Just wanted to make a post for ENGINEERING discussion of this fully printed firearm

Just wanted to make a post for ENGINEERING discussion of this fully printed firearm released by DefDist. (No politics/morality)

So - It’s quite obvious now that he has done it. The videos are proof enough, and I have the files and have inspected them carefully.

It’s obviously not going to take large amounts of rapid fire usage. However this is printed in ABS using FDM. Some articles mention acetone vapour smoothing and the heated chamber of the stratasys machine contributing to extra strength.

I have a bunch of Polycarbonate here. I am curious as to how that would perform. Better strength, better heat resistance.

From an engineering standpoint this is a really interesting challenge. I would have a go myself, but am legally hamstrung due to the laws of my country.

Links:
http://www.forbes.com/sites/andygreenberg/2013/05/05/meet-the-liberator-test-firing-the-worlds-first-fully-3d-printed-gun/2/
https://mega.co.nz/#!JplQVDDQ!Qi8kflIn8kMZl0hK96YW1h7RIc9vz2SfErzB-7qRV-0

acetone vapor is for cleaning the barrel out. any one trying this on reprap or makerbot?

I’m curious to see how well nylon holds up in this model.

Or use metal pipe for barrel. Actually the nut job creator WANT it to be undetectable on perpose. See his Alex jones interview.

I’ve actually talked to taulman about this. I think he’s pretty glad (just from a PR standpoint) that it wasn’t made with his filament.
I also find it interesting, even leaving the fact that it’s a really crappy gun aside, he printed it on a Stratasys machine. A $20k+ printer printing $400/kg plastic does not make for a cheap, easily accessible gun. Had he managed it on a RepRap I’d be way more impressed and the end result would be way more democratic as they claim it to be.

I am more interested in making parts with lost PLA or ABS casting. It would be nice to be able to print then cast some simple parts and pieces, I still don’t like the idea of a printed or cast barrels…

I’m surprised people are willing to print and test-fire this thing when its designer is on record saying he doesn’t know why it can survive the force of a bullet being fired.

I’m all for testing to failure, redesigning to fix the failure, and continuing to iterate like that until you get something that really works. But when it involves explosions you might want to work out the expected point of failure before initially testing it…

@Stephen_Baird I would only test this with a remote of some sort… but that is me. you could build a remote out of a bicycle break if you are cheap, but seriously, this thing would go nowhere near my face and or body.

Still, a little engineering work in the first place can save a lot of time and hassle dealing with a couple generations that fail in spectacular ways.

And even after having tested the thing remotely and seeing it function correctly, I don’t know that I’d want to be anywhere near one being fired without knowing just what kind of over-engineering margin exists between the forces it can sustain and the forces its expected to be subjected to while firing.

@Stephen_Baird Agreed. also layer adhesion can be substantially different between prints depending upon conditions. I would not fire one of these weapons either

@Sanjay_Mortimer I am curious, has anyone done a vapor bath on an assembly, as far as I am aware I have only seen vapor baths applied to show pieces, I think this could destroy the fit in the trigger assembly.

I’ve done vapor baths on basic assemblies. Sometimes it makes the movement much better, other times it makes the tolerances too large too work properly. it all depends on the design of the assmbly and how long you wash it for