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Printing TPU: flexible parts without the frustration

Filaments9 min readUpdated: 10/2026

are explained briefly when you hover over or tap them.

TPU is the filament for anything that should give way: phone cases, seals, dampers, non-slip feet or tyres for model cars. It feels like rubber and is very resistant to abrasion. It prints more slowly than other filaments, and not every printer copes with it equally well.

Shore hardness: how soft is soft?

The hardness of TPU is given on the Shore A scale. The lower the number, the softer the material.

Shore hardnessFeelPrintability
95A to 98Afirm but flexible, similar to a shoe soleeasy, good for getting started
90Anoticeably softermedium
85A and belowvery soft, similar to an eraserdifficult, only with a good extruder

95A is the best choice to begin with.

Settings at a glance

SettingGuide value
Nozzle temperature210 to 230 °C
Bed temperature40 to 60 °C
Speedslow, often 20 to 40 mm/s, depending on the printer
Retractionlow or off
Part coolingon, roughly 30 to 100 % depending on the filament

The values on the spool take priority.

On cooling: Most filament manufacturers leave the part cooling fan running for TPU. In its data sheet for TPU 95A (PDF), Prusament gives 30 to 50 %, Polymaker’s data sheet for PolyFlex TPU95 (PDF) says “Cooling fan: turned on”, and Bambu Lab gives 50 to 100 % for TPU 95A HF. Only the general guide to flexible materials in the Prusa Knowledge Base advises switching cooling off. More under Setting up cooling.

Why the extruder matters so much

Soft filament behaves like cooked spaghetti: if you push from behind, it compresses and bends instead of sliding forwards. That is why:

  • Direct drive extruders with a short, guided path between gear and nozzle make TPU much easier.
  • Bowden systems push the filament through a long tube. Hard TPU (95A) often still works with them, soft TPU hardly at all.
  • Multi-colour systems are usually not approved for normal TPU. Soft filament easily jams in the feed path. Which systems handle which TPU is covered below in TPU in the AMS and other multi-colour systems.

Tips for clean results

  1. Print slowly. The most common cause of problems is too high a speed. Start with your slicer’s TPU profile and work your way up slowly.
  2. Dry it. TPU absorbs a lot of moisture and then produces even more strings than usual. Dry it at 50 to 55 °C before printing.
  3. Little retraction. Strong retraction can compress the soft filament. Many profiles use only a very short retraction or none at all.
  4. Infill determines softness. A part with 10 % infill is much more yielding than one with 50 %. This lets you control the softness deliberately.
  5. Don’t overdo adhesion. TPU sticks very well, on smooth PEI sometimes too well. A release agent such as glue stick helps with removal.

TPU in the AMS and other multi-colour systems

In short: normal TPU at 95A and softer runs in hardly any multi-colour system. Some manufacturers approve only particularly hard TPU grades, which are specified in Shore D. Bambu Lab gives the order from hard to soft as: 77D, 70D, 68D, 55D, then 95A, 90A, 85A and softer. A TPU with 64D or 77D is therefore considerably harder than the usual 95A and feels less rubbery.

SystemTPU according to the manufacturer
Bambu Lab AMS and AMS 2 Pronormal TPU not compatible, Bambu “TPU for AMS” is approved
Bambu Lab AMS liteaccording to the AMS lite FAQ only TPU of 55D or harder, not 95A, 85A, 83A or 80A. The newer TPU guide lists only “TPU for AMS” as compatible with the AMS lite.
Bambu Lab AMS HTTPU only as a sealed dry box with its own TPU outlet, without automatic loading and unloading
Creality CFSno TPU, Creality rules out all TPU materials
Creality CFS liteharder grades such as TPU 77D and 64D, not TPU 95A or TPE
Anycubic ACE ProTPU 95A only for drying, not for printing via the ACE Pro
Anycubic ACE 2 Proonly “TPU for ACE” from Anycubic, no other flexible filament
QIDI BoxTPU 64D, not TPU 95A, “Generic TPU” or TPE

As of manufacturer information in October 2026. Firmware updates and new filaments may change this.

Why TPU causes problems in a multi-colour system

Bambu Lab explains that filaments that are too soft do not run cleanly through the channels of the AMS and AMS lite. The results are errors when loading and unloading, and blockages. Creality writes that soft filament such as TPU can accumulate inside the CFS box while printing. Multi-colour systems push and pull the filament over long distances and through several changes of direction. Soft TPU tolerates exactly that badly. Prusa also points out that automatic filament changing may not work reliably with flexible filament.

How to print TPU alongside a multi-colour system anyway

Bambu Lab recommends an airtight environment for TPU, because TPU absorbs a lot of moisture:

  • AMS HT: The spool sits protected in the AMS HT, but the filament runs out through the separate TPU outlet on the back and is pushed by hand as far as the extruder. Automatic feeding stays off.
  • Dry box: Spool on a holder with ball bearings, filament through the side outlet. Bambu Lab advises placing the box slightly raised so that the filament unwinds easily.

For the printers themselves, Bambu Lab names a lower limit: the printers currently do not support TPU below 85A, and the A1 series does not support 85A either. According to Bambu Lab, 85A requires a nozzle of 0.6 mm or larger.

Why TPU is printed slowly

TPU is yielding. If the extruder pushes too fast, the filament compresses between gear and nozzle instead of sliding forwards. It can then wind around the gears or block the nozzle. Prusa gives 20 mm/s as the typical speed for flexible filaments and 30 to 40 mm/s as the recommended upper limit. At higher speeds, according to Prusa, the risk of a clogged nozzle and of filament catching in the gears rises.

Then there is melting: at lower speed, according to Bambu Lab, the material has more time to melt completely. This reduces under-extrusion and gaps in the walls.

What manufacturers additionally recommend:

  • Relieve the extruder: Prusa advises reducing the gear pressure so that they feed the filament only gently.
  • Adjust temperature and flow together: If you set the nozzle about 5 °C cooler to combat strings, you should also reduce the maximum volumetric flow by 0.4 mm³/s, according to Bambu Lab.
  • Faster grades: Some manufacturers offer TPU for higher speeds, such as “TPU 95A HF” from Bambu Lab, along with accessories like a high-flow TPU hotend or a feeder module intended to reduce resistance when pulling the filament in. These are manufacturer statements for their own printers.

Typical problems

ProblemCommon causeSolution
Filament tangles in the extrudertoo fast, Bowden, too softslower, direct drive, harder TPU
Lots of stringsdamp, too hotdry it, lower the temperature
Gaps in the wallsunder-extrusion due to too high a speedprint more slowly
Part is hard to removeadhesion too strongglue stick as a release layer, cooler bed

TPU compared

How TPU compares with PLA, PETG, ABS and ASA is shown in the filament overview.

Sources