this post was submitted on 08 Sep 2023
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Have you ever wondered if the yellow/orange plastic windows that all resin/SLA 3D printers have are sufficient?

Here's your answer:

interesting data points:

  • 500nm: 54.9% (transmission)
  • 490nm: 37.9%
  • 480nm: 16.9%
  • 470nm: 1.6%
  • 460nm: 0.3%

**What does this mean? Feel free to comment. **

My take:

First of all, this instrument is not designed to measure OD, so it can barely measure down to OD3. The actual value for 400-450nm could be lower (e.g. 0.001-0.0001% transmission).

SLA 3D printers work at 405nm. This means that the enclosure will likely protect you from the UV radiation of the printer. This is good news.

Does it also protect the resin from sunlight? To answer this question, it is important to understand how the resin behaves to wavelengths above 460nm (not measured). In my practical experience, it does not provide adequate protection. Clean the vat after each print or add another light-blocking layer for (short-term) storage.-

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[–] [email protected] 13 points 1 year ago* (last edited 1 year ago) (1 children)

Largely it's bullshit. The color of the acrylic isn't what's doing it, it's that it's acrylic.

Here's the optical transmission properties for...just acrylic: https://www.sanatron.com/blog/optical-transmission-properties-of-acrylic.php

That's one of the first things to learn in 3D printing, is that if it's from China, it's bullshit. Those carbon filters they have on mSLA printers? Bullshit. Don't protect you at all. You're literally killing yourself if you're relying on them.

[–] [email protected] 6 points 1 year ago* (last edited 1 year ago) (2 children)

Hard to argue against measured data (window from an Anycubic printer).

If you notice your pure acrylic is blocking below 400nm. This orange is good for below 460nm and the reason it looks orange and not transparent.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

That was just a quick Google search online. I deal with these manufacturers directly, and I assure you - they are only sourcing orange acrylic. There is literally nothing special about it.

[–] [email protected] 4 points 1 year ago

They do and it's China. That's why I measured it in the first place as I wasn't sure they get the area around 400-430nm without gaps where you still have significant emissions from the LEDs.

The good news this particular color blocks all the wavelengths without gaps.

[–] [email protected] 3 points 1 year ago (1 children)

So having my printer sitting next to my cure station is perfectly fine

Especially considering the light has to go through 2 of the covers to get to the resin

Thank you for the info, I'd love to see the numbers for the smaller wavelengths but I have no idea the kind of equipment cost it'd take to get those.

[–] [email protected] 3 points 1 year ago

0.3%. Instrument limitation. So it's actually <0.3% for 465nm to 200nm.