EDIT: solution is in the comments. TL;Dr retractions ON and INCREASE speed. Both opposite to common knowledge.
I can’t print flexible TPU properly. It’s either foamy, inconsistent extrusion or jam city, nothing else. I wasn’t able to complete a single print properly in a week and probably 50 tries.
Tried
- 24 hours of active drying
- speeds of 10-30mm/s
- flow rate 1-1.2 (100-130%)
- temps 220-250 (mfg rec is 235-250)
- 0.4 and 0.6 nozzle
- Cura and PrusaSlicer
Direct drive (Biqu H2 V2s) on a well-tuned Ender 3 (no issues with ABS, PETG, even nylon). Part fan off. Printing on PP tape (no adhesion issue).
I can get halfway decent looking print with 250C and a Flow rate of ~140% but it eventually jams anyway. Lower temps give super inconsistent extrusion, nozzle spitting chunks intermittently.
At my wits’ end. Any more tips? I don’t have any other TPU ATM, may be just shitty filament? It’s a cheapo polish F3D Filament TPU 93A. Thanks!
These are very edge-case, and I only mention it because you had a lot of helpful details that eliminated stuff, but could the gap between the extruder drive and the hotend opening be too far apart? I’ve had a problem kind of similar where it would jam up the filament there. Otherwise, the other outlandish thing I could think of is maybe the inside of the hotend is pitted and damaged, but that is not as likely.
I hope this helps at all, or maybe gives you some kind of idea. Good luck!