heat sink attached to the 1500V rectifier). The paintball tank’s pressure gets the slug moving to 100 meters/second before it hits the rails. In early testing, a PLA part and a steel bolt broke, so the items got replaced with polycarbonate and nylon. Apparently, parts of the injector are polypropylene.
The rails themselves are made for replacement, since each shot damages them a bit. They are constructed of garolite (fiberglass and resin composite sort of like PCB material) and wrapped in carbon fiber. That’s one of the things that impressed us–this is a highly multimedia build with different materials used to do different jobs, digital and high voltage electronics, and pneumatics.
We’ve covered a lot of rail guns over the years and we’ve looked at robot-mounted coil guns, too. If you want something more portable, check out this tiny rail gun (although the Geocities cache for the article is dead, but there are others).
Thanks [caffeine_addict] for the tip!