3D Printing in a liquid medium
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Adric Landman
May 30, 2017, 7:10:50 PM5/30/17
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Hello All,
Lachlan and I are experimenting with materials we can use to 3d printing into a medium like the following video,
The medium in the video is a hair jell like substance.
We were trying to work out what we could inject into this medium to print like this. I was thinking of some sort of silicone or polypropylene.
If you have any idea of what they are using or what to join us experimenting with this post a message!
Adric
Clifford Heath
May 30, 2017, 10:25:15 PM5/30/17
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On 31 May 2017, at 9:10 AM, Adric Landman <adric....@gmail.com> wrote:
> The medium in the video is a hair jell like substance.
It could be just weak agar.
> The medium in the video is a hair jell like substance.
> We were trying to work out what we could inject into this medium to print like this. I was thinking of some sort of silicone or polypropylene.
Silicone yes. You need something whose curing is
compatible with being enclosed. Anything with a
moisture-triggered reaction should be ok in an
aqueous gel, but you'll need to print adjoining
features quickly enough to get adhesion before
the reaction is complete.
> If you have any idea of what they are using or what to join us experimenting with this post a message!
Clifford Heath.
Luke Weston
Jun 1, 2017, 10:46:00 AM6/1/17
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What is actually being laid down? It has to set extremely fast, and
yet be quite rigid and strong. I suspect the speeds in their video are
exaggerated.
Maybe a molten thermoplastic? It's not clear that they're operating
everything at room temperature. Maybe a really low-melting-point
thermoplastic like polycaprolactone which will melt at about 60C.
But it doesn't really melt to a pourable liquid consistency. You've
probably seen polycaprolactone before (like Polymorph or whatever
brand name) - when you put it under boiling water it still has a
clay-like consistency, you can form it by hand but it's not pourable
or pumpable.
A two-pack silicone or epoxy etc won't set anywhere near that fast.
But if it's held in place by the substrate material maybe that doesn't
matter - just leave it in place to set inside the scaffold material,
for however long that takes, then remove it. Maybe a really fast epoxy
(or polyurethane or whatever) system with over-catalyst. But the pot
life would be really sort - need to mix it and fill the machine and
run it just in time.
Maybe there's chemistry in the scaffold material that makes it harden
- the crosslinker or catalyst or whatever. But it's only in contact
with the injected material at the surface, not throughout.
Or a resin system that has a photoinitiator in it, like TPO or
Irgacure or whatever, where the resin will kick off under UV
irradiation and set relatively quickly.
(Kind of like stereolithography for 3D printing.)
It will work, but the "real time" aspect implied by the video isn't realistic.
Having a single-part mixture that sets itself (without outside
chemistry or light once it's laid down) will make it a pain to clean
the excess hardened resin out of the extruder.
The substrate looks like it's maybe weak, soft agarose (like maybe
0.5% agarose or something like that).
It's either that or maybe gellan gum, if I had to guess.
Gelatin might be cheaper, or agar.
Maybe mucking around with a bit of glycerol in there or something like
that to modify the rheology, making it just firm enough but not too
firm so it will "heal" behind the path of the needle, without leaving
a channel.
It needs to be soft enough to flow back in behind the needle track,
but hard enough to keep the injected resin structure supported.
It's interesting.
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yet be quite rigid and strong. I suspect the speeds in their video are
exaggerated.
Maybe a molten thermoplastic? It's not clear that they're operating
everything at room temperature. Maybe a really low-melting-point
thermoplastic like polycaprolactone which will melt at about 60C.
But it doesn't really melt to a pourable liquid consistency. You've
probably seen polycaprolactone before (like Polymorph or whatever
brand name) - when you put it under boiling water it still has a
clay-like consistency, you can form it by hand but it's not pourable
or pumpable.
A two-pack silicone or epoxy etc won't set anywhere near that fast.
But if it's held in place by the substrate material maybe that doesn't
matter - just leave it in place to set inside the scaffold material,
for however long that takes, then remove it. Maybe a really fast epoxy
(or polyurethane or whatever) system with over-catalyst. But the pot
life would be really sort - need to mix it and fill the machine and
run it just in time.
Maybe there's chemistry in the scaffold material that makes it harden
- the crosslinker or catalyst or whatever. But it's only in contact
with the injected material at the surface, not throughout.
Or a resin system that has a photoinitiator in it, like TPO or
Irgacure or whatever, where the resin will kick off under UV
irradiation and set relatively quickly.
(Kind of like stereolithography for 3D printing.)
It will work, but the "real time" aspect implied by the video isn't realistic.
Having a single-part mixture that sets itself (without outside
chemistry or light once it's laid down) will make it a pain to clean
the excess hardened resin out of the extruder.
The substrate looks like it's maybe weak, soft agarose (like maybe
0.5% agarose or something like that).
It's either that or maybe gellan gum, if I had to guess.
Gelatin might be cheaper, or agar.
Maybe mucking around with a bit of glycerol in there or something like
that to modify the rheology, making it just firm enough but not too
firm so it will "heal" behind the path of the needle, without leaving
a channel.
It needs to be soft enough to flow back in behind the needle track,
but hard enough to keep the injected resin structure supported.
It's interesting.
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Adric Landman
Jun 12, 2017, 12:38:21 AM6/12/17
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Well so far we have tried expander foam but we were using water so it was too light. I wonder it we could do it in a enclosed space under an agar like substance, it that would work better.
I was also thinking we could use chocolate ice magic as it sets in cold. We could pump it into a cold water solution and it would set solid.
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