The best slicer settings for TPU flexible filament (Shore 95A, 1.75 mm, direct drive, 0.4 mm nozzle) are a 230 °C nozzle, a 35–60 °C bed, a 3 mm³/s max volumetric speed (roughly 35 mm/s at 0.2 mm layers), 0–1 mm retraction at 20–30 mm/s, and moderate part cooling after the first layer. Most TPU failures come from speed and retraction, not temperature.
These values sit close to OrcaSlicer’s shipped generic TPU base profile and Prusa’s flexible-materials guidance. If you still build profiles by cloning PLA, the material profiles comparison explains what has to change first.
The starting profile for 95A TPU
| Setting | Start value | Reason |
|---|---|---|
| Nozzle temperature | 230 °C (tune 220–240) | Mid-range for 95A |
| Bed temperature | 35 °C textured PEI; 50–60 °C smooth PEI with glue | Release, not adhesion, is the problem |
| Max volumetric speed | 3 mm³/s | Limits what the extruder must push |
| Outer wall / first layer | 20–25 / 15–20 mm/s | Surface finish, first-layer bond |
| Retraction | 0.4–1.0 mm at 20–30 mm/s, or off | Long or fast pulls buckle the filament |
| Part cooling | Off for layer 1, then 30–60% | See the cooling section |
| Walls / infill | 2–3 / 15–25% gyroid | Keeps the part flexible |
| Support top Z distance | 0.3 mm | TPU fuses to tight interfaces |
| Flow ratio | Calibrate per spool | Never inherit the PLA value |
Prusa lists 230–245 °C for flexibles and suggests running about 5 °C hotter than usual to cut the filament’s resistance in the nozzle. The Prusament TPU 95A guide rates that filament at 220–240 °C, and OrcaSlicer ships 240 °C. Start at 230 °C and drop in 5 °C steps if it strings. NinjaTek’s troubleshooting guide says it plainly: the cooler the temperature, the less oozing.
On the bed, OrcaSlicer uses 35 °C on textured PEI. Prusa calls for 55–75 °C on its own sheets and does not recommend smooth PEI without a separation layer, because the bond can damage the surface. On smooth PEI, glue stick works as a release layer.
Why cap volumetric speed instead of print speed?
TPU fails on how much plastic the extruder has to push per second, not on how fast the head moves. A max volumetric speed in mm³/s throttles every feature automatically: perimeters on small parts stay fast, while wide infill lines at tall layers slow down. A single mm/s value either wastes time or overdrives the big features.
When the gear pushes faster than the hotend melts, soft filament buckles above the heat break or wraps the gear. The symptom is under-extrusion partway through a print, often on the first long infill pass.
OrcaSlicer’s generic TPU profile caps flow at 3.2 mm³/s. Prusa’s flexible filament article says its older PrusaSlicer flex profiles used 1.5 mm³/s. It gives 20 mm/s as a typical safe speed and 30–40 mm/s as the maximum. To convert a cap to mm/s, divide it by layer height × line width:
- 3.2 ÷ (0.20 × 0.42) ≈ 38 mm/s
- 3.2 ÷ (0.28 × 0.45) ≈ 25 mm/s
- 1.5 ÷ (0.20 × 0.42) ≈ 18 mm/s
OrcaSlicer, Bambu Studio and PrusaSlicer apply the cap for you. Cura has no per-filament volumetric limit, so run the numbers above and set Print Speed, Wall Speed and Infill Speed by hand.
Retraction and travel: retract less often, not just shorter
Each retraction compresses and stretches the strand between the gear and the melt zone, and enough of them in one area chew a groove into it. Prusa’s advice is to keep retraction as low as possible, or turn it off and add it back in small steps. OrcaSlicer’s profile uses 0.4 mm. On direct drive, 0.4–1.0 mm at 20–30 mm/s is the working window. If you are pushing past that to fix stringing, check temperature and moisture first.
How often the printer retracts matters as much as how far:
- Cura: Combing Mode set to Within Infill, a higher Retraction Minimum Travel, and a lower Maximum Retraction Count.
- OrcaSlicer / Bambu Studio: enable Avoid crossing walls and raise the retraction travel distance threshold.
- PrusaSlicer: enable Avoid crossing perimeters and raise Minimum travel after retraction.
NinjaTek also recommends faster travel moves and, if you use Z-hop, at least one layer height of it. TPU strings rub off a finished part; a jam ten hours in does not, so trade a few hairs for reliable feeding. The remaining checks are in how to fix stringing in Cura and apply in any slicer.
Should the part cooling fan be on for TPU?
Yes, at a moderate setting, because the official sources point in opposite directions. Prusa says to keep print cooling off entirely. OrcaSlicer’s generic TPU profile does the opposite: the fan stays off for the first layer, then runs at a 100% minimum. Start at 30–60% after layer one.
Each extreme suits a different part. Fan off fuses layers best, which matters for gaskets, bumpers and gripper pads that flex across layer lines. Full fan holds overhangs and bridges and keeps small parts from slumping. If a flexed part splits between layers, reduce cooling first.
Walls, infill and supports for flexible parts
How stiff a TPU part feels depends as much on walls and infill as on Shore rating. Prusa’s knowledge base says to add infill and perimeters for strength, and cut perimeters and top/bottom layers to keep a part flexible. The Prusa blog’s printed-tire example compares Flexfill 98A with 2 perimeters against Flexfill 92A with 1 perimeter, both at 8% infill, and notes that tire softness changes with infill and perimeter count; set them too high and the tires get too hard.
- Walls: 2 for a soft feel, 3–4 for wear surfaces and parts that take screws.
- Infill: 15–25% gyroid, which compresses evenly where grid and lines have stiff axes. The infill pattern comparison covers the trade-offs. NinjaTek suggests keeping NinjaFlex at 20% or more.
- Top layers: enough to close the surface, and no more, since extra top and bottom layers stiffen the part.
Avoid supports by orienting the part. When you need them, Prusa recommends a 0.3 mm top contact Z distance and at least 100% XY separation. TPU interfaces bend instead of snapping off, so the wider gaps matter. Apply them to the tree setup in Cura tree support settings.
Where each setting lives in OrcaSlicer, PrusaSlicer and Cura
| Setting | OrcaSlicer / Bambu Studio | PrusaSlicer | Cura |
|---|---|---|---|
| Volumetric cap | Filament > Max volumetric speed | Filament > Advanced > Max volumetric speed | None; set speeds directly |
| Retraction length | Filament > Setting overrides | Filament Overrides > Length | Travel > Retraction Distance |
| Fewer retractions | Avoid crossing walls | Minimum travel after retraction | Maximum Retraction Count |
| Part fan | Filament > Cooling | Filament > Cooling | Cooling > Fan Speed |
| Support gap | Support > Top Z distance | Top contact Z distance | Support Z Distance |
Make these changes in a cloned filament profile, not the generic one, so a slicer update cannot overwrite them.
Adjusting for softer TPU and wet spools
The Prusa blog reports its best experience with 92A and 98A TPU and notes that softer filaments are generally more difficult to print. Below 95A, lower the cap toward Prusa’s old 1.5 mm³/s figure, start with retraction off, and slow the first layer further.
On extruder tension the sources disagree. Prusa says to loosen the idler as much as possible; NinjaTek says to increase tension if under-extrusion persists. Start loose and tighten only if the gear slips without biting.
Wet TPU pops, strings and prints a rough, foamy surface regardless of retraction. For Prusament TPU 95A, Prusa gives at least 4 hours at 60 °C, then dry-box storage. Dry and reprint before blaming the profile or the brand.
How to verify the profile
Run these on the spool you will actually print with; results do not carry over between brands.
- Temperature tower, 240 to 220 °C in 5 °C steps. Pick the coolest band whose walls bend without gaps between layers.
- Max volumetric speed. The OrcaSlicer wiki defaults start at 5 mm³/s, already above the 3.2 mm³/s generic TPU cap, so use start 1, end 6, step 0.25. The result is start + (failure height × step): a failure at 10 mm gives 3.5 mm³/s. Take the wiki’s recommended 10–20% off, landing at 2.8–3.15 mm³/s.
- Flow ratio. Use the OrcaSlicer flow rate calibration with TPU loaded.
- Retraction tower from 0 to 1.5 mm in 0.1 mm steps. Keep the shortest length that leaves only hairs.
- Pressure advance. TPU compresses in the feed path, so calibrate it separately using the pressure advance guide.
Success criteria: a two-wall test strip folds flat 180° without layers separating, the drive gear leaves no shaved or flattened filament after a full plate, strings rub off by hand, and the first layer releases from textured PEI once the bed is cold.
FAQ
can you print tpu with a bowden extruder
Yes, 95A TPU can print through a Bowden tube if you slow it down and nearly eliminate retraction. Start with retraction off, a volumetric cap around 1.5 mm³/s, and travel set to avoid crossing walls. The tube leaves the strand room to coil, so softer grades are far harder to feed than on direct drive.
why does my tpu keep jamming in the extruder
TPU jams when the drive gear pushes faster than the hotend can melt, or when frequent retractions keep compressing the same section of soft filament. Lower the max volumetric speed, cut retraction to 0.4 mm or turn it off, and check for an open gap between the gear and the hotend inlet.
what layer height should i use for tpu
Use 0.2 mm on a 0.4 mm nozzle as the starting layer height for TPU. Taller layers cut print time, but they raise the plastic needed per millimeter, so the volumetric cap slows the head down and most of the time saving disappears. Thinner layers help only on small, detailed parts.
how do i get tpu off a pei sheet
Let the bed cool to room temperature, then flex the spring-steel sheet so the part peels away. If it still will not release, the bond is too strong. Print the next one on textured PEI, or put a thin glue-stick layer on smooth PEI. Prying with a blade risks gouging the coating.
Related across the network
- FDM Print Stringing: How to Stop It in Four Steps — fdmdesk.com
- How to Fix Stringing on 3D Prints: Retraction Settings — printlabguide.com
