Tpu is the worst with moisture. Even new rolls need drying.
this post was submitted on 23 Jul 2023
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I did. So this might be still too much moisture?
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.
Do these seam reasonable?
I don't go above 20 mm/s for any print setting with tpu.
All depends on your extruder. A decent extruder should have no problems with 200mm/s+
No
Just because you can't get it working doesn't mean it's impossible. Vez is printing tpu benchys under 6 minutes, so it's clearly possible.
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).
I'll try drying it again and play with the speed a little, thanks.
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?
Yeah. If you are good for pla, it's not likely the cause.
TPU is tricky. Did you tune All The Things for it, separate things PLU settings? Off the top of my head I use 230 nozzle, 40 bed temperature (instead of ~200/60) and the retraction settings are different. I think the base speed had to be tuned too. Even then, my prints don't turn out as smooth as id prefer. The balance of walls and infill numbers can be a dance.
I'm not sure, I pretty much set the exact same brand and filament type in PrusaSlicer (they have a built-in profile for it) and sliced it. The nozzle temperature was 240, the bed temperature was 45 or 50, not sure right now.
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.
Any recommendations? I dried it using a filament dryer before printing.
test
Test successful, I guess?