My experience printing Siraya Tech Flex TPU Air on a Core One
I was intrigued seeing TPU Air on Siraya Tech's website and picked up a roll. It's a foaming filament and "programmable" in that the Shore value (hardness) can range from approximately 85A to 65A depending on what temperature you print it at. I printed samples across the entire range and it has the consistency and feel of foam rubber. The filament has the consistency of overcooked spaghetti so there was no way I was getting it past the nextruder filament sensor.
I started with the following modifications to the Nextruder:
- Nextruder Filament Sensor Magnet Mod - allows softer filaments to pass through the sensor
- MK4S Bogie Idler & Main Plate - prevents flex filaments from wrapping around nextruder gear and all other filaments better guidance into the heat break tube
After making the above changes:
- Disabled the side sensor
- mounted the filament on the side spool
- Removed top (the rivets were replaced months ago with this: Prusa Core One Magnetic Top Cover
- Removed Bowden tube from Nextruder
- Draped filament over the side and fed into Nextruder
Dialing in the print setting took some trial and error however got a head start with this page: Siraya Tech TPU Air User Manual Key points are that retraction is set to 0, and that for a given temperature the correct extruder multiplier is set. The user manual shows this in a table toward the end. I've attached my profiles for 4 hardness levels. I'm still dialing it in but so far they look pretty good. Just import the config bundle into PrusaSlicer to pick up the filament configurations.
I used the BIQU Cryo sheet and a generic textured sheet. The prints stick too well so I run the bed 35C. I might even try with the bed turned off or even Magigoo as a separation layer for smaller parts. It's kind of a messy filament, it oozes and leaves behind a lots of strings and spots but I was able to easily clean it off of the sheet with 99% IPA and some Kimtech wipes.
RE: My experience printing Siraya Tech Flex TPU Air on a Core One
Thank you for sharing your config and experience. I just got a roll of this and I am eager to try it out...
RE: My experience printing Siraya Tech Flex TPU Air on a Core One
Independently, I came up with the same setup, essentially bypassing everything and drop the black spaghetti from above directly into the extruder. I also needed to switch off the sensor in the settings and convince the Core One to have FLEX loaded.
I started off at 270C with 55% flow rate. Worked pretty good, just had some dripping during travel, but that could possibly dialed in better.
I'm using the Satin build plate and the stuff is sticking pretty (very, very) well. So I sprayed some IPA around it and let it crawl under the print. After a half a minute, it was getting off easily.
RE: My experience printing Siraya Tech Flex TPU Air on a Core One
I dialed it in today and had to reduce the flow rate quite a bit.
Here's my settings:
1. Reduce the density to 1.15
2. Flow Rates:
240C -> 0.61
250C -> 0.55
260C -> 0.51
270C -> 0.45
This was done at 240C:
RE: My experience printing Siraya Tech Flex TPU Air on a Core One
I've since switched to PEBA Air. It's more expensive but I prefer it's properties over TPU. Especially for things like vibration pads.
RE:
Thanks for the info! I got a roll, worked out of the box with "generic flex", 260..265 °C and around 55 % extrusion multiplier (per their manual). Mk's table may be better tuned, I'm just noting down the numbers I used.
And restating the manual, humidity is critical so keep it dry. Foam or not, it tolerates quite harsh drying temperatures (up to 80°C)
RE:
Thanks for sharing the config and those recommended mods! Apologies for poking a slightly old thread, but may I ask what print speed settings you used that got the best results with this filament?
RE:
Thanks for sharing the config and those recommended mods! Apologies for poking a slightly old thread, but may I ask what print speed settings you used that got the best results with this filament?
It's been a while, trying to remember what I did - I think the main challenge is that it keeps extruding because of foaming action, extruder running or not.
It follows that I'd set all print speeds equal, and move rapidly (losing a few micrometers of precision won't matter). And the box insists that drying is very important.
RE: My experience printing Siraya Tech Flex TPU Air on a Core One
I didn't change speeds, used the defaults for 0.2 balanced, if I remember correctly
RE:
Use with caution: - I don't print it regularly but just decided the RC car may (maybe!) need new tires.
For the soft filament, extruder force became a bottleneck. It cannot push down into the nozzle and it cannot pull strongly from the drybox. Omit PTFE tubes and feed directly into the head. I put a short piece of PTFE tubing onto the drier so the 80°C-hot material has time to cool down (as humidity absorption increases dramatically with temperature).
Maybe 2 mm³/s volumetric flow rate cap seems a good idea, even better than setting equal speed for all features (as line width and layer height may be non-uniform). I just kicked off the voron (0.6 mm) and it starts to look like a tyre but this may be overly conservative after the head's 20 mm³/s default deformed the filament in the extruder.
Glue stick as separating layer (on smooth PEI) seems a must, also for the purge lines. It actually rips the glue stick layer clean off the PEI sheet.
RE:
Yeps... this doesn't seem totally wrong, at least. Starting to look good (raised VFR to 3 mm³/s)
Running print for the above design: https://storage.googleapis.com/prusa3d-content-prod-14e8-wordpress-forum-prod/2026/05/720975fe-airtpu.mp4
Video's sharper than the pic...
RE: My experience printing Siraya Tech Flex TPU Air on a Core One
... "edit post" still after print completion would be so nice ... anyway, it worked, see pic:
RE: My experience printing Siraya Tech Flex TPU Air on a Core One
in CAD, looks fairly accurate:
