WEBVTT

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I'm thrilled to be here tonight

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to share with you something
we've been working on

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for over two years,

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and it's in the area
of additive manufacturing,

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also known as 3D printing.

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You see this object here.

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It looks fairly simple,
but it's quite complex at the same time.

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It's a set of concentric
geodesic structures

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with linkages between each one.

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In its context, it is not manufacturable
by traditional manufacturing techniques.

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It has a symmetry such
that you can't injection mold it.

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You can't even manufacture it
through milling.

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This is a job for a 3D printer,

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but most 3D printers would take between
three and 10 hours to fabricate it,

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and we're going to take the risk tonight
to try to fabricate it onstage

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during this 10-minute talk.

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Wish us luck.

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Now, 3D printing is actually a misnomer.

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It's actually 2D printing
over and over again,

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and it in fact uses the technologies
associated with 2D printing.

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Think about inkjet printing where you
lay down ink on a page to make letters,

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and then do that over and over again
to build up a three-dimensional object.

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In microelectronics, they use something

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called lithography to do
the same sort of thing,

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to make the transistors
and integrated circuits

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and build up a structure several times.

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These are all 2D printing technologies.

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Now, I'm a chemist,
a material scientist too,

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and my co-inventors
are also material scientists,

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one a chemist, one a physicist,

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and we began to be
interested in 3D printing.

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And very often, as you know,
new ideas are often simple connections

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between people with different experiences
in different communities,

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and that's our story.

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Now, we were inspired

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by the "Terminator 2" scene for T-1000,

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and we thought, why couldn't a 3D printer
operate in this fashion,

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where you have an object
arise out of a puddle

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in essentially real time

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with essentially no waste

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to make a great object?

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Okay, just like the movies.

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And could we be inspired by Hollywood

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and come up with ways
to actually try to get this to work?

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And that was our challenge.

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And our approach would be,
if we could do this,

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then we could fundamentally address
the three issues holding back 3D printing

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from being a manufacturing process.

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One, 3D printing takes forever.

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There are mushrooms that grow faster
than 3D printed parts. (Laughter)

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The layer by layer process

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leads to defects
in mechanical properties,

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and if we could grow continuously,
we could eliminate those defects.

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And in fact, if we could grow really fast,
we could also start using materials

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that are self-curing,
and we could have amazing properties.

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So if we could pull this off,
imitate Hollywood,

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we could in fact address 3D manufacturing.

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Our approach is to use
some standard knowledge

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in polymer chemistry

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to harness light and oxygen
to grow parts continuously.

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Light and oxygen work in different ways.

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Light can take a resin
and convert it to a solid,

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can convert a liquid to a solid.

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Oxygen inhibits that process.

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So light and oxygen
are polar opposites from one another

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from a chemical point of view,

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and if we can control spatially
the light and oxygen,

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we could control this process.

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And we refer to this as CLIP.
[Continuous Liquid Interface Production.]

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It has three functional components.

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One, it has a reservoir
that holds the puddle,

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just like the T-1000.

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At the bottom of the reservoir
is a special window.

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I'll come back to that.

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In addition, it has a stage
that will lower into the puddle

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and pull the object out of the liquid.

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The third component
is a digital light projection system

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underneath the reservoir,

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illuminating with light
in the ultraviolet region.

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Now, the key is that this window
in the bottom of this reservoir,

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it's a composite,
it's a very special window.

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It's not only transparent to light
but it's permeable to oxygen.

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It's got characteristics
like a contact lens.

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So we can see how the process works.

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You can start to see that
as you lower a stage in there,

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in a traditional process,
with an oxygen-impermeable window,

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you make a two-dimensional pattern

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and you end up gluing that onto the window
with a traditional window,

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and so in order to introduce
the next layer, you have to separate it,

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introduce new resin, reposition it,

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and do this process over and over again.

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But with our very special window,

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what we're able to do is,
with oxygen coming through the bottom

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as light hits it,

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that oxygen inhibits the reaction,

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and we form a dead zone.

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This dead zone is on the order
of tens of microns thick,

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so that's two or three diameters
of a red blood cell,

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right at the window interface
that remains a liquid,

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and we pull this object up,

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and as we talked about in a Science paper,

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as we change the oxygen content,
we can change the dead zone thickness.

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And so we have a number of key variables
that we control: oxygen content,

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the light, the light intensity,
the dose to cure,

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the viscosity, the geometry,

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and we use very sophisticated software
to control this process.

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The result is pretty staggering.

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It's 25 to 100 times faster
than traditional 3D printers,

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which is game-changing.

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In addition, as our ability
to deliver liquid to that interface,

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we can go 1,000 times faster I believe,

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and that in fact opens up the opportunity
for generating a lot of heat,

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and as a chemical engineer,
I get very excited at heat transfer

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and the idea that we might one day
have water-cooled 3D printers,

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because they're going so fast.

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In addition, because we're growing things,
we eliminate the layers,

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and the parts are monolithic.

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You don't see the surface structure.

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You have molecularly smooth surfaces.

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And the mechanical properties
of most parts made in a 3D printer

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are notorious for having properties
that depend on the orientation

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with which how you printed it,
because of the layer-like structure.

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But when you grow objects like this,

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the properties are invariant
with the print direction.

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These look like injection-molded parts,

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which is very different
than traditional 3D manufacturing.

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In addition, we're able to throw

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the entire polymer
chemistry textbook at this,

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and we're able to design chemistries
that can give rise to the properties

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you really want in a 3D-printed object.

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(Applause)

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There it is. That's great.

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You always take the risk that something
like this won't work onstage, right?

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But we can have materials
with great mechanical properties.

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For the first time, we can have elastomers

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that are high elasticity
or high dampening.

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Think about vibration control
or great sneakers, for example.

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We can make materials
that have incredible strength,

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high strength-to-weight ratio,
really strong materials,

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really great elastomers,

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so throw that in the audience there.

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So great material properties.

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And so the opportunity now,
if you actually make a part

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that has the properties
to be a final part,

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and you do it in game-changing speeds,

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you can actually transform manufacturing.

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Right now, in manufacturing,
what happens is,

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the so-called digital thread
in digital manufacturing.

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We go from a CAD drawing, a design,
to a prototype to manufacturing.

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Often, the digital thread is broken
right at prototype,

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because you can't go
all the way to manufacturing

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because most parts don't have
the properties to be a final part.

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We now can connect the digital thread

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all the way from design
to prototyping to manufacturing,

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and that opportunity
really opens up all sorts of things,

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from better fuel-efficient cars
dealing with great lattice properties

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with high strength-to-weight ratio,

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new turbine blades,
all sorts of wonderful things.

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Think about if you need a stent
in an emergency situation,

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instead of the doctor pulling off
a stent out of the shelf

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that was just standard sizes,

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having a stent that's designed
for you, for your own anatomy

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with your own tributaries,

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printed in an emergency situation
in real time out of the properties

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such that the stent could go away
after 18 months: really-game changing.

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Or digital dentistry, and making
these kinds of structures

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even while you're in the dentist chair.

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And look at the structures
that my students are making

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at the University of North Carolina.

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These are amazing microscale structures.

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You know, the world is really good
at nano-fabrication.

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Moore's Law has driven things
from 10 microns and below.

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We're really good at that,

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but it's actually very hard to make things
from 10 microns to 1,000 microns,

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the mesoscale.

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And subtractive techniques
from the silicon industry

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can't do that very well.

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They can't etch wafers that well.

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But this process is so gentle,

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we can grow these objects
up from the bottom

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using additive manufacturing

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and make amazing things
in tens of seconds,

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opening up new sensor technologies,

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new drug delivery techniques,

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new lab-on-a-chip applications,
really game-changing stuff.

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So the opportunity of making
a part in real time

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that has the properties to be a final part

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really opens up 3D manufacturing,

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and for us, this is very exciting,
because this really is owning

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the intersection between hardware,
software and molecular science,

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and I can't wait to see what designers
and engineers around the world

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are going to be able to do
with this great tool.

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Thanks for listening.

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(Applause)