I’ve had some 3D prints made for my company via 3Dhubs using a Form 2 printer. The prints have all come out great except that the “clear” resin is actually yellowish. I know this is an inherent problem with supposedly clear resins, but I’ve seen the videos comparing the Vorex to the Formlabs clear resin, and it seems that it yellows “less” over time, however, it’s not apparent to me if the Vorex Clear resin starts off water-clear, or if it still has a yellow tinge to it. Can anyone here clarify for me?
Formlabs V1 and V2 both start out very clear, the problem is the printer sort of sun-burns it while curing it. Post-curing it will make it worse. And sunlight too. Clear v2 is supposed to stay clearer than v1 I hear.
I don’t know how Vorex compares.
Is there a write-up on keeping the clear resin as clear as possible? We just got a blurb in their newsletter about making clear prisms so without keeping them from getting yellow how can they be a prism?
I can’t imagine that a UV blocker would be a viable solution. Seems most of the UV exposure is during printing and curing, so the piece is going to be yellow from the start. A UV blocking would probably only delay further yellowing.
I’m really disappointed that there seems to be no way to 3D print truly colorless clear or at least “frosted” objects. 3D Printing has a long way to go before it will be really useful.
Though I haven’t made any optical parts, the clear parts I have printed with the clear version 2 seem to be holding their color. I have some small parts that have no yellowing and some larger parts that a client has been testing that had a very faint yellow but it is superficial.
Have you tried post curing under water with a uv lamp? Maybe the yellowing is an oxidation. I typically try to avoid IPA in cleaning and have been doing my post curing while the part is submersed to remove the tackiness.
Interesting. So, you’re not using the IPA at all? You take your print straight from the printer and put it in a water/UV cure? Wouldn’t that cure the excess polymer that’s on the print? Don’t you need the IPA to remove the uncured goo from it first?
Do you have any photos you could share so I could see the color? How does it look when put next to something truly white like a sheet of paper?
Few of us have been using a water based technique. I scrape the part into a lightly heated ultrasonic cleaner with Yellow Magic. On fragile parts or parts that are thin and susceptible to warping I will post cure in the solution with a uv lamp to remove the tacky. Unfortunately my UV lamp is not all that great so it takes a while. Beefier less critical parts I rinse the YM off the part dry it with a small compressor then give it a quick scrub in IPA then dry immediately.
JD first researched and found YM as one of the solutions to try and it really well. Prior to that my retired Uncle who was a chemist had modified a detergent base solution for this purpose but it is too costly to bring to market and YM actually works better because it is reclaimable.
So, getting back to the original topic I guess it’s safe to say that none of these different techniques will really matter when it comes to the colorless clarify of the “clear” resin, right? They all still involve a lot of extra UV exposure to cure the final print, and it’s the UV that makes it turn yellow, not the IPA or any other cleaning agent.
Perhaps the solution is to figure out which method requires the least amount of UV curing. I suppose the more goo that can be removed from the print the better since that will mean less time in the UV to harden that extra goo. Better to remove it rather than cure it.
I’m not even that concerned about it being optically clear like glass. I’m more concerned about it just being colorless and not tinted yellow. For what I’m trying to do a “frosted” translucent appearance would be perfectly acceptable, but a yellow tinged frosted appearance would not be fine.
I think the yellowing is more superficial from oxidation.
After cleaning the part ie water base or ipa, try a submersed post cure under water.
I have parts on my bench that don’t show any real yellowing.
As far as the goo, it is just a super thin layer that I was unable to measure and once the part is fully cured the part still has the same dimensions. No matter how you clean your part as long as the surface isn’t lumpy from uncured resin is important.
They show tutorials on the main site on making prisms and lenses using the clear resin.