What Is TPU (Flexible Filament)?
TPU is printable rubber. It bends, grips, seals and absorbs shock — and it behaves nothing like PLA, which is the whole point and the whole difficulty.
TPU is thermoplastic polyurethane. In practice it is a rubber you can print — it stretches, bounces back, grips, and takes abuse that would shatter PLA. It is the one filament that gives a printed part a property no rigid plastic can fake.
Shore hardness: the number that matters
TPU is not one material. It comes in hardnesses, measured on the Shore A scale, and the number changes what the part is.
- 95A — the common one, and the easiest to print. Firm. Bends like a shoe sole, not like a rubber band. Most functional flexible parts want this.
- 85A — noticeably softer and squashier. Good for seals, grips and damping. Harder to print; it wants to buckle in the extruder.
- 75A and below — genuinely floppy, like a soft rubber band. Difficult, slow, and only worth it if you truly need that softness.
- 98A / 60D — barely flexible. Tough and abrasion-resistant rather than bendy. Sits close to a rigid plastic that refuses to shatter.
If you say "flexible", we will ask which of those you mean, because they are different parts.
What TPU is actually good at
- Abrasion resistance. This is TPU's underrated superpower. It outlasts most rigid plastics on wear, comfortably.
- Impact. It absorbs a hit rather than transmitting or cracking. Bumpers, feet, corner protectors, drone parts.
- Grip. Non-slip feet, tool handles, pads, mat corners, anything that must not slide on a dashboard.
- Gaskets and seals. Printed seals, blanking grommets, cable pass-throughs, weather seals for enclosures.
- Living hinges and flexures. A TPU strap or hinge flexes indefinitely where PLA would snap on the third cycle.
- Vibration damping. Machine feet, mounts, isolators.
Vans and campervans are full of these jobs — grommets, seals, non-slip feet, trim bungs. Our automotive and campervan parts service leans on TPU for exactly that.
Why TPU costs more to print
Not because the plastic is dramatically more expensive. Because it is slow and fussy.
Pushing rubber down a tube is the problem. A rigid filament acts like a piston; TPU acts like a spring. It compresses, buckles and lags, which means:
- Slow printing. Often a fraction of PLA speeds. Print time is a main pricing lever, per how pricing works.
- No retraction to speak of, so stringing needs managing another way.
- Careful drying. TPU takes up moisture readily and prints badly wet.
- Softer grades need particular hardware. Below about 85A the filament path itself has to be right.
Print time, not material cost, is what moves a TPU quote.
Designing for TPU
Flexibility is a design variable, not just a material one. Wall count and infill change the stiffness of a TPU part more than the Shore rating does. A 95A part with two walls and light infill is squashier than an 85A part printed solid. That gives you a dial: we can tune how soft a part feels without changing the spool.
Other things worth knowing:
- Clearances are forgiving — a TPU part deforms into a fit that a rigid part would fail.
- TPU bonds to itself between layers unusually well, so the anisotropy that dominates rigid parts (see print orientation and strength) matters less here.
- It does not sand and it does not take paint. Choose the colour at print time.
- Bridging and steep overhangs are worse than with rigid materials. It droops.
Where TPU is the wrong choice
Honestly:
- Anything structural or load-bearing. It is rubber. If it needs to hold a shape under load, use PETG, ABS or nylon — see PLA vs PETG vs ABS.
- Tight tolerances. A flexible part has no exact size; it has whatever size you press it into. Not the material for a precision fit.
- A pressure or fuel seal. A printed seal is a shape, not a rated sealing component. For anything pressurised or safety-related, buy a moulded O-ring — they cost pennies and they are made for it.
- High heat. Most TPU softens well before ABS does.
- A cosmetic painted part. Paint cracks off flex. See painting and finishing.
- Sharp fine detail. TPU rounds it off.
Getting a TPU part made
Tell us how firm it needs to feel and what it does — grip, seal, damp, protect. That decides the grade, the walls and the infill together. Get an estimate · see the materials we print · browse the print library
Worked examples
Real models from our print library, priced by the same calculator that estimates your own part — so you can put numbers against the advice above.
| Example part | Size | PLA | PETG | ABS / ASA |
|---|---|---|---|---|
| 15mm Pipe Clip | 19 × 39 × 12 mm | £1.18 – £1.51 | £1.25 – £1.60 | £1.42 – £1.81 |
| 28mm Pipe Clip | 30 × 52 × 16 mm | £2.46 – £3.14 | £2.61 – £3.33 | £2.93 – £3.75 |
| L-Bracket (large) | 70 × 40 × 70 mm | £9.99 – £12.76 | £10.50 – £13.42 | £11.62 – £14.85 |
| Gusseted Shelf Bracket (large) | 90 × 60 × 90 mm | £21.97 – £28.07 | £23.09 – £29.51 | £25.54 – £32.64 |
Guide prices for a single unit, calculated from the measured geometry of each example model — not fixed quotes. Small parts land at or near the £0 minimum order, and per-unit prices fall with quantity. Your price depends on your own part, its material and its printability. How pricing works.
Models that show this in practice
Open-source designs from our print library. Each one has a full material and quantity price breakdown.
Furniture Foot (medium)
Garage Tool Rail (6-hook)
15mm Pipe Clip
Furniture Foot (small)
These are open-source example designs (CC0) we publish to show what the process suits and what it costs — not a record of past jobs. Prices shown are examples in PLA.
Get a 3D print estimate
Upload your file or describe the part. We review printability before confirming anything.
Services covering this
Related guides
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The route from a sketch to a batch you can sell — what each stage is for, what to test, and when to stop printing in PLA and start printing in something real.
How Many Prototype Iterations Should You Expect?
Three or four rounds for a simple part, more for anything with a mechanism. How to iterate cheaply — one change at a time, several variants per print — and how to know when to stop.
From Prototype to Production
What happens after the design is frozen — bridge batches, the point where tooling beats printing, the design changes that make moulding cheaper, and what a moulder actually needs from you.