Printing TPU and Flexible Filament on the Anycubic Kobra 3
TPU (thermoplastic polyurethane) and other flexible filaments produce parts with rubber-like properties — perfect for phone cases, gaskets, cable strain reliefs, and wear pads. The Kobra 3's direct-drive extruder makes it much better suited to flexibles than Bowden machines, but you still need to dial in a few settings.
Why Flexible Filaments Are Tricky
Flexible filaments compress under pressure. In a Bowden setup that compression causes jams. With direct drive it's manageable, but the Kobra 3's extruder spring tension and path length still need consideration. The ACE Pro feeder adds a short Bowden segment to the hotend — print slower than you would with a true all-direct machine.
Recommended Settings for TPU 95A
| Setting | Value |
|---|---|
| Nozzle temp | 220–230°C |
| Bed temp | 40–50°C |
| Print speed | 20–30 mm/s |
| Retraction | 0.5–1.0 mm, 20 mm/s |
| Fan | 0–20% |
| Layer height | 0.2 mm |
| Infill | 20–40% gyroid |
For 85A and softer grades, drop speed to 15–20 mm/s and reduce retraction to 0.3 mm.
Extruder Tension
The Kobra 3 extruder has an adjustable tension arm. For TPU, back it off about half a turn from your PLA setting. Too much grip chews through soft filament; too little causes slippage.
Bed Adhesion
Smooth PEI sheet works best — textured PEI can grab TPU so firmly it tears. If using textured PEI, add a thin layer of glue stick as a release agent. First layer squish should be slightly less than PLA.
Slicing Tips
- Disable combing or use 'not in skin'
- Enable 'extra perimeter on first layer' for better adhesion
- Set minimum layer time to 5 seconds to avoid heat buildup
- Gyroid infill at 20% adds elasticity
Multi-Color TPU with ACE Pro
The ACE Pro can feed TPU, but purge volumes need to increase significantly — set to 80–120% of your PLA value. Pre-heat longer before starting to ensure TPU is fully molten throughout the path.