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ED-SKaR

Jumping on the 3d printing bandwagon.

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I'm using the 3d printer at my college, it's an old design of layered dust that prints with ceramic dust. The parts are really brittle, the AK lip broke just by removing the pin a few times, but as a proof of concept it fit perfectly, so I'll have it printed properly.

 

Havn't got around to fitting the BB arm, that's from the TM M3 shotgun, I assume it will break within a few shots, but so long as I get it to function for two shots, I'll be happy to have that part CnC machined.

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For what it's worth, when I 3D print stuff that turns out to be too soft, what I do is I modify the 3D model to allow for piano wires, think of them as rebars in concrete, which I either make a snug fit so I hammer it through, or I use a little glue to go with it. 

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The first picture reminds me of my EGLM enhanced trigger. I had Shapeway print a plastic model for proof of concept first, and then a stainless steel model. The stainless steel model seems to be much better than the original one, and I think it will last a long time.

http://arniesairsoft.co.uk/forums/index.php?/topic/212268-eglm-grenade-launcher-trigger-mechanism-enhancement/&do=findComment&comment=2665276

 

Original trigger

EGLM+Broken+Fire+Mech_V2.JPG

 

Enhanced 3D-printed model

EGLM+Enhanced+Trigger1.jpg

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Stainless print by metal dust and glue or SLS? Ed, while you're still in your shotgun you may want to explore making the tri-nozzle as well. Pretty sure some folks are more than willing to sell their children for a replacement.

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Havn't got around to fitting the BB arm, that's from the TM M3 shotgun, I assume it will break within a few shots, but so long as I get it to function for two shots, I'll be happy to have that part CnC machined.

Redesign it if you want it machined, as it is that'd be a waste of material to machine, if you can replace the moulded pins with off the shelf dowel pins then it'll be far easier to machine and cheaper.

 

Ed, while you're still in your shotgun you may want to explore making the tri-nozzle as well. Pretty sure some folks are more than willing to sell their children for a replacement.

Can 3D printers even achieve a fine/smooth enough finish to do a part like that? I've never seen any 3D printed parts that looked like they were as smooth as the bore of each cylinder would need to be. I think metal tri-shot cylinders are one of those parts where lots of people say they'd pay for one but very few would be willing to pay the price they'd actually sell for, there's a good reason only the very simple parts like springs, piston heads and barrels have been done as aftermarket parts for the tri-shot tbh.

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That's the best I've seen but looking at the photo it's still not close to the sort of finish you'd achieve if the cylinder was rough machined and then bored out, probably passable though with some finishing work, the side of the slide and hammer has obviously being polished so if the same could be done with a cylinder bore it could work well.

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Ed, while you're still in your shotgun you may want to explore making the tri-nozzle as well.

Already on it ;)

 

 

Wow, how much was that to print for a piece like that? I've had quotes before for DMLS here in the UK it was astronomical..

There are a few 3d printing companies that you can send files to have printed in polymers/resins and they come out resonably cheep. The one I've been looking at seems to have the strength for internal airsoft components like the BB arm, or an auto disconnecter in a 1911... :D

 

Having parts printed in metal is prohibitively expensive, however, unless you are making batches of over ten thousand.

 

Redesign it if you want it machined, as it is that'd be a waste of material to machine, if you can replace the moulded pins with off the shelf dowel pins then it'll be far easier to machine and cheaper.

I tried to repair the origonal part by drilling a hole through it and running a metal pin in place of the broken pins. I never managed to get the pin to stay at the right angle(even with resin) and the gun malfunctioned when the pin slips even ~5 degrees.

 

Can 3D printers even achieve a fine/smooth enough finish to do a part like that?

Totally, choose the right material, find the machine that prints with enough resolution (usually the expensive ones owned by 3d printer companies rather than one you'd get at home) and finish the part properly.

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I tried to repair the origonal part by drilling a hole through it and running a metal pin in place of the broken pins. I never managed to get the pin to stay at the right angle(even with resin) and the gun malfunctioned when the pin slips even ~5 degrees.

Just drilling the hole won't cut it if that little movement causes issues, it needs drilling and reaming really, if you were to have them machined specify that you either need a tight hole tolerance or interference fit with the pins and buy ground & hardened steel dowel pins for it (providing the diameter/length can be found as a standard size).

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