Originally Posted By: tfabris
An interesting philosophical discussion about this has recently occurred in my household.

We saw the video where someone had 3D-printed the "reciever" portion of a machine gun (the part of the gun that is legally considered the "gun", as opposed to the other parts that attach to it like handle and barrel) and it was able to get off several rounds before failing.

We came to the conclusion that, for those of us who want stricter gun control, we're quickly approaching an era where that point will become moot, and what we really should be asking for is bullet control. Bullets are harder to make, and won't be 3D-printed any time soon. (I mean, consistent, accurate, and deadly bullets are harder to make from scratch. I mean, any ball bearing can be turned into a bullet, but the gun that fires it isn't exactly the kind of thing that would be used to commit crimes frequently.)


Perhaps we should just ban fingers or even entire arms. Then people couldn't even use a knife! But they could kick, I guess. We should probably ban legs, too. They could still bite, but we can't ban their mouths because that WOULD INFRINGE ON THEIR FIRST AMENDMENT RIGHTS!!! At least they couldn't move around. Safest of all would simply be to ban people. Then we'd all be safe.

This idea that we can (or should) remove the *means* to act violently is stupid. We should logically focus on how to defend ourselves from the small minority of (inevitably) bad and violent people. Not that I expect even a countable minority on either side of this issue to be rational for one moment. But I would point out that only the *initiation* of violence against peaceful people is immoral and undesirable. Peaceful people have the moral right to defend themselves using violence against an aggressor. Any restriction of means restricts the means to defend one's self. Since most people are good, this kind of "control" disproportionately harms good, peaceful people.

Back to the OT: as a mechanical engineer who has used these tools since the earliest versions (when we called it stereolithography), I can say it is useful technology, but it will never fulfill the hype surrounding it today. This is because of the mechanical properties of the materials and the process used. The gun example is a good one. A quality gun receiver is forged, or perhaps machined, of high-strength steel, then heat treated to withstand the stresses involved. The tolerances aren't so much the issue, as the "printing" technology will eventually allow adequate geometric tolerance. The issue is the process and the materials. If all you're interested in making is plastic crap like toys or ikea-quality items, then "3D printing" will do it. But a deposition process can't provide the properties needed when strength is required (there is a weakness between each "level" of deposition). And for plastic manufacture at scale, injection moulding is dirt cheap per unit.

This is the next video phone or 3D television. It's also already a bubble, so it's the wrong time to jump in as an investor.

But great speculation opportunities exist in gold mining stocks right now, and also in shorting the US stock and bond markets. Consider a double- or triple-short ETF.

Jim