Just figured this out more or less by accident today: (some) regular PLA can be heat-treated like Proto-pasta’s HTPLA and it turns it into an absolute beast of a plastic! Seriously, this is objectively much stronger and more heat resistance than ABS or any of the other common filaments.
https://www.youtube.com/watch?v=CZX8eHC7fwshttps://www.youtube.com/watch?v=CZX8eHC7fws
I was thinking about that, it’s probably true for any filament.
I use annealing when I print with Polymaker PC-Plus. It is must there as the internal forces are so high that is your print is bigger than 20-30 mm the part can be teared by itself. The annealing should be done to temperature near but lower than Tg of the filament this why your regular PLA may shrink so much. The Tg of filled and unfilled filament differ a little and if you go above the part will shrink and also may deform. Anyway the PC-Plus annealed parts are really strong, so strong that I can compare to anything other that I have been print so far. The Tg of PC-Plus is 112 C and I do annealing around 105 C for hour.
@Stephanie_A annealing any thermoplastic will reduce residual printing stresses and consequently help strengthen up the bonds between strands that are under internal shear due to printing thermal contraction. It’s analogous to a post-weld heat treatment. That can add a lot of mechanical strength when warping filaments are printed outside their proper temp range (eg ABS or PC without a fully heated chamber). Printing in “ideal” conditions like a Stratasys machine leaves the print in nearly-annealed condition to start with, so there is minimal strength gain from further annealing. That’s all with standard amorphous polymers like ABS, PC, and PETG. But PLA has some weird crystallinity behavior that makes it much more affected than most, for many/most blends. It undergoes a series of solid state phase changes with different crystalline structures. That’s comparable to actually heat-treating and tempering steel to get a particular microstructure.
Nylon also has some interesting behavior – it should get more rubbery (flexible / lower yield) when annealed. It has its highest strength and stiffness when the polymer molecules are stretched out by residual stresses or strains. Most people don’t print fast enough to do that, but if you print nylon fast with low layer heights (even perimeters) it develops different mechanical properties than if you print slow and hot like normal.
How about microwaving parts instead of baking them? I think that is supposed to make carbon nanotubes bond together. I wonder if carbon fiber will bond too. For the PLA and ABS and such, it might have different warping and bonding affects.
Thanks for that! I always appreciate empirical test results.
Is there any advantage to make the annealing process in water (submersed)? More regular temperature profile?
@Michael_Memeteau I remember trying to anneal PLA in water at 70 degrees Celsius, but it was a disaster. The result was very weak and brittle.
Water much hotter than 70 tends to turn the PLA into a blob.