Looking at the forum posts it seems most resins have a 12 month shelf life and several months in the tray. But I didn’t see anything about what actually happens to prints as the resin expires.
I typically print in surges - with months in between prints. I’ve noticed that I have a large amount of variation in print behaviour regarding curing - meaning a lot of prints are heavily overcured - where holes as large as 1mm will actually be closed up, and larger holes will be “constricted” by up to 0.3mm per wall.
Previously I didn’t pay attention to resin age, and put the overcuring down to firmware changes combined with machine variability, combined with resin type variability. Since different resins seemed to behave so differently,
Then I started getting good dimensionally accurate results with Grey V4 and stopped worrying about overcuring, until now. On the latest print surge I think I may have experienced a fair amount of variability printing with the same cartridge.
It looks as though the resin sitting in the tray for almost 2 months (in summer 22degC+ temps with a couple of 30+ heatwaves) since the last print surge may have been overcuring when compared against prints that came from the fresher resin near the end of the cartridge.
Is that what happens to resin as it nears and passes expiry - it overcures?