3D Printers... how do they work? And DO they work?

[Rath Darkblade]

I've come across some articles about 3D printers, and I'm curious. I know they're very expensive compared to existing laser printers, which is why they'd only be considered by private business or the manufacturing industry (who have got pots of money).

But my question is twofold:

1. How do 3D printers work? Presumably there has to be some raw material - perhaps plastic, perhaps metal, perhaps paper. I also know there are .CAD files involved with the design. But how is the raw material then shaped into the shape you need?

2. Is it possible to use 3D printers to print guns? According to the ABC Factfile, creating a 3D-printed gun runs into three problems: it's very expensive, you can only print parts of a gun that you then need to assemble, and even then it probably won't work (because if you make a plastic 3D-gun, the plastic won't be able to stand the stresses of escaping gases and explode - and if you try to make a metal gun, it would become even more expensive). But according to this cite-note on the wiki-article on 3D printing, a man in Japan has been arrested and imprisoned for 2 years for creating two 3D-printed guns.

So what's the truth? I can see that "printing" guns on 3D printers is possible - but is it economically viable, given the cost of doing so, the cost of assembling the guns, and the risk that said guns will simply not work anyway?

Thanks!

[adeyke]

I'm not aware of anyone here having special expertise on this topic, but this is something you can just find out about by googling.

[Rath Darkblade]

I have googled about this, but the discussions and articles about 3D-printers I have found left me a little... well, baffled. So I thought someone here might know more than I do.

[Tawmis]

Never used one, so I know nothing about it. But I know they do work, and it's a shame the person who made those 3D printings of Sierra characters, isn't on this forum to better answer your question.

[Collector]

He is on Twitter, but I barely pay any attention to it.

[DeadPoolX]

3D printers work by layering material over and over.

At the moment, 3D printers seem to be limited to various forms of plastic, but in the future there might be ones that can do metal or cloth.

As for firearms, it's theoretically possible to make a working gun in a 3D printer, but given the quality of plastics used in these devices right now, any gun created would be more or less a ticking time bomb. It might work for a few shots and then fall apart or it could explode in your hand.

Until 3D printers start making stuff out of metal, the chances are slim that reliable and fully functioning guns will be created by people using 3D printers at home.

My concern isn't guns, but knives and IEDs. Neither of those weapons are as temperamental as firearms.

[Rath Darkblade]

OK, that makes a little more sense. Hmm... DPX, what do you mean by "layering material over and over"? I can picture what you mean - like putting layers of lasagne over each other, I guess?

I understand your point about knives and IEDs - the one can be used over and over, while the other (while being a one-shot weapon) can kill many people all at once. But how can 3D printers create knives and IEDs, if these 3D printers cannot do metal or cloth yet? From what I understand, IEDs have to contain metal of some kind in order to be effective.

[BBP]

I've seen one at work at the Evoluon, where they sold 3d printed keychains.

They work VERY slowly.

It's sort of like with soft serve ice cream, you know the stuff that comes out of the lever and whoever makes the icecream needs to move the recepticle around to get a nice cone? That's what it looks like except it's the machine that moves, not the receiver.

I bought one of those keychains and it's a very odd type of plastic, very lightweight and it seems very fragile. It's very expensive material too - for the advantage of having an unregistered gun, you have the disadvantages of those things being: A really expensive to make; B a lot more fragile than you want a mini cannon to be. With current techniques, using a plastic gun may not be viable, practical or safe.

[Collector]

It's sort of like with soft serve ice cream, you know the stuff that comes out of the lever and whoever makes the icecream needs to move the recepticle around to get a nice cone? That's what it looks like except it's the machine that moves, not the receiver.

I was going to make the same analogy, but didn't have the time to post last night.

[BBP]

Great minds think alike?

[DeadPoolX]

OK, that makes a little more sense. Hmm... DPX, what do you mean by "layering material over and over"? I can picture what you mean - like putting layers of lasagne over each other, I guess?

Imagine slicing any object into tons of thin layers. That's basically what a 3D printer does, only in reverse. It applies tons of thin layers, over and over, until a full object is created.

This also presents some limitations, in that hinges or moveable parts can't be manufactured at the same time as other pieces.

But how can 3D printers create knives and IEDs, if these 3D printers cannot do metal or cloth yet? From what I understand, IEDs have to contain metal of some kind in order to be effective.

Knives can be created from just about anything, as prison inmates could easily tell you. They've fashioned blades from soap, cardboard, and even newspaper, so a 3D printer using rigid plastic wouldn't have a difficult time at all creating a sharp stabbing implement.

Slicing would be more of a challenge, but in the end, you don't need metal to cut skin. Anyone who's ever got a nasty papercut or steppled on a child's toy could tell you that.

As for IEDs, all the 3D printer would have to do is create a container or object in which to house the explosive itself. People have done this with pressure cooks and pots in the past, so using a 3D printer in this capacity is easily doable.

The most complicated part would be finding enough objects to use as ballistic weaponry. Given the force of the explosion present in most IEDs, even something as innocuous as Legos would suffice.

It wouldn't be difficult for people to find sharper and more deadly objects around their house or at a big box store. Even a few small rocks from someone's yard would work.

[Rath Darkblade]

Hmmm... all right, I see your point. *thinks* As you've pointed out, though, people have used pressure cookers or pots in the past to serve as a container for the explosive. Given that, is it even necessary for them to use a 3D printer? It seems like even a large plastic box would do the job.

As for the ballistic weaponry - I know the Tsarnaevs used ball bearings, but heck, if even a few rocks would work, why would you bother with ball bearings? :-\ Not that rocks would cause much less damage. In ancient times, armies would use slingers to hurl rocks and lead or bronze pellets at the enemy. These would come at you at speed, and would be polished so that they would penetrate the skin and cause even more damage. Nasty. I can just imagine how much damage an IED would cause.

As for knives... again, knives are available just about anywhere. (Obviously, I mean things like kitchen knives and the like - not army knives or something specialised). So, again - if someone was intending to commit a knife crime, why use a 3D printer? It seems much simpler to me for this person to go into a supermarket somewhere and buy a kitchen knife or a butcher's knife, etc.

[DeadPoolX]

As you've pointed out, though, people have used pressure cookers or pots in the past to serve as a container for the explosive. Given that, is it even necessary for them to use a 3D printer? It seems like even a large plastic box would do the job.

[...]

As for knives... again, knives are available just about anywhere. (Obviously, I mean things like kitchen knives and the like - not army knives or something specialised). So, again - if someone was intending to commit a knife crime, why use a 3D printer? It seems much simpler to me for this person to go into a supermarket somewhere and buy a kitchen knife or a butcher's knife, etc.

I could see three reasons:

1. Mass production.

2. There's no record of purchasing the weapon, just the 3D printer and the material used in it. That could be used for making toy cars or stabbing implements. No one would know which one you're planning.

3. The "it's not metal" factor. Bring a regular knife onto an airplane, the metal detector goes off. Now try it with a plastic knife. No alarm.

[BBP]

Two things:
1 You'd still need a metal firing pin for a plastic gun;
2 3D printers aren't suitable for mass production. They work very slowly.

[DeadPoolX]

Two things:
1 You'd still need a metal firing pin for a plastic gun;
2 3D printers aren't suitable for mass production. They work very slowly.

1. You're absolutely right and anyone who's designed a working 3D-printed gun has that covered. That said, the gun may still blow up in that person's hand, but I suppose they might get a shot or two off before finding out if they'll need a trip to the ER.

BTW, the bit about "no metal" was in reference to knives. You don't need a firing pin for bladed weapons, although that'd be pretty neat.

I think the Spetsnaz actually had a knife that could shoot its blade. Of course, that means it's a one-time thing and now you no longer have a knife, but I bet a lot of people didn't see it coming.

2. Yes, 3D printers work slowly, but for crazy people who feel the need to make their own weapons, this is a way to produce weapons relatively quickly without interacting with people or society in general.

Remember, the sort of person who sees the need to stock up on home-made weapons for an upcoming "race war" or a Mad Max scenario is not thinking clearly.