TPU: density, print temperature and when you need a flexible filament
TPU (thermoplastic polyurethane) is the only mainstream filament that stays flexible after printing. It is used for cases, shock-absorbing pads, seals and anything that should bend or spring back instead of snapping.
Key properties
| Parameter | Value |
|---|---|
| Density | 1.21 g/cm³ |
| Nozzle temperature | 210–230°C |
| Bed temperature | 30–60°C (often unheated) |
| Part cooling | 30–50% |
| Shrinkage | minimal |
| Enclosure required | no |
When to use it
- Phone cases, protective covers, vibration-damping feet.
- Seals, gaskets, flexible hinges and living joints without metal hardware.
- Parts that need to spring back or absorb vibration.
When to pick something else
- The part must stay rigid and hold shape under load — TPU is the wrong tool; use PLA/PETG/ABS.
- Printing on a bowden-extruder machine with no time to tune speeds — soft filament tends to jam in the tube, making prints slow and failure-prone.
- Print speed is critical — TPU prints noticeably slower than rigid plastics.
Pros and cons
Pros: stays elastic after cooling, absorbs impacts and vibration well, resists oils and some solvents better than PLA/PETG.
Cons: prints slowly (high speed causes under-extrusion and layer bonding issues), fussy on bowden extruders, costs more per kilogram than standard PLA/PETG.
Calculate your price in a minute
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How it affects your print cost
Low print speed is the main cost driver with TPU: the same part takes noticeably longer than in PLA, and print time usually weighs more in the calculation than the material itself. Its 1.21 g/cm³ density is close to PLA, so material consumption per volume is nearly the same — the premium you pay is in printer hours.