Posted on 12/24/2012 7:53:12 PM PST by marktwain
This is the lower receiver of an AR-15 rifle, printed in fused plastic filament from a digital model that was, until this week, freely available for download on Thingiverse.
This part is significant because all other parts of the common rifle can be readily purchased in the open market. A person who builds a working lower receiver has, in the eyes of the state, essentially built a working AR-15. It is legal to do so for personal use (at least under US law), but until lately the required tools, time, and talent put the project beyond the reach of most casual tinkerers.
The rise of desktop manufacturing, however, may be set to change all that. Recently, a 3D printed AR-15 lower receiver made of fused plastic filament was demonstrated to fire and cycle six times before breaking.
Andy Greenberg over at Forbes has the story on the removal of this model, and other key firearms-related physibles, from Thingiverse. As of this writing, no official statement appears on either MakerBot’s or Thingiverse’s sites, though the action seems entirely consistent with Thingiverse’s established Terms of Use, which were updated following the the site’s first firearms controversy back in 2011 to include proscriptions against content that “contributes to the creation of weapons.”
Up to now, however, the policy has gone largely unenforced.
From the comments: Sean Ragan on December 20th, 2012 at 6:56 pm said:
I note, as an aside, that it just took me about 3 minutes to nab a torrent containing digital models of an AR-15 lower (and the parts for a 5-round magazine) from The Pirate Bay’s “physibles” section.
They lock up Criminals for 23 hours a day, with one hour exercise time in the Yard at Maximum Security Prisons.
They routinely find hand made knives on those same Prisoners.
Human Ingenuity knows no bounds. Don’t believe me, just ask Captain Kirk about the time he had to fight that big Lizard on Star Trek.
3-D printer ping!
>> demonstrated to fire and cycle six times before breaking.
KABOOM!
Does the printer come in a box from ACME?
You can’t put the Genie back in the bottle. There is this thing called the Internet and information will always be available, just because one site remove the information means nothing it will soon be available on ten. Removing the information on lower at this time means nothing, as was pointed out it broke after six rounds were fired. It is just not worthwhile to build a gun with that limited potential. But someone will soon figure out how to beef up the lower so it will withstand more firings.
Yup! (But don't tell Zero and Feinstein -- they'll require printed plastic receivers for all ARs and AKs!)
I would wonder if one of these could be used to create a mold for a metal version using something analogous to the lost-wax technique.
3-D printer aren’t limited to plastics.
Yeah, but can that machine print up those full auto triple action semi-bullet burst fire assault ‘clip’ thingies to.....??
Not for anyone with casual familiarity with the phrase "lost wax process."
If this part can be made of wax, it can be used as a core in investment casting of brass or aluminum by the lost-wax method. Just attach a sprue(s), pour the plaster-of-paris based investment around it in a steel-can container, heat and drain out the wax, then pour in molten metal. This is how dental casting is done.
One method would be to coat the plastic part with curable silicone rubber. Then after cured cut and remove the rubber form, reassemble it and fix that in a case to hold its form; and use it to pour in hot wax to make one of many cores for investment casting.
Or you could make the part out of stainless steel the way jet engine turbine blades were made back in my day. I think maybe hand-gun parts are already being made by this form of investment casting, perhaps.
“Recently, a 3D printed AR-15 lower receiver made of fused plastic filament was demonstrated to fire and cycle six times before breaking.”
And they call them “assault rifles”? High tech garbage.
I considered that possibility. Lost wax produces very accurate copies.
Printing workable magazines is much easier.
http://www.freerepublic.com/focus/f-bloggers/2971732/posts
Something that did these consumer-CAM molds in “loseable” wax would be more useful than something that did them in a thermosetting plastic.
So it doesn't bother the government when it's too hard for most people, but they worry when it's easy for people? I didn't know "rights" were skills-based.
This is roughly analogous to Wilbur and Orville's first 3 or 4 hundred foot flight at Kitty Hawk.
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