How to 3D Print With Flexible TPU Filament

Hot End

Temperature: 230-250 °C

Hot Bed

Temperature: 45-60 °C
Enclosure not required

Cooling

Cooling required

Build Surface

Blue painters tape
PEI

TPU is a great durable, flexible filament to have for those unique designs that need soft or rubbery properties. TPU is available in multiple colours, flexibility and durability. TPU plastic is commonly used in drive belts, protective phone cases and footwear.

3D Printing TPU

Printing with TPU filament for the first time can be very daunting. It is harder to print with due to its elastic properties, making it more difficult for your extruder to push it into the hot end. Make sure there are no gaps that the filament can get stuck in on the way from the extruder to the hot end. Use Teflon tube to guide it if necessary.

Pro Tips for Success
- Keep it dry! Use a resealable bag with a silica gel pad where possible. Most flexible filaments are hygroscopic to some degree, and will pop and sizzle if you try extruding it wet. These are pockets of water that steam up instantly, leaving voids in your print.
-A few tweaks to your spool holder can also make a big difference with flexible materials. Try mounting the spool above your printer so that the filament unwinds in a downward direction which can reduce the resistance. Mount the spool’s hub on a bearing to allow the spool to spin as freely as possible is the best option if possible.

Slow It Down!

TPU needs to be printed at a much slower speed than ABS or PLA to try to avoid it binding or wrapping around your extruder gear. Depending on your printer, there may be printable files to help prevent this from happening. Here's a flexible filament extruder upgrade for the CR-10 by Joshvv on Thingiverse. We find around 15-20 mm/s works well with Kiwi3D TPU Filament 

Turn Retraction Off

Turn retraction off completely for the entire print. Constant retraction will cause under-extrustion in your print due to pressure being let off in your hot end. Retraction also greatly increases the likelihood of the filament wrapping around the extruder gear mid-print. This will cause slight stringing, but a lighter takes care of that easily.

Use A Large Layer Height

Using a smaller layer height greatly increases the chance of a blocked nozzle. Try bumping your layer height up to 0.3mm. This will allow the TPU to flow easily and constant. The great thing about TPU is that it melts together really well to create a smooth and strong part even with larger layer heights.

Build Surface Type & Leveling

TPU filament will stick to most build surfaces, but I find blue painters tape works best. No glue or hair spray needed. Level your bed a little higher than you usually would to make sure the nozzle doesn't drag through the soft first layers.

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