I’m Tom and today i’m going to talk about
Polycarbonate.
Now, Polycarbonate, or short / PC, is one
of the highest-performing plastics out there,
both in terms of strength and temperature
resistance.
It’s also optically clear, which makes it
ideal for things like shatterproof sunglasses,
face shields, protective glasses or even as
a component in bullet-proof windows.
It’s also often used in composites where
glass or carbon fibers are added to make the
material even stronger and stiffer.
For 3D printing, you’ll probably be using
polycarbonate without fiber additions, but
just by itself i, Polycarboneate is already
a pretty impressive material.
It is a bit stiffer than ABS, but not quite
as hard as PLA; It has an enormous amount
of layer bonding and it takes way higher forces
to break a printed part than one made from
“normal” plastics.
Even getting the brim off of your print can
be quite challenging.
Now, Polycarbonate isn’t a new material,
RichRap has been printing Polycarbonate since
2011, but it isn’t really popular, yet,
either.
And that has couple of reasons.
First of all, i already mentioned that it
is very temperature-stable with a glass transition
temperature of about 150°C, compared to 100°
for ABS or just above 60° for PLA, but that
also means that you’ll have to print Polycarbonate
at much higher temperatures.
You can extrude it as cold as 260°C, but
at that temperature, it has almost no layer
adhesion.
So realistically, you’ll be printing Polycarbonate
beyond 300°C, which simply isn’t something
that normal hotends that use PTFE or PEEK
in the heated parts / can handle.
I mostly used 315°C. You will need an all-metal
hotend and possibly a specialized thermistor
or another way of measuring the hotend’s
temperature since even the stock thermistor
of the E3D v6 is only rated for up to 300°C.
Now, the thermistor probably won’t spontaneously
combust at 301°C, but it will have a reduce
accuracy and a shorter lifespan at those temperatures.
/ You might also want to retighten your nozzle
once the hotend is up to temp for the first
time to keep if from oozing out in the wrong
spots.
The other thing that i’ve found extremely
challenging was getting my prints to stick
to the build plate.
I tried Glue stick, Kapton, PET tape and ABS
glue slurry stuff, and the only ones of those
that worked somewhat decently were PET tape
and, to a lesser degree, Kapton tape.
Bed temperatures of 120 or 140°C made very
little difference, and while smaller and weaker
prints like this octopus worked pretty well
on PET tape at 125°C, stronger parts like
the Formlabs rook detached mid-print every
single time.
Kapton has a bit of an advantage here since
the part stays stuck to the tape while the
tape itself lifts off of the bed.
But neither are ideal.
And that, i think is the biggest downside
to polycarbonate.
Of course, you could use a polycarbonate sheet
and print onto that, but to keep your parts
from permanently bonding to the sheet, you’d
have to apply the exact right amount of hairspray
or some other release agent to it and still
wouldn’t have a surface that reliably works
each time.
One other thing that was quite nasty about
Polycarbonate was the smell.
Because it smells like sweet burnt rubber
and, going by what i’ve read about it so
far, also releases quite a lot of particles
into the air, so it’s probably not something
you want to be in the same room with while
it’s printing.
YOu should also open your windows.
Even if it’s cold outside.
Polycarbonate seems to require a minimum speed
to print well.
If you go too slow, it will start bubbling
up and turn your print from clear to opaque
white.
On the other hand, if you print too fast,
the filament might kink in the extruder and
the layers of the finished print will have
less adhesion to each other.
But a slighly larger extrusion width can help
with that, especially for things like vases.
And while the acetone vapor method works pretty
well for smoothing out ABS prints, you will
need need MEK to dissolve or smooth polycarbonate,
and that is basically a stronger and nastier
version of acetone.
Acetone by itself will instantly make Polycarbonate
brittle instead of dissolving it.
The thing is, though, you will rarely need
to smooth out Polycarbonate prints since the
prints just by themselves will usually look
very, very clean without any post-processing.
Now, this might all sound like Polycarbonate
is something that you wouldn’t really want
to use.
And it’s true, it’s not ever going to
replace ABS or PLA as a daily driver filament.
But, just like Nylon, it is a material that
is well suited for special applications, especially
for those where Nylon is too soft.
I’ll be using it for 1:10th scale RC car
spares, where using printed ABS parts instead
of the original composite parts just doesn’t
feel quite right.
Because of its neat optical properties, Polycarbonate
is also well-suited for glowy things, but
PET filaments like Colorfabb XT or Taulman
T-glase are probably the better choice for
those things since PET is / actually printable.
So it really boils down to high-temp or high-strength
parts, and ever there there’s some competition.
Taulman are now offering Tritan filament,
and from what i’ve seen about that, it seems
to be a very promising plastic that is much
more printable than Polycarbonate while only
lacking the extreme temperature resistance.
I’m still waiting to get some Tritan and
i’ll post a comparison once i’ve tried
it out.
So there you have it!
Polycarbonate right now is both a solution
and source of problems, but it is a pretty
neat material for the right applications.
And it’s not even that much more expensive
than regular filament.
So, thank you to E3D for sending me a roll
of Polycarbonate a while back, i just now
got around to trying it out.
If you want to purchase some, i’ve put some
links in the description where you can do
just that.
Before you ask, no i cannot share the file
for the Formlabs rook, that file was give
to me so that i’d able to run some direct
comparisons to the sample part they are handing
out.
I was going to do a quick mechanical test
in the same way i did for PLA, ABS, Nylon
and the Formlabs part in the plastic destruction
video, but i just didn’t manage to print
a complete rook without it detaching from
the build plate.
So that’s it for today, please do not hesitate
to use those like, share and subscribe buttons
on the Youtube page.
And as always, thanks for watching!
See you next week.
