The colors are added in, of course, with it being an electron microscope image. Another picture:

  • @Wogi
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    52 days ago

    These are manufactured differently from most of the stuff you’d be looking at.

    Rather than milling and grinding, the needles are made from a sheet of stainless that’s rolled and welded, then drawn down to whatever size it needs to be, basically stretching the material out. Kinda like when you make a snake with silly puddy and pull it apart.

    Then the points are ground in. Gives you a ridiculously smooth finish.

    • @[email protected]
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      fedilink
      31 day ago

      Interesting info, thanks!

      But I think you may have accidentally typed in the wrong thread? I was talking about the image manipulation, not the manufacturing :-)

      • @Wogi
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        219 hours ago

        Sure did. Whoops!

      • @Wogi
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        2
        edit-2
        19 hours ago

        Extrusion is a little different but similar. It would be easy to confuse the two.

        Extrusion is forcing material through a die to get a shape. There’s a play dough toy that is effectively a play dough extruder. You put the dough in the hopper, press a lever, and you get a star or whatever.

        The surface finish you get kinda depends on the material, it will feel very smooth but won’t be nearly as smooth under a microscope as this. If you’re in to 3D printers, the aluminum arms are generally made of 80/20 T slot, which is an extruded material. Also like, all dry pasta is made this way.

        Drawing is stretching the material. You’re pulling it through the die rather than pushing it, and getting a shape, and the act of stretching it out makes it incredibly smooth and can yield a stronger product.

        This is also how record stylus needles are made. And frequently brass tubes. It’s not done through dies, but Chinese noodles are made in a similar process, constantly stretching until they’re the desired size.