Really, Really, Really hard print of arteries

Discussion in 'Show off' started by Henry feldman, Dec 6, 2016.

  1. Henry feldman

    Henry feldman Well-Known Member

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    So hardest 3D print I have ever done (and this is take 4). The is a very, very, very accurate (0.5mm in all dimensions) model of the radial and ulnar arteries (arteries in your forearm up to your palm) as part of a radial artery catheterization simulator I am building with a colleague for both interventional radiology and interventional cardiology to train fellows in wire insertion under fluoroscopy, ultrasound and palpating. This is printed in scaffold as we will locate this inside our arm mold and then pour the silicone around it. Sadly 98% of this print is wasted support material, but damn, it freakin' worked. This is about the resolution that simplify3D would even print the artery (when printed closer to horizontal it failed, as I needed the oval to make it printable) as the diameter of the artery is about 2.75mm. Actually not even sure how I can get it off the support, but will try a razor, and can maybe use my hot knife if necessary with the flat cutting blade on it?

    [​IMG]

    [​IMG]
     
    #1 Henry feldman, Dec 6, 2016
    Last edited: Dec 6, 2016
    mike01hu, Greg Holloway and R Design like this.
  2. Greg Holloway

    Greg Holloway Administrator
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  3. A Dragon In A Pie Costume

    A Dragon In A Pie Costume Well-Known Member

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    hey greg, do you think sdding a 4 to 1(or any ratio really) gear reduction ratio for the x/y motion system could help the bb print eith these finer?
    also awesome print,must have been a pain...
    will we get a pic without the supports?
    for a print like this using scaffold could really be beneficial lol
     
  4. Greg Holloway

    Greg Holloway Administrator
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    Yes and no, you'll get improvements to a degree but then you'll run into issues with steps in the extruder showing up too. You'll also run into imperfections in the mechanical system and all sorts of other oddities with the bearings, belts and pulleys.

    Dare I say it but if you want really very high detail you'll need to swap to an SLA printer such as the Formlabs 2.
     
  5. Henry feldman

    Henry feldman Well-Known Member

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    I do own (or at least have paid for - Ha Ha) a SLA printer (the Slash) but the reason this was printed on my BigBox was because this is big! Remember this is your entire arm from your elbow to your palm... So that was the biggest challenge was printing something this fine at that scale...
     
  6. Henry feldman

    Henry feldman Well-Known Member

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    I think v2 of this specific print (I am working on a way more complicated one for the pelvis - but that's easy since the diameter of the femoral artery/iliacs are around 1cm+) I may instead use a heat gun on lower temps and simply bend the 2.85 scaffold I have for my Taz into shape since your arm is pretty straight. I can use the supports here as a basic guide. Won't be as sub-mm accurate, but pretty damned close and way, way easier... This thing is super fragile
     
  7. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    Henry, what if you printed it horizontally?
     
  8. Henry feldman

    Henry feldman Well-Known Member

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    It didn't survive. Tried it in many orientations. This stuff is fragile when used as primary material.
     
  9. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    Is there a TPE or TPU material you could use that is close enough to the properties you need to have?
     
  10. Henry feldman

    Henry feldman Well-Known Member

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    For the arteries? The point is I need them to dissolve away leaving their cast in the silicone. We are going to try actually dipping them in harder silicone to simulate the vessel wall, then pour the main flixible silicone around it to form the soft tissue.
     
  11. Christian Riesen

    Christian Riesen Active Member

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    Have you considered going the opposite way? 3D print the mold so to speak?
     
  12. Henry feldman

    Henry feldman Well-Known Member

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    I do actually want to figure out how to cast PVA, but that is likely a very advanced skill. This would also be a very tiny mold (it's about 2.75mm in diameter). For the larger artery that I am working on (iliac/femoral) it could much more easily be cast, if I knew anything about pouring molten plastic...

    Here is the larger one (this was all printed on the taz in the lab as the BB was busy printing another project)
    [​IMG]

    Which I will add was an absolutely heroic save as the supports fell over, and I taped them in place up in the air, then 25 hours later it started to tip, and with more tape, saved the model (which was a 53 hour special)... Luckily figured out early that electrical tape (which was right there) sags under the heat, and used office tape.

    [​IMG]
     
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