I’ve been trying to print some things in TPU, using a fairly soft 85A TPU, and I keep having under extrusion.
I’ve already reduced speeds to max 25mm/s, and reduced retraction. My printer uses a direct drive extruder, and as far as I can tell, it’s grabbing the filament just fine. I’m printing at 240°C, using my default 0.4mm volcano CHT brass nozzle.
It’s been a while since I last printed TPU.
I think I’ve always had to set a slightly higher flow rate for TPU, probably because it always compresses a bit when pushed by the extruder.
My TPU roll printed somewhat colder than yours at about 220C.
I usually start with a very low speed (15-30mm/s), retraction completely off, cooling fan very low (25%).
Tune the flow rate and speed then add a tiny amount of retraction (<1mm).
YMMV
I completely forgot about flow rate, increasing that completely fixed the issue. Thanks!
Great! Good to hear.
Don’t forget to turn it back down with less springy filaments.
I have seperste filament profiles for everything, so these changes only affected my “TPU 85A” profile
I always kinda hated printing with TPU, it was am absolute nightmare on my old printrbot.
It’s much less so on my prusa, but I’m still used to avoiding it whenever I can.