First time printing with TPU. Another problem I had was that it didn’t stick to the textured print bed, had to go for smooth PEI which I read (and now can confirm) is not ideal. Would satin be better?
That’s inconsistent extrusion.
As others have mentioned, the first thing I’d look at is thoroughly drying the filament. TPU is very hygroscopic and will become nearly unprintable within a couple of days of coming out of the dryer.
Beyond that, you may be trying to run it faster than your hotend can melt it. TPU is pretty resistant to melt and cranking temp doesn’t help a whole lot. Actual flow can vary pretty wildly between brands depending on their exact blend but I’ve seen TPUs that refuse to flow more than around 2mm³/s through a standard 0.4 nozzle. (Volumetric flow is roughly layer height * width * linear speed).
test
Tpu is the worst with moisture. Even new rolls need drying.
Not necessarily. If you don’t hear any sizzle like little pops when extruding you are fine.
Also watch out for retraction amount and speed. You don’t want more than 1 or 2 mm of retraction at 15mm/s and try to only print that slow as well.
I had similar messy results at one point – it tuned out to be a bad zOffset. Having said that, my part also as a messy top layer – not sure if yours has that or not with the little nub there.
No, that nub is not on the head, it’s slightly beyond, this is due to the angle. The z offset works for PLA, I assume I don’t have to change it for TPU?
That looks like a moisture issue to me. Some TPU filaments will absorb so much water from the air that when heated, the water boils out and creates awful bubbling and pitting in the printed part.
