Glossary · Post-processing
Post-curing
After washing, a resin part goes under UV light once more. Only then does it reach its full strength.
Explained in more detail
A freshly printed resin part is not yet fully cured. During post-curing under UV light, in some stations with additional heat, the resin cross-links further and reaches the properties given in the datasheet. The part must be completely dry beforehand, Formlabs specifies at least 30 minutes, otherwise solvent is trapped and the part does not become properly solid. There is no general time, as it depends on the resin, the lamp and the part size. According to the resin manufacturer Power Resins, post-curing for too long makes the resin more brittle.
Where does the term come from?
Post-curing means curing afterwards. In plastics engineering, curing means the cross-linking of a resin.
In practice
- Turn the part at least once so that all sides get light, or use a station with a turntable.
- Formlabs recommends removing supports only after post-curing, because soft parts can warp without supports.
- With standard resin, post-curing is optional according to Formlabs, and necessary with functional resins.
- According to Elegoo, transparent resin yellows easily under too much UV light. Cure it only as long as necessary.
Not to be confused
Post-curing is not the exposure in the printer: in the printer the shape is built layer by layer, and post-curing then brings the finished part to full strength.
Frequently asked questions
How long does a resin part need to post-cure?
It depends on the resin, the lamp and the part size. As an example, Prusa gives 3 minutes in the CW1S after drying at 45 °C, and Phrozen gives one hour or less for its Cure Mega curing chamber. The datasheet of your resin is what counts.
Do I have to post-cure every resin part?
For standard resin, according to Formlabs, it is optional, but the part becomes stronger. Functional resins only reach their properties after post-curing.