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Comment on 3D Printing Patterns Might Make Ghost Guns More Traceable Than We Thought | 404 Media

theangriestbird@beehaw.org ⁨3⁩ ⁨days⁩ ago

key excerpt:

Most 3D printers work by heating up a filament—often, but not always, plastic—and extruding it through a metal nozzle. The nozzle puts down hundreds, or even thousands, of layers of the heated plastic to form a solid object. Each individual level of the print is called the print line. “So on the firearm, I’m seeing from the trigger guard—maybe print line 200—and the top of the magazine well—print line 400—the marks are staying consistent,” Garrison said.

It was an exciting discovery but it also wouldn’t be admissible as evidence in a criminal trial. Despite the promise that we may one day be able to match a printer to the object that made it, Garrison stressed that the work was in its very early days and that it would take years, perhaps even a decade, of science to work out the truth of toolmarks and 3D printers.

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jatone@lemmy.dbzer0.com ⁨3⁩ ⁨days⁩ ago
unless its unrelated to the nozzle it’ll be easily circumvent by replacing said nozzles.

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- Cyv_@lemmy.blahaj.zone ⁨3⁩ ⁨days⁩ ago
  Yeah I can’t fuckin print consistent prints on purpose, good fuckin luck doing some kind of forensic a analysis about it.
  
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- Saleh@feddit.org ⁨3⁩ ⁨days⁩ ago
  Yeah, this is absurd. Also if someone makes a “ghost gun” they can easily destroy the printer before using that thing.
  
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  - moody@lemmings.world ⁨3⁩ ⁨days⁩ ago
    If someone makes a 3d-printed ghost gun, they can destroy the gun beyond any chance at recognition by tossing it into a fire.
    
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    Sandbar_Trekker@lemmy.today ⁨1⁩ ⁨day⁩ ago
    Depends on whether their 3D printer could print out metal objects or not.
    
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  - jatone@lemmy.dbzer0.com ⁨3⁩ ⁨days⁩ ago
    yes and no. I think the idea here long term is similar to the printer dots on normal printers. where they track/record those from factory to the point of sale. if the nozzles leave identifying marks (something I’d totally believe) then even destroying said printer might not help you if you used a credit card to purchase it.
    
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    Vodulas@beehaw.org ⁨3⁩ ⁨days⁩ ago
    Unless there is something inserted into the gcode, nozzles are a wear item. You would not be able to put a consistently identifiable mark on the nozzle
    
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    SteevyT@beehaw.org ⁨3⁩ ⁨days⁩ ago
    I can change what an individual print line looks like to the naked eye just by something as simple as tweaking temperature or print speed. Good luck getting anything remotely consistent intentionally by clever nozzle machining.
    
    Also, nozzles are dead simple to make, it’s literally just a large drill bit (1.75mm diameter or so) with a smaller (.05mm to 1mm) drill poking the last bit through. Tip is slightly flattened off and away it goes.
    
    Also, as someone else said, nozzles are a wear item, it’s like trying to track a car down by the brake pads, or a pencil down by the shape of the lead at the tip, using it changes the characteristics of it.
    
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Ulrich@feddit.org ⁨3⁩ ⁨days⁩ ago

Each individual level of the print is called the print line

It’s called a layer.

“So on the firearm, I’m seeing from the trigger guard—maybe print line 200—and the top of the magazine well—print line 400—the marks are staying consistent,” Garrison said.

…I don’t even understand what that’s supposed to mean? “The marks are staying consistent”? What marks? Consistent with what?

Even if they were able to match a print to a nozzle (which they won’t be), nozzles are cheap and replaced often. They’re a wear item. You replace them in 2 minutes.

However, none of this will stop DAs from trying to use this shit as evidence, just like all the other junk science they pay people to lie about.

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nous@programming.dev ⁨3⁩ ⁨days⁩ ago
Also worth pointing out:

There are other issues too. All of Law and Blair’s tests were done with one kind of 3D printer—a Prusa MK4S. There’s hundreds of different devices on the market that all behave differently. Law also pointed out that brass nozzles warp over time themselves and may produce different results after hundreds of prints and that different nozzles made from different materials may work very differently. Law would also want an examiner rate study—a formal scientific inquiry into false positives and examiner bias.

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