this post was submitted on 23 Jul 2023
16 points (100.0% liked)

3DPrinting

16926 readers
177 users here now

3DPrinting is a place where makers of all skill levels and walks of life can learn about and discuss 3D printing and development of 3D printed parts and devices.

The r/functionalprint community is now located at: or !functionalprint@fedia.io

There are CAD communities available at: !cad@lemmy.world or !freecad@lemmy.ml

Rules

If you need an easy way to host pictures, https://catbox.moe/ may be an option. Be ethical about what you post and donate if you are able or use this a lot. It is just an individual hosting content, not a company. The image embedding syntax for Lemmy is ![](URL)

Moderation policy: Light, mostly invisible

founded 2 years ago
MODERATORS
andypiper@lemmy.world
j4k3@lemmy.world
henry_rowengartner@lemmy.world
GrayBackgroundMusic@lemm.ee
16
Why do my TPU prints look like this? (imgur.com)
submitted 2 years ago by rikudou@lemmings.world to c/3dprinting@lemmy.world
21 comments fedilink hide all child comments
 

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?

top 21 comments
sorted by: hot top controversial new old
[–] commandar@kbin.social 3 points 2 years ago (1 children)

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).

[–] rikudou@lemmings.world 1 points 2 years ago

I'll try drying it again and play with the speed a little, thanks.

[–] MrSlicer@lemmy.world 2 points 2 years ago (1 children)

Tpu is the worst with moisture. Even new rolls need drying.

[–] rikudou@lemmings.world 1 points 2 years ago (1 children)

I did. So this might be still too much moisture?

[–] MrSlicer@lemmy.world 1 points 2 years ago (1 children)

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.

[–] rikudou@lemmings.world 1 points 2 years ago (1 children)

Do these seam reasonable?

[–] MrSlicer@lemmy.world 1 points 2 years ago (1 children)

I don't go above 20 mm/s for any print setting with tpu.

[–] TwanHE@lemmy.world -3 points 2 years ago (1 children)

All depends on your extruder. A decent extruder should have no problems with 200mm/s+

[–] MrSlicer@lemmy.world 0 points 2 years ago (1 children)

No

[–] TwanHE@lemmy.world 1 points 2 years ago (1 children)

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.

[–] MrSlicer@lemmy.world 1 points 2 years ago (1 children)

I don't know what you are talking about. I make real things out of tpu that get used everyday for years. I don't know who pez is and I'm not interested in bench speed runs.

[–] TwanHE@lemmy.world 1 points 2 years ago

I get that speedbencys aren't functional objects but as long as you're not running out of flow rate the material properties shouldn't differ between 20mm/s and 200

[–] Moldy@kbin.social 1 points 2 years ago (1 children)

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.

[–] rikudou@lemmings.world 1 points 2 years ago

Any recommendations? I dried it using a filament dryer before printing.

[–] ciko22i3@sopuli.xyz 1 points 2 years ago (1 children)

test

[–] rikudou@lemmings.world 1 points 2 years ago

Test successful, I guess?

[–] tenzen@lemmy.ca 1 points 2 years ago (1 children)

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@lemmings.world 1 points 2 years ago (1 children)

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?

[–] tenzen@lemmy.ca 1 points 2 years ago

Yeah. If you are good for pla, it's not likely the cause.

[–] FiddlersViridian@sh.itjust.works 1 points 2 years ago (1 children)

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@lemmings.world 1 points 2 years 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.