Polycarbonate is widely considered to be the
king of consumer 3D printing materials when
it comes to strength and toughness and I actually
had to learn that the hard way during my tests
since it destroyed one of my test fixtures.
Polymakers PolyMax PC is one specific material
that is very often named when people talk
about polycarbonate.
So, for todays video I have thoroughly tested
this filament for printability, mechanical
performance and thermal resistance.
Let’s find out more!
Guten Tag everybody, I’m Stefan and welcome
to CNC Kitchen!
Since the days I’ve started 3D printing
I often heard people discussing that, if a
3D printed part needs to be strong, then you
need to print it out of Polymakers PolyMax
PC, or as it was called in the past, Polymaker
PC Max.
Polycarbonate in general is a very abundant
material in consumer items and can be found
in CDs and DVDs, your glasses, car headlights
or even bulletproof glass and is also known
under brandnames like Lexane.
The reason for that is, that PC is a very
tough material but also features visual clarity.
It has been around as a 3D printing material
for almost a decade but is not that commonly
used, because it needs quite high extrusion
temperatures and suffers from warping and
challenging adhesion problems to printbeds.
Over the last years it also fell in a bit
of disrepute since a compound named bisphenol
a is used for it’s production that can cause
severe health problems and is therefore not
used anymore in baby or even your normal drinking
bottles.
Honestly, I don’t really know why I haven’t
done a review of this filament so far, because
for all it claims it seems to be a really
great contestant for mechanical applications.
I did include it in the cold temperature performance
test video where it faired very well, but
just never got to a full review.
But this will change today and I ran a ton
of prints with it to compare it to other materials.
Just by the way, if you like content like
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PolyMax PC comes on 750g rolls that sell for
around $45 with makes a kilo price of $60
which is definitely not cheap but totally
in the range what other technical materials
also sell for.
Polymaker also has a “Lite” version of
this material in their program which sells
basically for half and the only significant
difference I could see was, that the impact
resistance of the less expensive version is
not that good and it only comes in a clear
color.
I haven’t tested it myself and the following
tests will only cover the PolyMax variant.
It comes nicely packed and sealed in a box
and also includes one of these metallized
storing bags with a zipper that reduces moisture
ingress.
Similarly, to most other technical materials,
Polycarbonate also needs to be stored and
printed dry, so I always used my selfmade
drybox out of which I printed.
First, I tested the extrusion factor that
showed the best results at the standard 100%
which also shows that the filament diameter
seems to be tuned in quite well.
Next I continued by printing 2 of 3DMakerNoobs
test towers where I tested different printing
temperatures on one and different part cooling
fan settings on the other, even though Polymaker
recommends to not use any fan at all.
Recommended print temperatures go from 250°C
to 270°C but since thermistor readings can
be a bit off, I tested even 240°C all the
way up to 280°C. The bed was set to 105°C
which worked for the most part but when one
print failed because a part let loose from
the buildplatform, I switched over to applying
some Magigoo PC and that just helped tremendously.
Interestingly the material didn’t smell
during printing but there are a couple of
health concerns with hot PC why I urgue you
to not print in the room you work and thoroughly
ventilate it afterwards.
The tower printed successfully with all of
the temperatures but you were able to spot
a light discoloration of the material at the
highest temperature which is a sign of warning.
The printing quality increased the lower the
temperature was set.
I tend to break of the spikes with my fingers
to get a feeling of layer adhesion and that
unfortunately also decreased with decreasing
temperature.
The fan test was very interesting because
at no fan at all the print didn’t look particularly
pretty but at only the slightest amount of
cooling, in this case 15%, quality got so
much better.
But again, I could feel that layer adhesion
suffered.
So in order to find out with which fan setting
and temperature I should go for the rest of
the prints I ran a short layer adhesion test
and printed samples at 250°C and 270°C without
fan and 270°C with 15% fan.
The idea was to find out how the impact of
this small amount of cooling was and or if
it was better go just go with a lower printing
temperature.
I tested these new types of samples on my
universal test machine, that feature spherical
bearings on both ends and found out, that
indeed, the 270°C samples without fan were
the strongest.
250°C and no fan was just a tiny bit weaker
and also showed more scatter.
The interesting thing to find out was what
impact that small amount of cooling had because
that lead to a reduction of 30% in strength.
By the way, looking at the numbers you can
already see that we have a really interesting
material right here because with a strength
of over 50MPa between the layers we are already
stronger than PETG or ABS in layer direction!
The nuts that are used on that jig were also
the parts that failed under the unusually
high amount load.
Well, I reprinted them out of PolyMax PC and
they held ever since.
So from these results I concluded that for
such a technical material I probably have
to live with the decreased print quality to
get the maximum amount of strength.
I also decided to go with 270°C on the nozzle
for best layer adhesion, though in hindsight
I think, I should have rather used 250°C
for a bit better printing quality.
The overhang test showed what I already suspected
and that was that the quality just wasn’t
the best because the material stayed too soft
due to the lack of cooling.
The stringing and small details test was surprisingly
good.
It showed some hairs but overall nothing was
really deformed.
The bridging test was also not fabulous and
shows again that the material is not made
for super esthetically looking prints.
The 3DBenchy didn’t look so bad though and
by increasing the minimum layer time to 20s
even the chimney was just a little deformed.
Though on closer inspection you can see the
artefacts in overhanging areas which is also
backed up by the 3D scan I made with my ATOS
Core 3D scanner that GOM gratefully provided
for me to use for a couple of weeks for my
research.
Just out of curiosity I also printed a 3DBenchy,
still at 270°C, but with 15% cooling fan
which brought the quality to a point that
it was basically perfect besides the steep
overhang in the front but that also looks
very similar on a PLA print.
Now we finally get to the interesting part
and this is the mechanical tests!
With 64MPa of tensile strength of the lying
specimens, PolyMax PC is just shy of the strength
of PLA.
But in contrast to the otherwise strong PLA,
the polycarbonate didn’t just snap with
a brittle failure, it nicely deformed and
plasticized.
Layer adhesion was great and as I have already
teased before, the layer adhesion samples
were able to bear 51MPa which is 80% of the
material strength.
Just on a side note – this is very impressive
but also materials like PLA and PETG can have
similarly good layer adhesion properties,
if you reduce partcooling quite a bit, as
I have shown in a previous video.
I checked the stiffness of PolyMax PC with
a 3-point-bending test where I measure the
deformation of a specimen at different loads.
A stiffer part deforms less under the same
amount of load and with this test we can compare
this important property.
I usually do that with a dial gauge but since
I had the 3D scanner from GOM I thought I
use it’s stereo cameras to perform 3D point
tracking which this device is also capable
of.
I put a couple of measuring dots on the fixture
and the pin that loads the sample and filmed
the test with the ATOS Core.
I later imported that footage into GOM Correlate
where I can track the points over time and
since the device is calibrated, I don’t
even need to take a reference measurement.
The cool thing is that this technique allows
me to even track the deformation of the bearings
and really only measure the relative deformation
between bearings and the load introduction
point.
In this case it was a good idea that I additionally
applied this method, because I later noticed
when checking the footage that the dial gauge
was not properly perpendicular to the specimen
and that way measured values a bit too big.
Since there are probably not many around that
also have access to such a neat measuring
device, I wanted to point out that their software
can be downloaded for free and you can use
the same tracking method also with just normal
camera footage.
You need a reference dimension in that case
and need to be aware of lens distortion and
perspective error, but for some applications,
this can still be a horribly powerful and
free tool.
And just on a side note, because I might cover
that in a separate video, you can ever use
GOM Correlate, spray a part with a speckle
pattern, film it during test and calculate
the strains on the part.
So the results of the stiffness test showed
a bending stiffness of 2300MPa which is softer
than PLA but stiffer than PETG or ABS.
Next I tested my Test Hook which should be
a more realistic part than the generic test
samples.
The part that was printed lying outperformed
everything I’ve tested to far and broke
at 74kg probably also due to the behavior
that it doesn’t just snap like PLA but gives
more and redistributes the load more efficiently.
Unfortunately, the hook that was printed standing
already failed at 47kg of load, which still
is impressive but not the 80% of the strength
we’ve seen with the layer adhesion sample.
Next I did the impact test and there, as expected,
PCMax outperformed everything, even the really
flexible PP.
So a great material for everything that needs
to take a beating.
The standing samples unfortunately only had
30% of the impact resistance, which is quite
a bit lower, but the values are still above
what PETG, PLA or nylon generally are able
to take in their ideal printing orientation.
Last I checked the thermal resistance in my
oven where I gradually increased the temperature
until the sample, that was loaded with a specific
weight, deformed.
That started at around 105°C and it then
totally failed just 5°C higher.
This property again is very good and even
a tiny bit better than what you can see with
ABS.
So, verdict time!
What do I think about Polymakers PolyMax PC?
It’s great strength makes it a perfect candidate
for mechanical demanding applications and
especially it’s good stiffness and impact
resistance sets it off from Nylon.
After I used Magigoo PC I didn’t have any
printing issues whatsoever which does make
it not the most demanding material to print
with and since you can print it even at 250°C
you might even be able to work with it on
cheaper printers that have a Teflon Bowden
tube right up to the nozzle.
Printquality is not the best with no fan at
all but if you either design parts with 3D
printing in mind or sacrifice a little strength
and use some fan, the print results can still
be really nice.
With a price of $45 for a roll I’d still
say that it is reasonably priced for what
it delivers.
So in my opinion, if you have applications
for it, it’s definitely worth buying and
lives up to its reputation.
You can find links to the material and the
test methods I use down in the description.
The detailed test report together with print
profile and all test sample are available
for my Patrons.
If you enjoyed this video and learned something
then hit the like button and subscribe to
the channel for more.
If you have suggestions and comments about
my methods, please leave them down below and
let me know what other material you would
like to see me investigate in the future.
Until then, thanks for watching, auf wiedersehen
and goodbye!
