How to Print TPU: The Complete Flexible Filament Guide

TPU (Thermoplastic Polyurethane) is one of the most useful filaments you can print — phone cases, gaskets, shoe insoles, wheel tires, cable protectors, and hundreds of other applications that need rubber-like flexibility. It's also the filament most likely to make a beginner want to throw their printer out the window.

The good news: once you understand why TPU behaves the way it does, it becomes very manageable. This guide covers everything.

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What Makes TPU Different

TPU is flexible and rubbery — that's the whole point. But flexibility is also what makes it difficult to print. Unlike rigid filaments that push through the extruder cleanly, TPU can:

• Buckle and tangle in the extruder pathway before it reaches the nozzle
• Under-extrude at any speed that's even slightly too fast
• Blob and ooze because it's stickier and has more thermal expansion than PLA or PETG

The solution to all of these: slow down and use a direct drive extruder if possible.

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Shore Hardness: Choosing Your TPU

TPU comes in different hardness ratings measured on the Shore A scale:

Shore A	Feel	Common Use
85A	Very soft, highly stretchy	Gaskets, grips, flexible toys
95A	Medium — most popular	Phone cases, wheels, cable sleeves
98A	Firm, slight flex	Functional parts, hinges

For beginners, start with 95A. Softer grades are harder to print. 98A behaves almost like a rigid filament and is the easiest to start with if you're new to flexible printing.

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Direct Drive vs Bowden Extruder

This is the single most important variable for TPU printing.

Direct drive extruder (Bambu, Prusa MK4, Ender 3 S1): The extruder motor sits directly on the print head. The filament path from extruder to nozzle is very short — typically 1–3cm. TPU handles this well because there's very little room to buckle.

Bowden extruder (original Ender 3, many budget printers): The extruder motor is mounted on the frame, and a long PTFE tube carries filament to the print head. With TPU, the filament can buckle or bunch up inside this tube — especially at higher speeds.

If you have a Bowden printer:

• Use 95A or harder TPU only (softer grades are extremely difficult)
• Print very slowly: 15–20 mm/s maximum
• Disable retraction entirely or use minimal retraction (0–0.5mm)
• Keep the PTFE tube tight with no gaps between tube and nozzle

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TPU Print Settings

Temperature

Setting	Value
Nozzle	220–240°C
Bed	30–60°C (optional — TPU sticks well cold)

Start at 230°C. If you see under-extrusion, raise by 5°C. If you see excessive oozing or blobs, lower by 5°C.

No enclosure needed. Unlike ABS, TPU doesn't require an enclosed printer.

Print Speed

This is where most TPU prints fail. Go slow.

Setting	Value
Print speed	15–30 mm/s
First layer	10–15 mm/s
Travel speed	100–150 mm/s (this can stay fast)

On a well-tuned direct drive printer (Bambu, Prusa) you can push 30–40 mm/s. On a Bowden printer, stay at 15–20 mm/s.

Retraction

Retraction is often the cause of TPU jams. The flexible material bunches up when pulled back too aggressively.

Extruder type	Retraction distance	Retraction speed
Direct drive	0–1 mm	25 mm/s
Bowden	0–2 mm (try 0 first)	20 mm/s

Many experienced users print TPU with zero retraction. You'll get slightly more stringing, but no jams. Deal with strings post-print with a heat gun.

Fan Cooling

• Cooling fan: 50–100% — TPU benefits from active cooling to solidify quickly and hold its shape
• More cooling = less oozing and better details
• First layer: no fan or 25%

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Common TPU Problems and Fixes

Under-Extrusion / Grinding

Symptom: Clicking from the extruder, gaps in prints, very rough or holey surfaces.

Fixes:

1. Slow down — this is almost always the cause
2. Raise nozzle temperature by 5°C
3. Reduce or eliminate retraction
4. Check for partial nozzle clog (do a cold pull)

Tangling / Jamming Mid-Print

Symptom: Print starts fine, then suddenly no extrusion, clicking sounds, filament tangled above the extruder.

Fixes:

1. This is typically a Bowden issue — filament buckled in the tube
2. Reduce speed dramatically
3. Check that the PTFE tube is properly seated against the nozzle with no gap
4. Try a direct drive upgrade

Excessive Stringing

Symptom: Fine hairs everywhere between features.

Fixes:

1. Lower temperature by 5°C
2. Increase travel speed
3. Enable or increase retraction slightly
4. Add a 1–2mm "combing" or "avoid crossing perimeters" setting in your slicer

Elephant's Foot / Squished First Layer

Symptom: The base of the print flares outward.

Fixes:

1. Increase Z offset slightly (move nozzle higher)
2. Lower bed temperature
3. Add a small negative horizontal expansion in slicer

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Best Practices for TPU

1. Feed slowly by hand the first time. Before printing, heat the nozzle and manually push TPU through. It should extrude as a smooth ribbon, not sputter.

2. Store it dry. TPU absorbs moisture and becomes very stringy and bubbly when wet. Store with desiccant; dry at 50–55°C for 4–6 hours if needed.

3. Don't leave it loaded. TPU can fuse inside a hot nozzle if left for hours without printing. Unload it after sessions.

4. Use a smooth PEI bed or glass + glue stick. TPU sticks very well to most surfaces — sometimes too well. A light coat of hairspray or glue stick on PEI prevents it from bonding permanently.

5. Print hotter, slower, drier. When in doubt, these three adjustments fix 90% of TPU problems.

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What to Print with TPU

• Phone and tablet cases — the most popular use case
• RC car tires — outstanding grip and durability
• Gaskets and seals — excellent chemical resistance
• Cable strain relief — flexible boot around cable ends
• Grip handles and knobs — comfort and vibration absorption
• Flexible hinges — print-in-place designs
• Shoe insoles — custom orthotics
• Drone motor dampeners — reduce vibration

Find TPU filament settings for your specific printer in our Settings database.