Today’s controversy about 3D printed guns has brought the technology further into everyday life. Plastic guns have been around for decades. You can machine pieces of solid plastic into various parts, and then assemble them into a gun capable of firing. They were made illegal many years ago. The Undetectable Firearms Act of 1988 makes it illegal to manufacture, import, sell, ship, deliver, possess, transfer, or receive any firearm that is not as detectable by walk-through metal detection as a security exemplar containing 3.7 oz. (105 g) of steel, or any firearm with major components that do not generate an accurate image before standard airport imaging technology.
The fact is you wouldn’t print “a gun”. You would print individual pieces that can assemble into a gun. The idea of printing gun pieces isn’t a new thought. Up until lately, the biggest failing of 3D printed parts in general is that while they look and feel like the part you designed, if your end use has any kind of structural, temperature or chemical demands on it, the 3D printed parts may not be suitable for any kind of physical testing. So after designing and printing your 3D part, you may still need to create actual physical prototypes of the part in its final form, whether machined, injection or compression molded, to physically test it.
So go ahead and print your gun pieces, the first problem has been that the resins available to 3D print your gun not hold up to the violent pressures experienced when a bullet goes off in the chamber.
The second problem lies in the 3D process itself. The primary difference between machined plastic gun parts and 3D printed gun parts is that the plastic resin in the machined version is solid. The plastic resin in the 3D printed is layered. The primary methodology of 3D printing is a machine laying layer after layer of resin, like building a sandwich. In 3D printing there is very minimal binding or bonding of the individual layers together. So compared to the solid block of plastic, the 3D printed part is much less durable.
Yes, 3D printing is evolving, very quickly I might add. There are new resins developed constantly that provide higher level capabilities. Today though, the most common 3D printers are still a layering process and there will be inherent frailties.
You want to 3D print gun pieces, assemble them and try shooting it? First, it is illegal, secondly, let me know before you pull the trigger, I don’t want to be around.