Looking for some recommendations from materials guys out there on printing LED light diffusing caps with Bambu’s transparent PC filament. (settled on this filament as PC is commonly used for this in the video world)
I’ve already printed several with no issues on my x1c, but I’m not satisfied with the diffusing results. I’ve tested with various infill %, layer heights and patterns, with ok results, but I’d like to make these LED caps the best I can.
The model thickness of the caps is 2mm, should I be making it thinner and using something like .08 layer heights?. I read on one of the PETG posts about using completely solid infill what is aligned, would this apply here too? (this was for making completely transparent prints, not necessarily for light diffusion).
I’m aiming if possible to something more like this
Translucent might sound like the right choice, but you are aiming to diffuse rather than all light straight through.
Firstly, translucent isn’t transparent, so there will be some diffusion, but you may see parts of the LED that are not the light parts and that will likely not be the effect you are seeking.
If you are going to use RGB LEDs, you would be best off using white PLA.
If your LEDs are white and you wish to introduce colour, pick a suitable PLA colour.
Thickness, or rather, thinness is your friend.
Do a test using 2 layers of 0.2 layer height, make it thicker if still too bright.
I would not use any infill on the areas the light should shine through as it will deflect light.
Ideally, you would have a thin white (or other suitable colour if using white LEDs) front with a darker rear the LEDs sit in side. Pocking up into a hole you can push the LEDs into. Or a think piece of diffuser material placed in front of a darker rear housing.
How you place depends on your model.
But, the thin layer is at the front with a black or other dark colour behind the LED. If you are stacking LEDs close to each other that are not meant to interfere with each other, also aim for dark (black) sides. This will stop any light leaking from one LED to another.
I’ve been exploring this topic since 2023 with mixed results - some excellent, some mediocre. My goal was the opposite of diffusion: I was trying to achieve optical clarity.
Here’s what I mean. The left-hand sample is what I was aiming for and ultimately achieved. The right-hand sample was an experiment that went wrong:
@ExtremeElementz started a great thread in 2023 that led me deep down the transparency rabbit hole:
That thread contains a lot of trial-and-error, including my failed attempts - many of which produced the kind of foggy, diffused look you’re actually targeting.
Based on that, here are some suggestions. First, unless your diffuser will be exposed to high heat, avoid transparent PLA - it’s barely transparent and not worth the trouble. PETG might be better, but note that the foggy sample above is Sunlu’s “transparent” PETG, which was anything but transparent.
To achieve optical clarity, I used @ExtremeElementz’s “icecube” profile. Here’s how it works - and how you can reverse the principles to promote diffusion:
Line Width
Clarity requires oversized line width to eliminate air gaps. For diffusion, do the opposite: reduce line width to intentionally introduce inter-filament air gaps.
Print Speed
Clarity demands slow speeds. To create diffusion, increase speed. This introduces turbulence and creates more internal scattering surfaces.
Here’s a test configuration I’d try for maximizing light diffusion (note: I haven’t tested this exact combo, but it’s informed by my failures achieving transparency):
Walls: Set wall loops to 1 - prevents a solid outer rim from forming.
Top/Bottom Layers: Set to 0 - ensures only the infill is visible.
Infill %: Try values above 70% - promotes internal gaps and irregular paths for light.
Infill Pattern: Start with Hilbert Curves - they create uniform but turbulent patterns. Lightning infill is also worth trying, though it may be too chaotic.
I just purchases some transparent PETG from CC3D during Prime Day that I haven’t gotten a chance to test yet. However, In the example above I can report that Sunlu transparent PETG was very foggy and has no right calling itself transparent, translucent maybe but not transparent. You could try that if you need temperature resistance and don’t want to use PLA.
Hope this helps steer your experimentation. Your goal may be the opposite of mine, but the process still overlaps in all the right (and wrong) ways.
thank you @Olias and @MalcTheOracle for your suggestions, I want to stay away from PLA as the product I’m printing will need to be more heat resistant than what PLA can give me, which is why I opted for the PC filament (the rest of the print is with black ABS). But this is still good info and I might have to fall back to it if things don’t turn out, so thanks
@Olias, I will try this and get back to you, this sounds promising
Everything I said is about colour of the materials and encapsulation.
If you don’t want PLA, swap in any other more heat appropriate material you prefer.
My solution works on white for the diffuser and black for the encasement.
If you are running something with a lot of heat it is likely giving off more light than you require. LEDs by design give off very little heat for their light performance.
If you are running lots of heat, increase layer count and still no infill, keep the direction of print consistent.
Your photo shows an LED strip, I’m not sure how you would be generating enough heat to exclude PLA.
You maybe using something other than shown in the photo though.
Purchasable diffusers are usually acrylic with a light sanding to create the diffused effect.
The heat is not related to the LED’s as much as some of the environments where the devices may be used (careless users that might leave devices in hot cars, stuff like that). The photo is of actual polycarbonate sheeting and I’m testing both COB stips and this type of LEDS
