Asking this because I’ve been thinking about resin printing and how a small layer of said liquid could, in theory, be used to make the prints faster and negate any problems regarding the FEP film (which can wrinkle, tear and be a hassle to clean when small pieces are stuck to it). The ideal liquid would have to be:

  • Inert to UV light
  • Not miscible with the resin
  • Denser than 1.25g/cm³

Maybe the liquid doesn’t even need to have a small refraction, so long as the light doesn’t diffuse too much after going through ~1mm of it. That or doing some compensation on the print.

  • Clasm@lemmy.worldEnglish
    5·
    10 months ago

    Technically, I believe Mercury fulfills those requirements.

    Otherwise, maybe something like Glucose?

    There are a few substance here that meet that density: https://www.engineeringtoolbox.com/liquids-densities-d_743.html

    But, as far as resistance to UV and immiscability with UV resin, testing would be required, as I’m assuming you intend to replace the FEP film layer with a dense liquid.

    • I Cast Fist@programming.devOPEnglish
      1·
      10 months ago

      Mercury? Isn’t it opaque and fully reflective? Or does UV light pass through it?

      For initial testing, the FEP would remain, but as this liquid would theoretically not stick to the resin, the FEP would remain intact, pretty much eliminating risks that have anything to do with it.

      I have seen something like this before, but it uses two different lightwaves in order to make the denser liquid remain inert, so it’s impossible to try it with consumer printers.

      • AmalgamatedIllusions@lemmy.mlEnglish
        3·
        10 months ago

        Assuming we’re talking about refractive index here, metals technically still have a refractive index despite being reflective (light can penetrate a very short distance through metals). In the UV, the refractive index of mercury is <1 and of course it’s very dense. But that’s probably not going to be useful to you.

        For transparent materials, water actually has a lower refractive index than most liquids (around 1.34 in the UV). You can check this website to see if there’s anything better (probably an organic), but I doubt it would be by much.

        I don’t know much about 3D resin printing, but I assume you a focus an image (in the UV) onto a resin layer to selectively cure it. As you suggest, the presence of a liquid would refract the focusing light rays and change the position of the focal plane. This could in principle be accounted for by changing the distance from the focusing optic, though there could be some (perhaps minor) blurring of the image.