3D printing TPU with 0.2mm nozzle is possible

Many claim that TPU cannot be printed with a 0.2mm nozzle. But that's not true. This type of printing just has its own limitations.

First, you need to set up your printer for TPU printing with maximum flow. That means dialing in the temperature and extruder pressure. Run several tests, look at the results, and choose the best one. I prefer testing maximum volumetric flow like CNC Kitchen does - by weighing the printed part. When you push flow too high, the extruder can't deliver enough plastic — so flow drops instead of rising. It's quite difficult to accurately measure the thickness of a single TPU layer with calipers, but scales don't have this problem.

For example, my A1 mini prints TPU 90A at a volumetric flow of 12mm³/s with a 0.4mm nozzle. To achieve this, I had to slightly modify the filament pressure mechanism on the extruder - specifically, just file down the handle. Instructions are available online.

After that, you can install the 0.2mm nozzle and set these parameters:

• Maximum volumetric flow 4mm³/s. Your number may be different.
• Minimum volumetric flow 2mm³/s. This is mandatory! There's no dedicated parameter for this, so you'll have to adjust other parameters and check the preview to ensure the flow doesn't go below 2mm³/s. Going below this limit causes the most problems.
• Retraction 0. Or minimal.

And that's it. Happy 0.2mm TPU printing!