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 itself has the consistency of wet noodles 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 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.