TPU is the most useful filament most printers struggle with. Flexible mounts, drone bumpers, GoPro cases — all need it. But feed TPU into a stock Bowden extruder and it kinks inside the tube like a garden hose. Here’s how to print TPU reliably, from 95A (stiff) down to 85A (rubber-band flexible).
Direct Drive: Non-Negotiable for TPU
Bowden extruders push filament through a 40-60cm PTFE tube. With PLA, the rigid filament transmits force like a piston. TPU compresses — push on one end and the other end squishes instead of advancing. By the time pressure builds enough to extrude, the filament has buckled inside the extruder gear housing.
A direct drive extruder shortens the filament path to 5-10mm. Force transfer is near-instant. If your printer has a Bowden setup, install a direct drive conversion kit before attempting TPU. The Creality Sprite Pro, Micro Swiss NG, and Bondtech LGX are reliable upgrades. Budget option: 3D-print a direct drive bracket for your existing extruder motor.
Extruder Tension
TPU needs less extruder tension than PLA. Over-tensioning deforms the filament into an oval shape that jams in the heatbreak. Start with the tension screw fully loose, then tighten in quarter-turn increments until the extruder grips without slipping. Test: extrude 50mm at 10mm/s. If the filament slips (clicking sound, under-extrusion), increase tension slightly. If the filament deforms visibly, back off.
Dual-gear extruders (BMG, Bondtech) grip TPU from both sides with less deformation than single-gear designs. Worth the upgrade if you print TPU regularly.
Print Speed
TPU prints slowly. 15-25mm/s for all features — perimeters, infill, and travel. Fast retractions create a vacuum inside the nozzle that pulls molten TPU into the cold zone, causing jams. Keep all speeds equal (no “inner wall faster than outer wall”) to maintain consistent back pressure.
Travel moves can be faster (40-60mm/s) since no extrusion occurs, but avoid combing (travel within printed area) — the nozzle drags across soft TPU and picks up strings.
Retraction: Less Is More
TPU stretches under retraction instead of snapping back cleanly like PLA. Long retractions create ooze, not prevent it, because the stretched filament recoils slowly after the retraction ends.
Set retraction distance to 0.5-1.5mm for direct drive, 2-3mm for Bowden (if you must). Retraction speed: 15-25mm/s. Faster retractions stretch the filament more — counterintuitive, but slower is cleaner.
Disable z-hop. The vertical movement creates additional pressure changes that pull TPU into the cold zone. If you’re fighting stringing, add 0.2mm wipe distance before enabling z-hop.
Temperature and Cooling
TPU prints at 210-235°C depending on shore hardness. 95A TPU needs 220-235°C for good layer adhesion. 85A prints at 210-220°C — lower temperature reduces ooze.
Cooling fan: 20-40% after the first layer. Too much cooling prevents layer adhesion and creates delamination. Too little creates sagging on overhangs. TPU bridges poorly regardless of cooling — design around it or use supports with a dense interface layer.
Bed Adhesion
TPU sticks aggressively to PEI and BuildTak — sometimes too aggressively. Large flat TPU parts can tear PEI surfaces during removal. Apply a thin glue stick layer as a release agent, not for adhesion. For glass beds, TPU bonds so strongly that it can chip the glass during removal — always use glue stick or hairspray as a barrier.
Bed temperature: 40-50°C for 95A, 30-40°C for 85A. Flexible TPU has low shrinkage — high bed temperatures cause elephant’s foot because the soft first layers sag under their own weight.
TPU Printing Quick Reference
| Parameter | 95A TPU | 85A TPU |
|---|---|---|
| Nozzle Temperature | 220-235°C | 210-220°C |
| Bed Temperature | 40-50°C | 30-40°C |
| Print Speed | 20-25 mm/s | 15-20 mm/s |
| Retraction Distance (DD) | 1.0-1.5mm | 0.5-1.0mm |
| Retraction Speed | 20-25 mm/s | 15-20 mm/s |
| Cooling Fan | 20-40% | 10-30% |
| Extruder Type Required | Direct Drive recommended | Direct Drive mandatory |
What Most Printers Get Wrong
Mistake 1: Using the same retraction settings as PLA. 6mm retraction on a Bowden setup creates an air bubble in the melt zone. TPU stretches instead of retracting, and the next extrusion starts with a delay while pressure rebuilds. Consequence: severe stringing that looks like under-extrusion but is actually retraction-induced ooze. Fix: Cut retraction distance by 70-80% compared to PLA. Accept that some stringing is normal — a heat gun cleans it in seconds.
Mistake 2: Printing TPU that’s absorbed moisture. TPU is hygroscopic — it pulls water from the air faster than PLA or PETG. Wet TPU pops and sizzles during printing, leaving surface pits and weak layer bonds. Consequence: a TPU drone mount that delaminates on the first crash. Fix: Dry TPU at 50-55°C for 4-6 hours before printing. Store in a sealed container with desiccant. Print from a dry box if humidity exceeds 40%.
Mistake 3: Running the part cooling fan at PLA levels. 100% fan on TPU flash-cools each layer, preventing polymer chains from entangling across the layer boundary. Consequence: part looks great but snaps along layer lines under load. Fix: Cap fan at 40% maximum. For structural parts (drone mounts, bumpers), run 0-20% fan for maximum strength.
Mistake 4: Using a 0.4mm nozzle for 85A TPU. Very flexible TPU flows unpredictably through small orifices. The softer the filament, the more it deforms under extruder pressure rather than extruding cleanly. Consequence: inconsistent extrusion width, intermittent under-extrusion that ruins functional parts. Fix: Switch to a 0.6mm nozzle for 85A TPU. The larger orifice reduces back pressure and produces consistent extrusion at the same linear advance settings.
⚠️ Safety Notice: TPU printing at elevated temperatures releases isocyanates and volatile organic compounds (VOCs) at low concentrations. While not classified as hazardous at hobbyist volumes, ventilation is recommended for extended printing sessions. Always verify your printer’s thermal runaway protection is enabled — TPU’s low melting point increases fire risk if the thermistor or heater cartridge fails. As of 2026, some jurisdictions require VOC filtration for commercial 3D printing operations.
For printing functional FPV drone parts in TPU and PETG, see our guide to 3D printed drone components. If you’re dealing with filament moisture issues, our filament dryer guide has drying times and temperatures for every material.
The uavmodel TPU filament (95A) ships vacuum-sealed with desiccant and prints consistently at 225°C on direct drive extruders — formulated specifically for durable FPV drone mounts and bumpers.