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?

  • commandar@kbin.social
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    1 year ago

    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).

      • MrSlicer@lemmy.world
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        1 year ago

        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.

  • tenzen@lemmy.ca
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    1 year ago

    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.

    • Rikudou_Sage@lemmings.worldOP
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      1 year ago

      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?

  • Moldy@kbin.social
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    1 year ago

    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.

  • FiddlersViridian @sh.itjust.works
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    1 year ago

    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.

    • Rikudou_Sage@lemmings.worldOP
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      1 year ago

      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.