<p>This is the <a href="https://www.creality.com/products/sprite-extruder-pro-kit" rel="nofollow noreferrer">Creality Sprite Extruder Pro</a>.</p>
<p>The tension is controlled by a bolt with a square-shaped nut that is pressing on the lever with a spring. To increase tension to the gears that feed the filament the adjustment bolt is turned clockwise.</p>
<p>However, you have to be very careful not to turn it too far, or the bolt will unhook from the internal nut. Turning anti-clockwise in this situation does nothing.</p>
<p>If you're lucky, like I was, it will get stuck in a position of max tension no matter what you do. If unlucky, the various parts can go into the gears and cause permanent damage.</p>
<p>It is a most unfortunate design as there is no way to tell if you turned it too far!</p>
<p>In my case, having it at max tension at all times caused it to under-extrude. Adding more flow alleviated the problem somewhat. I had to open everything up to see what was going on there. In my case, just putting the nut back on the bolt solved my problem.</p>
<p>TPU is much softer than PLA so it's more sensitive to tension. While PLA can print okay at max tension, TPU cannot.</p>
<p><a href="https://i.sstatic.net/aieth.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/aieth.png" alt="Tension adjustment bolt" /></a></p>

CC BY-SA 4.0
2023-01-04T00:31:53.560Z
Remember to accept your answer if it solved your problem.
kosteklvp
CC BY-SA 4.0
2023-01-03T19:04:37.120Z
2023-01-03T19:18:40.917Z
2023-01-03T19:18:40.917Z
mikabytes
<p>First time trying the <a href="https://www.3dprima.com/filaments/primacreator-easyprint-flex-95a-1-75mm-1-kg-red_24162_5259" rel="nofollow noreferrer">EasyPrint Flex TPU filament</a>. When printing a solid, I can see clear lines with plenty of air on both sides. This gives me the idea that it is not extruding enough filament.</p>
<p>I've tried many tweaks:</p>
<ul>
<li>Adding/removing tension to the extruder</li>
<li>Pulling at the filament to see if the gears have a good grip at it (they do).</li>
<li>Printing at ridiculously slow speeds (5 mm/s)</li>
<li>Bypassing the runout sensor, in case that is adding too much friction or something.</li>
<li>Adding flow rate in Klipper (maxes out at 200 %, slight improvement)</li>
<li>Adding flow rate in Cura to 600 %</li>
</ul>
<p>The last tweak makes the most apparent improvement. Printing at 25 mm/s, it's somewhat decent. There's still some air going through each layer, but much less. The result is still dissatisfactory.</p>
<p>As this printer uses a direct extruder there shouldn't be any problem with the feeding.</p>
<p>Can I now conclude that this is simply a crappy filament and my best bet is to buy something better? If not, then am I missing something obvious here?</p>

CC BY-SA 4.0
2023-01-01T21:08:21.503Z
Welcome to 3DPrinting.SE! Do you have a photo to include (before and after)?
0scar
CC BY-SA 4.0
2023-01-02T12:41:16.303Z
Have you calibrated your extruder E-steps properly?
kosteklvp
CC BY-SA 4.0
2023-01-03T19:08:19.190Z
Thanks for your feedback @Oscar @kosteklvp! While taking the photos as requested I got enough motivation to take everything apart and found the issue, posted below as an answer. This was a tough problem to reason about. Happy to have learnt some new things though.
mikabytes
CC BY-SA 4.0
2023-01-03T20:32:38.027Z
Great you found the problem and posted the answer, make sure to accept it after 48 hours!
0scar
<creality-ender-3><ultimaker-cura><klipper><tpu>
TPU on Ender 3 S1 Pro only works when flow is set to 600 %
mikabytes
# TPU on Ender 3 S1 Pro only works when flow is set to 600 %

(Asked by: username_0 on 2023-01-01)

First time trying the [EasyPrint Flex TPU filament](https://www.3dprima.com/filaments/primacreator-easyprint-flex-95a-1-75mm-1-kg-red_24162_5259). When printing a solid, I can see clear lines with plenty of air on both sides. This gives me the idea that it is not extruding enough filament.

I've tried many tweaks:

* Adding/removing tension to the extruder
* Pulling at the filament to see if the gears have a good grip at it (they do).
* Printing at ridiculously slow speeds (5 mm/s)
* Bypassing the runout sensor, in case that is adding too much friction or something.
* Adding flow rate in Klipper (maxes out at 200 %, slight improvement)
* Adding flow rate in Cura to 600 %

The last tweak makes the most apparent improvement. Printing at 25 mm/s, it's somewhat decent. There's still some air going through each layer, but much less. The result is still dissatisfactory.

As this printer uses a direct extruder there shouldn't be any problem with the feeding.

Can I now conclude that this is simply a crappy filament and my best bet is to buy something better? If not, then am I missing something obvious here?

**Tags:** creality-ender-3, ultimaker-cura, klipper, tpu
> **Comments:**
> **username_1**: Welcome to 3DPrinting.SE! Do you have a photo to include (before and after)?  
> **username_2**: Have you calibrated your extruder E-steps properly?  
> **username_0**: Thanks for your feedback @Oscar @kosteklvp! While taking the photos as requested I got enough motivation to take everything apart and found the issue, posted below as an answer. This was a tough problem to reason about. Happy to have learnt some new things though.  
> **username_1**: Great you found the problem and posted the answer, make sure to accept it after 48 hours!  

---

## 1 answers

### Answer by username_0 on 2023-01-03. Score: 2 | Accepted answer

This is the [Creality Sprite Extruder Pro](https://www.creality.com/products/sprite-extruder-pro-kit).

The tension is controlled by a bolt with a square-shaped nut that is pressing on the lever with a spring. To increase tension to the gears that feed the filament the adjustment bolt is turned clockwise.

However, you have to be very careful not to turn it too far, or the bolt will unhook from the internal nut. Turning anti-clockwise in this situation does nothing.

If you're lucky, like I was, it will get stuck in a position of max tension no matter what you do. If unlucky, the various parts can go into the gears and cause permanent damage.

It is a most unfortunate design as there is no way to tell if you turned it too far!

In my case, having it at max tension at all times caused it to under-extrude. Adding more flow alleviated the problem somewhat. I had to open everything up to see what was going on there. In my case, just putting the nut back on the bolt solved my problem.

TPU is much softer than PLA so it's more sensitive to tension. While PLA can print okay at max tension, TPU cannot.

[![Tension adjustment bolt](https://i.sstatic.net/aieth.png)](https://i.sstatic.net/aieth.png)

> **Comments:**
> **username_2**: Remember to accept your answer if it solved your problem.  

---

