What is TPU filament? The flexible, rubber-like print material

What TPU is good at

TPU fills the role no rigid filament can. Phone cases, shoe soles, RC tires, gaskets, watch straps, and vibration mounts all rely on a material that gives instead of cracking. A printed TPU bumper can drop onto concrete and bounce; the same shape in PLA would shatter. Hardness varies by grade, usually marked on the Shore A scale, so a softer TPU feels like a rubber band and a harder one feels like a shoe heel.

The cost is speed and setup. TPU prints slow, and on a Bowden printer the flexible strand can buckle inside the tube. Direct-drive extruders handle it far better. Expect to drop your print speed and turn retraction down.

TPU print settings, in short

Print TPU slow and dry. Polymaker’s PolyFlex TPU95 runs a 210 to 230 C nozzle, a bed up to 60 C, and a speed of 20 to 40 millimeters per second. Keep retraction low or off, because long retractions make the soft strand tangle. TPU also absorbs moisture, so dry it (Polymaker suggests 70 C for about 12 hours) and store it sealed, or it will string and print rough. A direct-drive extruder makes flexible filament far easier than a Bowden tube.

TPU vs rigid filaments

TPU trades stiffness for flex, so it is not a drop-in replacement for PLA or PETG. For parts that must hold threads or take precise loads, a rigid material is better. The PETG vs TPU comparison breaks down where a tough-but-rigid plastic beats a flexible one. For a classic TPU use case, the best filament for phone cases page covers the choice in depth.

For where TPU sits among the six common families, see the 3D printer filament overview.