## TPE – TPU Thermoplastic Elastomers
In general, there are three classes of TPE that are processed into filaments.
### TPE-S
Filament made from SEBS (Styrene-Ethylene-Butadiene-Styrene). Adhesion to PP and PE is possible. TPE-S filaments are rarely offered and have a hardness range of approx. 70 Shore A to 60 Shore D.
### TPEE
Thermoplastic copolyester elastomers, also called TPC. They adhere to ABS, PET-G, PLA, and TPU. High resilience (excellent elastic recovery), but not UV color stable. Hardness range approx. 30–55 Shore D.
### TPU
Thermoplastic polyurethane. Most commonly offered and available in a hardness range from 65 Shore A to 60 Shore D.
We differentiate between three of the most important TPU classes:
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### Ester TPU
Most commonly available and relatively cost-effective. High chemical resistance and high resilience. Susceptible to hydrolysis (mechanical properties slowly degrade in high humidity/temperature), not UV color stable. Frequently used for shoe soles.
### Ether TPU
Higher quality than Ester TPU. Resistant to microbes and hydrolysis, high chemical resistance, not UV color stable. Often used in the automotive industry due to its long lifespan. Usually colored black, so UV yellowing is not an issue.
### Aliphatic TPU
Very expensive. Main advantage is UV resistance, even in light colors. Otherwise similar to Ether TPU. For example, used in flexible transparent rear windows of convertible tops. Very rarely offered as filament.
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## Working with TPU in 3D Printing
TPU is often viewed negatively when it comes to processability in 3D printing. This is partly due to the quality of the polymer itself, the filament quality, and also because many 3D printers are not designed for flexible materials.
### Bowden Printers
Only TPU types with sufficient stiffness and hardness can be processed. We recommend TPU in the range of 98 Shore A to 60 Shore D.
Direct-Drive Systems
Better suited for TPU. With these printers, you can sometimes print TPU down to approx. 60 Shore A (extremely soft).
Soft TPU types may need to be printed at slower speeds, typically 20–40 mm/s.
Adhesion to the print bed can be extremely good, and warping is generally not an issue. However, as TPU hardness increases, bed adhesion decreases and warping may increase. From 98 Shore A up to 60 Shore D, we recommend using a heated print bed and applying blue tape to improve adhesion and reduce warping.
A blower fan is generally helpful to cool printed TPU quickly.
TPU is mechanically very durable, does not break easily, and is highly cut- and abrasion-resistant. It also bonds very strongly to harder plastics, which is beneficial for dual-material (2K) objects. Good adhesion partners for TPU include ABS, ASA, PC, PLA, and PETG.