Transparent FDM 3D Prints are Clearly Stronger!

Explore how special FDM 3D printing parameters create transparent, stronger PETG parts without resin printers.

Ask about this video. Answers come from its transcript only — with the timestamp, so you can check them.

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Key Takeaways

Optimized FDM printing parameters can produce transparent parts with superior strength.
Eliminating voids between layers is crucial for both transparency and mechanical performance.
PETG filament is a practical choice for transparent FDM prints, especially when freshly dried.
Turning off cooling and increasing extrusion flow improves clarity but may affect print quality on complex features.
Transparent FDM prints offer a resin-free alternative for applications requiring clear and strong parts.

What the video covers

The video demonstrates printing transparent FDM parts using PETG filament with optimized parameters to eliminate voids.
Transparent FDM parts show significantly improved layer bonding and mechanical strength compared to typical prints.
Rygar1432’s settings from Printables.com inspired the parameter adjustments, focusing on infill, extrusion multiplier, and cooling.
The video compares PETG and PCTG filaments, noting PETG is more common but PCTG can yield clearer results when freshly dried.
Key parameters include 0.12 mm layer height, aligned rectilinear infill at 0°, no cooling, slow print speed, and increased extrusion flow.
Higher extrusion multiplier (>100%) helps fill microvoids, improving transparency and strength.
Cooling off improves clarity but reduces quality on overhangs and bridges.
Material moisture and temperature affect clarity; overheating causes bubbling and yellowing.
The video emphasizes that transparent FDM prints are a practical alternative to resin prints, avoiding resin’s mess and smell.
Potential applications include strong transparent parts, light pipes, and optics.

Chapters

Can FDM printers produce truly transparent parts like resin printers?

While FDM printers cannot achieve the same level of transparency as resin printers, optimized parameters can produce nearly clear parts with significantly improved strength and reduced voids.

What filament is recommended for transparent FDM prints?

PETG filament, especially brands like OVERTURE and dasFilament, is recommended due to its clarity and mechanical properties, with freshly dried PCTG also showing good results.

How do printing parameters affect transparency in FDM prints?

Parameters such as layer height, extrusion multiplier, infill pattern, print speed, and cooling significantly impact transparency by reducing voids and improving layer bonding.

Full Transcript — Download SRT & Markdown

Speaker A

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!

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Let’s find out more. Guten Tag everybody, I’m Stefan and welcome to CNC Kitchen. This video is sponsored by Squarespace.

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Let’s find out more. Guten Tag, everybody, I’m Stefan and welcome to CNC Kitchen. This video is sponsored by Squarespace.

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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.

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Create your own beautifully looking website and get 10% off your first purchase by going to squarespace.com/CNCKITCHEN.

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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

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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.

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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.

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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.

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Even if you get clear resin parts by clear coating or resin coating them, they usually start yellowing quite quickly.

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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

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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.

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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

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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.

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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.

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However, those were mainly for vase mode parts. We’ll focus on real, thick-walled FDM parts today.

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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.

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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.

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Even if you get clear resin parts by clear coating or resin coating them, they usually start yellowing quite quickly.

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Filaments from different manufacturers will behave differently, and also your machine might react in another way.

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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.

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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.

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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.

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In my case, I used a roll from dasFilament, which I purchased a while back for another project.

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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?

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Yet some are more significant than others and Rygar pointed them out in their post.

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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.

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There is layer height, perimeters, extrusion width, or outline overlap and probably a ton more.

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There’ve also been a bunch of videos on how to print transparent parts using Polymaker’s Polysmooth material and then vapor smoothing them.

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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.

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However, those were mainly for vase mode parts. We’ll focus on real, thick-walled FDM parts today.

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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.

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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.

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This tremendously helped to get rid of the last remaining pores. I also limited speeds to only 15 mm/s and turned cooling off.

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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.

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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.

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This is why I thought it might be interesting to dive a little deeper into the parameters and what influence they have because Rygar’s recipe will not work for all of you.

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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.

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Filaments from different manufacturers will behave differently, and also your machine might react in another way.

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The side walls, due to their roughness still are not perfectly transparent, but even lower layer heights might help you in that regard.

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So take this as a guideline, what you could change to achieve transparent parts yourself.

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Next, I tested the extrusion temperature. The dasFilament PETG prints quite cold, and I tried 215 °C to 250 °C in 5 K increments.

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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.

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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.

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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.

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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.

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In my case, I used a roll from dasFilament, which I purchased a while back for another project.

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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.

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Modern slicers have hundreds of settings, and a significant portion of them will influence the clarity of our prints.

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So light refracts when it moves from one medium to another and bends depending on the materials and inclination angle.

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Yet some are more significant than others and Rygar pointed them out in their post.

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Even if we print with 100% infill, there are still a ton of voids in our parts where refraction happens.

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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.

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So if we want to print transparent parts, they need to be really 100% filled, and the extrusions need to melt together perfectly.

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There is layer height, perimeters, extrusion width, or outline overlap and probably a ton more.

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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.

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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

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Finally, I tested print speed because maybe something I didn’t make that clear yet, printing these transparent parts is horribly slow.

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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.

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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.

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Link in the description, by the way. I set the extrusion width for all features to 0.50 mm and only used one perimeter.

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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

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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.

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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.

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This means that the infill is not printed in a criss-cross pattern but with all infill lines parallel.

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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.

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This tremendously helped to get rid of the last remaining pores. I also limited speeds to only 15 mm/s and turned cooling off.

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You can choose from a wide range of templates and then just customize them to your needs.

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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%.

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And even though this sounds scary complicated it’s super simple because Squarespace will take care of everything in the background.

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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.

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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!

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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.

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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.

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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.

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My transparent parts were printed at 230 °C nozzle, 0.12 mm layers, 102% flow and no fan.

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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.

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samples. The parts came out okay but definitly with some printing problems due to the high extrusion amount and lack of cooling.

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The side walls, due to their roughness, still are not perfectly transparent, but even lower layer heights might help you in that regard.

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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.

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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!

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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.

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Next, I tested the extrusion temperature. The dasFilament PETG prints quite cold, and I tried 215 °C to 250 °C in 5 K increments.

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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

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I only got some weird printing problems at the lowest temperatures, but all the others looked fairly similar at first glance.

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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.

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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.

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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.

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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.

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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!

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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.

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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.

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So maybe remember this point, and if you’re serious about clear printing, then dry your material.

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On the ones printed standing, the transparent parts were also stronger but didn’t reach the performance of the ones printed on the bed.

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Overall, 220 °C looked the best for my material, and keep in mind that besides the bubbling we saw, materials will even degenerate if they are too hot for too long, which I’ve also seen on some parts due to their brownish hue.

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That’s a bit of a bummer but something that can be dealt with. So there we have it!

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Let’s, at this point, also talk about why regular prints with transparent material are not as transparent as glass, for example.

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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.

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So light refracts when it moves from one medium to another and bends depending on the materials and inclination angle.

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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!

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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, d

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I tested thin layers as well as overextrusion in the past and never got these great results.

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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!

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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.

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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.

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And if it’s not strength, then just think about complex light pipes or even optics.

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But what are your thoughts? Please let me know down in the comments! Thanks for watching everyone!

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I hope you find this video interesting. If you want to support my work, head over to Patreon or become a YouTube member.

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Also, check out the other videos in my library. I hope to see you in the next one.

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Auf wiedersehen and good bye!

Topics:FDM 3D printingtransparent 3D printsPETG filament3D print strength3D printing parameterslayer bondingextrusion multiplier3D printing clarityCNC KitchenRygar1432 settings

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