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TPU stringing without causing jams

Symptom: Flexible filament leaves strings but extra retraction causes buckling or jams.

Most likely causes

  • Printing too fast
  • Too much retraction
  • Wet TPU
  • Loose filament path

Test in this order

  1. Dry TPU first.
  2. Reduce speed to 15–30 mm/s.
  3. Use minimal retraction, especially on direct drive.
  4. Keep the filament path constrained and avoid aggressive acceleration.
Stop changing multiple settings at once. Save the model, filament condition and room conditions, then change one variable and compare.

Relevant starting profiles

TPU settingsChoose your printer for a hardware-aware profile

Reviewed 2026-07-22. Results vary by filament formulation, moisture, nozzle and slicer.