<p>So I adjusted my print temperatue to 205 °C and the bed temperature to 55 °C. In addition, I changed my retraction to 1.0 mm instead of 2.5 mm (which was the default). Re-ran the print that kept failing and it completed as expected. Ran two more prints that also completed as expected. My guess at this point was that the retraction was set high.</p>

CC BY-SA 4.0
2024-05-13T20:02:33.260Z
2024-05-15T06:28:21.390Z
2024-05-15T06:28:21.390Z
Snyperx
<p>I've had the same issue after switching to an all metal hotend. You might have to lower your retraction settings as the molten plastic can retract too much and clog the cool upper pipe. Just retracting a tiny amount (around 1mm)on a direct drive extruder is usually enough and prevents liquid plastic from solidifying upwards.</p>

CC BY-SA 4.0
2024-05-07T08:45:14.457Z
2024-05-13T09:39:02.590Z
2024-05-13T09:39:02.590Z
Hacky
<p>These modern bi-metallic heatbreak allow you to use less heat. You should first lower the temperature, try 5 °C per try, secondly, try reducing the retraction length. I'd start with a 1 mm retraction length and increse this every few millimeter per height of a test print with 0.25 mm. There should be plenty retraction test prints to find freely on the well known model sharing platforms (Thingiverse, Printables, etc.) or create your own with OpenSCAD (e.g. based on <a href="https://www.printables.com/model/873264-parametric-retraction-test-pillars" rel="nofollow noreferrer">this example</a>), Fusion360 or any other 3D modelling program.</p>
<p>If you use Cura you can insert G-codes at certain heights to modify certain settings.</p>

CC BY-SA 4.0
2024-05-08T20:14:01.560Z
2024-05-08T20:14:01.560Z
0scar
<p>I have a Neptune 3 Pro with Klipper/MainSail. Direct drive extruder. Recently went to an all metal hotend. I replaced the heatbreak (I am using a 1.75 mm POLISI3D Improved Nano Coated Bimetallic heatbreak) as well as the block (block is all copper now), and the thermistor (M3 type).</p>
<p>I did all my PID tuning. I have had good luck printing PLA at 200/60 °C.</p>
<p>PursaSlicer Settings:</p>
<ul>
<li>2.5 mm Retraction Length</li>
<li>25 mm/s Retract Speed</li>
<li>40 mm/s Deretraction speed</li>
<li>2 mm Min. travel after retraction</li>
<li>70 % Retract amount before wipe</li>
</ul>
<p>Since going to the all metal hotend I have now had two clogs. I attempted higher temperatures, but the plastic started to get scorched (turning brown). I then swapped out the brass 0.4 mm nozzle for a 0.4 mm steel nozzle. The clogs are happening with a larger print at around the 50 % mark.</p>
<p>Not sure how to resolve so any help from the Stack is appreciated.</p>

<extruder><nozzle><klipper>
Help troubleshooting clogging issue
Snyperx
# Help troubleshooting clogging issue

(Asked by: username_0 on 2024-05-06)

I have a Neptune 3 Pro with Klipper/MainSail. Direct drive extruder. Recently went to an all metal hotend. I replaced the heatbreak (I am using a 1.75 mm POLISI3D Improved Nano Coated Bimetallic heatbreak) as well as the block (block is all copper now), and the thermistor (M3 type).

I did all my PID tuning. I have had good luck printing PLA at 200/60 °C.

PursaSlicer Settings:

* 2.5 mm Retraction Length
* 25 mm/s Retract Speed
* 40 mm/s Deretraction speed
* 2 mm Min. travel after retraction
* 70 % Retract amount before wipe

Since going to the all metal hotend I have now had two clogs. I attempted higher temperatures, but the plastic started to get scorched (turning brown). I then swapped out the brass 0.4 mm nozzle for a 0.4 mm steel nozzle. The clogs are happening with a larger print at around the 50 % mark.

Not sure how to resolve so any help from the Stack is appreciated.

**Tags:** extruder, nozzle, klipper


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## 3 answers

### Answer by username_0 on 2024-05-13. Score: 2 | Accepted answer

So I adjusted my print temperatue to 205 °C and the bed temperature to 55 °C. In addition, I changed my retraction to 1.0 mm instead of 2.5 mm (which was the default). Re-ran the print that kept failing and it completed as expected. Ran two more prints that also completed as expected. My guess at this point was that the retraction was set high.


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### Answer by username_1 on 2024-05-07. Score: 3

I've had the same issue after switching to an all metal hotend. You might have to lower your retraction settings as the molten plastic can retract too much and clog the cool upper pipe. Just retracting a tiny amount (around 1mm)on a direct drive extruder is usually enough and prevents liquid plastic from solidifying upwards.


---

### Answer by username_2 on 2024-05-08. Score: 1

These modern bi-metallic heatbreak allow you to use less heat. You should first lower the temperature, try 5 °C per try, secondly, try reducing the retraction length. I'd start with a 1 mm retraction length and increse this every few millimeter per height of a test print with 0.25 mm. There should be plenty retraction test prints to find freely on the well known model sharing platforms (Thingiverse, Printables, etc.) or create your own with OpenSCAD (e.g. based on [this example](https://www.printables.com/model/873264-parametric-retraction-test-pillars)), Fusion360 or any other 3D modelling program.

If you use Cura you can insert G-codes at certain heights to modify certain settings.


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