This is not a resin print! These parts have been printed from filament
using a special set of parameters that make sure that no voids are within the parts, giving
them this transparent look and in my opinion even more importantly making them significantly
stronger! Let’s find out more. Guten Tag everybody, I’m Stefan and welcome
to CNC Kitchen. This video is sponsored by Squarespace. Create your own beautifully looking website
and get 10% off your first purchase by going to squarespace.com/CNCKITCHEN. If you ever bought yourself a roll of clear
3D printing filament, you might have been quite disappointed that the parts you printed
didn’t come out transparent and rather just looked more like a transparent whitish color. Though I recently stumbled over an article
on printables.com where a user named Rygar1432 shared their settings with which they were
able to print really nice looking, almost clear parts. The prints didn’t only look really nice,
but I also asked myself what the strength of these parts was because they looked as
if the layers perfectly bonded together, potentially eliminating the weak point of FDM 3D prints
which is that they often tend to break within the layers. I don’t want to spoil the results - but
I wasn’t disappointed! So before we dive in here, let me quickly
talk about something I’m sure many of you are already typing on your keyboards: Just
use a resin printer if you need transparent parts! So yes, that’s theoretically an option but:
Not everyone has a resin printer and wants to deal with the mess and the smell. Even if you use a resin printer, it’s kind
of hard to get really transparent parts because they still usually turn out matte after the
washing process due to the inherent voxel structure of the parts. Even if you get clear resin parts by clear
coating or resin coating them, they usually start yellowing quite quickly. Then there is the selection of different materials
for filament-based printing, which is just way bigger, and the properties, especially
long term, are way better known. and in the end, it’s just an interesting
challenge to achieve transparent parts with an FDM printer and also see what effect this
has on the mechanical properties. So let’s save the challenge of printing
real transparent resin parts for another video and if you have already started typing why
don’t you tell me what applications you see for transparent FDM prints? I’m not the first to do this because there
is already a really old blog article from Colorfabb around as well as a nice video Tom
did on that basis. There’ve also been a bunch of videos on
how to print transparent parts using Polymakers Polysmooth material and then vaper smoothing
them. However, those were mainly for vase mode parts. We’ll focus on real, thick-walled FDM parts
today. All of this came to my attention again, when
a post by Rygar1432 on Printables circled around a couple of weeks ago with a set of
recommended parameters that I tried out on a simple part and that worked really well
on the first print. My first parts were in PCTG, but when I switched
over to the more common PETG the parts still looked good but not as great anymore as on
my first try. This is why I thought it might be interesting
to dive a little deeper into the parameters and what influence they have because Rygars
recipe will not work for all of you. Filaments from different manufacturers will
behave differently, and also your machine might react in another way. So take this as a guideline, what you could
change to achieve transparent parts yourself. Rygar recommends OVERTURE PETG, to which I
put a link down in the description, and I’ve also read in different sources that some materials
work better for transparent parts than others. I’ll say right away that I overall got even
better results with freshly dried PCTG, but since PETG is way more common, all the investigations
here will be done with PETG. In my case, I used a roll from dasFilament,
which I purchased a while back for another project. Modern slicers have hundreds of settings,
and a significant portion of them will influence the clarity of our prints. Yet some are more significant than others
and Rygar pointed them out in their post. I picked the flow multiplier, extrusion temperature,
part cooling, and printing speed for my investigation but there are even more that might be relevant
for you. There is layer height, perimeters, extrusion
width, or outline overlap and probably a ton more. For each of my print jobs, I only varied one
parameter at a time. I’m well aware that there are cross-influences
and I’m certain I didn’t find the best parameter combination but this test series
still showed me which parameter was more or less important. I used PrusaSlicer for all of my tests and
sliced a small test part I designed for this investigation at 0.12 mm layer height. Link in the description, by the way. I set the extrusion width for all features
to 0.50 mm and only used one perimeter. And I think most importantly for the incredible
results that Rygar got was setting the Infill to Aligned Rectilinear at a 0° angle with
0 top and bottom surfaces. This means that the infill is not printed
in a criss-cross pattern but with all infill lines parallel. This tremendously helped to get rid of the
last remaining pores. I also limited speeds to only 15 mm/s and
turned cooling off. The first one and probably also the most important
parameter I played around with was the extrusion multiplier which I varied between 91 and 105%. The parts got clearer the higher I set the
extrusion multiplier, and I already got really great-looking parts at a bit above 100% flow,
where the material was able to flow into all the remaining cracks and voids. The parts didn’t get less clear at higher
extrusion amounts, but you’ll get swollen-up parts due to over-extrusion and really rough
top surfaces. Due to the lack of cooling, overhangs and
holes didn’t look particularly great. Off the bed, the parts might not look as nice
as in some pictures. I use gluestick on my bed and that leaves
a matte bottom layer, but if you polish that up or even only add a drop of water or oil,
you can really get an idea of how the inside of a part looks and how clear you can get
the parts. The side walls, due to their roughness still
are not perfectly transparent, but even lower layer heights might help you in that regard. Though what should be totally clear is that
you need to leave a like and subscribe to the channel if you find interest in what I’m
doing here! Next, I tested the extrusion temperature. The dasFilament PETG prints quite cold, and
I tried 215 °C to 250 °C in 5 K increments. I only got some weird printing problems at
the lowest temperatures, but all the others looked fairly similar at first glance. However, a closer look revealed that I got
some milkiness at higher temperatures due to microbubbles that formed in the material,
probably due to moisture. And this is something I noticed over my whole
test campaign. When I started the PETG was freshly out of
the box, and the PCTG just came out of the dryer. The first print results were the most consistent
and the easiest to achieve. The longer the material set around outside,
the harder it was for me to get nice results. So maybe remember this point and if you’re
serious about clear printing, then dry your material. Overall, 220 °C looked the best for my material
and keep in mind that besides the bubbling we saw, materials will even degenerate if
the are too hot for too long which I’ve also seen on some parts due to their brownish
hue. Let’s, at this point, also talk about why
regular prints with transparent material are not as transparent as glass for example. So light refracts when it moves from one medium
to another and bends depending on the materials and inclination angle. In our case, the two materials are air and
PETG. A regular print is not solid material, so
the light passes through dozens of these interfaces, where it refracts, diffracts, and reflects,
which is completely irregular and, therefore, parts rather appear shining white than really
translucent. Even if we print with 100% infill, there are
still a ton of voids in our parts where refraction happens. These are gaps between the extrusions but
also the interfaces between individual extrusions where the polymer is not properly melted together,
which also makes those parts appear milky. So if we want to print transparent parts,
they need to be really 100% filled, and the extrusions need to melt together perfectly. A parameter that could affect the bonding
of layers might be part cooling, and Rygar warned about that. I tried it myself and printed parts at 0,
20, 50 and 100% cooling and indeed, the parts without any cooling were the clearest, though
interestingly the parts where I turned cooling on only turned a bit milky yet showed a way
better part quality at bridges and overhangs. So if the clarity of your parts is not your
primary goal but you want only really strong prints, then maybe turn a bit of cooling on,
especially since I’ve seen a very interesting impact on static strength as we’ll see in
a bit! Finally, I tested print speed because maybe
something I didn’t make that clear yet, printing these transparent parts is horribly
slow. The very thin layers and the 100% infill are
part of that problem, but the low recommended printing speed makes them even take longer. The small test samples took 50 minutes each
to print, a 3DBenchy takes 5.5 h and my MiniMe figurine would take over 16 h to print, which
is kind of ridiculous. In my test, I tried speeds from 5 all the
way to 60 mm/s and the results were really interesting. 5 and 10 mm/s were not as clear as I thought
due to microbubbles that formed in the material because the filament remained too long in
the meltzone. 15 mm/s looked the best, but also, the higher speeds didn’t look that
much worse, so there is definitely some speed potential left. Before we take a look at the admittedly very
interesting part strength, let's quickly talk about today's video sponsor Squarespace. I’ve been using Squarespace for years for
my own website, and it’s the place where viewers can find additional content, get in
touch with me and find the products that we sell. Having a professional looking yet easy-to-create
and maintain a website is more important than ever. Squarespace is the all-in-one solution that
will help you to create the website you always wanted, regardless of if you’re a business,
an artist, or a maker who wants to share your projects. If you’ve been thinking about creating your
own website or if your existing one is horribly outdated, then pause the video right here
and go to squarespace.com/CNCKITCHEN and simply give it a try. You can choose from a wide range of templates
and then just customize them to your needs. Create a blog to share your stories, add a
shop to sell your creations and even add a members-only area to unlock new revenue streams. And even though this sounds scary complicated
it’s super simple because Squarespace will take care of everything in the background. No backups, no updates so you can focus on
creating the web presence you always wanted that will also look good on any device. So stop procrastinating, try it out yourself
and even get 10% off your first website and domain purchase by visiting squarespace.com/CNCKITCHEN
and using coupon CNCKITCHEN when checking out! Now that we’ve seen that printing clear
admittedly is not fast but not super hard to do if you know some impacting factors,
let’s look at what really sparked my interest. How strong are these transparent prints, especially
between the layers? And just to make things clear, even though
I did all of these tests with natural clear material, these printing parameters can be
easily transferred to dyed materials with probably the same effects on strength. To test how strong the transparent parameter
really is, I printed tensile samples in horizontal and vertical orientation as well as impact
specimens to get an idea about the toughness. My transparent parts were printed at 230 °C
nozzle, 0.12 mm layers, 102% flow and no fan. The reference parts I printed used standard
PrusaSlicer parameters at 100% infill. I printed sets of my simple samples, but since
I wanted to get an idea of how everything also behaved on bigger parts, so I also printed
standard ISO dogbones and bigger layer adhesion samples. The parts came out okay but definitly with
some printing problems due to the high extrusion amount and lack of cooling. Yet, you could clearly see the difference
between the milky-looking parts with stock parameters and the clear-looking transparent
parameter parts. Usually, part cooling decreases layer adhesion,
but since the lack of it, especially at the 100% infill, also caused slight printing problems,
I also printed a set of samples at 30% cooling, which were still transparent but quality-wise
looked way nicer. I tested the samples one after the other on
my DIY universal test machine and measured each of the test sections to take the real
dimensions into consideration. Let’s start with the reference that I printed
with regular parameters. The horizontal specimens failed at 52 MPa
on average, whereas the ones printed standing failed at only 34 MPa. This is less, but a layer adhesion strength
of 65% is still remarkable for FDM prints. So let’s get to the parts that I printed
with the “transparent parameter”. The horizontal specimens were already stronger,
with 59 MPa on average, probably because the optimized parameter was able to print a fully
dense part, so there was more material to take the load. They also significantly yielded whereas the
parts with the standard parameter simply snapped. The layer adhesion samples impressed even
without looking at the numbers because they significantly yielded before breaking, which
is something you usually don’t see with these samples. With 44 MPa failure load on average, they
were not only 30% stronger than parts printed with a normal parameter, they also reached
75% layer adhesion which is impressive. What’s even more impressive is that the
samples that I printed with the transparent parameter but 30% cooling even outperformed
these samples, probably due to fewer printing issues, and reached over 80% layer adhesion. And I need to be even more enthusiastic because
the bigger samples performed even better. The ISO dogbones failed at 59 MPa, just like
the small samples, but the bigger and round layer adhesion samples reached 54 MPa, which
is 93% layer adhesion and is something I would not have expected and blows me away! This shows the potential of this transparent
parameter because if you’re able to set it up for your material and have parts that
can be printed with it, the strength of these parts will be almost independent of the printing
orientation, which is basically the holy grail of 3D printing! For completeness, let’s also talk about
impact performance, where I smash a hammer with known energy into parts and measure how
much energy is absorbed during the impact. The more energy it takes to break the part,
the tougher it is. On the horizontal samples, the transparent
parameter outperformed a regular part quite a bit but also showed significant scatter. On the ones printed standing, the transparent
parts were also stronger but didn’t reach the performance of the ones printed on the
bed. I think that this is simply one of the limitations
of the process because even though layers bond very well together, the majoriy of the
polymer chains will remain oriented in the print plane, which decreases toughness and
ductility perpendicular to it. That’s a bit of a bummer but something that
can be dealt with. So there we have it! Prints with this transparent parameter are
not only really nice to look at, but they are significantly stronger than parts printed
with regular parameters, and we were able to reach almost perfect layer adhesion. If you want to tackle that yourself, use my
or Rygars parameters as a start, and you’ll be able to get good results very soon. The questions that remain for me are if this
process can be adapted for other materials and how easy it is to find the sweet spot
for filaments that are not transparent because this was our perfect indicator for that test. I also want to see how we can speed up the
process because, for the moment, you can only seriously apply that to small parts! Unfortunately, I think that the low speed
is one of the key factors why this method works so well and why the layer bonding is
so good. I tested thin layers as well as overextrusion
in the past and never got these great results. Though this means that there is still a ton
of research neccessary to dial this in for other materials and find that sweetspot parameter,
that’s very strong but still fast! If you want to use this for your designs,
make sure they are suitable because the results on very complex geometrys at the moment are
not great. Regardless, I think this is again another
small yet significant way forward for stronger parts and also if gas or fluid-tightness is
something that you’re after. And if it’s not strength, then just think
about complex light pipes or even optics. But what are your thoughts? Please let me know down in the comments! Thanks for watching everyone! I hope you find this video interesting. If you want to support my work, head over
to Patreon or become a YouTube member. Also, check out the other videos in my library. I hope to see you in the next one. Auf wiedersehen and good bye!
