I wanted to make my dad a present: a support that lets him rest the body of his guitar on his knee. The plan was to print it in PETG. The problem is that PETG is hard, and pressing it straight against a guitar would leave marks, so I decided to put a soft cushion between the PETG and the guitar.

That means TPU. eSUN’s TPU 95A happened to be on sale on Amazon at the time, so I bought a spool to try it.

This was my first time printing TPU at all. On top of that, my printer is a Creality K2 Pro, and I had heard that TPU cannot be fed through its CFS (Creality Filament System), so it was also my first time feeding a spool directly.

  • With drying and a speed cap, it printed on the first try with no jams
  • The 95A hardness is just right for a cushion. It dents when pressed, but it is not floppy, and it is doing its job against the guitar
  • It works on a K2 Pro too, fed straight from a top-mounted spool holder

The link below goes to Amazon Japan, where I bought mine. The product page is in Japanese, so check shipping availability for your country before ordering. You may well find the same eSUN filament on your local Amazon as well.

eSUN TPU 95A Filament 1.75mm 1kg Black

eSUN TPU 95A Filament 1.75mm 1kg Black

View on Amazon.co.jp

What eSUN TPU 95A is

TPU is a flexible filament that bends like rubber. The “95A” is a Shore hardness rating, and it sits at the firmer end of what gets sold as TPU. The spool I bought is 1.75 mm, 1 kg, black.

The eSUN TPU 95A spool next to its box. The label reads TPU-95A, 1.75 mm, 1 kg

How it went in practice

First, getting around the CFS. On a K2 Pro the filament normally travels from the CFS through a tube to the extruder. Soft TPU buckles and jams somewhere along that path, so it cannot go that way, and the advice I kept seeing was to feed it as directly as possible. So I first printed the Top Mount Filament Spool Dispenser Bracket for the K2 Pro, published on Creality Cloud. It is a spool holder that sits on top of the printer and feeds the filament straight into the extruder. Thanks to whoever designed it.

The TPU spool on a top-mounted spool holder sitting on the K2 Pro, with the filament running straight down to the extruder

Then drying. TPU absorbs moisture readily, and wet TPU means bubbles and stringing. I ran it through a filament dryer at 55°C for about 8 hours before loading it. The build plate is the double-sided frosted PEI plate that ships with the K2 Pro, as is, with a thin layer of glue stick just to be safe.

The result: first try. No jams, and the part came out in the shape the cushion was supposed to be. No stringing, no bubbles, and no visible layer defects. The surface is matte. I had heard TPU was hard to print, but apart from the time it takes at reduced speed, it behaved far better than I expected. Quietly pleased with that. It used about 18 g, so the 1 kg spool is still practically full.

The hardness is what matters most, and it is enough. Sandwiched between the PETG body and the guitar, the part is doing exactly the cushioning job it was printed for.

The guitar cushion printed in eSUN TPU 95A: a black, open-topped box shape with a matte surface

The settings I used on the K2 Pro

I duplicated the “Generic TPU” preset in Creality Print and changed only what needed changing. The nozzle is 0.4 mm. Three things matter most.

  1. Chamber temperature control OFF, air filtration (exhaust) ON. If the chamber warms up, the TPU in the feed path softens, buckles at the extruder, and jams
  2. Cap the maximum volumetric speed at 3.5 mm³/s. The K2-series extruder is said to be prone to buckling TPU, so the rule is to push it slowly
  3. Short, slow retractions. TPU is rubber. Pull it fast and far, and it just stretches instead of coming back
SettingValue
Nozzle temperature (first layer / other layers)225 / 225°C
Bed temperature (first layer / other layers)50 / 50°C
Maximum volumetric speed3.5 mm³/s
Minimum print speed10 mm/s
Retraction length / speed0.8 mm / 20 mm/s
Z hop0.2 mm
Part cooling fan (min / max)40 / 70%
No cooling for the first layers1 layer
Pressure advance0.05
Flow ratio1.00

On the print-settings side I also dropped acceleration to around 2000 mm/s² and set outer wall speed to 30 to 40 mm/s. The volumetric cap does nothing to acceleration, so that has to come down separately.

Downsides and things to know

  • It is slow. A 3.5 mm³/s volumetric cap is glacial compared to PLA. Brace yourself if you want to print anything large
  • Drying is mandatory. You cannot print straight out of the box; there is a multi-hour drying step in between
  • You need a spool holder first. The CFS is out, and direct feeding is the recommended path anyway, so you have to print a separate spool holder before you can start

Wrap-up

eSUN TPU 95A turned out to be a well-behaved filament, even for a first-time TPU user, once you accept the drying and the speed cap that come with TPU in general. It printed cleanly with no stringing. For small, soft parts like cushions or non-slip feet, it is an inexpensive spool that is well worth trying. I have been wanting to make gasket-like parts, so that is next.

The link goes to Amazon Japan.

eSUN TPU 95A Filament 1.75mm 1kg Black

eSUN TPU 95A Filament 1.75mm 1kg Black

View on Amazon.co.jp