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

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• t3rmit3@beehaw.org ⁨2⁩ ⁨days⁩ ago

  Just more scientifically unsound forensic “evidence” for prosecutors to bamboozle juries with.

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• mctoasterson@reddthat.com ⁨1⁩ ⁨day⁩ ago

  A criminal could buy an Ender3 or other extremely ubiquitous, non-internet-connected printer. Maybe used, in cash, on various marketplaces.

  Filament can be bought in cash as well from a bunch of retailers and the leftover stock (evidence) easily disposed by dumping or burning/melting after the “suspect objects” are created.

  Furthermore, nozzles are like $1 apiece in some cases. Printbed replacements or sheets of glass (also often used as printbed surfaces) are like $20 and can be changed often and easily. Changing these two components completely invalidates the “match” of the toolmarks.

  This type of forensics is only practical if the target suspect is dumb enough to use the same settings for everything, never change a nozzle or bed, keep all his empty filament spools and receipts, pay for everything with credit cards in his name, and have a bunch of cloud-saved bambu-sliced files called “super illegal weaponry.gcode” associated with his printer.

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• theangriestbird@beehaw.org ⁨2⁩ ⁨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 ⁨2⁩ ⁨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 ⁨2⁩ ⁨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 ⁨2⁩ ⁨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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  • Ulrich@feddit.org ⁨2⁩ ⁨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 ⁨2⁩ ⁨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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• Rolive@discuss.tchncs.de ⁨2⁩ ⁨days⁩ ago

  But… you’d need to do several test prints with the suspects 3D printer to get a matching profile right? It doesn’t seem practical but indeed every 3D printer has it’s own fingerprint.

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  • sleepundertheleaves@infosec.pub ⁨2⁩ ⁨days⁩ ago

    It’s not any less practical than, for example, test firing a gun to match the rifling on its bullets to bullets found at a crime scene.

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    • SteevyT@beehaw.org ⁨2⁩ ⁨days⁩ ago

      You’d also have to use the same slicer settings, similar room conditions, make sure that you have the same filament roll (assuming it’s an FDM printer), make sure that nothing hardware wise was tweaked (eg. fixing belt tension), make sure nothing software wise was tweaked (it’s nuts how much difference temp can make), make sure nothing firmware wise was tweaked, and the nozzle cant have had too many prints between the suspicious one and now (or like half of a glow in the dark or carbon fiber filled pring).

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• CanadaPlus@lemmy.sdf.org ⁨2⁩ ⁨days⁩ ago

  Is this how ghost gun printing is working? One person with a machine making and selling oodles?

  If you’ve printed your own it seems like this would have limited applications, because you’ve either destroyed or lost it, or it’s still in your possession.

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