Form Cure & Curing in air vs water?

General Discussion
1

Could someone from FormLabs (or anyone else for that matter) explain to me the curing in air vs water?

Does oxygen inhibit curing?

I’ve cured with parts submerged in water. And anecdotally it seems to do better than air, but I’m curious about this.

As well as the importance of heat in the example of Form Cure.

I’d also be interested in more cost effective ways to create a curing chamber. I have 405nm LED strips but haven’t felt I understood the physics/chemistry enough to build one. DIY or more cost effective solutions welcome :slight_smile:

Please help :slight_smile:

2

They posted that years ago seems oxygen slows the curing. so underwater cures better

3

If that were true, then why does does the Form Cure not submerge the parts?

Where is the official documentation that submerged curing is optimal?

4

Probably because in-air curing is enough for most types of resin. Flexible might need underwater curing for better surface quality

Also there are companies like Wicked Engineering which sells “curing gels” to apply on the parts before curing, in order to shield the part from oxygen.

That is mostly for surface quality though, and most likely only for very fine parts. Probably most useful to jewelers and other artists dealing with small intricate designs. I have never felt the need to do this.

As for heat, it is critical to meet the specified mechanical properties of each resin. As per Formlabs’ Post-curing white paper :

With increasing post-cure temperature, there is a shorter time to achieve a fully post-cured state in which the material has reached the maximum mechanical
properties possible at that temperature. In addition to an increased cure rate, the maximum obtainable modulus and tensile strength increase with temperature. A higher post-cure temperature not only yields a fully cured state more quickly, but it also yields a fully cured state with higher mechanical properties

5

This is a great response. Thanks. If you have any links to that documentation, I’d appreciate if you could link me to it.

I’m still curious @Formlabs: if it’s understood submerged curing is optimal, why is the Form Cure done in air?
(@Frew, anyone else at @Formlabs)

6

Dig into these pages :

This is the direct link to the post-curing one :

I’m still curious @Formlabs: if it’s understood submerged curing is optimal, why is the Form Cure done in air?

My guess is that it would make the Cure much more complicated for not much gain to most users.