Heavy Metal

Discussion in 'Show off' started by Ephemeris, Jun 24, 2016.

  1. Ephemeris

    Ephemeris Well-Known Member

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    And now for something completely different, a cast radiation shield (don't ask :rolleyes:). I haven't cleaned up the overflow yet, so what you see is exactly what popped out of the BigBox printed mold. This piece is about a kg.

    Might be worth a tutorial after I refine my process. Not a lot of free time right now...
     

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  2. Henry feldman

    Henry feldman Well-Known Member

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    Did you a use lost-wax style process or did you directly pour into a plastic mold? What plastic did you use for the mold?
     
  3. Ephemeris

    Ephemeris Well-Known Member

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    That was cast directly into the mold printed using colorFabb HT (aka Eastman Amphora HT5300)
     
  4. Henry feldman

    Henry feldman Well-Known Member

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    Wow, did the mold survive?
     
  5. Ephemeris

    Ephemeris Well-Known Member

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    There was no obvious damage to the mold on this test. HT is a pretty amazing filament.
     
  6. R Design

    R Design Well-Known Member

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    What material is it cast in?
     
  7. Ephemeris

    Ephemeris Well-Known Member

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    It's a lead-bismuth alloy (lead bismuth eutectic to be specific) A little less dense than pure lead but it melts easier and bismuth is fairly low toxicity. A lot of the low temperature casting alloys contain cadmium and I'm not inclined to go that way.

    Here's a fun fact, the Soviet navy used this molten metal as the nuclear reactor coolant in their Alfa attack subs.
     
    #7 Ephemeris, Jun 25, 2016
    Last edited: Jun 25, 2016
  8. R Design

    R Design Well-Known Member

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    mpt. 123.5 °C ?

    Super interesting. Keep the thread alive!
     
  9. Ephemeris

    Ephemeris Well-Known Member

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    Yes it melts cleanly at 255 F or 124 C.
     
  10. TimV

    TimV Well-Known Member

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    Very interesting, but what about availability?
    And price? (the sole one I found was 115$/bar (5pounds=Bar))
     
  11. Ephemeris

    Ephemeris Well-Known Member

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    That's a bit high. Rotometals.com sells it in 1 lb ingots for $15 apiece. Free shipping on $100 orders.
     
  12. eca

    eca Well-Known Member

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    I think it is amazing/great to see how many people are using 3d printers for the medical field and I am not talking about printing organs, that news has been done to death.
     
  13. Henry feldman

    Henry feldman Well-Known Member

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    As someone who does, a lot of this is for show. Much of the "the surgeon could not have done the surgery without a 3D print of the CT scan" stories are crap. We already have a 3D reconstruction on the screen (which is easier to digitally dissect on screen anyway to see surgical planes) which is the source to make the 3D print in the first place. And we painfully learned in medical school anatomy the relationship between parts. Surgeons already have a high spacial-relationship IQ since otherwise surgery would be very unsuccessful which it is not. I mean if someone tells me there is a 2.25 speculated tumor with a necrotic center 1cm from the ampulla of vater causing extrinsic compression of the common bile duct with no superior mesenteric vessel involvement, I sure don't even need to see the CT scan since I can see that in my mind (thank you Drs. Bogart and Rosenfeld back in anatomy class). However photos of the 3D model in the foreground with a nice shallow depth of field with the surgical team does create nice marketing materials for the medical centers... :rolleyes:

    As opposed to prototyping medical devices, creating surgical and medical simulation devices and for teaching like I do it is invaluable as an inexpensive way to do iterative design or do very short run manufacturing. In addition the direct 3D printing of custom implants from imaging (or a mold for implants as we often do here at our medical center since FDA certified silicone is not yet reliably 3D printable) is also equally invaluable since that is something that couldn't be done before.
     
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