Does printing with a larger nozzle increase
the strength of 3D prints? This and the question
how you can get the same effect with your
standard sized nozzle, is what I investigated
for this video. Let’s find out more! Guten
Tag everybody, I’m Stefan and welcome to
CNC Kitchen.
This video is sponsored by Squarespace. Squarespace
is an all-in-one platform that I use to easily
provide write-ups and the results of my research.
Create your own website by browsing squarespace.com/cnckitchen.
More on Squarespace at the end of this video!
I’m sure you’ve all heard or even experienced
it already that using a larger nozzle in you
3D printer seems to result in quite a bit
more sturdy parts. I also had the same impression
in the past but always asked myself if my
3D prints really are stronger because the
layers bond together better or if it’s just
additional material you put down that reinforce
the parts. So, first things first, let me
know in the comments if you regularly use
bigger nozzles and for which purpose. In order
to provide you with a proper answer I’ve
investigated exactly that. For this reason,
I printed my test hook in it’s standing
orientation with a standard 0.4mm and a 0.8mm
nozzle on my Original Prusa i3 MK3S. I chose
this combination of diameters because it gives
me the possibility to keep the wall thickness
the same for both parts. If you’ve also
watched my previous video, you’ll know that
by adjusting the extrusion width you can not
only fuse the layers at least a little better
but also extrude quite a bit wider than the
bore diameter of the tip. This also posed
the question if instead of switching nozzles
you could also use this setting to get the
same effect.
In the end, I wanted to find out if parts
printed with a bigger nozzle are stronger
due to the additional amount of material or
if somehow the layers bond together better.
As a bonus I also tried if you can avoid switching
out nozzles by just using higher extrusion
widths. This is the test matrix I came up
with. I printed parts with the 0.4mm nozzle
using a standard extrusion width of 105% but
we’ll also emulate the 0.8mm nozzle by using
an extrusion width of 210% which is pushing
material out of the nozzle quite a bit wider
than the orifice. For the 0.8mm nozzle I printed
parts with one and two perimeters which results
in the same wall thickness as with the smaller
nozzle and 2 or 4 perimeters. For one set
of samples I also increased the layer height
to 0.3mm which is more reasonable than 0.15mm
on such a big nozzle. As I’ve shown in the
past, layers that are too thin can result
in worse printing quality. For each set of
parameters, I printed 3 samples to at least
have some statistics. For these tests I’ve
also used no infill whatsoever because I noticed
that depending on the position of the parts
on the building platform and the infill algorithm
in PrusaSlicer it can happen that the infill
significantly reinforces the shell which will
spoil our results and introduce more scatter.
I also didn’t use my layer adhesion samples,
even they probably would be more scientific
due the pure tension they’re loaded with.
They are a bit hard to tune in but the results
correlate very well with the hooks which are
just nicer to look at. All parts were printed
in SpoolWorks PLA and I limited the material
flow to a maximum of 3mm³ per second which
is only a fourth or a fifth what a normal
V6 hotend is able to handle. This way we don’t
get different results due to insufficient
melting.
All parts printed without a problem. The only
thing I was able to see was, that the quality
of the hooks with the large 0.8mm nozzle at
a layer height of 0.15mm didn’t look particularly
well. This corresponds very well to my previous
findings that you shouldn’t go below ¼
the nozzle diameter in layer height without
extensive tuning. Interestingly the parts
where I emulated a bigger nozzle by upping
the extrusion width did basically look the
same. When I increased the layer height to
0.3mm the print results were gorgeous again
with the big nozzle. Interestingly the hooks
printed with the 0.4mm nozzle at 210% extrusion
width did look differently on the top surfaces.
It looked like they were under-extruded but
due to the small material flow and also a
very similar weight that’s probably not
the case. What that basically means is that
you can emulate a bigger nozzle by upping
the extrusion width but at some point, the
flow dynamics under the nozzle will change.
For a reference of how far the standing hooks
are away form the optimal lying printing orientation,
I also printed flat hooks with 0.84mm and
a 1.68mm wall thickness which is equivalent
to 2 and 4 perimeters with the 0.4mm nozzle
or 1 and 2 walls with the 0.8mm nozzle. Since
you can’t always trust the weight values
in the slicer, I also put all parts on a scale
to see how heavy they really are. The parts
with similar wall thickness weight pretty
much the same, only the hooks from the lying
printing orientation differed a bit, probably
due to the slicing algorithm. I’ll take
these values intro consideration later when
we evaluate the strength by weight.
Let’s now finally get mechanical test that
I performed on my DIY universal test machine.
Before that, please make sure that, if you
like this video, you are subscribed and selected
the notification bell. Also hit the like button
so that YouTube will recommend this video
to more science and 3D printing interested
viewers.
I mounted all of the parts in my DIY universal
test machine and loaded them at the same speed
to remove the human factor from testing. The
load is constantly measured during the test
so that in the end, I can easily determine
the failure load. The 23 samples that I tested
failed from 116N all the way up to 808N of
force. The weakest one was the hook with the
small nozzle and only 2 perimeters, the highest
strength came from the reference hook that
had 1.68mm wall thickness and was printed
lying.
Since my suspicion was that the higher strength
of prints with a bigger nozzle results from
the additional material, so in this case,
thicker walls, I grouped the strength values
for wall thickness. The results from the parts
with the 0.84mm walls already confirm this
because the average strength of the parts
is almost exactly the same, though there is
more scatter at the parts printed with the
0.4mm nozzle as with the parts printed using
a 0.8mm nozzle and just one perimeter. The
reference hook in the optimal printing orientation,
was by the way able to handle 330N of load
which is more than double the load bearing
capability.
Now, let’s get to the hooks with double
the wall thickness. Here again, if we also
take the scatter into consideration, all parts
broke on average at roughly the same level
of load, again around 50% below the reference
strength of the lying hook. Even the hooks
printed with the emulated big nozzle, were
I only increased extrusion width but kept
the 0.4mm nozzle, did not perform worse which
is great because that might mean that if you
rarely want to print with larger nozzles,
save yourself the hassle and just increase
extrusion width. Sorry nozzle manufacturers…
The results even barely change if we take
the weight of the samples into consideration.
The strength is basically proportional to
the used amount of material and in this case,
the wall thickness. This means that bigger
nozzles don’t seem bond layers together
better or reinforce the plastic. As I said
in the past, I’m working in aerospace and
here it’s usually important to use material
efficiently, so maximum strength at minimum
weight. If you’re not concerned with weight,
you’ll also be able to achieve the same
strength of your parts at similar wall thicknesses
and infill ratios regardless of the nozzle.
Though, I guess the interesting point here
is in what amount of time will you achieve
which strength. This is where the advantage
of bigger nozzle comes into play, because
they allow you to push more material out in
the same amount of time. Disregarding maximum
flow rate, cooling issues and keeping speeds
the same, a 0.8mm nozzle at double the line
width and double the layer height pushes out
4 times as much material out in the same amount
of time in comparison to a standard 0.4mm
nozzle. If we apply this to our tested samples,
we can finally see, where the bigger nozzles
shine and the impression that parts with a
bigger nozzle are stronger, comes from. The
strength per time is by factors higher if
you print with larger nozzles and larger layers.
In this test you can even get a similar effect
by just upping the extrusion width and layer
height on standard nozzles, though there are
limits in the end!
I think I was able to nicely show that the
additional strength of prints with bigger
nozzles results from the additional material
that is printed and not any reinforcement
in the plastic. I’ve already made a video
in the past about the most efficient way to
improve the strength of 3D prints and that
is not the infill ratio but the wall thickness.
If you keep the number of perimeters the same
and just use a bigger nozzle, especially the
walls will be thicker and therefore the strength
is improved significantly! Though, these thick
walls can be achieved with a big or a small
nozzle by adjusting the number of perimeters.
The big advantage of bigger extrusions is
if you take the time factor into consideration
as well because the with a bigger nozzle you
can increase the strength of a part by factors
in a similar amount of time. I’ve also shown,
that you might not always need a larger nozzle
for that effect because if you stay within
the capabilities of your system you can emulate
bigger nozzles just by increasing extrusion
width and layer height. Going all the way
to double the extrusion width and layer height
might be a bit much but emulating a 0.6mm
nozzle with a 0.4mm nozzle and therefore more
than doubling your strength per time should
be possible without an issue. So consider
creating yourself a fast and strong printing
profile for your current printer! But what
do you think of these results? Leave your
thoughts down in the comments!
The detailed test results are available for
my Patron supporters but if you only want
to take a second look at the graphs than make
sure to check out my new website where I started
posting write-ups of all of my videos. This
is thanks to todays videos sponsor Squarespace.
Squarespace is a is THE all-in-one platform
to build a beautifully looking online presence.
They have a ton of professional templates
for you to start with and free stock photos
for quick customization. Their online editor
is so intuitive to use and helps you create
and maintain your website with no hassle at
all. If you also have a business or just want
to share your latest hacks and prints or even
create a shop in a professional manner than
start your free Squarespace trial today at
squarespace.com/cnckitchen and use code CNCKITCHEN
to get 10% off your first purchase. As you
know, I do like data and Squarespace provides
a powerful Analytics tool I use to optimize
my business presence and they even have a
simple app available for your phone. Try out
Squarespace 2 weeks for free by browsing squarespace.com/cnckitchen
and let them know who send you by using code
CNCKITCHEN for 10% off upon checkout. Thank
you Squarespace for supporting this channel!
Thank you for watching! I hope you learnt
something new today. If you did, then please
leave a like and make sure that you’re subscribed
for future investigations. If you want to
support my videos and research than consider
becoming a Patron or help me out in other
ways. Also check the rest of my video library,
because I’m just about to reach 100 videos
and there is a ton more for you to watch and
enjoy. I hope to see you in the next one,
auf wiedersehen and goodbye!
