When printing with some filaments the final outcome can be quite satisfying but sometimes it can be disappointing as well. When somebody tries for the first time a transparent filament usually they remain dissatisfied. It is very difficult to achieve crystal clear prints and the result is more a translucent white than anything.
Contents
Introduction
In this article, I will examine the most common transparent filaments and I will talk about which is better in terms of transparency, plus I will go through the print parameters that makes a distinction and the factors that help increase the clearness.
There are some cool usages for transparent filaments, I principally use them for aesthetical purposes, for instance, the fact that the infill is rather noticeable in the printed part could be a good thing! Using a particular infill pattern can make your printed part look more stylish. Also, transparent filaments work great to create lamps shades. The light refracted through the transparent filament changes with print orientation and the design of the shade, creating interesting effects.
Why these filaments are more translucid than clear?
This effect is produced by the imperfections inside the printed part, and when I say imperfections I mean each layer. Why?
Each layer inside the printed element acts as a mirror and reflects light anywhere it wants, making it bounce all around with no direction causing the translucent effect. The fact that the printed part is not consistently filled and that air bubbles remain trapped inside make everything worse. If we print horizontally, we will see things much more clearer in the opposite direction so take in mind this information. Some other factors help improve transparency and avoid and a non uniform surface.
Print Settings
Adjusting the print settings can help us a lot in our mission. Other than avoiding non-uniform walls and air bubbles we want to avoid the number of “lenses”, and as by lenses, I refer to every little line that can reflect the light. So the most important factor is to reduce our total layers.
Layer Height
Somebody may believe that with a lower layer height the overall quality and transparency should improve, but this is wrong. We need to reduce it,so using a higher layer hight permits light to pass more uniformly thought the print improving clearness.
Surely this means sacrificing quality but in the end, it’s worth it.Other than the layer height we need to take into consideration the printing directions.
Speed
Speed is important also, using a higher speed means the filament cools faster and it becomes more translucid I usually print at 50% of the normal speed, especially for the walls.
Temperature
Temperature contributes mostly by eliminating the air bubbles and makes your filament more liquid and transparent. My best advice here is to use the maximum temperature of the filament you use.
Flow
Pushing more filament on each layer ,making them fuse together ,results in a perfect uniform piece. It is important to increase your flow rate so it has just a little bit of over extrusion, I never go higher than 10%.
This actually improves a lot the transparency especially when we have only solid walls as they fuse together better
For some of you, these print settings may sound insane, and they are a little bit, but let’s not forget our purpose here!
PETG vs PLA
The reason I’ve chosen those 2 materials is that they are the most commonly used and the easiest to print but they have different results based on the print parameters and the post-production. We will see some quite particular things here.
Now let’s see how they react with different print settings.
For this experiment, I will print exclusively in vase mode, in this way we should spot the differences very easily.
I will print a test model sliced with a standard 0.1 Cura profile and after that, I will tweak some parameters and compare the results.
PLA SETTINGS: Temperature:190C Layer Height:0.1mm Speed: 60mm/S PETG SETTINGS: Temperature:200C Layer Height:0.1 Speed:60mm/s
Speed/Flow Settings
The idea behind this is to avoid the fast cooling of the filament and fuse the layers more tightly. I increased the percent of flow by 15% and used a speed of 30mm/s.
If we zoom on the photo you will see that I haven’t quite achieved a difference but the layers are significantly more consistent and there aren’t differences of transparency between layers making our printed part more uniform. Which is what we need from these settings.
PETG/PLA TEST ONE SETTINGS: Flow Rate:115% Print Speed:30mm/s
Temperature/Layer Height
To push these settings to the limits I’m using a 0.5 mm nozzle to print my vase at 0.3 mm layer height. This way I hope to limit the number of spirals and diminish the refractions from each piece.
PETG->original left/Test right 
PLA-> original left/Test right
It is pretty obvious that increasing these settings is a game-changer, you can see much better inside the vase and it is more transparent.
Increasing the layer hight diminishes the number of layers and the high temperature makes the filament more liquid and transparent.
PETG/PLA test 2 settings: Layer Height:0.3mm Temperature:220C
Now, what will happen if we combine all those settings and do the third test?
Pushing all the settings to the max
Using all those settings combined gives us the best result
PETG->original left/Test right 
PLA-> original left/Test right
So the idea behind is to achieve consistent prints using a slow printing speed, increased flow rate, and high temperature, but the biggest game-changer is layer hight, use a high value and you will see some results
PETG/PLA test 2 settings: Layer Height:0.3mm Temperature:220C Flow Rate:115% Print Speed:30mm/s
PETG PLA which is better?
In my opinion, the fact that PETG is shinner than PLA doesn’t help here, in our model we can see that certain angles reflect light making it more whiter than transparent .Instead PLA is less bright making it transparent all the way around.
Post-production
If you’re still not satisfied with the results, and really need to achieve better transparency then you need to know that with a little bit of extra work and the help of some resin you could significantly increase the transparency, coating the printed part with resin eliminates all the imperfections and also helps by providing better refraction, the material acts as a thin layer of glass forcing light to pass easily.
I mainly use this kind of resin
Product | Photo | Shop |
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It’s the best product of it’s kind and it’s specifically made for 3D printing. It’s auto-leveling and dries very fast.
I didn’t do a great job coating these pieces as they are small and it’s impossible reaching inside, but the results speak for there selfs, the difference is spectacular, but the most awesome thing is that now our PETG vase is the most transparent one and looks like glass. I’m sure that with a better job than mine you can achieve crystal clear prints!
Conclusion
So after this first test, we learned what determinates transparency and how to play with it. There are better materials out there for this kind of job, but they cost much more and are hard to find. Using some cheap PLA/PETG does a great job as you saw!
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