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!

  • monotremata
    1•1 year ago

    So, one thing to consider is whether you could have remnants of a previous filament getting stuck in your hotend and carbonizing and causing partial clogs. That depends a bit on what you were running just before running this filament. If this is the issue, a cleaning filament can help. Another possibility is that your nozzle isn’t tight against the heatbreak, in which case plastic can accumulate there and cause issues. The only way to fix that is to disassemble the hotend and put it back together correctly–this usually involves tightening the nozzle when it’s hot, but check the details for your specific printer.

    But yeah, it could also just be bad filament. That’s probably the easiest thing to fix, anyway.