Using a resin printer for (helmet) lenses and other transparent pieces

[Citruspers]

I've been messing about with my resin printer for a bit, and I think I have a decent technique down that I'm ready to share.

Let's start at the end, just to give you an idea what's possible:

So let's get started. You're free to model your own lenses, or use the ones I designed: Printables

Modeling:

You probably want to keep these lenses fairly thin, as even "clear" 3D printing resin isn't entirely clear.
Thin lenses will also need less time to cure, which will help us later.

Printing:

I used a resin printer (Mars 2) at 0.02mm layer heights, with Anycubic Clear resin. It's the only clear resin I've used so far, though I've heard good things about Sirayatech Blu Clear as well.
As you can see, the lenses are extremely clear right out of the tank, but unfortunately they're not ready for use yet.

Cleaning:

Wash the lenses in IPA, and wash them well. I use a two-stage process to get rid of any excess resin. First 7 minutes inside a wash&cure stirrer, and then some manual shaking in a pickle jar with very clean IPA.
The cleaning process gives the lenses a frosted appearance, this is normal.

Curing:

I cure these lenses under water. As I understand it, this helps prevent (most of the) yellowing, and also allows for much shorter curing times. In this case, 1.5m was more than plenty for 4 lenses. You can go longer, but you risk (increased) yellowing.

Coating:

The last step, and the one what brings back most of our transparency. Get some glossy clear coat spray and apply generously! I've also heard good things about pledge/future floor polish, but have not tried it myself yet.

Before varnish on the left, after varnish on the right:

Good luck, and please let me know if this worked for you as well, or if you have suggestions for improvement!

 

[Fallen]

A couple of drops of blue dye for resin helps combat yellowing as well. Just around 1-3 drops for a full vat tends to be enough.

As for resin type, I'm currently using Anycubic as well, but want to try out Nova3D Ultra Clear resin at some point. At around US$ 33 for 500g (US$ 50 for 1kg) it's definitely on the pricier side though.

 

[Citruspers]

A couple of drops of blue dye for resin helps combat yellowing as well. Just around 1-3 drops for a full vat tends to be enough.

As for resin type, I'm currently using Anycubic as well, but want to try out Nova3D Ultra Clear resin at some point. At around US$ 33 for 500g (US$ 50 for 1kg) it's definitely on the pricier side though.

I've heard of that technique, but with the short underwater curing, the yellowing isn't too bad with the anycubic clear resin imho. Clarity could be improved, though.

I did just try some Siraya tech Blu (Emerald Blue color), and it seems a bit clearer post-cure. I let the prints sit in hot (~60c) water for 15 minutes or so before curing, which also helped prevent yellowing. Siraya described the process here: How to turn reduce yellow in Blu (Blu Emerald Blue and Blue Clear V2

I haven't tried their clear version yet, but it may be a nice competitor to the Nova3d resin you've shared.

 

[IRanWitScissors]

Very nice! I bought a Saturn 2 pretty much for to try and see if I could print visors instead of vacuum forming lol. Looks like I need to get to work

 

[RyFISH]

I've been messing about with my resin printer for a bit, and I think I have a decent technique down that I'm ready to share.

Let's start at the end, just to give you an idea what's possible:
View attachment 325586
View attachment 325592

So let's get started. You're free to model your own lenses, or use the ones I designed: Printables

Modeling:

You probably want to keep these lenses fairly thin, as even "clear" 3D printing resin isn't entirely clear.
Thin lenses will also need less time to cure, which will help us later.

Printing:

I used a resin printer (Mars 2) at 0.02mm layer heights, with Anycubic Clear resin. It's the only clear resin I've used so far, though I've heard good things about Sirayatech Blu Clear as well.
As you can see, the lenses are extremely clear right out of the tank, but unfortunately they're not ready for use yet.
View attachment 325588

Cleaning:

Wash the lenses in IPA, and wash them well. I use a two-stage process to get rid of any excess resin. First 7 minutes inside a wash&cure stirrer, and then some manual shaking in a pickle jar with very clean IPA.
The cleaning process gives the lenses a frosted appearance, this is normal.
View attachment 325590

Curing:

I cure these lenses under water. As I understand it, this helps prevent (most of the) yellowing, and also allows for much shorter curing times. In this case, 1.5m was more than plenty for 4 lenses. You can go longer, but you risk (increased) yellowing.
View attachment 325591

Coating:

The last step, and the one what brings back most of our transparency. Get some glossy clear coat spray and apply generously! I've also heard good things about pledge/future floor polish, but have not tried it myself yet.

Before varnish on the left, after varnish on the right:

View attachment 325587

Good luck, and please let me know if this worked for you as well, or if you have suggestions for improvement!

Man, the 405th has the coolest stuff ever! I didn’t even know you could print resin. Maybe you could use it for some light up details or something

 

[Citruspers]

Very nice! I bought a Saturn 2 pretty much for to try and see if I could print visors instead of vacuum forming lol. Looks like I need to get to work

Very nice indeed! I just upgraded to a original Saturn, which just about fits the helmet visor for my mkVI build.....so I guess that makes two of us? I'm not entirely convinced my process alone is enough to make it clear enough to see through, but a visor should be relatively simple to polish/buff and get rid of the pixel artifacts.....

I have some flashlight shells with relatively flat surfaces in the printer right now, printed with Blu (emerald blue), maybe I'll give those a coat and see how viable polishing is.

Interesting reading material: Printing Lenses on the Form 1+

 

[Citruspers]

Man, the 405th has the coolest stuff ever! I didn’t even know you could print resin. Maybe you could use it for some light up details or something

Oh you're in for a treat! Look up MSLA printing if you're interested, you might be amazed what's possible.

And yeah, light up details (like needler spikes) and inserts for armor and guns are very viable with this technique.

 

[RyFISH]

Oh you're in for a treat! Look up MSLA printing if you're interested, you might be amazed what's possible.

And yeah, light up details (like needler spikes) and inserts for armor and guns are very viable with this technique.

Msla is insane I just looked up Timelapse’s of it and it looks insane!

A resin light up magnum would be sick.

 

[Citruspers]

Very nice! I bought a Saturn 2 pretty much for to try and see if I could print visors instead of vacuum forming lol. Looks like I need to get to work

Well, wish me luck....

 

[N8TEBB]

I'm very interested to see how this visor comes out. I've only ever made vacuum formed visors, printing one is gonna be interesting.

 

[Citruspers]

Well, the print itself seems a success. There's a small imperfection on the right where a piece of lint seems to have made its way into my print vat, and from there into the visor, but overall I'm rather pleased.

Unfortunately, taking the print off the bed developed a small crack in the side. Not completely unexpected given how it wasn't fully cured yet, and I was being pretty rough with the scraper, but something to be mindful of. I assume flex plates will help a lot here.

After washing and curing, the formerly transparent surface frosted over (as expected), so the real question is how I'm going to polish it.

I tried wet-sanding the center of the visor at 800 grit (the finest grit sandpaper I have) and that got rid of any layer lines I could feel, but after coating it with clearcoat it's not clear enough (though definitely clearer than the unsanded bits).

So it seems sanding is the way to go, I just need to go finer. According to Formlabs glossiness starts at 3000 grit, and reflectiveness starts at 12000 grit, so I ordered some sandpaper up to 10000 for a start.

 

[IRanWitScissors]

Snag yellow or some dye for your next one. Seeing yours I went overboard on supports lol. I printed 3 to test different methods on

 

[Citruspers]

Nice work IRanWitScissors !
I plan on doing the effect with spray paint, hopefully giving it a light gold+silver coat on the outside will make it close to a one-way mirror.

And yeah, supports seem a bit overboard, but my visor has a small "wrinkle" that might have been prevented with more supports.

Are we both printing the same MkVI helmet visor by the way? If so, I made a variant that's a bit thinner, I think it'll help achieve maximum transparency (at the cost of strength, as my previous post showed lol). Let me know, I'll be happy to share it.

 

[PlanetAlexander]

Well, the print itself seems a success. There's a small imperfection on the right where a piece of lint seems to have made its way into my print vat, and from there into the visor, but overall I'm rather pleased.

View attachment 326228

Unfortunately, taking the print off the bed developed a small crack in the side. Not completely unexpected given how it wasn't fully cured yet, and I was being pretty rough with the scraper, but something to be mindful of. I assume flex plates will help a lot here.

After washing and curing, the formerly transparent surface frosted over (as expected), so the real question is how I'm going to polish it.

I tried wet-sanding the center of the visor at 800 grit (the finest grit sandpaper I have) and that got rid of any layer lines I could feel, but after coating it with clearcoat it's not clear enough (though definitely clearer than the unsanded bits).

View attachment 326230

So it seems sanding is the way to go, I just need to go finer. According to Formlabs glossiness starts at 3000 grit, and reflectiveness starts at 12000 grit, so I ordered some sandpaper up to 10000 for a start.

I've heard of people using Pledge/Future floor wax to help polish clear resin prints, perhaps it's worth looking in to?

 

[Citruspers]

I've heard of people using Pledge/Future floor wax to help polish clear resin prints, perhaps it's worth looking in to?

I actually mentioned in my start post, haha. I've yet to obtain some though, Pledge is a common brand here in the Netherlands, I just haven't found a bottle yet (only sprays).

 

[Citruspers]

I did some more testing regarding (post)curing techniques. I printed a couple of 75mm curved plates with plenty of detail in the .stl file (so any artifacts come from the printer, not the mesh itself) and post-cured them in different ways:

1: Cured straight off the build plate, so it's still covered in liquid resin

This method definitely resulted in the best transparency, but with a couple of caveats:

* Needs a LONG time to cure
* Massive yellowing due to curing in air and long curing times
* Remains sticky, requiring even more curing
* Supports are now nigh-impossible to remove (because they're cured AND resin dripped around those supports, reinforcing them)

2: Dumped into water straight from the build plate, and then cured in said water

The part turned milky just like your regular parts after washing/curing, but is noticeably glossier/smoother. The downside is, the water interacts with the resin as you dunk it in, causing some "drips" to form on the surface, almost as if you applied too much spray paint from a can, causing drips to run down an object. Also, the water is now pretty contaminated with resin (even if it's cured).

3: Cleaned in IPA, dried, then cured under water

Milky, matte finish, but at least it's consistent. Yes, you still get artifacts from AA and pixels etc, but you don't get drips from the resin/water interacting.

I've attached the supported and unsupported versions of my test file if anyone wants to try for themselves

 

[SnakeandNape]

This is awesome a whole new way to make visors glad I found this might have to get a resin printer now.

 

[IRanWitScissors]

Nice work IRanWitScissors !
I plan on doing the effect with spray paint, hopefully giving it a light gold+silver coat on the outside will make it close to a one-way mirror.

And yeah, supports seem a bit overboard, but my visor has a small "wrinkle" that might have been prevented with more supports.

Are we both printing the same MkVI helmet visor by the way? If so, I made a variant that's a bit thinner, I think it'll help achieve maximum transparency (at the cost of strength, as my previous post showed lol). Let me know, I'll be happy to share it.

It looks like we are. The file by Rainyfire?

As of now I have one that is really close to being done. I took it up to 5000 wetsand and have been using automotive swirl remover and plastic headlight polish. So far about 2 hours invested into sanding/polishing. Plan on going low speed on my Dremel to save my fingers and getting into the tight areas. I broke one of the visors already but you can see how clear I was getting it. The glue is about 6in away so no cheating up close

 

[Citruspers]

It looks like we are. The file by Rainyfire?

As of now I have one that is really close to being done. I took it up to 5000 wetsand and have been using automotive swirl remover and plastic headlight polish. So far about 2 hours invested into sanding/polishing. Plan on going low speed on my Dremel to save my fingers and getting into the tight areas. I broke one of the visors already but you can see how clear I was getting it. The glue is about 6in away so no cheating up close

View attachment 326324

Indeed! Let me know if you want to try the thinner version, I can send it to you, but it's too big to upload here.
Once cured it seems reasonably sturdy, probably because it flexes instead of breaking.

I'm also getting good results wet-sanding by hand from 800 to 10000 grit. I also spent around 2 hours polishing the visor, but I messed it up when I put on too thick a coat of clearcoat.....so it's back to sanding for me. Visibility was pretty good though, so I'm confident with enough sanding this is a viable (if time consuming) method of making a visor. I should probably get some polishing compound like you though, and use a dremel....

Sample card at 10.000 grit and a light coat:

Interestingly there's distortion from a specific vertical angle (probably from the layer lines), but none when looking from left to right (horizontal angle). So it seems the pixel pitch doesn't cause any internal reflections at ~45um, but the layer lines at 0.05mm do.