Durable Resin for Insect Wings?


#1

Hey folks, I have a client who wants larger than life insect wings modeled and printed in a translucent resin. They will attach via a 4mm ball and socket joint to the insect body. The wings will be between 1mm and 2mm thiick with veining approx 2 to 3mm thick.

Durable has the translucency and would be, well durable.

However, the info for the resin states it does not handle detail well.

I would appreciate perspectives from those who have used it. Does my application sound reasonable for use of it?


#2

If it has to withstand considerable stress, then you don’t really have another option than durable anyway. If not, clear would be the way to go IMHO. Keep in mind durable is quite yellow. Clear is, well, quite clear once it comes out of the printer, but to avoid it becoming yellow you’d have to skip post-curing and paint it with an UV blocker.


#3

Thanks P3D - I doesn’t necessarily need to be a functional piece, other than posing of the wings via the ball and socket.

I agree that clear may be the way to go. Good to know about yellowing. I was not aware of that. I gather that by not curing, the resin will not be as hard, but otherwise serviceable.

Thanks again for your reply.


#4

Actually that’s not a bad thing. Because the resin remains somewhat flexible it’s more resilient. Fully cured standard resins, like clear, become very brittle and can shatter easily once fully cured. Especially something thin like a insect wing.

If I was building that model, I would print the wing in clear, then only do post print clean-up, no post curing what so ever, then apply a coat of UV resistant clear.


#5

Sounds like a good course. Thanks.


#6

if I was building the model, I would use the printer to print MOLDS of the wings, and then Cast them in Water Clear Urethane.

A clearer, more detailed, and more durable part overall- and the ability to make more as needed,


#7

I second Sculptingman. A characteristic of SLA resins is that the prints are brittle. UV exposure will make that more true over time. Thin wings are going to be very fragile.


#8

The client had originally posited printing molds. I would jump at the chance to do that. However, for whatever reason he opted for prints, in hopes of reducing labor.

Where I do print molds, would you opt for flexible resin? I could see despite good molds that avoid undercuts, that resin would be difficult to pop out of resin.


#9

You would use a release agent- for urethanes a silicone release should work well.
Or a wax that is NOT water based.

The issue in my mind is that no matter WHAT clear material you make the wings out of, short of glass, they will yellow over time. So anytime I have to make something for display that involves clear parts- I generally plan to make it out of the most stable clear resin I can that is not too fragile… and water clear urethanes fit that bill nicely- they will last longer, are resistant to breakage and can be painted and clear coated with a UV resistant urethane top coat.

There are 2 ways to make the mold- one would be to print the tool you would cast into…that would end up being a rigid tool into which you would be casting a rigid resin. That is simply creating 2 keyed blocks each of which has a cavity printing one half of the wing shape.

The Other way is to print a Split master. That is 2 keyed blocks also- but instead of a cavity- each block has a Positive image of half the wing. With this tool you would take the print and pour a thin silicone rubber over each half- the 2 silicone parts would then be peeled off the split master halves, and fit together with keyed surfaces, to form the final mold- but your mold would be in a flexible rubber capable of casting multiple copies and easily releasing from your cast parts.

the silicone mold would require No release agent- cast silicone releases cleanly from acrylics like grey resin- and no release would be needed for the urethane- so your parts would be both dry and clean of any release and easier to paint with better paint bonding.

The only issue here is to find out if the water clear urethane you can source has an inhibition issue with certain silicones- condensation cure silicone’s give off ethanol vapor that can prevent certain water clear urethanes from compounding properly. So find out what silicone they are compatible with before pouring silicone mold parts.

PS- Durable printed that thin is still not clear- and its really bendy.


#10

PPS
when printing Mold tooling or split masters- you should also note that you can achieve much thinner parts than can be reliably printed. The model you derive the tool models from can be 0.5 mm or even less- if you design the mold to minimize any warpage.
Additionally, you can have the opportunity to retouch the pattern in positive or in negative- to achieve even cleaner, more detailed parts than the printer can produce.
For example- you could spray a gloss coat on the rigid tool cavity or on the split master- to achieve a glass smooth finish, prior to pouring the silicone mold. Or use an engraving point to etch very fine lines surpassing the best the printer can do.


#11

Thank you Sculptingman, your points are compelling, and I have relayed them to the client (as well as points made by other posters). I really appreciate the detailed info.