Unapologetically stolen from Hackaday. 
– This write-up details someone using a sous vide hot water bath in order to anneal PLA plastic.
http://justinmklam.com/posts/2017/06/sous-vide-pla/
Very nicely done article.
This is one hell of an article!
Good article, how about testing another plastics in later articles?
Superb!
Nice report. I wonder if anyone has done test for other materials. ABS prints are so full of internal stresses, I’m sure this would help.
@1111122 @Dale_Dunn Most filaments don’t exhibit the same weird crystallinity phase-change behavior that PLA does. ABS polymer is amorphous (disordered spaghetti) meaning there’s no crystallization occurring, so it’s not going to undergo microscopic property changes like glass point elevation. But annealing at the glass point can definitely decrease the residual warping stress in any FDM plastic. That’s valuable even if you’re not getting major performance changes in the base polymer.
PLA is special for annealing because it has multiple possible crystalline phases (different ways of organizing the polymer chains) and it will switch between them depending on the temperature history of the plastic. Rapid cooling from melt makes it “freeze” basically amorphous and disordered, with a low glass point. That’s good, in a way – amorphous polymers shrink less as they cool so you get less warping. Then annealing the PLA makes the polymer chains reorganize and become ordered and crystalline, which raises the glass point.
Nylon should also experience significant change in properties when annealed, but I believe it will get more rubbery, not stronger like PLA does.