You can print TPU without jams at 220–235 °C on the nozzle, 20–30 mm/s print speed and retraction shortened to 0.5–1.5 mm — these three settings eliminate most problems with flexible filaments. Add a dry spool and a slow first layer, and a filament like Porima TPU 95A will come off your printer as predictably as PLA. Flexible filaments have a reputation for being difficult, but that reputation dates back to the days when everyone printed on Bowden extruders and nobody dried their spools.
In this guide you will find a complete set of TPU settings: a starting table, the differences between direct drive and Bowden, retraction step by step, speeds for popular printer configurations and a list of the mistakes that most often end with tangled filament in the extruder. All values apply to TPU in the 95A–98A hardness range — the most popular flexible filaments on the market.
Starting settings for TPU — table
| Parameter | Value | Comment |
|---|---|---|
| Nozzle temperature | 220–235 °C | Start at 225 °C; drop 5 °C if you see stringing |
| Bed temperature | 30–50 °C | TPU sticks hard; an overly hot bed makes prints difficult to remove |
| Print speed | 20–30 mm/s (direct) / 15–20 mm/s (Bowden) | The most important parameter — too fast means a jam |
| First layer speed | 15–20 mm/s | A slow first layer means reliable adhesion |
| Retraction — distance | 0.5–1.5 mm (direct) / 2–4 mm (Bowden) | Flexible filament stretches instead of retracting |
| Retraction — speed | 20–30 mm/s | Slower than PLA; fast retraction twists the filament |
| Cooling | 50–100 % | TPU handles cooling well; it improves bridging quality |
| Layer height | 0.2 mm | A safe standard for a 0.4 mm nozzle |
| Flow | 100–105 % | Flexible material likes a slight flow surplus |
| Travel moves | 120–150 mm/s | Fast travel shortens the time available for stringing |
We have gathered the values for the other materials — PLA, PETG, ABS and ASA — in one place, in our printing temperature table. It is worth keeping at hand, because TPU follows different rules than rigid filaments and it is easy to slip up when switching profiles.
Why does TPU jam in the extruder?
Rigid filament behaves in the extruder like a pushed rod: the drive gear grips it and pushes it straight into the melt zone. TPU works differently — under pressure it first compresses like a spring and only then moves. If the resistance at the nozzle is too high (temperature too low, speed too high), the flexible filament has nowhere to go and buckles sideways, into every free gap between the drive gear and the hotend inlet. That is how the classic jam forms, ending with a knot wrapped around the drive gear.
The second culprit is moisture. TPU is one of the most hygroscopic materials in 3D printing — it can absorb moisture from the air within a single day of sitting on your desk. Wet TPU hisses in the nozzle, strings uncontrollably and has much higher flow resistance, which in turn increases the risk of a jam. How to recognise damp material and how to save it is covered in detail in our guide on storing and drying filament.
The third piece of the puzzle is the filament path. Every millimetre of play between the extruder and the nozzle is a place where flexible material can buckle. The key to trouble-free TPU printing is therefore not one magic parameter but limiting the places where the filament has freedom: a short, tight feed path, moderate speed and a temperature high enough for the material to flow without resistance.
Direct drive or Bowden — what really matters
The extruder type is the most important hardware decision when printing flexible filaments. Both systems can print TPU, but the difference in comfort is enormous.
Direct drive — short path, few problems
In a direct drive extruder the drive gear sits right above the hotend, so the section where TPU can buckle is only a few centimetres long. That allows printing at 20–30 mm/s — and even faster on well-tuned machines — and using a short 0.5–1.5 mm retraction. If you plan to regularly print gaskets, RC model tyres or shock-absorbing housings, direct drive simply pays off.
Bowden — possible, but take it easy
In a Bowden setup the filament travels through 40–60 cm of PTFE tube, and flexible material in such a long tunnel behaves like an elastic band — it stretches before anything reaches the nozzle. Printing is possible but requires patience: 15–20 mm/s speed, retraction extended to 2–4 mm (or disabled entirely in favour of combing mode), and harder TPU 98A instead of soft 95A significantly improves your chances. The good news: a PTFE tube seated firmly at both ends, with no play at the couplings, solves half of Bowden's problems.
Retraction and the fight against stringing
Retraction with TPU is a balancing act: too short leaves strings between walls, too long twists the filament in the extruder and ends the print with a jam. With flexible materials we therefore aim for the minimum that still works.
Symptoms of too much retraction
A characteristic clicking of the extruder during travel moves, filament with tooth marks from the drive gear, gaps in extrusion right after a travel move and finally a complete jam mid-print — these are all signs that retraction is too aggressive. Shorten the distance by 0.5 mm and lower the retraction speed to 20 mm/s, and the symptoms usually disappear.
How to tune retraction step by step
Start at 0.8 mm and 25 mm/s (direct drive) and print a stringing test tower. If the strings are thick and numerous, add 0.3 mm of distance or lower the temperature by 5 °C — stringing with TPU is more often caused by temperature and moisture than by retraction itself. If instead you hear clicking, subtract 0.3 mm. Two or three such steps are enough to find the optimum for a given spool. Also enable combing (travel moves over infill), because it limits the number of retractions to the necessary minimum.
Print speed — slower means more stable
With TPU, speed is a safety parameter, not a productivity one. Pressure in the nozzle grows with speed, and flexible filament responds to high pressure by buckling in the extruder. The 20–30 mm/s range is therefore not a recommendation for the cautious but a real limit above which the risk of a jam rises sharply — especially with soft TPU 95A.
Modern CoreXY printers with well-tuned pressure advance can print TPU faster, but the principle stays the same: if anything goes wrong — skip the tempting “fast” profiles for now and go back to 25 mm/s. The time lost on one print is smaller than an evening spent disassembling a jammed extruder. Remember the first layer too: 15–20 mm/s gives the flexible material time to bond properly with the bed.
Drying TPU — half the battle
No set of parameters will save a wet spool. TPU absorbs moisture faster than PLA and PETG, and the symptoms are easy to recognise: hissing and popping at the nozzle, a matte, porous print surface, runaway stringing and reduced layer strength. If a spool has been left unprotected for more than a few days, dry it preventively before an important print.
The safe standard is 50–60 °C for 6–8 hours in a filament dryer or a convection oven with an accurate thermometer. After drying, store TPU in an airtight container with silica gel — and ideally print straight from the dryer, because flexible filaments can absorb moisture again during a long print.
Shore hardness — 95A or 98A?
The Shore A scale describes the hardness of elastomers: the lower the number, the softer and more rubbery the material. TPU 95A is the universal middle ground — flexible enough for gaskets, straps and dampers, yet stable enough to print on most direct drive machines. The harder TPU Flex 98A behaves in the extruder almost like a rigid filament: it tolerates higher speeds, works with Bowden setups and is the best starting point if this is your first adventure with flexible materials.
A practical rule of thumb: if the part is supposed to bend and return to shape (tyres, covers, grip elements) — choose 95A. If it is meant to damp vibration and carry mechanical loads while keeping its form (pads, feet, connectors) — 98A will be easier to print and more dimensionally predictable.
Settings for popular configurations
| Configuration | Speed | Retraction | Notes |
|---|---|---|---|
| Direct drive (typical Cartesian printer) | 25–30 mm/s | 0.8 mm / 25 mm/s | Trouble-free configuration; start at 225 °C |
| Bowden | 15–20 mm/s | 2–4 mm / 20 mm/s | Choose TPU 98A; check for play at the PTFE couplings |
| CoreXY with Klipper and pressure advance | 30–50 mm/s | 0.5–0.8 mm / 30 mm/s | Calibrate pressure advance separately for TPU |
| Printer with an AMS/CFS system | 20–30 mm/s | 0.8 mm / 25 mm/s | Feed TPU from an external holder — multi-spool systems usually do not support flexible filaments |
Most common mistakes
Printing with a wet spool. The most common cause of stringing and weak layers — dry TPU for 6–8 hours at 50–60 °C before every important print.
PLA-level speed. A 60 mm/s profile carried over from rigid filaments ends in buckling and a knot in the extruder — slow down to 20–30 mm/s.
PLA-level retraction. 5–6 mm of retraction twists flexible filament around the drive gear; with direct drive 0.5–1.5 mm is enough.
Extruder tension at maximum. An over-tightened drive gear crushes soft filament and changes its cross-section — loosen the tension until the teeth leave a clear but shallow mark.
Bed too hot. Above 60 °C TPU sticks so hard that removing the print risks damaging the bed surface — 30–50 °C is entirely sufficient.
Printing through an AMS or long tubes. Every extra metre of path and every coupling is a place to buckle — feed flexible filament along the shortest possible route from an external holder.
Frequently asked questions
Can you print TPU on a Bowden extruder?
Yes, but with limitations: 15–20 mm/s speed, 2–4 mm retraction or none at all, harder 98A material instead of 95A and a tight PTFE tube with no play at the couplings. Direct drive remains more comfortable, but Bowden does not rule flexible filaments out.
What nozzle temperature should I set for TPU?
The 220–235 °C range, ideally starting at 225 °C. With excessive stringing lower the temperature by 5 °C; with poor layer bonding or signs of under-extrusion raise it by 5 °C.
Why does TPU string despite good retraction?
Moisture is usually to blame, not retraction. Wet TPU strings regardless of settings — dry the spool for 6–8 hours at 50–60 °C and only then fine-tune retraction and temperature.
Does TPU need a heated bed?
It is not essential — TPU adheres well even to a cold PEI bed. A temperature of 30–50 °C improves first layer adhesion, but higher values make prints difficult to remove.
How fast can you print TPU?
The safe range is 20–30 mm/s on direct drive and 15–20 mm/s on Bowden. CoreXY printers with calibrated pressure advance reach 30–50 mm/s, but treat any speed above 30 mm/s as a bonus, not a starting point.
Summary
TPU is not a difficult material — it is a material that does not forgive settings carried over from rigid filaments. Slower printing in the 20–30 mm/s range, retraction cut to the minimum, a temperature of 220–235 °C and a dry spool solve the problem nine times out of ten. The rest is a matter of matching the profile to your specific printer, and the two tables in this guide will help you do exactly that.
If you are just starting your adventure with flexible materials, pick the harder TPU 98A for your first prints, and once you are comfortable with the material, reach for the more rubbery 95A. You will find both in our collection of flexible filaments — with full specifications and print profiles for every spool.