You probably already know that filled materials
like carbon fiber filament can wear down your
3D printers nozzle in no-time. There are a
couple of other materials that have a similar
effect you might not be aware of. In todays
video I’ve tested the wear behavior of brass
nozzles and the effect on print quality as
well as how you can spot if your nozzle is
worn. So let’s find out more! Guten Tag
everybody, I’m Stefan and welcome to CNC
Kitchen!
In the past I never really worried much about
nozzle wear because I rarely printed abrasive
materials and when I did, I switched my nozzle
for a hardened steel one. One day I noticed
after I inspected my changed nozzle a bit
more closely that it showed severe marks of
wear even though the only thing I printed
before was just standard materials but probably
for more than 1000 hours. At this point I
asked myself where this abrasion is coming
from and what influence it has on the print
quality of my parts.
So what we will be doing in this video is
simulating the nozzle wear with different
sized nozzles. Then, we’ll print abrasive
materials with new brass nozzles and see how
they actually wear and check the influence
of this wear on print quality. We’ll also
take a close look at the nozzles with imprints
using cold pulls and I’ve also cut a couple
of them open to see how they look inside,
so make sure you stay until the end. A lot
of interesting investigations to look forward
to!
Before we start with the investigation some
words on nozzles and abrasive filaments. Nowadays
most of our 3D printers nozzles are machined
from brass. Due to it’s ease of machining
and very good thermal properties it’s an
ideal material for this application with an
important downside. Brass isn’t the hardest
material and has the tendency to wear over
time. For most of the materials we print with,
this isn’t an issue. PLA, PETG, ABS and
so on are not really abrasive by themselves
and you can print many hundred hours and probably
a dozen kilos and don’t see anything at
all. Though, these polymers get more and more
abrasive depending on what they are mixed
with and this already starts with the pigments.
White materials for example can contain titanium
dioxide which is a very common white pigment
but just as in your toothpaste that also contains
it, this ingredient can increase the wear
during printing. It gets really bad with glow
in the dark filament because the strontium
aluminate that is used as the component that
glows in the dark can chew away a brass nozzle
only after a couple of hundered grams of material.
I found a thread on reddit where a user has
collected some experiences. Take a look at
them. Next, we come to the materials probably
most are aware of and these are the fiber
filled ones. Carbon fiber or even glass fiber
reinforced materials can chew away a nozzle
in no-time and this is actually something
we’ll test later. Also be aware of wood
filaments, because these fibers can also cause
an early death of your shiny nozzle. The same
is also true for metal filaments. I also learned
that standard materials can be mixed with
other things to improve properties like warping
and can also lead to more wear.
When I started with this project idea, I thought
that nozzle wear will primarily increase the
diameter of the orifice. In order to simulate
that I sliced a 3DBenchy with a normal 0.4mm
profile in PrusaSlicer and then printed always
the same file with nozzles starting from 0.4mm
all the way up to 0.8mm to see the effect
on print quality. Just because I was curious,
I also printed the same GCode with a 0.25mm
nozzle. So first things first, all parts printed
and finished which is already something. Our
baseline 3DBenchy printed with the suitable
0.4mm nozzle came out very nice besides a
bit of stringiness. The first thing that was
notable was that the amount of stringiness
increased the bigger the nozzle diameters
got. At 0.6mm we can also see a significant
number of holes forming in the outer shell
of the parts and 0.8mm already looks quite
nasty. We also are able to see that details
slowly get lost and overhangs become worse.
Interestingly the part printed with the small
0.25mm nozzles looks even cleaner, was without
strings and I might be doing more tests in
the future if that could be a way to improve
printing quality and due to the higher line
width improve the adhesion of the layers.
Though you have to be aware that smaller nozzles
have a higher tendency to clog. So we have
seen, that a worn out orifice diameter can
be noticed in decreased printing quality.
So maybe take a closer look at your nozzle
when you notice some wired change in printing
quality. The cold pull method I use to measure
the nozzle diameter will be covered later.
This was the simulated worn out nozzle test
but how fast and in which way do nozzles really
wear. In order to find that out, I bough a
bag of cheap Chinese nozzles that will be
sacrificed for science. In hindsight it probably
would have been better to use genuine, good
quality E3D nozzles but I didn’t have anything
else at that point. I don’t want to say
that all cheap nozzles are that bad but there
is a high ,chance that you get what you payed
for! I’ll test two different materials:
DAS FILAMENT Glow in the dark PLA and some
leftover Colorfabb XT-CF20 which is Carbon
fiber PETG. For each material I’ll at first
print a 3DBenchy with some regular PLA, then
print a block of the abrasive filament, and
print another Benchy to see if the print quality
changed. I’ll try to judge nozzle wear with
some close-up pictures I took with my macro
lens and do a cold-pull to measure the diameter
of the orifice. This is actually a really
cool method, though violently looking, to
get a perfect imprint of the internals of
your nozzle. I’m usually using very dry
PLA filament because if you get bubbles the
results will be unusable. I heat the nozzle
up to 180°C, feed a couple of mm of the material
and let it cool down to below 40°C. I disengaged
the extruder gears so they don’t imprint
on the surface. I carefully remove the leftover
material that oozed out of the nozzle during
cooling. Then I heat it up again and as soon
as it reaches 65°C I pull hard on the filament
while supporting my printhead. As easy as
it sounds I wouldn’t recommend this method
to everyone since, if the temperature is only
slightly off, you can really horribly block
your filament path. That has already happened
several times to me and taking the whole hotend
apart isn’t something for everyone. The
Imprint can then be used to judge surface
finish and even to measure the nozzle diameter.
Make sure before you measure that you don’t
accidently measure the chamfered part and
get values that are too high.
The glow in the dark material was spectacular
to print, especially when you turn off the
lights but the wear I had been expecting from
the reddit post was really underwhelming.
After 330g of material there was more or less
no wear detectable. The cold-pull still showed
the same nozzle diameter as in the beginning.
Maybe the edges were a tiny bit rounded but
nothing really serious. Much more interestingly
was to see how the internal surface finish
of the cheap nozzle looked like. There was
actually a spiral pattern in all of the cheap
nozzles from the drilling procedure which
we’ll see in more details in the cutups
later. The thing is that if I was asked to
machine a pattern like this, I wouldn’t
even know how to do it. So if you have a clue
how to make this, then let me know in the
comments! Also, our 3DBenchy just looked like
the control. So there is obviously a difference
in glow in the dark filaments and some wear
more than others. I checked back with DAS
FILAMENT and they confirmed that they do use
strontium aluminate as a pigment but maybe
particle size and shape might play a role
there. By the way: If you find these kinds
of videos and investigations helpful make
sure you are subscribed to the channel and
have selected the bell to not miss any upcoming
videos.
Next, we’ll get to the more interesting
material and that is Carbon Fiber filled PETG.
It was hurting me a bit on the inside to just
print blocks of plastic with it but hey, it’s
for science. The blocks were really just 100%
infill boxes to get the material as fast as
possible though the nozzle. These results
were very interesting for me because I noticed
that the diameter of the orifice wasn’t
really changing during the tests. What I was
able to spot though was that the tip was horribly
wearing. This wasn’t only visible on the
macro shots but I also noticed that the first
layer thickness increased over time due to
the nozzle becoming shorter and shorter. Also,
the abrasive carbon fibers rounded off all
of the edges which is a very clear sign that
something is wrong. The pattern you can see
on the nozzle is due to the fact that with
my generic test parts, the printhead is only
moving in X and Y direction and +-45°. After
360g of material my leftover filament was
gone and the same goes for the nozzle. Interestingly
the print quality wasn’t impacted as much
as you would think. There is a definite increase
in strings, you can spot holes on the parts,
overhangs don’t look remarkably good and
some details are gone but not as bad as our
0.8mm nozzle test. The thing is, that if I
would have gone further with this test I would
have at some point started to wear it down
to the point where the internal chamfer starts
and this will increase the orifice drastically
with every but more of wear until you get
to the point where your filament can pass
right through the nozzle orifice.
Now let’s really take a look on the inside
of some nozzles to find out how their internal
geometry looks like and which wear marks we
can see. For this I’ve screwed the nozzles
one by one into an old heaterblock and mounted
that in my small vise on my GoCNC Next3D CNC
router. I mounted it on the right side so
that the cutting forces won’t unscrew to
nozzle from the block. I used a 6mm, 4-flute
carbide endmill that I mostly buy from Banggood
and that are really good to be honest. A link
to those is in the description by the way.
I moved the tool to its zero position with
my newly added gamepad controller. I programmed
a short cycle where I face mill the brass
part at 500mm/min at 25000rpm spindle speed.
In each cycle I removed half a millimeter
of material until half of the nozzle was gone.
I did my best to deburr the edges with an
exacto knife and polished the machined surface
with a sharpening stone.
The cutup of the cheap Chinese nozzle confirmed
the rough spiral patter, I still can’t explain
how they even managed to machine. If we also
take a look at the nozzle that was tortured
with glow in the dark filament, there isn’t
much of a change besides the color change
on the inside. The interesting part is the
one I printed carbon fiber filament with.
Here the tip is almost worn away and very
rounded off. The orifice is only slightly
enlarged and the wear on the diameter is not
that high. But probably only a couple of hundred
grams of more materials and it would have
completely destroyed itself. I still think
this is a very interesting sectional cut.
Out of curiosity I also murdered a brand new
E3D V6 nozzle where we have a great internal
surface finish. Besides that, there are two
major differences that I noticed and that
is that the E3D nozzle uses a point angle
of 60° instead of 90° that the knockoff
has which is probably beneficial for the flow
behavior. Much more importantly is probably
the tip itself or better the end of the nozzle
bore. The ones I’ve tested were slightly
chamfered whereas the E3D nozzle shows a sharp
transition. The interesting thing is and this
is, I promise, no marketing shenanigan, that
with the E3D nozzle our Benchy is free of
stringing, with the Chinese nozzle, it’s
not. I’m quite sure that the internal surface
finish plays only a minor role in print quality
and more the point where the molten material
leaves the nozzle. I’m not sure why this
is the case but I could imagine, that having
the chamfer on the edge causes the nozzle
to act like a bigger one and we know what
the result of that is. Another possibility
could be that the nice laminarly flowing molten
plastic gets a way better flow separation
at the edge then it does with a rounded or
chamfered one. What do you guys think? The
reason why we probably see the chamfer on
the cheep nozzle is, that this is an easy
way to remove the burr from drilling. Interestingly
my worn out E3D nozzle I talked about in the
beginning shows kind of a similar geometry
where the once sharp edge was rounded by wear,
degenerating the print quality slightly. So,
does this actually invalidate my results since
I didn’t start with ideal conditions? I
think maybe and no. Maybe because the initial
stringiness was already due to a low quality
nozzle and therefore I cant tell you at which
point a good nozzle would have started with
this behavior. But also no, because this is
just an initial small problem and printing
quality only starts to really degenerate when
there is way more wear. One of the main points
also was to understand how the nozzles wear,
how bad that is and how we can check for it.
But what do you think, what should I have
done differently and what would be something
for future tests? Let me know your comments
down below!
But now to sum this all up. Brass nozzles
do wear. The speed is depending on the material
you print with. Rather than the diameter of
the nozzle, the tip will primarily wear at
first until we reach the inner tapered section
and the wear of the tip results in an increased
nozzle diameter. If the nozzles only wear
slightly and even the nozzle diameter increases
there is a change in print quality visible
though not as bad as I thought and most significantly
we can see that in the amount of stringing.
If you want to check your nozzle for wear,
take a look at the tip at first, and see if
material is missing and if you can see rounded
edges. If you want to buy cheap nozzles, make
sure that they are not chamfered, if you don’t
what to risk that buy genuine E3D nozzles
or from some other reputable manufacturer.
For not worrying about nozzle wear, get yourself
a wear resistant nozzle, be it hardened steel,
ruby, tungsten carbide or whatever and this
will be something I’m actually planning
to test in one of the next videos, so stay
tuned for that.
Thank you very much for watching this rather
long video. I hope it was worth your time
and you learned something. If you did, then
leave a like make sure you are subscribed
and have selected the bell. If you want to
support me, then consider becoming a Patron
or help me out in other ways. Also check my
other videos where I also did very interesting
investigations. I hope to see you in the next
one, auf Wiedersehen and until next time!
