TPU (Thermoplastic Polyurethane) is the most popular flexible 3D printing filament, used for phone cases, shoe insoles, gaskets, cable protectors, grips, and hundreds of other applications requiring rubber-like flexibility with 3D-printable properties. It's also one of the most misunderstood materials — the settings that work for PLA or PETG will fail with TPU. This guide covers everything you need to print TPU successfully.
TPU Print Settings — Quick Reference
Nozzle Temperature: 210–240°C (start at 225°C)
Bed Temperature: 25–60°C (no heated bed required)
Print Speed: 20–30 mm/s — slow is critical for TPU
Cooling Fan: On, 50–100%
Retraction: 0.5–1.5mm at 20–30 mm/s (short and slow)
Extruder: Direct drive strongly preferred; Bowden requires careful calibration
Drying: 70°C (158°F) for 7 hours — always dry TPU before printing
Why TPU Is Different From Other Filaments
TPU is a flexible elastomer — it behaves completely differently from rigid filaments like PLA or PETG. The key challenge is that TPU's flexibility, which makes it useful, also makes it difficult to push through a Bowden tube. The filament can buckle and curl inside the tube under the pressure needed to extrude it, causing jams, under-extrusion, or inconsistent flow. This is why print speed and extruder type matter so much for TPU.
Direct Drive vs Bowden for TPU
A direct drive extruder is strongly recommended for TPU. Direct drive extruders grip the filament immediately before the hotend, leaving no gap for the flexible filament to buckle. Most modern printers with direct drive extruders (Bambu Lab X1/P1, Prusa MK4, Creality K1, Voron, Ender 3 with direct drive upgrade) can print TPU reliably.
Bowden extruders can print TPU but require significantly more tuning: print speed must be reduced to 15–20 mm/s, retraction should be reduced or eliminated entirely, and the Bowden tube must be properly secured with no gaps. Loose Bowden connections cause TPU jams.
Do not use AMS (Automatic Material Systems) for TPU — the multi-filament hub cannot reliably feed flexible filament and will jam.
TPU Print Temperature
The recommended TPU print temperature is 210–240°C. Start at 225°C. If you see under-extrusion or rough surface texture, increase by 5°C. If you see excessive stringing or oozing, reduce by 5°C.
Unlike rigid filaments where going lower helps reduce stringing, TPU requires a narrow temperature window — too low and the material does not flow properly through the nozzle; too high and it strings aggressively. Most TPU users find their sweet spot within 215–230°C.
TPU Print Speed — Why Slow Matters
Print speed is the single most important setting for successful TPU printing. TPU must be printed slowly — 20–30 mm/s for standard TPU (95A shore hardness). Printing faster causes the extruder to push more material than the flexible filament can transmit to the nozzle, resulting in buckling in the Bowden tube or inconsistent extrusion on direct drive systems.
For travel moves, keep speed at 100–150 mm/s — faster than this can cause the flexible filament to bounce unpredictably between print points.
If print speed is a priority, Overture High Speed TPU is engineered to print up to 5x faster than standard TPU while maintaining the same 95A flexibility and durability — ideal for prototyping or production prints where time matters.
TPU Retraction Settings
Retraction settings for TPU are counterintuitive compared to rigid filaments. Where PLA benefits from 4–6mm retraction on Bowden, TPU requires very short retraction: 0.5–1.5mm at 20–30 mm/s. The reason is TPU's flexibility — pulling back more than 1.5mm on a flexible filament causes it to stretch rather than retract, which then over-extrudes when the next move begins, or worse, causes the filament to buckle inside the extruder.
If you still see stringing after optimizing retraction, the better fix is to reduce print temperature by 5°C rather than increasing retraction. Drying the filament also eliminates moisture-caused stringing that retraction cannot fix.
TPU Bed Adhesion
TPU adheres well to most bed surfaces without special treatment. On PEI (smooth or textured), TPU typically sticks reliably at room temperature. If adhesion is insufficient, increasing bed temperature to 40–50°C usually solves the problem.
A more common problem with TPU is the print sticking too well — flexible materials can be difficult to flex off a textured PEI sheet. If removal is difficult, let the bed cool to room temperature first, then gently flex the build plate to release the print. For parts with large flat contact areas, a thin layer of glue stick can act as a release agent.
How to Dry TPU Filament
Always dry TPU before printing, especially in humid climates. TPU is highly hygroscopic — wet TPU produces crackling sounds, excessive stringing, rough surface texture, and weak layer adhesion. The correct TPU drying temperature is 70°C for 7 hours. A food dehydrator or dedicated filament dryer works well. After drying, print directly from the dryer or seal in an airtight bag with desiccant immediately — TPU re-absorbs moisture quickly in humid conditions.
Common TPU Print Problems and Fixes
Filament jamming in extruder: Reduce print speed to 20 mm/s, reduce retraction to 0.5mm, increase temperature by 5°C
Stringing: Reduce temperature by 5°C, dry filament, enable Combing mode
Under-extrusion: Increase temperature, reduce speed, check for partial jam in Bowden tube
Rough surface texture: Dry the filament — this is almost always moisture-related
Print not sticking to bed: Increase bed temperature to 40–50°C, clean bed with IPA
Print too hard to remove: Apply glue stick as release agent, let bed cool fully before removal
What Shore Hardness Should I Choose?
Shore hardness measures flexibility — lower numbers are softer and more flexible, higher numbers are stiffer. Overture TPU is 95A hardness, which is the most common for 3D printing:
85A–88A: Very soft, like a soft rubber band — harder to print, requires very slow speeds
95A: Standard flexible filament hardness — flexible but not floppy, most printable
98A–TPU 'hard': Nearly rigid, minimal flex — prints like a stiff PETG, easiest to handle
For most applications — phone cases, cable protectors, gaskets, grips — 95A is the correct hardness. It is flexible enough for practical use while being stiff enough to print reliably even on Bowden printers with careful settings.
Overture TPU 95A Filament 1.75mm — the standard for flexible 3D printing.
Frequently Asked Questions
Can I print TPU on an Ender 3?
Yes, but the stock Ender 3 uses a Bowden extruder, which makes TPU significantly more challenging. Reduce print speed to 15–20 mm/s, reduce or eliminate retraction, and ensure the Bowden tube is secured with no gaps. A direct drive extruder upgrade (such as the Micro Swiss or Creality Sprite) transforms TPU printing on the Ender 3 and is highly recommended if you plan to print TPU regularly.
Why does my TPU keep jamming?
TPU jams are almost always caused by one of three things: print speed is too high (the extruder pushes faster than the flexible filament can transmit), retraction is too long (the filament buckles inside the extruder on retract), or the filament is wet (moisture causes inconsistent extrusion that jams the extruder). Reduce print speed to 20 mm/s, reduce retraction to 1mm, and dry the spool to resolve most TPU jam issues.
Is TPU the same as flexible filament?
TPU (Thermoplastic Polyurethane) is the most common type of flexible 3D printing filament, but not the only one. TPE (Thermoplastic Elastomer) is a broader category that includes TPU as well as softer variants like TPA and TPC. For practical purposes, when people refer to 'flexible filament' in 3D printing, they almost always mean TPU at 95A hardness.
What can I print with TPU?
TPU is used for phone cases, tablet cases, shoe insoles and orthotic inserts, cable organizers and strain reliefs, grips and handle covers, custom gaskets and seals, bumpers and dampening mounts, drone propeller guards, wearable props and costume parts, and flexible joints in articulated models. Any application requiring rubber-like flexibility, impact absorption, or a soft-touch surface is a candidate for TPU.
