Perfect TPU Settings

Printing with TPU (Thermoplastic Polyurethane) can be a rewarding experience, but it comes with its challenges. Unlike rigid materials like PLA or ABS, TPU is highly flexible, which makes it prone to issues such as stringing, poor layer adhesion, and inconsistent extrusion. Additionally, TPU's hygroscopic nature means it absorbs moisture from the air, which can lead to print defects. However, with the right settings and preparation, TPU can be successfully printed to produce flexible, durable, and high-quality prints.

This guide covers key considerations for printing TPU, including moisture management, temperature, cooling, speed, bed adhesion, support, retraction, and additional tuning tips.

I've included a video guide, as well as a text guide down below. Enjoy!

Video Guide:

Moisture Management

TPU is highly susceptible to moisture absorption, which can result in poor print quality, bubbling, and extrusion issues. To ensure optimal results:

- Always store TPU in a dry environment.

- Printing directly from a dry box is highly recommended to keep moisture at bay.

Temperature Settings

Finding the right extrusion temperature is crucial for TPU printing:

- A temperature of 230°C provides a good balance of surface quality and strong layer adhesion.

- Lowering the temperature to 220°C resulted in fuzzy surfaces and even nozzle clogging, so maintaining a higher temperature is advisable.

Cooling Considerations

Cooling can impact print quality, but results may vary:

- Experimenting with extruder fan speeds between 20% and 100% showed little difference in quality.

- Disabling the auxiliary fan seems to reduce overall print quality, so keeping it enabled is recommended.

Speed Optimization

Printing TPU requires slower speeds to maintain quality:

- Surfaces look good at speeds up to 40mm/s, but reducing all print speeds to 15mm/s significantly minimizes stringing.

- Enabling “Slow down for curled perimeters” helps prevent curling at sharp corners.

- Keeping travel speed high (200mm/s or more) reduces stringing by preventing excess filament oozing during movement.

Bed Temperature and Adhesion

Bed adhesion is a common challenge with TPU, and recommendations vary widely:

- A bed temperature of 35°C combined with PVA glue stick on a smooth PEI build plate provided good adhesion.

- For print removal, using a scraper to peel up a corner and flowing IPA (isopropyl alcohol) underneath helps the print release more easily.

Support Settings

If using supports for TPU prints:

- Adjusting Top-Z Distance to 0.25mm allows for easier separation of support from the model.

- While only bed-supported structures were tested, adjusting Bottom-Z Distance should provide similar improvements for model-originating supports.

Retraction Settings

Retraction tuning is crucial to reduce stringing:

- Disable Z-hop, as it can introduce unwanted movement and inconsistencies.

-Increasing retraction from 0.4mm to 1.5mm significantly reduced stringing.

- Enabling wiping may further improve results by cleaning the nozzle between moves.

Additional Tuning Tips

For further optimization:

- For Bambu printers, Bambu Lab recommends increasing max volumetric flow to a value between 3.2 and 3.6

- Pre-extruder tension affects extrusion consistency; ensure filament tension is set low to maintain smooth feeding.

Conclusion

While every 3D printer and TPU filament brand will behave slightly differently, the settings and tips outlined above provide a strong starting point. TPU requires careful tuning, but with the right adjustments, it can yield durable and flexible prints with excellent quality. Experimenting with these settings and making incremental adjustments will help you achieve the best results for your specific printer and filament combination.

Happy Printing!